AU2020103603A4

AU2020103603A4 - An influenza virosome-coated biomimetic nanovaccine and the preparation method

Info

Publication number: AU2020103603A4
Application number: AU2020103603A
Authority: AU
Inventors: Gang Chen; Fei Wang; Yuehua Xu
Original assignee: Yangzhou University
Current assignee: Yangzhou University
Priority date: 2020-11-23
Filing date: 2020-11-23
Publication date: 2021-02-04
Anticipated expiration: 2028-11-23

Abstract

The invention discloses an influenza virosome (VI)-coated biomimetic nanovaccine and the preparation method. The biomimetic nanovaccine, which is a core-shell nanosystem, comprises the VIs, the small-size fluorinated particles and a DNA vaccine, wherein the VI is a lipid vesicle containing influenza virus envelope protein, and the core of the nanosystem is a small-size fluorinated particle for loading the DNA vaccine, with the surface coated with VIs. The VI has the receptor binding activity, lysosomal membrane fusion activity and antigentic activity of influenza viruses; the small-size fluorinated core can deliver DNA into the nucleus and promote the protein expression. The nanosystem can simultaneously load protein vaccine and DNA vaccine and deliver each component to specific sites, which can improve the immune effects due to the synergistic effects. The invention belongs to the field of pharmaceutical preparations and biomedical technology. The biomimetic nanovaccines can effectively prevent influenza virus infection and has high clinical application value. -1/5 Gold nanoparticle Influenza virus Fluorinated DNA Influenza VI cationic vaccine coated biomimetic polymers nanovaccine Figure 1

Description

-1/5

Gold nanoparticle

Influenza virus Fluorinated DNA Influenza VI cationic vaccine coated biomimetic polymers nanovaccine

Figure 1

An influenza virosome-coated biomimetic nanovaccine and the preparation method

TECHNICAL FIELD

The invention relates to the field of pharmaceutical preparations and biomedical technology, in particular to an influenza VI-coated biomimetic nanovaccine and the preparation method.

BACKGROUND

The seasonal influenza virus transmission poses a great threat to global public health, and seriously affects human health and economic development. Vaccination is still one of the main measures to prevent and control influenza viruses. Now, the influenza vaccines have been approved are mainly inactivated vaccines and attenuated vaccines. However, the influenza vaccine based on the modification and inactivation of virus strains still confront potential security problems, which primarily include the retromutation of pathogens, allergies, autoimmunities and other adverse effects. In contrast, the DNA vaccines and protein vaccines have the advantages of good safety, high purity, strong specificity and etc. But the naked DNAs and proteins cannot be effectively taken up by antigen presenting cells (APCs), and can only induce short term immunity or humoral immunity driven by Th2 cells, so that the application of the DNA vaccines and the protein vaccines is greatly limited. To enhance the immune effects of DNA vaccines and protein vaccines, experts from the fields of biology, medicine and material sciences are paying more attention to the application of nanotechnology in the field of vaccines.

The VI is derived from the membrane of the host cell during viral proliferation and comprises the glycoprotein of the virus itself. The glycoproteins on the surface of an influenza VI consists of the HA and NA, wherein the HA binds to the sialic acid receptor of the host cell during the viral infection and mediates the viral endocytosis. Studies have shown that the in vitro prepared VI is a spherical monolayer vesicle with an average particle size of less than 200 nm. Compared with the artificially prepared liposomes, the VI contains the functional HA and NA glycoproteins, but no viral genetic materials. The in vitro prepared VI retains the receptor binding activity, lysosomal membrane fusion activity and antigenicity of influenza viruses. The receptor binding activity is beneficial to the APC uptake of nanovaccines. The lysosomal membrane fusion activity is beneficial to the lysosome escape of the nanoparticle core. The antigentic activity can be directly used as vaccines. Thus, the VI is a promising carrier system and vaccine material.

To induce robust immune responses, the DNA vaccine must enter the cell nucleus and be transcribed and translated, but delivering foreign DNA into the nucleus is limited by multiple cell barriers, primarily including the cell membrane barrier, lysosome barrier and nuclear membrane barrier. At present, a plenty of approaches are used for promoting the transmembrane transport of DNA. The most common one is to form complexes with the plasmid DNA (pDNA) and cationic liposome, which can interact with the negative charged glycoprotein on the cell membrane to promote the nonspecific endocytosis. For the lysosome barrier, the lysosome escape is primarily attributed to the lysosome rupture caused by the increasing of the osmotic pressure. For a long time, the nuclear membrane barrier is the main factor that hinders the DNA into the nucleus to transcript and express. At present, the commonly used strategy is to modify the pDNA by using a nuclear localization sequence (NLS) peptide so as to improve the probability of entering the nucleus. However, the expression efficiency of the NLS modified pDNA is limited. Besides, the charge interaction between the anionic DNA and the cationic NLS will bury the NLS into the DNA and restrict the functions of NLS. Studies have shown that the size of nuclear pores is 20-70 nm, and particles smaller than 50 nm can enter into the nucleus. In addition, the fluorination modification can effectively improve the transfection efficiency and the in vitro and in vivo stability of the cationic polymers, and significantly increase the genetic distribution in the nucleus, which can help improve the transcription and expression of the pDNA.

SUMMARY

Objective: The invention aims to solve the technical problem of providing influenza VI-coated biomimetic nanovaccines.

The second technical problem to be solved by the invention is to present a preparation method of the influenza VI-coated biomimetic nanovaccines.

Technical scheme: To solve the above technical problems, the invention provides influenza VI-coated biomimetic nanovaccines, comprising the influenza VIs, the small-size fluorinated particles and DNA vaccines.

Wherein the biomimetic nanovaccines are core-shell nanosystems; the VI is a lipid vesicle containing influenza virus envelope protein, and the core of the nanosystem is a small-size fluorinated particle for bearing the DNA vaccine, with the surface coated by Vis.

Wherein the influenza VIs are derived from influenza viruses including but not limited to HIN1, H3N2, H5N1, H7N9, H9N2, and other subtypes.

Wherein, the nanostructure of small-size fluorinated particles is formed by coating the gold particles with fluorinated modified cationic polymers.

Wherein the fluorinated modified cationic polymers are gene vectors, including, but not limited to, polyamines, such as linear or branched polyethyleneimines (PEI); poly (amido amines), PAAs, e.g., dendrimer PAMAM, hyperbranched polyamidoamine (HPAMAM); polymethacrylatesates, e.g., polydimethylaminoethyl methacryla (pDMAEMA); polyaminoacids, e.g., polylysine (PLL); polyesters, e.g., linear or branched poly (p-amino ester) (PBAE); and natural polysaccharides, e.g., chitosan.

Wherein the size of the gold particles is 10-30 nm.

The content of the invention also includes the preparation method of the influenza VI-coated biomimetic nanovaccines, which comprises the following steps:

1) Preparation of VIs: Adding 1,2-dihexanoyl lecithin into influenza viruses for ice bathing, collecting the supernatant after an ultracentrifugation, dialyzing the supernatant in HBS buffer solution, and removing the 1,2-dihexanoyl lecithin to obtain the recombinant VIs;

2) Synthesis of the fluorinated cationic polymers: Carrying out reaction according to the molar ratio of amino, heptafluorobutyric anhydride and triethylamine in the cationic polymer of 1:3:1.2, wherein the reaction medium is methanol; stirring at room temperature, dialyzing the reaction product in deionized water with a pH value of 3-4 after finishing the reaction, and freeze-drying to obtain the fluorinated cationic polymers;

3) Preparation of the FAus: Slowly dropping 10-30 nm Gold particles into the fluorinated cationic polymers, slowly shaking and centrifugally collecting the precipitate to obtain the small-size fluorinated particles (FAus);

4) Preparation of FAus loaded with the DNA vaccine: Mixing the FAus prepared in step 3) with the DNA vaccine, slowly and gently shaking, wherein the mass ratio of the cationic polymer to the DNA is 1.5-3, and obtaining small-size fluorinated particles loaded with the DNA vaccine;

5) Preparation of the ARVs: Mixing the recombined VIs prepared in step 1) with the small-size fluorinated particles prepared in step 4), extruding the mixture back and forth by an extruder, and centrifugally collecting the mixture to obtain the ARVs.

Wherein the ultracentrifugation conditions of step 1) are 4 °C, 100.000*g and 1.5 h.

Wherein the HBS buffer solution used in step 1) is an HEPES buffer solution with 0.15 M NaCl.

Wherein the concentration of the fluorinated modified cationic polymer prepared in step 3) is 5-10 mg/mL.

Wherein the DNA vaccine prepared in step 4) comprises, but not limited to, a full-length DNA sequence or a partial DNA sequence of nucleoprotein (NP), matrix protein (M1), membrane protein (M2), hemagglutinin (HA) or neuraminidase (NA) of influenza viruses.

Wherein the pore size of the filter membrane of the extruder used in step 5) is -100 nm.

Advantages: Compared with the prior art, the invention has the following advantages: the naked DNA vaccine and the protein vaccine cannot be effectively taken up by APCs, and the induced immune response is rather weak. In addition, due to the different properties of different active components, simultaneously loading every component and the effectively releasing at different target sites is always a challenge during preparation. According to the invention, the nanovaccines are specifically combined with the sialic acid receptor on the APC surface through the HA on the surface and mediates the endocytosis of particles into an endosome/lysosome; The VI is fused with a lysosomal membrane to release the nanoparticles into cytoplasm, which load the DNA vaccine; and the nanoparticles escaping from the lysosome enter the cell nucleus for transcription and expression due to the advantages of fluorination and small particle size. The nanovaccines simulate the virus replication mechanism, realizes the site-specific sequential delivery of the protein vaccine and DNA vaccine, achieving a synergistic effect to improve the immune effects. The prepared method of the nanovaccines is simple and controllable, low in production cost, good in repeatability, suitable for large-scale production. The carrier is very stable and safe. The vaccine can effectively reduce and control the influenza virus infection risk.

BRIEF DESCRIPTION OF THE FIGURES

Figure 1: A schematic diagram of the principle of preparing the influenza VI coated biomimetic nanovaccines;

Figure 2: The characterization of the influenza VI-coated biomimetic nanovaccines presented in the invention;

A: the particle size of the influenza VI-coated biomimetic nanovaccines;

B: the zeta potential the influenza VI-coated biomimetic nanovaccines;

Figure 3: Membrane fusion and delivery of pDNA into the nucleus of the influenza VI-coated biomimetic nanovaccines presented in the invention;

A: The ARVs and VIs prepared in Example 1 in the invention are separately incubated with red blood cells. The OD540 ultraviolet absorption curve changes with pH;

B: Membrane fusion experiments of the influenza VI-coated biomimetic nanovaccines at the pH value of 5.5 and 7.4, respectively;

C: The delivery of pDNA into the nucleus by the ARV' (containing non fluorinated cationic polymer) and the ARV prepared by the invention;

Figure 4: The cell immunity and humoral immune responses of the influenza VI coated biomimetic nanovaccines presented in the invention;

A: The influenza VI-coated biomimetic nanovaccine group, namely ARV group, is prepared by subcutaneously injecting the nanovaccines at the base of the tail in the first and the third week, separating the spleen at the fourth week, preparing a single cell suspension, incubating the single cell suspension with CD3 and CD8 antibodies, and detecting the content of CD8'T cells in mice by the flow cytometry; The Saline group is prepared by subcutaneously injecting physiological saline at the base of the tail in the first and the third week, and the rest steps are the same as in the ARV group case; The VI group is prepared by subcutaneously injecting the VI at the base of the tail in the first and the third week, and the remaining steps are the same as in the ARV group case; The pFAu group is prepared by subcutaneously injecting the pFAu at the base of the tail in the first and the third week, and the remaining steps are the same as in the ARV group case.

B: Taking the spleen single cell suspension, incubating it with CD3 and CD4 antibodies, and detecting the content of CD4' T cells in mice by the flow cytometry;

C: After the mice were immunized, collecting serum samples in the fourth week and measuring the IgG titers;

Figure 5: The protection against the viral infection of the influenza VI-coated biomimetic presented in the invention;

A: The influenza VI-coated biomimetic nanovaccine group, namely ARV group, is prepared by subcutaneously injecting the nanovaccines at the base of the tail of in first and the third week, infecting the mice with 1*104 CFU PR8 viruses in the fifth week, and continuously recording the weight of the mice for 14 days; The Saline group is prepared by subcutaneously injecting the physiological saline at the base of the tail in the first and the third week, infecting the mice with 1*104 CFU PR8 viruses in the fifth week, continuously recording the weight of the mice for 14 days; and the Normal group is prepared without treatment, and continuously recording the weight of the mice for 14 days.

B: Recording the survival rate of the mice after challenge;

C: Separating lung tissues four days after challenge, and measuring the virus titer;

D: Separating lung tissues four days after challenge, and measuring the lung index;

E: Separating lung tissues four days after challenge, and performing HE staining.

DESCRIPTION OF THE INVENTION

The present invention will now be further described with reference to specific embodiments thereof. It should be understood that various changes and modifications may be made by those skilled in the art without departing from the principles of the invention and these are to be considered as falling within the scope of the invention. The experimental methods in the following examples are the conventional methods, if not specified. The experimental materials used in the following examples were purchased from conventional biochemical reagent stores, if not specified.

Materials and Equipment:

(1) The gold particles were purchased from Nanoeast Biotech CO., LTD, China;

(2) The polyethyleneimine (PEI) was purchased from Sigma, USA;

(3) The heptafluorobutyric anhydride (HFBA) was purchased from Sigma, USA;

(4) The nuclear/cytoplasmic extraction kit was purchased from Biovision Company, USA;

(5) The Cy5 nucleic acid labeling kit was purchased from Mirus Bio Company, USA;

(6) The DNA vaccine of influenza virus NP was synthesized by Changzhou Jiyu Biotechnology Co., Ltd. (eukaryotic expression vector obtained by inserting NP sequence of influenza virus PR8 into PCDNA3.1(+) ;

(7) The influenza virus strain was PR8 stored in our laboratory;

(8) The 1,2-dihexanoyl lecithin was purchased from Shanghai Aladdin Biochemical Science and Technology Co., Ltd.;

(9) The extruder and filter membranes were purchased from Morgec Machinery (shanghai) Co., Ltd.;

(10) The CD3, CD4, CD8 flow antibodies were purchased from eBioscience, USA;

(11) The DOPC and cholesterol were purchased from Avanti Polar Lipids, USA;

(12) The fluorescence energy resonance transfer (FRET) reagents for NBD-PE and Rho-PE were purchased from Biotium, USA.

Example 1

(1) Preparation of VIs: Using the influenza virus PR8, performing ultracentrifugation, collecting the bottom precipitate; adding 375 PL of 200 mM 1,2 dihexanoyl lecithin per 5 mg of the precipitated viruses, ice bathing for 30 min. Collecting the supernatant after an ultracentrifugation, dialyzing the supernatant in HBS buffer solution for 24 h, and removing the 1,2-dihexanoyl lecithin to obtain the recombinant VIs, wherein the ultracentrifugation condition is 4 °C, 100.000*g, and 1.5 h;

(2) Synthesis of the fluorinated polymers: The reaction was carryied out according to the molar ratio of 1:3:1.2 of amino in cationic polymers, heptafluorobutyric anhydride and triethylamine, wherein the reaction medium is methanol; stirring for 48 h at room temperature, dialyzing the reaction product in distilled water with a pH value of 3-4 for 2 days after finishing the reaction, and freeze-drying to obtain the fluorinated cationic polymers, wherein the cationic polymers used in the embodiment was 25 kDa PEI;

(3) Preparation of FAus: Slowly dropping 3*10' Gold particles of 10-30 nm into the fluorinated cationic polymer, slowly shaking for 30 min, centrifuging at 10000 rpm for 10 min, and collecting the precipitate to obtain the small-size fluorinated particles;

(4) Preparation of ARVs: Mixing the FAus prepared in step (3) with the DNA vaccines encoding the influenza virus NP, slowly shaking for 30 min, and obtaining the small-size fluorinated particles (pFAus) loaded with DNA vaccines with the mass ratio of the cationic polymer to the DNA of 1.5. Mixing the VIs prepared in step (1) with pFAus, and extruding the mixture for 10 times by an extruder, wherein the pore size of the filter membrane is 100 nm, and centrifuging the mixture at 1000 rpm for 10 min, and collecting the nanovaccines (ARVs).

The prepared ARV was characterized by Zeta potential. As shown in Figure 2A, the ARV size was 68.2 nm, and the polydispersity coefficient (PDI) was 0.21; as shown in Figure 2B, the ARV potential was -5.6 mV.

Example 2

The low pH condition of cell endosome/lysosome can induce the conformational change of the influenza virus HA and cause the fusion of the virus envelope with the endosome/lysosome membrane. Therefore, when the HA adsorbed on the red blood cell undergoes the conformational change under acidic conditions, the red blood cell membrane may be broken, leading to heme release and the hemolytic reaction. Thus, the fusion process of the membrane can be simulated as hemolysis experiments. As shown in Figure 3A, the ARVs and VIs prepared in Example 1 were separately incubated with red blood cells, and the UV absorption of OD540 increased with the decrease of pH, and both ARVs and VIs had hemolysis, indicating that membrane fusion occurred. Further utilizing anionic liposome to simulate the celll membrane structure, and encapsulating FRET compounds which comprises the DOPC, cholesterol and FRET reagent pair of the NBD-PE and Rho-PE, wherein the molar ratio of the DOPC to cholesterol to NBD-PE to Rho-PE is 10:1:0.1:0.05. At pH values of 5.5 and 7.4, ARVs were incubated with anionic liposomes and the fluorescence intensity of liposomes (450 nm/595 nm) was measured at specific time points. The ratio of lipid fusion=(It-Io)/(I-Io) x 100%, where Io was the fluorescence intensity before incubation, It was the fluorescence intensity at each measurement time point, and I was the fluorescence intensity of liposomes treated with 0.1% (v:v) Tween X 100. As shown in Figure 3B, the membrane fusion rate of ARVs was 35% at pH value of 5.5 and less than 10% at pH value of 7.4 after1 h incubation, indicating that ARVs could effectively fuse cell membranes under the acidic conditions of lysosomes. To investigate the nuclear delivery ability of ARVs to pDNAs, labeling pDNAs with Cy5 nucleic acid labeling kit and incubating them with mouse dendritic cells DC2.4 for different time, extracting nuclei and detecting the fluorescence intensity of Cy5. As shown in Figure 3C, compared with the ARV' group, the fluorescence intensity of the ARV nuclei was significantly enhanced (P<0.005), so the ARVs could efficiently deliver the pDNA into the nucleus.

Example 3

Mice (C57BL/6, 20±2 g, male) were immunized with the ARVs prepared in Example 1 by subcutaneous injection at the base of the tail in the first and the third week, and each dose was 40 pg ARV proteins. The spleen was isolated in the forth week to prepare the single cell suspension. Two million cells were collected and put into a 1.5 mL centrifuge tube. After centrifuging at 1600 rpm for 5 min, the supernatant was removed and washed with 1 mL PBS for two times. Finally 100 Pl PBS was resuspended, the cells were labeled with CD3 and CD8 antibodies and CD3 and CD4 antibodies, and incubated at 4 °C for 30 min in the dark. Subsequently fixing with 4% paraformaldehyde and followed by the flow test. As shown in Figures 4A and 4B, the VIs, pFAus and ARVs can effectively induce the increase of CD8 T and CD4' T cells in vivo, and the induction ability of ARVs is the strongest. Serum samples of immunized mice were prepared in the forth week and IgG titers in serum were determined. As shown in Figure 4C, the prepared ARVs had strong humoral immune effect on mice, and there was significant difference compared with VIs and pFAus (P<0.05, P<0.01). Therefore, the nanovaccines can effectively induce the humoral immunity and cell immune responses in vivo.

Example 4

Mice (C57BL/6, 20±2 g, male) were used and the ARVs prepared in Example 1 by subcutaneous injection at the base of the tail in the first and the third week, and each dose was 40 pg ARV proteins. In the fifth week, each mouse was infected with 1*104 CFU PR8 viruses, and recording the weight and survival rate of the mice in the next two consecutive weeks. In the first and the third week, the Saline group mice were subcutaneously injected at the base of the tail with the same volume of physiological saline as the ARV. In the fifth week each mouse was infected with 1*104 CFU PR8 viruses, and recording the weight and survival rate of the mice in the next two consecutive weeks; the Normal group mice were not treated, but recording the weight and survival rate of the mice in the next two consecutive weeks. As shown in Figure 5A, the weight of mice in the normal group increased slowly with the lapse of time, while the weight of mice in the Saline group continued to decrease, and the weight of mice in the ARV immune group was between the two. During the first to forth day, the weight of mice in the ARV immune group decreased, and after the fifth day, the weight of mice in the ARV immune group showed a slowly increasing tendency. As shown in Figure 5B, all the mice in the Saline group died by the twelfth day, while there was no death in the ARV group and the Normal group. The results of lung virus titers and lung index statistics showed that ARV immunization significantly reduced lung virus levels and damages to lungs (Figures. 5C-5D). The HE staining of the lung tissues showed (Figure 5E) that a large number of inflammatory cells infiltrated into lungs after the challenge, while the Normal and the ARV immune groups showed good morphologies, intact tissue structure and no obvious inflammation. Therefore, the prepared nanovaccines display obvious immune prevention effects against influenza viruses.

Claims

1. An influenza VI-coated biomimetic nanovaccines, wherein the biomimetic nanovaccines comprises the influenza VIs, small-size fluorinated particles and DNA vaccines.

2. The influenza VI-coated biomimetic nanovaccines according to claim 1, wherein the biomimetic nanovaccines are core-shell nanosystems, comprises the VIs, the small-size fluorinated particles and a DNA vaccine, wherein the VI is a lipid vesicle containing influenza virus envelope proteins, and the core of the nanosystem is a small-size fluorinated particle for loading the DNA vaccines, with the surface coated by Vls.

3. The influenza VI-coated biomimetic nanovaccines according to claim 1, wherein the influenza VIs are derived from influenza viruses, including the HINI, H3N2, H5N1, H7N9 or H9N2 subtype.

4. The influenza VI-coated biomimetic nanovaccines according to claim 1, wherein the nanostructure of small-size fluorinated particles is formed by coating the gold particles with fluorinated cationic polymers.

5. The influenza VI-coated biomimetic nanovaccines according to claim 4, wherein the cationic polymer is a gene carrier and comprises one or more of polyamines, polyamidoamine, hyperbranched polyamidoamine, polymethacrylates, polyamino acids, polyesters or natural polysaccharides.

6. The influenza VI-coated biomimetic nanovaccines according to claim 4, wherein the particle size of the gold particles is 10-30 nm.

7. The preparation method of the influenza VI-coated biomimetic nanovaccines according to claims 1-6, wherein the preparation method comprises the following steps:

The content of the invention also includes the preparation method of the influenza VI-coated biomimetic nanovaccine, which comprises the following steps:

2) Synthesis of fluorinated cationic polymers: The reaction was carryied out according to the molar ratio of 1:3:1.2 of amino in cationic polymers, heptafluorobutyric anhydride and triethylamine, wherein the reaction medium is methanol; stirring at room temperature, dialyzing the reaction product in deionized water with a pH value of 3-4 after finishing the reaction, and freeze-drying to obtain the fluorinated cationic polymers;

3) Preparation of FAus: Slowly dropping 10-30 nm Gold particles into the fluorinated cationic polymer, slowly shaking and centrifugally collecting the precipitate to obtain the small-size fluorinated particles (FAus);

8. The method for preparing the influenza VI-coated biomimetic nanovaccines according to claim 7, wherein the concentration of the fluorinated cationic polymers in step 3) is 5-10 mg/mL.

9. The method for preparing the influenza VI-coated biomimetic nanovaccines according to claim 7, wherein the DNA vaccine of step 4) comprises a full-length or a partial DNA sequence of NP, M1, M2, HA or NA of influenza viruses.

10. The method for preparing the influenza VI-coated biomimetic nanovaccines according to claim 7, wherein the pore size of the filter membrane of the extruder in step 5) is 50-100 nm.

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