CN101289513B - The detection of primary infections with pathogens - Google Patents

Abstract

The present invention relates to the detection of primary infections with pathogens.The present invention relates to the fusion protein of the test antigen being suitable as in the detection of pathogenic infection, especially primary infections with pathogens.Moreover, it relates to for detection and differential mensuration antibody, the method for the IgM antibody especially being infected generation by causal organism.Further it is provided that for the test reagent implementing these methods.

Description

The detection of primary infections with pathogens

Technical field

Melting of the test antigen that the present invention relates to be suitable as in the detection of pathogenic infection, especially primary infections with pathogens Close polypeptide.Moreover, it relates to the method for the IgM antibody produced by pathogenic infection for detection and differential mensuration.This Outward, it is provided that for realizing the test reagent of these methods.

Background technology

In addition to round pcr, immunity test still plays an important role in infecting serology.By different immune globulins The specific assay of white classification, immunology makes the stadium of analysis of disease be possibly realized.By measuring for some virus antigen IgM and IgG titer, may distinguish different infective stage, such as actute infection, recurrent infection, chronic/persistent infection or Disease stadium after infection.Such as, the IgG molecule for viral glycoprotein only produces cytomegalovirus infection late period (the JID (1997) 175,533-544 such as Schoppel；Eggers etc., J.Med.Virol. (2001) 63,135-142).

In the presence of each other immunoglobulin class, reliably the importance of specific detection IgG and IgM is, Effective epi-position concentration of detection antigen or effective epitope density.Highly effective epi-position concentration refers to, there is high epitope density, and All epi-positions can be used in antibodies.In contrast, polypeptide aggregate also has high epi-position concentration, but effectively epi-position concentration Low, because epitope moiety ground or be fully blanked or hide, and thus it is not useable for antibodies.High epi-position concentration is special Property the premise that identifies of IgM, and low epi-position concentration is the premise of specific IgG identification.The IgM molecule for antigen A should detected Classics sandwich IgM test in, by polymer antigen A be used as immobilized capture antigen.Carry the identical poly of reporter group Isoantigen A is used as detection antigen.IgM analyte combines capture antigen and detection antigen, thus is immobilized in by reporter group In phase (being such as coated the pearl of Succ-PEG-DSPE).In order to avoid the interference of the IgG molecule for A, add in test Enter unlabelled monomeric antigen A, as interference elimination reagent (WO98/23955, US 6,489,129 B1).Correspondingly, specificity IgG sandwich assay (WO98/23961, US 6,645,732 B1) could be included for detecting the monomeric antigen of IgG and avoiding Unlabelled polymer antigen with IgM interference.

Allow the principle molecular structure based on each of which of the specific detection of IgM and IgG molecule.Pentamer IgM has There are 10 identical antigens to combine paratope, and each molecule of monomer IgG only has 2 binding sites.The detection of IgG is based on right The affinity of analyte, and the detection of IgM is based on affinity (avidity).In the first scenario, by epi-position and paratope High-affinity between (i.e. IgG antigen-binding site) interacts and realizes combining；In the case of the latter, by several low The collaborative enhancing that affinity interacts realize combining (affinity refers to, single dissociation constant is not to be added, but is multiplied, I.e. k_DAbout 10^-5The most weak interaction of M is increased by 2 independent binding events, to produce k_DAbout 10^-10The high-affinity of M Interact).Therefore, it is possible to say empirically rule, monomeric antigen is used for detecting IgG, and oligomer/polymer antigen is used for Detection IgM.

By same or heterobifunctional crosslinker chemical crosslinking monomeric antigen, it is possible to achieve antigen oligomerization or multimerization.Logical Often, optimization can be carried out by regulation reaction condition (albumen and the concentration of cross-linking agent, pH, temperature, stir speed (S.S.), response time) Oligomerization or multimerization, this is the most time-consuming and laborious.While it is true, be likely to be obtained different crosslinkings in different batches Degree, this needs fractionated subsequently and/or calibration procedure.Additionally, the higher degree of cross linking frequently results in the reduction of dissolubility, this The problem that may cause experimental performance.It is then desired to find that improves provides polymer to resist in that determine and reproducible mode Former method.

United States Patent (USP) 6,207,420 describe a kind of fusion sequence, and it comprises and the having of target heterologous peptides or protein fusion The carrier protein of the dissolubility probability of at least 90% prediction, including escherichia coli (E.coli) albumen.Preferably, heterologous peptides or When albumen is expressed in antibacterial, the most insoluble.

WO 03/000878 describes a kind of fusion protein, and it comprises at least one target polypeptide and is positioned at its upstream at least One FKBP chaperone, described FKBP chaperone is selected from: FkpA, SlyD and the triggering factor.Target polypeptide can be that suckling is moved Thing gene outcome or mammalian pathogen gene outcome.

Summary of the invention

The first aspect of the invention relates to fused polypeptide, and it comprises

(i) at least one multimerization domain, and

(ii) from multiple copies of epitope region of pathogen.

Described fused polypeptide molecule can form polymer.Polymer comprise multiple via multimerization domain by non-covalent Interact the monomelic subunit combined.Polymer can be come by incubation fused polypeptide molecule the most under suitable conditions Formed.

The fused polypeptide of the present invention is genetic fusions, and they can be a large amount of according to standard method and with reproducible quality Produce.Fused polypeptide and the polymer formed by it have high stability and dissolubility, and thus in detection by pathogenic infection The method of the antibody produced is excellent test antigen.Preferably, fused polypeptide is used for measuring IgM antibody, more preferably uses In differential mensuration IgM antibody, it is most preferably used for the early stage IgM that differential mensuration produces in acute and/or primary infection Antibody.Fused polypeptide can carry reporter group and/or capture group, and thus can serve as detection and/or capture antigen.This Outward, fused polypeptide is also suitable and makees interference elimination reagent.

The fused polypeptide molecule of the present invention preferably comprises 1 or 2 multimerization domain, more preferably 1 multimerization knots Structure territory.Multimerization domain is preferably located in N-and/or the C-end of fused polypeptide, more preferably N-end.Multimerization domain It is the peptide sequence supporting independent fused polypeptide molecule multimerization, is wherein formed and comprise and be attached to one by noncovalent interaction The polymer of the multiple monomelic subunit risen.The monomelic subunit of complex is genetic fusion albumen, and wherein said independent aminoacid is residual Base is connected by peptide bond.Polymeric monomelic subunit is preferably identical.

Such as, multimerization domain can be dimerization domain, i.e. supports the structure of the Non-covalent binding of 2 subunits Territory, supports the trimerising domain of the Non-covalent binding of 3 subunits, four multimerisation domain or the most much higher dimerization structure Territory.Preferably, multimerization domain is dimerization domain, trimerising domain or four multimerisation domain.

Multimerization domain can be selected from protokaryon or eukaryotic protein companion, does not preferably rely on the chaperone of ATP.Poly The instantiation changing domain is from colibacillary albumen FkpA, Skp and SecB or from they of other protista Straight homologues.FkpA is from the colibacillary pericentral siphon dimerizing protein companion not relying on ATP.Skp comes arrogant The pericentral siphon trimerizing chaperone not relying on ATP of enterobacteria.SecB is from the colibacillary kytoplasm not relying on ATP Four dimerization chaperones.Other suitable multimerization domain is from eucaryon or procaryotic heatshock protein, such as Hsp25, does not i.e. rely on the eucaryon kytoplasm/core oligomeric proteins companion of ATP.Other suitable multimerization domain is that MIP is (huge Phagocyte infectivity reinforcing agent), structurally relevant to the FkpA dimerizing protein companion not relying on ATP.Depend on ATP Chaperone such as GroEL (from the colibacillary kytoplasm seven dimerization chaperone depending on ATP) or ClpB (from large intestine The six dimerization chaperones depending on ATP of bacillus) or ClpX be also suitable.Additionally, multimerization domain can be selected from upper Stating fragment or the variant of polypeptide, they retain it and form polymeric ability.

The fused polypeptide of the present invention comprises multiple copies of epitope region.Epitope region comprises by the aminoacid of antibody recognition Sequence.Thus, described polypeptide comprises multiple binding sites of the antibody identifying each epi-position.Preferably, independent epitope region Aminoacid sequence is identical or substantially the same.But, one or more epitope region are probably different, as long as this A little differences will not negatively affect the identification of test antibodies.Described fused polypeptide comprise at least 2 of epitope region, preferably 2-10, more preferably 2-6 and most preferably 2,3,4,5 or 6 copies.

The polymer being made up of multiple independent fused polypeptide subunits preferably comprise at least 4 of epitope region, more preferably At least 6 and most preferably at least 8 copies.Described polymer can comprise up to 40 of such as epitope region, Up to 30 and most preferably up to 25 copies.

Generally, described fused polypeptide includes multiple copies of only one epitope region.In this case, described fused polypeptide There is a kind of antibody specificity.But, in some embodiment, it is therefore foreseen that to described fused polypeptide comprise 2 or more not Multiple copies of same epitope region, preferably 2 different epitope region.In this case, described fused polypeptide is applicable to detect several The antibody specificity of type.

The length of epitope region is typically at least 5 aminoacid, preferably at least 6 aminoacid and more preferably at least 8 ammonia Base acid.The greatest length of epitope region is typically 100-120 aminoacid, preferably 80 aminoacid and more preferably 70 amino Acid.Most preferably, the length of epitope region is 15-50 aminoacid.

The independent epitope region of fused polypeptide can be separated by intervening sequence.Intervening sequence is preferably and epitope region The sequence of source causal organism allos.In order to put into practice purpose, intervening sequence is selected from hindering this fusion hardly in any program Polypeptide is as the sequence of the application of the test antigen measuring antibody.It means that intervening sequence to test antibodies be nonimmune instead Answering property.Preferably, intervening sequence comprises glycine and/or serine residue.Especially preferably polyglycine intervening sequence. The length of intervening sequence is preferably 1-10 aminoacid, more preferably 2-5 aminoacid and most preferably 3 or 4 aminoacid.Especially Preferably (Gly)₃Intervening sequence.

Additionally, intervening sequence can be there is between multimerization domain and epitope region.This intervening sequence can have Such as 1-100 amino acid whose length.Preferably, this intervening sequence and multimerization domain and epitope region allos.Preferably, Intervening sequence is described above.

The epitope region of fused polypeptide is the antigen sequence from pathogen, and it can be combined in the biological of pathogenic infection The antibody produced in immunoreaction process.It is preferably chosen epitope sequences, with the antibody institute produced in the moment infected Identify, " in early days " epi-position such as preferentially identified by the antibody during early infection state, or excellent in Infection Status late " late period " epi-position first identified.In preferred embodiments, epitope region comprise by described pathogenic infection early stage and/or The epi-position of the antibody specificity identification that acute phase produces.In especially preferred embodiment, epitope region comprises described The epi-position of the antibody specificity identification that the early stage of primary infections with pathogens and/or acute phase produce.In another embodiment In, epitope region comprises by the late stage of described pathogenic infection or the epi-position of antibody specificity identification that produces after infecting. In another embodiment, epitope region comprises the antibody specificity being continued by described pathogen or producing in recurrent infection The epi-position identified.

Epitope region can be derived from any virus, antibacterial or protozoacide (protozoic) pathogen, and it can cause and can examine The immunoreation surveyed, i.e. as the result infected, produces antibody, especially IgM antibody.Such as, described pathogen is selected from:

(i) herpesvirus such as human herpes simplex vicus 1 and 2 (HHV1 and HHV2), varicella zoster virus (HHV3), Epstein-Barr virus (HHV4/EBV) or human cytomegalic inclusion disease virus (HHV5) and Human herpesviryus 6,7 and 8；

(ii) rubella virus；

(iii) hepatitis virus such as hepatitis A virus (HAV), hepatitis B virus (HBV) and hepatitis C virus (HCV)；

(iv) paramyxovirus such as Measles virus and mumps virus；

(v) toxoplasma (Toxoplasma) biological and

(vi) Borrelia (Borrelia) is biological.

From the example of the appropriate epitope of these pathogen, described in many files the most described in detail below.These literary compositions Part and document cited therein are herein incorporated by reference.

Indicate the specific detection of the IgM molecule of early infection, clinically to the many viruses in people, antibacterial and former Raw zoogenetic infection is important.Herpetoviridae (herpesviridae), such as comprise herpes simplex virus 1 and 2 (HHV1, HHV2), varicella zoster virus (HHV3), Epstein-Barr virus (HHV4), human cytomegalic inclusion disease virus (HHV5) and Human herpesviryus 6,7 With 8.Human cytomegalic inclusion disease virus (HHV5) plays a crucial role in gestation routine diagnosis: when not for body fluid or the cell of this virus When the child-bearing woman of immunity experiences primary infection during first trimester, fetus can be caused destructive to damage by it.

Drawn by epi-position, in different herpes antigen, identified many important immunologic determinants.Such as, Greiier etc., J.Clin.Microbiol. (1999) 37 (1), 179-188 summarize HCMV antigen pp150, p52, gB and The antibody response of the independent epi-position in pp28.Schoppel etc., J.Infect.Dis. (1997) 175 (3), 533-544 describe Other epi-position.As for herpes simplex virus, the most respectively immunodominant epitope is mapped at the ripe glycoprotein from HSV-2 (Marsden etc., J.Med.Virol. (1998) 56,79-84 in sequence 552-578 of G；Liljeqvist etc., J.Gen.Virol. (1998) 79,1215-1224) and glycoprotein g1 from HSV-1 sequence 112-127 ( Deng, J.Gen.Virol. (2000) 81,1033-1040).These epi-positions can mix in the fused polypeptide of the present invention.

Parameter in screening as gestation plays outstanding role, Mus toxoplasma (Toxoplasma gondii) and rubella virus And human cytomegalic inclusion disease virus and herpes simplex virus type 1 and 2 types constitute TORCH family.These pathogen are at first trimester Primary infection to anemia of pregnant woman (lacking humoral and cellular immune response), may cause the serious infringement to fetus.This is in the urgent need to distinguishing The reliable differential diagnosis of primary and recurrent sexuality dye.As it has been described above, immundominance determinant in several HCMV antigens from Document would know that, such as from sequence 595-636 of pp150 and 1011-1048, from sequence 266-293 of p52 and 295- 312, from sequence 792-809 of Glycoprotein B and 60-81 and from sequence 15-45 of pp28 and 130-160 (Greijer etc., Ibid).Similarly, on the immundominance envelope protein E1 of rubella virus, Primary epitope is being identified.Such as, ammonia 3 neutralizing epitopes are contained in region between base acid 243-286, as Terry etc. (Terry etc., Arch.Virol. (1988) 98, 189-197) reported.Another kind neutralizes E1 epi-position area attribute (Mitchell between aminoacid 213-239 Deng, J.Clin.Microbiol. (1992) 30 (7), 1841-1847).On the second rubella envelope protein E 2, differentiate Go out to have at least one immunodominant epitope (Green Dorsett, J.Virol (1986) 57 (3), the 893-of neutralising capacity 898).Immunodominant T-cell epitope and several linear B-cell epitope have been positioned in E2 region 31-105 (McCarthy etc., J.Virol. (1993) 67 (2), 673-681；Wolinsky etc., J.Virol. (1991) 65,3986- 3994).These epi-positions can mix in the fused polypeptide of the present invention.

By from Mus toxoplasma several albumen differentiate for immunodominant antigen: dense granule protein GRA1 (p24), GRA2 (p28), GRA4 (p41), GRA6 (p32), GRA7 (p29) and GRA8 (p35), surface antigen SAG1 (p30) and SAG2 (p22), clava antigen ROP1 (p66) and ROP2 (p54), matrix protein AG1 (p65) and filaggrin MIC3 and MIC5 (Pfrepper etc., Clin Diagn.Lab.Immunol. (2005) 12 (8), 977-982).Resist about anti-toxoplasma IgM The detection of body, is suggested previously combination (Aubert etc., the J.Clin.Microbiol. (2000) of GRA7, GRA8 and ROP1 38:1144-1150).These epi-positions can mix in the fused polypeptide of the present invention.

Another key areas serological covers hepatitis virus such as HAV, HBV and HCV.Every kind of such pathogen Immunodominant antigen and respective immunodominant epitope be well-known.Such as, HBV nucleocapsid protein is chronic hepatitis B The main target of middle host immune response, and characterized several immunodominant epitope.Hbs antigen (HBsAg) On important B-cell epitope be positioned in aminoacid 74-89,130-138 (Salfeld etc., J.Virol. (1989) 63, 798-808) with 107-118 (Colucci etc., J.Immunol. (1988) 141,4376-4380).These epi-positions can mix this In the fused polypeptide of invention.

The immunodominant epitope having characterized many hepatitis C antigen (is summarised in Carlos etc., Clin.Immunol. (2004) 111,22-27).Such as, core (7-18), E2 (484-499), NS3 (1248-1265) and NS4 are had been defined for (1767-1786) epi-position of immunodominant regions, and from E2 HVR1 genotype 1a (386-406), E2 HVR2 gene The table of the hypervariable region of type 1a (472-485), E2 HVR1 genotype 1b (386-406) and E2 HVR2 genotype 1b (472-485) Position.These and other HCV epi-position can mix in the fused polypeptide of the present invention, and should demonstrate that can be used for exploitation according to the present invention's The immunoassay of difference IgM.

Other important human pathogen is Measles virus and mumps virus, and both of which broadly falls into Paramyxoviridae, and 6 structural protein compositions of each freedom.The nucleocapsid protein N of Measles virus is the main target of humoral immunoresponse(HI), and the B-for N is thin Born of the same parents' response is crucial in Control Measles infects.Recently, map the N between aminoacid 419 and 525 by immunodominant epitope In antigens c-end.Specifically, (Zvirbliene etc., Arch.Virol. in linear epitope can be positioned the sequence of 440-448 (2007) 152,25-39).Similarly, the albumen NP that the nucleocapsid from mumps virus combines constitutes major antigenic determinant, And the restructuring variant of NP shows high antigenic, and it is highly suitable for specific detection IgM (Samuel in parotitis serology Deng, J.Med.Virol. (2002) 66,123-130).

(B. burgdorferi (B.burgdorferi), loud, high-pitched sound borrelia burgdorferi (B.garinii), A Shi dredge Borrelia Spirillum (B.afzelii)) immunologic diagnosis cause growing interest, this is because this spirochetal merciless is propagated. Owing to trailing the warm winter on the horizon of significant climate change, it is assumed that the impact of Borrelia the most even can Increase more.Have been described with the immundominance conserved region of B. burgdorferi VlsE antigen, it be highly suitable for sensitive and Specific serum diagnosis (Liang etc., J.Clin.Microbiol. (1999) 37 (12), 3990-3996).So-called IR6 or C6 region (Liang & Philipp, Infect.Immun. (1999) 67,6702-6706；Liang etc., J.Immunol. (1999) 163 (10) 5566-5573) comprise 26 constant aminoacid sections, it can mix in the fused polypeptide of the present invention.

The method of described the fused polypeptide preferably antibody in detection sample, especially IgM antibody is used as test reagent. For this purpose it is proposed, fusion protein can carry report and/or coupling group.Suitably the example of reporter group is by vision means Detectable group, such as fluorophor, luminophore, such as chemiluminescent groups, or microgranule group such as metal, such as Gold or latex particle.Certainly, other reporter group such as enzyme group, radioactive group, haptenic group etc. are also suitable.Special The most preferably electrogenerated chemiluminescence reporter group, especially ruthenio group, such as ruthenium (bipyridyl) 3 or ruthenium (phenanthroline) 3 group.Especially It is the most also hapten reporter group, such as Digitoxin group, and it can be with the most anti-ocean of anti-hapten antibody Granules glycosides antibody test.

In another embodiment, described fused polypeptide can carry at least one coupling group.Coupling group is to use In group fused polypeptide being coupled on other compound or material (such as solid phase or reporter group defined above).Coupling Group could be for the group of covalent coupling or non-covalent associations.Preferably, coupling group be specific binding pair first Gametophyte, it with combine to the second gametophyte specifically interact.Preferably combine being biotin/avidin 9 In vain, biotin/streptavidin, biotin/anti-biotin antibodies, hapten/anti-hapten antibody and carbon hydrate Thing/agglutinin.Preferably, coupling group is biotin group, including biotin derivative, i.e. relevant to biotin in structure Compound, its ability keeping combining Succ-PEG-DSPE and/or avidin.

According to usual manner, fused polypeptide can be attached in report and/or coupling group.For example, it is possible to preparation bag Containing report and/or the conjugation reagents of coupling group.These reagent can also comprise can be with the base of radical reaction present on polypeptide Group, such as hydroxyl, amino, carboxyl and/or thio group.The instantiation of coupling group is active ester group, such as N-hydroxyl Butanimide group or maleimide base group.

The invention still further relates to encode the nucleic acid molecules of above-mentioned fused polypeptide.Described nucleic acid molecules is preferably DNA molecular.For Increase the stability of nucleic acid molecules, preferably encode independent epitope region (they preferably be identical at amino acid levels) Part there is the different IPs nucleotide sequence in the range of genetic code degeneration, wherein use the different IPs of coding same amino acid Thuja acid triplet codon.It is highly preferred that each part encoding independent identical epitope region has is different from other parts Nucleotide sequence.

Moreover, it relates to expression vector, it comprises at least one and is operably connected on expression control sequenc Above-mentioned nucleic acid molecules.Described expression vector can be protokaryon or eukaryotic vector, and it additionally comprises in respective host cell Maintain and the genetic elements of breeding, such as origin of replication and/or selectable marker gene.Described expression control sequenc can be protokaryon Or eukaryotic expression controls sequence, it can be composing type or induction type.Select expression control sequenc, to allow required host Effective expression in cell.Suitably the example of expression vector and expression control sequenc is known to the skilled person, and is documented in mark In quasi-textbook, such as Sambrook etc., Molecular Cloning-A Laboratory Manual (1989), Cold Spring Harbour Press, or can be available commercially.

Moreover, it relates to the host cell transfecting with above-mentioned nucleic acid molecules or expression vector or converting.Described host Cell can be prokaryotic cell, such as gram negative bacterial cell, such as escherichia coli, or eukaryotic cell, such as yeast are thin Born of the same parents, insect cell or mammalian cell.Host cell may be used for being prepared by recombinant of above-mentioned fused polypeptide.Preferably, restructuring Production comprises following step:

I () provides above-mentioned host cell,

(ii) under conditions of expressing fused polypeptide, described host cell is cultivated, and

(iii) described fused polypeptide is separated.

As it has been described above, the fused polypeptide of the present invention preferably acts as the detection examination in the method for the antibody in detection sample Agent.Described antibody is preferably IgM antibody.It is highly preferred that detection comprises the differential mensuration of IgM antibody.In especially preferred reality Executing in scheme, antibody is the IgM antibody produced infection, especially primary infections with pathogens early stage or in acute phase.

In another embodiment, described fused polypeptide can be used as interference in the method for the antibody in detecting sample Eliminate reagent.In this embodiment, antibody is preferably IgG antibody.

The present invention also relates to the test reagent test kit for detecting the antibody in sample, it is many that it comprises at least one fusion Peptide and other test component.Described test reagent can comprise the single fused polypeptide containing single type epi-position, or containing 2 kinds Or the single fused polypeptide of more kinds of dissimilar epi-position, or containing single type epi-position or two or more dissimilar tables Two or more fused polypeptide of position.The fused polypeptide of the present invention can be detectable or interference elimination reagent.If merged Polypeptide is detectable, then it preferably comprises report as above and/or coupling group.Eliminate if fused polypeptide is interference Reagent, then it does not the most comprise any reporter group.Described interference eliminates reagent and is characterised by, its effective epi-position concentration or Density is different from effective epi-position concentration of detectable.Preferably, epi-position concentration or the epitope density of interference elimination reagent is less than The epi-position concentration of detectable or epitope density.

The method that the present invention also relates to detect in sample antibody for causal organism, it comprises following step:

Sample described in (a) incubation and the test reagent comprising at least one above-mentioned fused polypeptide and other test component, and

(b) by evaluating the reaction of sample component and test reagent, measure the existence in described sample of the described antibody and/ Or concentration.

Described test reagent preferably comprises detectable and at least one interference eliminates reagent, and step (b) comprises mensuration Required sample component (i.e. test antibodies type) and the reaction of detectable, wherein eliminate reagent, capture with at least one interference Unwanted sample component, the most different classes of antibody, the distinctive IgG of the most unrelated infective stage and/or IgM antibody. In preferred embodiments, test antibodies is IgM antibody, more preferably infect, especially primary infection early stage and/or acute The IgM antibody produced in stage.In this case, test reagent the most also comprises the interference elimination examination for capturing IgG antibody Agent, and/or the interference elimination reagent of the IgM antibody produced in later period of infection and/or recurrent infection for capture, Qi Zhongsuo State interference elimination reagent and do not carry reporter group.Described interference eliminates reagent and is characterised by, its effective epi-position concentration or close Degree is different from effective epi-position concentration or the density of detectable.Differential detection is carried out infecting early stage providing detectable And/or in the case of the IgM antibody of acute phase generation, effective epi-position concentration or the density of interference elimination reagent are lower.Such as, Epi-position concentration or the density of interference elimination reagent should not exceed the 50% of detectable epitope density.

Preferably, sample is eliminated reagent precincubation with one or more interference, then contacts detectable.

It is antigen that IgG interference eliminates the example of reagent, including the fragment containing monomer epi-position.In preferred embodiment In, it is fused polypeptide that IgG interference eliminates reagent, and it comprises monomeric protein companion's domain (such as from colibacillary SlyD) Single copy with the fragment comprising epi-position from pathogen.Eliminate present in reagent in IgG interference that epi-position can be with inspection Epi-position in test agent is identical.

For capture, also thus the example of the interference elimination reagent of quencher IgM antibody in late period is to comprise multiple epi-position many Aggressiveness antigen.But, in this embodiment, interference eliminates reagent and comprises the epi-position than detectable lesser number.Preferably, Interference eliminates reagent and comprises at least 2 epi-positions and be up to the half of each detectable epi-position.Astoundingly, find so Polymer interference eliminate reagent and can capture also thus quencher IgM antibody in late period, find that they have than early antibody to be measured more The high affinity to epi-position, and the detection to required early stage IgM antibody do not has significant negative effect.Thus, such as, IgM Interference eliminates reagent can comprise 2-6 of epi-position, such as 2,3,4 or 6 copies, and IgM detectable can comprise in early days At least 8 of fragment containing epi-position, for example, at least 12 or 16 copy.It can be such as that interference eliminates reagent, comprises monomer Chaperone domains such as SlyD and the fused polypeptide of multiple epi-position, or comprise multimerization domain and single epi-position or 2 The fused polypeptide of epi-position copy.Eliminate present in reagent in IgM interference that epi-position preferably can be identical with the epi-position in detectable.

The method of the present invention realizes preferably as double antigens sandwich test, and wherein said test reagent comprises 2 kinds as above Described fused polypeptide, the first fused polypeptide wherein said is carried reporter group or carry and be can be incorporated on reporter group Coupling group.The second fused polypeptide is combined in solid phase, or carries the coupling group for being immobilized in solid phase.Real at this Execute in scheme, by forming complex with the first with the second fused polypeptide, and detect the described complex in described solid phase, Measure antibody analysis thing.

In another preferred embodiment, the method for the present invention can realize as indirect test, wherein said Test reagent comprises a kind of fused polypeptide, and it carries the coupling group for being immobilized in solid phase and identifies test antibodies classification The receptor of (such as Anti-Human's IgM antibody), wherein said receptor carries reporter group, and wherein by many with merging in solid phase Peptide and receptor form complex and measure antibody.Or, it is immobilized or can be immobilized that this indirect test can comprise use Receptor and the fused polypeptide comprising reporter group.

As it has been described above, the present invention allows differential diagnosis IgM antibody.Thus, another embodiment relates to specific assay The IgM antibody produced in later period of infection and/or recurrent infection.In this embodiment, detectable comprises at least one There is the polymer antigen of above-mentioned low epitope density, the most preferably comprise melting of 2-6, such as 2,3,4 or 6 epi-position copy Closing polypeptide, its interference that may be useful as in the test of " in early days " IgM antibody eliminates reagent, but carries report and/or coupling base Group.Capture the interference elimination reagent of IgG antibody described above it addition, this test preferably comprises and/or capture on infection rank in early days The interference of the IgM antibody produced in section, the most primary and/or actute infection commitment eliminates reagent.Preferably, " in early days " The interference of IgM antibody eliminate reagent correspond to for measure " in early days " but IgM antibody does not has the test reagent of reporter group. Or, differentiated IgM is measured and can be realized by differential analysis, i.e. only detects a class IgM antibody (such as " in early days " having Antibody) test reagent in the presence of first test and use second test of test reagent detecting all IgM antibody.

In another embodiment, test antibodies is IgG antibody.In this case, detectable is monomeric antigen, example Monomeric fusion protein described above.It addition, test reagent comprises the interference for capturing IgM antibody eliminates reagent, it is to comprise The polymer antigen of fused polypeptide complex of the present invention as above, the most each fused polypeptide comprise multimerization domain and Multiple epi-positions copy.Interference eliminates reagent and does not preferably contain reporter group.

Another aspect of the present invention relates to the method for the IgM antibody in differential detection sample, and wherein said sample can To comprise selected from interference IgM antibody and/or the interference antibody of interference IgG antibody.According to the method, use and comprise multiple antigen Test reagent, described antigen i.e. comprises the antigen of test antibodies combinable multiple epi-positions copy.Preferably, test antigen Comprise reporter group.

The method of the present invention tests antigen based on the polymer using effective epitope density and/or the concentration with preliminary election, It is suitable for IgM antibody type to be measured.It is combined that test antigen preferably eliminates reagent with interference, and described interference eliminates reagent and fits Close the combination eliminating unwanted IgM antibody type with test antigen.

Test effective epitope density of antigen or concentration are suitable for the type of IgM antibody to be measured, such as infecting, the most primary The IgM antibody produced in the early stage infected or acute phase, or the IgM antibody produced at later period of infection, produce after infection IgM antibody and/or continue or recurrent infection in produce IgM antibody.Preferably, the detection of differential IgM antibody is having At least one interference eliminates in the presence of reagent and carries out, and it can comprise the antigen of specific binding interference IgM antibody and/or special Property combine interference IgG antibody antigen.

In preferred embodiments, described method comprises following step:

Sample and test reagent described in (a) incubation, described test reagent comprises:

The receptor R1 of (i) at least one specific binding IgM antibody,

(ii) the receptor R2 of at least one specific binding IgM antibody wanting differential detection, wherein R2 carries report base Group,

(iii) optionally, the receptor R3 of at least one specific binding interference IgM antibody, and

(iv) optionally, the receptor R4 of specific binding IgG antibody,

(b) permission following complex of formation:

I () comprises R1, the described IgM antibody wanting differential detection and the complex of R2, described complex carries report base Group,

(ii) optionally, comprise R3 and the complex of described interference IgM antibody, thus eliminate described interference IgM antibody with The interference of R2 combines,

(iii) optionally, comprise R4 and the complex of described interference IgG antibody, thus eliminate described interference IgG antibody with The interference of R2 combines, and

C () measures and is attached to the described reporter group in the described IgM antibody wanting differential detection by R2, as described The tolerance of IgM antibody described in sample.

Described test can measure form with double antigens sandwich or indirect form as above is carried out.At double antigens sandwich In form, receptor R1 can be polymer antigen, its specific binding IgM antibody to be measured.In indirect test form, receptor R1 Can be the receptor of any people IgM in specific binding any IgM, especially sample, such as Anti-Human's IgM antibody.Preferably, Solid phase detects the combination of required IgM antibody type.For this purpose it is proposed, receptor R1 preferably carries for being immobilized to solid phase On coupling group, coupling group, preferably biotin such as above.The reporter group of the receptor R2 of labelling is as above institute The reporter group stated, preferably electrogenerated chemiluminescence group.When using interference to eliminate the i.e. receptor R3 and/or R4 of reagent, they are excellent Selection of land and sample precincubation, be subsequently adding receptor R1 and/or R2.

IgG interference eliminates receptor R4 and is preferably monomeric acceptor, i.e. comprises the antigen of single epi-position copy.Test receptor R2 Eliminating receptor R3 with IgM interference is polymeric acceptor, i.e. comprises the antigen of multiple epi-position copy.But, R2 and R3 has difference Effective epitope density or concentration, and thus preferentially combine different types of IgM antibody.About in infection, preferred primary infection Early stage or the differential mensuration of IgM antibody that produces of acute phase, the receptor R2 of labelling can comprise for example, at least 6, excellent At least 8 and more preferably at least 12 are selected to be copied by the epi-position of IgM antibody identification to be measured, up to 40, preferably up to 30 Individual and most preferably up to 25 epi-positions copy.Compared with the epitope density of test receptor R2 or concentration, to " late period " I_gM antibody Specific interference eliminates effective epitope density or the concentration of receptor R3, can be the most at most 1/2, and preferably up to 1/3, and Preferably up to 1/4 or even lower.In this embodiment, interference elimination receptor R3 can comprise 2-8, preferred 3-6 table Position copy.

Polymer test receptor R2 is preferably the above-mentioned fused polypeptide of first aspect of the present invention.Polymer interference eliminates Receptor R3 can also be fused polypeptide as above.It should be noted, however, that in this embodiment of the present invention, it is also possible to Use conventional polymer test antigen, such as, obtained by same or heterobifunctional crosslinker chemical crosslinking monomeric antigen or epi-position Polymer antigen.Or, polymer antigen can be carrier molecule, and the carrier such as containing peptide epitope sequence with its coupling is many Peptide or multimeric peptide, the such as branch described in (Nature Biotechnology 23 (2005), 1517-1526) such as Lee Multimeric peptide, its content is herein incorporated by reference.

Another aspect of the present invention relates to the test examination of the IgM antibody in differential detection sample for pathogen Agent, wherein said sample can comprise selected from interference IgM antibody and/or the interference antibody of interference IgG antibody, and it comprises:

The receptor R1 of (i) at least one specific binding IgM antibody,

(ii) the receptor R2 of at least one specific binding IgM antibody wanting differential detection, wherein R2 carries report base Group,

(iii) optionally, the receptor R3 of at least one specific binding interference IgM antibody, and

(iv) optionally, the receptor R4 of specific binding IgG antibody.

Figure below and examples further illustrate the present invention.

Accompanying drawing explanation

Fig. 1: by the purification of the Skp-p52-X4 that SDS-PAGE proves.Swimming lane 1, undyed from Invitrogen Protein standard labelling 12；Swimming lane 3, excess produces the thick lysate of chaotropic of e. coli strains BL21/DE 3；Swimming lane 5, IMAC flows Logical；Swimming lane 6, imidazole wash fraction, swimming lane 8, imidazoles elutriated fraction；Swimming lane 9, the Skp-after gel filtration (Superdex 200) p52-X4.In the simple step code described in method part, can be with high yield pulp1 ground purification and refolding Skp-p52-X4.

Fig. 2 A-I: aminoacid sequence (reference sequences table).

Detailed description of the invention

Sequence table

The aminoacid sequence (AA 1-165) of SEQ ID NO.1:SlyD

The aminoacid sequence (AA 26-270) of SEQ ID NO.2:FkpA

The aminoacid sequence (AA 21-161) of SEQ ID NO.3:Skp

The aminoacid sequence (ppUL32=HCMVpp150, AA 587-640) of SEQ ID NO.4:Skp-ppUL32-X1

The aminoacid sequence of SEQ ID NO.5:Skp-ppUL32-X4

The aminoacid sequence (pp150=HCMV pp150, AA 999-1048) of SEQ ID NO.6:Skp-pp150-X1

The aminoacid sequence of SEQ ID NO.7:Skp-pp150-X4

The aminoacid sequence (p52=HCMV p52, AA254-293) of SEQ ID NO.8:Skp-pp150-X1

The aminoacid sequence of SEQ ID NO.9:Skp-p52, AA 254-293

Embodiment

Embodiment 1: the production of fused polypeptide test reagent

1. material and method

1.1. material and reagent

Chlorination guanidine (guanidinum-Cl) (GdmCl) is purchased from NIGU (Waldkraiburg, Germany). Protease inhibitor pellet, imidazoles and EDTA without EDTA are purchased from RocheDiagnostics GmbH (Mannheim, Germany), Other chemical reagent all are all AGs, purchased from Merck (Darmstadt, Germany).Ultrafiltration membrane (YM10, YM30) is purchased From Amicon (Danvers, MA, USA), microdialysis film (VS/0.025 μm) and ultra filtration unit (biomax ultrafree Filter devices) purchased from Millipore (Bedford, MA, USA).For filtering celluloid and the vinegar of thick lysate Acid cellulose film (1.2 μm/0.2, μm/0.45 μm) purchased from Sartorius (Germany).

The clone of 1.2 expression cassettes

Sequence (the SkP:SwissProt registration of Skp, FkpA and SlyD is obtained from SwissProt (UniProt) data base Number P11457；FkpA:SwissProt registration number P45523；SlyD:SwissProt registration number P0A9K9).By PCR, from greatly The gene of enterobacteria strain BL21 (DE3) amplification escherichia coli Skp, FkpA and SlyD, after limiting enzyme action, connects and expresses into pET24a Carrier (Novagen, Madison, Wisconsin, USA).In order to prevent by disulfide formation covalent adduct, remove SlyD The C-terminal part (166-196) of rich cysteine, and the SlyD form AA 1-165 (SEQ ID NO.1) of truncate is used as Fusion partner.Kytoplasm in order to ensure target molecule is expressed, and eliminates the signal sequence of periplasm protein companion FkpA and Skp.Cause And, FkpA form AA 26-270 (SEQ ID NO.2) and Skp form AA 21-161 (SEQID NO.3) is used as fused polypeptide Module.As described in (J.Mol.Biol.345 (2005), 1229-1241) such as Scholz, the expression cassette of design fusion protein.Make Produce point mutation with the round pcr of QuikChange (Stratagene, La Jolla, USA) and standard, lack and insert change Body or restriction site.All recombiant protein variants all contain C-end hexahistidine tag, with the purification promoting Ni-NTA-to assist And refolding.

Expression, purification and the refolding of 1.3 fusion protein variants

Use practically identical code, purification all peptide fusion variant.With the addition of kanamycin (30 μ g/ml) In LB culture medium, carry e. coli bl21 (DE3) cell of specific pET24a expression plasmid to OD 37 DEG C of cultivations₆₀₀For 1.5, and by adding 1mM isopropyl-β-D-thiogalactoside, induce kytoplasm overexpression.Induce latter 3 hours, by centrifugal (20 minutes, 5000g) harvesting, freezing, and-20 DEG C of preservations.Cell is cracked, freezing precipitation is resuspended in The 50mM sodium phosphate pH 8.0 of cooling, in 7.0M GdmCl, 5mM imidazoles, in stirred suspension 2 hours on ice, to complete cell Cracking.After being centrifuged and filtering (nitrocellulose filter, 0.45 μm/0.2 μm), lysate is applied to comprising 5.0mM TCEP The Ni-NTA post of the lysis buffer balance of (three (2-carboxyethyl) phosphine).Washing step subsequently is made to be suitable for respective target protein, And 10-25mM imidazoles (SlyD and FkpA in the range from being dissolved in 50mM sodium phosphate pH 8.0,7.0MGdmCl, in 5.0mM TCEP Fusion protein) to 30mM imidazoles (Skp fusion protein).Apply the lavation buffer solution of at least 10-15 volume.Then, by GdmCl Solution replaces with 50mM sodium phosphate pH 7.8,100mM NaCl, 10mM imidazoles, 5.0mM TCEP, the egg combined with inducer substance White conformation refolding.In order to avoid the reactivation of co-purified proteins enzyme, by protease inhibitor cocktail (cocktail) (Without EDTA, Roche) it is included in refolding buffers.In reaction overnight, application 15-20 column volume altogether Refolding buffers.Then, by with the 50mM sodium phosphate pH7.8 of 3-5 column volume, 100mM NaCl, 40mM imidazole wash, taking Go out TCEP and/ inhibitor mixture without EDTA.Then, the 250mM imidazoles being used in same buffer, wash De-native protein.Pass throughDescribed in von JagoW (Anal.Biochem.166 (1987), 368-379) Tricine-SDS-PAGE, passes judgment on the purity of the fraction containing albumen, and merges.Finally, albumen is carried out size exclusion chromatography (Superdex HiLoad, Amersham Pharmacia), merges the fraction containing albumen, and at Amicon cell (YM10) Middle concentration.

Produce following Skp fused polypeptide:

Skp-ppUL32-X1 (SEQ ID NO.4) and Skp-ppUL32-X4 (SEQ ID NO.5)

These fused polypeptide comprise 1 (X1) or 4 of Skp Fusion Module and human cytomegalic inclusion disease virus (HMCV) epi-position ppUL32 Individual (X4) copies.This epi-position correspond to the aminoacid 587-of HCMV big structure phosphoprotein pp150 (Uniprot ID P08318) 640。

Skp-pp150-X1 (SEQ ID NO.6) and Skp-pp 150-X4 (SEQ ID NO.7)

These fused polypeptide comprise 1 (X1) or 4 (X4) copy of Skp Fusion Module and HMCV pp150 epi-position, should Epi-position correspond to the aminoacid 999-1048 of HCMV pp150.

Skp-p52-X1 (SEQ ID NO.8) and Skp-p52-X4 (SEQ ID NO.9)

These fused polypeptide comprise 1 (X1) or 4 (X4) copy of Skp Fusion Module and HMCV p52 epi-position, this table Position correspond to the aminoacid 254-293 of HCMV polymerase auxilin p52 (UniprotID P16790).

1.4 spectroscopes are measured

Use Uvikon XL double beam spectrophotometer, carry out protein concentration measurement.Use (the Protein such as Pace Sci.4 (1995), 2411-2423) described in program, measure molar extinction coefficient (ε₂₈₀)。

1.5 ruthenium part and the coupling of fusion protein

The ruthenium labelling activated with N-hydroxy-succinimide, at the protein concentration of about 10mg/ml, modifies fusion protein Lysine s-amino groups.Depend on respective fusion protein, labelling: protein mole ratios scope is 2: 1 to 7: 1.Reaction buffer is 150mM potassium phosphate (pH 8.0), 50mM potassium chloride, 1mM EDTA.Reaction is carried out 10 minutes in room temperature, and buffered by addition L-lysine, to final concentration 10mM, terminates reaction.In order to avoid the hydrolysis of labelling inactivates, at anhydrous DMSO (seccosolv Quality, Merck, Germany) in prepare respective stock solution.All fusion protein of research are the most well tolerable in reaction buffering The DMSO concentration of up to 20% in liquid.After coupling reaction, by making crude protein conjugate pass solvent resistant column (Superdex 200HiLoad), unreacted free label and organic solvent are removed.

The immunoreactivity of 1.6 chaperone fusion protein

It is used for chaperone Fusion Module detecting the IgM antibody for antigen p52 and pp150 from HMCV, they Produce in a large number in human serum when showing effect cmv infection.μ-capture form is used (that is, to capture total IgM set, and pass through special The anti-ig M IgG of property is immobilized in solid phase), in automatizationAnalyser is challenged immunoreation Property.

?Signal detection in immunoassay is based on electrogenerated chemiluminescence.The IgM of biotin-put together is caught Obtain antibody immobilization to Succ-PEG-DSPE-coated magnetic bead surfaces, and signal transmission antigen carries the ruthenium sun of complexation Ion is as luminous component.In the presence of anti-p52/ anti-pp150IgM antibody, the ruthenium complex added lustre to is bridged to solid phase On, and after platinum electrode excites, send 620nm light.Signal output is calculated by arbitrary light unit.With regard to they conductsFor the purposes of antigen, concentrate the solvable p52/pp150 fusion protein in research, and sub-with N-hydroxy-succinic acyl The ruthenium part that amine activates is modified, as described in (2005) such as Scholz above.Chaperone merges variant in immunoassay are measured Concentration be about 20-100ng/ml.Use at least 5 parts of negative serums as comparison.In order to make false positive results minimize, generalization The unlabelled chaperone module learning polymerization adds in sample, as anti-interference material.

2. result

2.1 high expressed yield

A large amount of overexpression Skp, FkpA, SlyD and their fusion variant in BL21 (DE3) e. coli strains.Due to height Synthesis rate, target protein is partly accumulated in escherichia coli kytoplasm as Inclusion.The refolding of substrate coupling becomes with non- The highest yield makes Skp, FkpA, SlyD and their alternative approach merging variant renaturation.Substantially, renaturation code follow into SlyD fusion protein exploitation method (Scholz etc. (2005), ibid；Scholz etc., Biochemistry45 (2006), 20- 33).After the purification and refolding code of coupling, can obtain more than 20mg target protein from 1g wet E. coli cells.As Example, the purification of the Skp-p52-X4 proved by SDS-PAGE is as shown in Figure 1.

Embodiment 2:CMV IgM tests

Develop the test measuring the IgM antibody for CMV.This test allows to distinguish acute/primary infection stage in early days With later infections stage or recurrent infection.Detectable comprises complex, and the fusion that each complex comprises 3 units is many Peptide, each fused polypeptide comprises trimerising domain Skp and 4 with ruthenium (bipyridyl)₃(BPRu) the CMV epi-position (UL32 of labelling Or 150).Thus, the multimeric molecule of detectable comprises 12 epi-position copies.This test not or have interference eliminate reagent In the presence of carry out, described interference eliminate reagent i.e.: monomer IgG interference eliminate reagent lyD-X, wherein X is UL32 or 150 epi-positions, Dimer or tetramer IgM interference eliminate reagent (FkpA-X)₂(FkpA-X2)₂, wherein FkpA is dimerization domain, and X It is epi-position UL32 or pp150, and trimer or six aggressiveness IgM interference eliminate reagent (Skp-X)₃(Skp-X2)₃, wherein Skp is Trimerising domain, and X is UL32 or pp150 epi-position.

1. material and method

1.1 component

Buffer B 1

Variant 1:

50mM MES pH of buffer 6.5,150mM NaCl；1mM EDTA, 0.1% methyl-isothiazol ketone And oxypyrione, prolidocanol and 0.2% bovine serum albumin (BSA) (methylisothiazolone)

The 1mg/L biotinylated monoclonal anti-human IgM of Mab-.

Variant 2:

Such as variant 1+2mg/L SlyD-pp (UL32) x1 and 2mg/ml SlyD-pp (150) x1

Variant 3:

Such as variant 1+2mg/L FkpA-pp (UL32) x1 and 2mg/ml FkpA-pp (150) x1

Variant 4:

Such as variant 1+2mg/L Skp-pp (UL32) x1 and 2mg/ml Skp-pp (150) x1

Buffer B 2

50mM MES pH of buffer 6.5,150mM NaCl；1mM EDTA, 0.1% methyl-isothiazol ketone and Oxypyrione, prolidocanol and 0.2% bovine serum albumin (BSA).

Immune component in B2: the CMV antigen of ruthenium (ruthenylated).

40ng/ml Skp-(pp150) x4-BPRu and 40ng/ml Skp-(UL32) x4-BPRu

Test procedure on 2.Elecsys 2010 instrument

Blood serum sample (diluting with Elecsys Diluent Universal 1: 20)+75 μ l buffer of 10 μ l dilutions B1.After incubation 9 minutes, add 75 μ l the buffer B 2 and 40 μ coated pearls of l Succ-PEG-DSPE.After 9 minutes, Mixture is transported to measuring chamber, and measures ECL signal.

3. result

Result of the test is as shown in Tables 1 and 2.

4. interpretation of result

To from the individuality being uninfected by, from the serum of patient after suffering from actute infection patient and infecting, carry out based on described The immunoassay of μ-capture form.Summarize result in Table 1.First row (variant 1) illustrates is not having any interference to eliminate The signal obtained under reagent or quencher module.The counting obtained with CMV-feminine gender human serum is about 700, and in negative and positive blood Exist between Qing and clearly distinguish.Secondary series (variant 2) shows the letter obtained in the presence of monomer quencher module SlyD-X Number.As remnant signal strength (based on %) confirms, the quenching effect of SlyD-X is equal for serum after acute serum and infection It is insignificant.This with expectation consistent because SlyD-X as monomer can not effectively with the interaction of molecules of multivalence IgM.

3rd row (variant 3) show the signal obtained in the presence of dimer quencher module FkpA-X.Residue signal Intensity confirms the insignificant FkpA-X quenching effect to acute serum, and significant FkpA-X is to the quencher of serum after infecting Effect.This discovery reflects compared with SlyD-X, higher epi-position (X) density of FkpA-X.Obviously, FkpA-X with from CMV Metainfective ripe IgM molecule interacts significantly, but it divides with the immature early stage IgM from acute cmv infection Son interacts the most weakly.

In row second from the bottom (variant 4), highlight trimer interference and eliminate the quenching effect of reagent Skp-X.Acute Serum is found that some signal quencher, but after infection much higher signal quencher observed by serum.This indicates sudden Module Skp-X of going out and the interaction of early and late IgM molecule.Because Skp-X is the highest with the interaction of IgM molecule in late period In the interaction with early stage IgM molecule, so the differential detection of the early stage IgM antibody of instruction actute infection is possible.

In a word, SlyD-X, FkpA-X and Skp-X really with the IgM interaction of molecules for epi-position X, thus quencher letter Number μ-catch assay, wherein Skp-X4 is used as signal and conducts antigen.Quencher efficiency relatively is according to SlyD-X ＜ FkpA-X ＜ Skp-X Order be incremented by, this is corresponding with effective epitope density.The quencher efficiency of ripe IgM molecule (after carrying out self-infection) is high, and not The quencher efficiency of ripe IgM molecule (from actute infection) is at a fairly low.

Our discovery makes it possible to clearly distinguish early and late infection, such as virus and infects.By using labelling Have the detectable such as Skp-X4 detection module (12 epi-positions copy) of high epitope density and unlabelled have lower The epitope density of SlyD-X (1 epi-position copy), FkpA-X (2 epi-positions copies) or Skp-X (3 epi-positions copies) type sudden Going out module, can distinguish early and late infection, this is important clinically.Up to now, such differentiation is at different IgM Between fraction or the most impossible, but attempted by carrying out IgG affinity tests: in brief, do not having In the presence of the chaotropic agent such as urea of non denatured concentration or chlorination guanidine, detect IgG.Chaotropic agent preferentially reduce immature (" early Phase ") combination of IgG molecule, but it only minor way ripe, the binding property of high-affinity (" late period ") IgG molecule. With and without the signal height ratio in the presence of chaotropic agent, produce the mark of high-affinity (chaotropic agent-resistance) IgG molecule. In affinity tests, high percentage reflects the advantage mark of high-affinity IgG molecule, and low percentage ratio reflects low-affinity (in early days) the advantage mark of IgG molecule.Thus, in affinity tests, high percentage indicates later infections, and low percentage ratio refers to Show early infection.

Last string in table 1 and 2 summarizes the acute and result of serum after infecting, and they have carried out the IgG parent of business Make a concerted effort to measure (RADIM).Result clearly shows, acute serum shows low residue signal (＜ 20%), and serum table after infecting Reveal high residue signal (＞ 60%).These results are the most consistent with the method for quenching of the present invention.This be particularly remarkable as The method of the present invention focuses on the differential detection of IgM molecule, and affinity measures the differential inspection being generally focused on IgG molecule Survey.The information obtained by distinct methods is complementary: immature immunoglobulin (along with early immune response) causes High quencher (last string) in IgG affinity mensuration, but the at a fairly low quencher in causing the Skp-X suppression of the present invention to measure (row second from the bottom).

Ripe immunoglobulin (along with after infecting or recurrent infection) cause IgG affinity to measure in low quencher (last string), but the at a relatively high quencher in causing the Skp-X suppression of the present invention to measure.Immature immunoglobulin (along with acute or early infection) causes the high quencher in IgG affinity mensuration, but causes the Skp-X suppression of the present invention to be surveyed Low quencher in Ding.Thus, when the commitment distinguishing the early and late stage infected and detection infection is important Waiting, the method for the differential detection IgM molecule of the present invention is that diagnostic field with the addition of valuable information.

Sequence table

Claims (57)

1. fused polypeptide, it comprises

(i) at least one multimerization domain, and

(ii) from multiple copies of epitope region of pathogen,

Wherein said multimerization domain is the protokaryon chaperone selected from FkpA and Skp, and

Wherein said causal organism is selected from:

(i) herpesvirus；

(ii) rubella virus；

(iii) hepatitis virus；

(iv) paramyxovirus；

(v) toxoplasma biological and

(vi) Borrelia is biological.

2. the polypeptide of claim 1, wherein said herpesvirus is human herpes simplex vicus 1 (HHV1), human herpes simplex vicus 2 (HHV2), varicella zoster virus (HHV3), Epstein-Barr virus (HHV4/EBV), human cytomegalic inclusion disease virus (HHV5), herpes virus hominis 6, herpes virus hominis 7 or human herpes virus 8；Described hepatitis virus is hepatitis A virus (HAV), hepatitis B virus (HBV) Or hepatitis C virus (HCV)；And described paramyxovirus is Measles virus or mumps virus.

3. the polypeptide of claim 1, wherein said multimerization domain is selected from: from colibacillary FkpA and Skp.

4. the polypeptide any one of claim 1-3, it comprises at least 2 copies of the described fragment containing epi-position.

5. the polypeptide any one of claim 1-3, it comprises 2-10 copy of the described fragment containing epi-position.

6. the polypeptide any one of claim 1-3, it comprises described containing the 2 of fragment of epi-position, 3,4,5 or 6 copies.

7. the polypeptide any one of claim 1-3, wherein the length of epitope region is 5-120 aminoacid.

8. the polypeptide any one of claim 1-3, wherein the length of epitope region is 15-50 aminoacid.

9. the polypeptide any one of claim 1-3, wherein said epitope region is separated by intervening sequence.

10. the polypeptide of claim 9, the length of wherein said intervening sequence is 1-10 aminoacid.

The polypeptide of 11. claim 9, the length of wherein said intervening sequence is 1-10 aminoacid, and comprise glycine and/or Serine residue.

12. claim 1-3, polypeptide any one of 10 and 11, wherein said epitope region comprises by described pathogenic infection Early stage or the epi-position of antibody specificity identification that produces of acute phase.

13. claim 1-3, polypeptide any one of 10 and 11, wherein said epitope region comprises by described pathogen primary The epi-position of the antibody specificity identification that the early stage infected or acute phase produce.

14. claim 1-3, polypeptide any one of 10 and 11, wherein said epitope region comprises by described pathogenic infection Late stage or the epi-position of antibody specificity identification that produces after infecting.

15. claim 1-3, polypeptide any one of 10 and 11, wherein said epitope region comprises and is continued by described pathogen Or the epi-position of the antibody specificity identification produced in recurrent infection.

The polypeptide of 16. claim 1, wherein said pathogen is selected from human cytomegalic inclusion disease virus, Mus toxoplasma and rubella virus.

17. claim 1-3, polypeptide any one of 10,11 and 16, it carries at least one report and/or coupling group.

The polypeptide of 18. claim 17, it carries biotin coupling group.

The polypeptide of 19. claim 17, it carries electrogenerated chemiluminescence reporter group, or hapten reporter group.

The polypeptide of 20. claim 17, it carries ruthenium reporter group, or Digitoxin reporter group.

21. claim 1-3,10,11,16 and 18-20 any one of fused polypeptide, its as polymer exist.

The nucleic acid molecules of 22. codings polypeptide any one of claim 1-20.

The nucleic acid molecules of 23. claim 22, the part encoding identical epitope region of wherein said nucleic acid molecules has to be lost Pass the different IPs nucleotide sequence in the range of code degeneracy.

24. expression vectors, it comprises the core of at least one claim 22 or 23 being operably connected with expression control sequenc Acid.

25. host cells transfecting with the nucleic acid molecules of claim 22 or 23 or the expression vector of claim 24 or converting.

The methods of 26. preparation fused polypeptide any one of claim 1-20, it comprises following step:

I () provides the host cell of claim 25；

(ii) under conditions of expressing fused polypeptide, described host cell is cultivated, and

(iii) described fused polypeptide is reclaimed.

The method of polymer fused polypeptide of 27. preparation claim 21, its be included in suitably form polymeric under the conditions of, knot Close multiple monomeric fusion polypeptide.

Fused polypeptide any one of 28. claim 1-21 is used for detecting the detection in the method for the antibody in sample in preparation Purposes in reagent.

The purposes of 29. claim 28, wherein said antibody is IgM antibody.

The purposes of 30. claim 29, wherein said method is for the differential mensuration of IgM antibody.

Purposes any one of 31. claim 29 or 30, wherein said antibody is to produce infecting early stage or in acute phase Raw IgM antibody.

The purposes of 32. claim 31, wherein said infection is the primary infection of pathogen.

Fused polypeptide any one of 33. claim 1-21 is used for detecting the interference in the method for the antibody in sample in preparation Eliminate the purposes in reagent.

The purposes of 34. claim 33, wherein said antibody is IgG antibody.

35. for detecting the test kit of the antibody in sample, and it comprises the fusion any one of at least one claim 1-21 Polypeptide and other test component.

The test kit of 36. claim 35, wherein said fused polypeptide is detectable.

The test kit of 37. claim 35, wherein said fused polypeptide is that interference eliminates reagent.

Fused polypeptide any one of 38. at least one claim 1-21 is used for detecting in sample for pathogen in preparation The purposes in test reagent in the method for antibody, described method comprises following step:

I sample described in () incubation and described test reagent, described test reagent comprises at least one claim 1-21 arbitrary The fused polypeptide of item and other test component, and

(ii) by evaluating the reaction of sample component and described test reagent, the existence in described sample of the described antibody is measured And/or concentration.

The purposes of 39. claim 38, wherein said test reagent comprises detectable and at least one interference eliminates reagent；And Step (ii) comprises the reaction measuring required sample component with detectable, wherein eliminates reagent with at least one interference and captures not The sample component needed.

The purposes of 40. claim 38 or 39, wherein said antibody is to produce primary infection early stage or in acute phase IgM antibody, and described test reagent comprises the fused polypeptide any one of at least one claim 1-21, it carries report And/or coupling group.

The purposes of 41. claim 40, wherein said test reagent also comprises the interference for capturing IgG antibody and eliminates reagent, And/or eliminate reagent for capture interference of the IgM antibody of generation in later period of infection and/or recurrent infection.

Purposes any one of 42. claim 38,39 or 41, wherein said test reagent comprises and carries the first of reporter group The second fused polypeptide of the coupling group planting fused polypeptide and carry for being immobilized in solid phase, and wherein by with first Plant and the second fused polypeptide forms complex, and detect the described complex in described solid phase, measure antibody.

Purposes any one of 43. claim 38,39 or 41, wherein said test reagent comprises and carries for being immobilized to The fused polypeptide of the coupling group gone up mutually and the receptor identifying test antibodies carrying reporter group, and wherein by many with merging Peptide and receptor form complex in described solid phase, measure antibody.

Purposes any one of 44. claim 38,39 or 41, wherein said test reagent comprises the fusion carrying reporter group Polypeptide and carry the receptor identifying test antibodies of coupling group for being immobilized in solid phase, and wherein by many with merging Peptide and receptor form complex in described solid phase, measure antibody.

45. are preparing in differential detection sample for pathogen according to the fused polypeptide of any one of claim 1-21 Purposes in the test kit of IgM antibody, wherein said sample comprises selected from interference IgM antibody and/or the interference of interference IgG antibody Antibody, described method comprises following step:

Sample and test reagent described in (a) incubation, described test reagent comprises:

The receptor R1 of (i) at least one specific binding IgM antibody,

(ii) the receptor R2 of at least one specific binding IgM antibody wanting differential detection, wherein R2 carries reporter group,

(iii) optionally, the receptor R3 of at least one specific binding interference IgM antibody, and

(iv) optionally, the receptor R4 of specific binding IgG antibody,

(b) permission following complex of formation:

I () comprises R1, the described IgM antibody wanting differential detection and the complex of R2, described complex carries reporter group,

(ii) optionally, comprise R3 and the complex of described interference IgM antibody, thus eliminate described interference IgM antibody and R2's Interference combines,

(iii) optionally, comprise R4 and the complex of described interference IgG antibody, thus eliminate described interference IgG antibody and R2's Interference combines, and

C () measures and is attached to the described reporter group in the described IgM antibody wanting differential detection by R2, as described sample Described in the tolerance of IgM antibody,

Wherein

-R1 is polymer antigen or Anti-Human's IgM antibody；

-R2 is the fused polypeptide any one of claim 1-21；

-R3 is polymer antigen and has such effective epitope density or concentration, and described effective epitope density or concentration are for being subject to The epitope density of body R2 or at most the 1/2 of concentration；

-R4 is the monomeric antigen comprising single epi-position copy.

The purposes of 46. claim 45, wherein said receptor R2 with R3 is to have Bu Tong effectively epitope density or the poly of concentration Receptor body.

Purposes any one of 47. claim 45-46, wherein said IgM antibody to be measured is infecting early stage or acute rank Section produce IgM antibody, and wherein said interference IgM antibody be later period of infection or infect after produce IgM antibody, and/or In the IgM antibody continued or produce in recurrent infection.

Purposes any one of 48. claim 45-46, wherein said IgM antibody to be measured is primary infection early stage or urgency Sexual stage produce IgM antibody, and wherein said interference IgM antibody be later period of infection or infect after produce IgM antibody, And/or in the IgM antibody continued or produce in recurrent infection.

The purposes of 49. claim 47, wherein said receptor R2 is polymeric acceptor, and it comprises IgM antibody identification to be measured extremely Few 6 epi-positions copy.

The purposes of 50. claim 48, wherein said receptor R2 is polymeric acceptor, and it comprises IgM antibody identification to be measured extremely Few 6 epi-positions copy.

The purposes of 51. claim 47, wherein said receptor R2 is polymeric acceptor, and it comprises IgM antibody identification to be measured extremely Few 8 epi-positions copy.

The purposes of 52. claim 48, wherein said receptor R2 is polymeric acceptor, and it comprises IgM antibody identification to be measured extremely Few 8 epi-positions copy.

The purposes of 53. claim 47, wherein said receptor R2 is polymeric acceptor, and it comprises IgM antibody identification to be measured extremely Few 12 epi-positions copy.

The purposes of 54. claim 48, wherein said receptor R2 is polymeric acceptor, and it comprises IgM antibody identification to be measured extremely Few 12 epi-positions copy.

Purposes any one of 55. claim 45-46, wherein said receptor R1 carries the coupling for being immobilized in solid phase Group.

Purposes any one of 56. claim 45-46, wherein said receptor R3 and R4 and sample precincubation, be subsequently adding and be subject to Body R1 and/or R2.

57. in the differential detection sample for the test reagents of IgM antibody of pathogen, wherein said sample comprises and is selected from Disturbing IgM antibody and/or the interference antibody of interference IgG antibody, it comprises:

The receptor R1 of (i) at least one specific binding IgM antibody,

(ii) the receptor R2 of at least one specific binding IgM antibody wanting differential detection, wherein R2 carries reporter group,

(iii) optionally, the receptor R3 of at least one specific binding interference IgM antibody, and

(iv) optionally, the receptor R4 of specific binding IgG antibody,

Wherein

-R1 is polymer antigen or Anti-Human's IgM antibody；

-R2 is the fused polypeptide any one of claim 1-21；

-R3 is polymer antigen and has such effective epitope density or concentration, and described effective epitope density or concentration are for being subject to The epitope density of body R2 or at most the 1/2 of concentration；

-R4 is the monomeric antigen comprising single epi-position copy.