AU672610C - Preparation for activation of natural killer cells (NK-cells), said preparation containing interferon-alpha and histamine, serotonin or substances with corresponding receptor activity - Google Patents

Description

PREPARATION FOR ACTIVATION OF NATURAL KILLER CELLS (NK-CELLS), SAID PREPARATION CONTAINING INTERFERON-α AND HISTAMINE, SEROTONIN OR SUBSTANCES WITH CORRESPONDING RECEPTOR ACTIVITY

TECHNICAL DOMAIN

The present invention concerns a pharmaceutical preparation or system for activation of natural killer cells (NK-cells) , in order for example to treat tumors or virus infections.

BACKGROUND OF THE INVENTION

Natural killer cells (NK-cells) are a group of spontaneously cytotoxic lymphocytes that destroy tumor cells by lysis with no antigen specificity or restriction by histocompatibility mol¬ ecules. Monocytes are involved in the regulation of the NK-cell's function, both through mechanisms involving cell contact and through providing soluble NK cell-regulating mediators. Recently, a cell contact-mediated mechanism has been described whereby monocytes regulate NK-cells. This type of monocyte-mediated regulation is exerted by monocytes that are obtained directly from peripheral blood through counterflow centrifugal elutriation (CCE) and is regulated the biogenic amines histamine and sero- tonin (Hellstrand and Hermodsson, 1986, J. Immunol. 137, 656-660 Hellstrand and Hermodsson, 1987, J. Immunol. 139, 869-875 Hellstrand and Hermodsson, 1990, Scand. J. Immunol. 31, 631-645 Hellstrand and Hermodsson, 1990, Cell. Immunol. 127, 199-214 Hellstrand, Kjellson and Hermodsson, 1991, Cell. Immunol., 138, 44-54). These NK-cell regulating mechanisms caused by biogenic amines should be of importance to the NK cell-mediated defence against metastatic tumors in vivo (Hellstrand, Asea and Her¬ modsson (1990), J. Immunology 145, 4365-4370).

Interferon-α (IFN-α) is an important regulating factor for NK cells. It enhances the NK cell's cytotoxicity (NKCC) both in vivo and in vitro (Trinchieri, 1989, Adv. immunol. 47, 187-376; Einhorn, Blomgren and Strander, 1978, Int. J. Cancer 22, 405-412; Friedman and Vogel, 1984, Adv. Immunol., 34, 97-140).

Owing to the high rate of cancer and the only partially success- ful treatment methods available today, there is a constant demand for other improved methods of treatment of tumors. There is also a great demand for improved treatment methods for virus infec¬ tions.

PURPOSE AND MOST IMPORTANT CHARACTERISTICS OF THE INVENTION

The goal of the invention is to create a pharmaceutical prepara¬ tion or system that effectively stimulates NK cells, e.g., in order to treat tumors, primarily myelomas, renal cancer, leu- kemias and melanoma, or to treat virus infections, primarily chronic hepatitis B and hepatitis C. The preparation or system according to the invention involves a first composition, contain¬ ing interferon-α or analogues thereof, and a second composition containing at least one substance with histamine H₂, or serotonin 5-HT_1A.receptor agonist activity, whereby said first and second compositions are either mixed in a preparation or supplied in separate doses in an amount sufficient for the intended treat¬ ment. The invention also comprises a method for treatment of viral or neoplastic disease comprising the step of coadminis- tering to an animal, including a human, an effective amount of a histamine H₂ receptor agonist or a serotonin 5-HT_1Λ receptor agonist. Furthermore, the invention includes use of a histamine H₂ receptor agonist or a 5-HT_1A receptor agonist in the prepara¬ tion of a medicament for treatment of viral or neoplastic disease by coadministration with interferon-α, as well as the use of interferon-α in the preparation of a medicament for treatment of neoplastic or viral disease by coadministration with a histamine H₂ receptor agonist or a serotonin 5-HT_1A receptor agonist.

The invention shall be described in greater detail below, making reference to reported in vitro experiments. DESCRIPTION OF THE ILLUSTRATIONS

Figure 1 shows in tumor graph form the synergistic NK cell activation aqainst cultured target cells produced by IFN-a and histamine or serotonin for various concentrations of IFN-α (0-100 U/ml) . Figure 2 shows in graph form the synergistic NK cell activation produced against freshly recovered human leukemic cells by IFN-α and histamine for various concentrations of IFN-α (0-lOOU/ml).

DESCRIPTION OF THE INVENTION

The invention is based on the unexpected discovery in vitro that IFN-α and the biogenic amines histamine and/or serotonin produce a synergistic activation the anti-tumor activity of NK cells.

The experiments reported hereafter show that eluted monocytes effectively suppress the activation of NK cells induced by IFN-α. Furthermore, it is shown that histamine or serotonin, which act through defined bioaminergic receptors, remove the monocyte- induced suppression and thereby restore the ability of the NK cells to respond to IFN-α.

Analogues of histamine with H₂-receptor agonist activity or other compounds with H₂-receptor agonist activity and analogues of serotonin with 5-HT_1Λ-receptor agonist activity or other com¬ pounds with 5-HT_1A-receptor agonist activity that are suitable for use in the present invention are known within the art and shall not be described more closely here. For example, these analogues can have a chemical structure resembling that of histamine or serotonin, but modified by addition of groups that do not negatively affect the H₂ or 5-HT_1A receptor activities. Known H₂-receptor agonists include histamine, dimaprit, cloni- dine, tolazoline, impromadine, 4-methylhistamine, betazole and histamine congener derivatives such as

(CH₂)₅-CH₃ CH-(CH₂)₃- 9C-NH -Q „- CH₃ described as compounds 1, 6, and 9 in Khan et al., J. Immunol., Vol 137 pp 308-315 (1986). Known serotonin 5-HT_1A.receptor ago¬ nists include 8-OH-DPAT, ALK-3, BMY 7378, NAN 190, lisuride, d- LSD, flesoxinan, DHE, MDL 72832, 5-CT, DP-5-CT, ipsapirone, WB 4101, ergotamine, buspirone, metergoline, spiroxatrine, PAPP, SDZ (-) 21009, and butotenine.

IFN-α and histamine/serotonin can be administered separately or in the same preparation. The method of administration can be either local or systemic injection or infusion. Other methods of administration can also be suitable.

The compounds can even be administered intraperitoneally or in another parenteral method. Solutions of the active compounds in the form of free acids or pharmaceutically acceptable salts can be administered in water with or without a tenside such as hydroxypropylcellulose. Dispersions making use of glycerol, liquid polyethyleneglycols, or mixtures thereof with oils can be used. Antimicrobial compounds can also be added to the prepara- tion.

Injectable preparations may include sterile water-based solutions or dispersions and powders that can be dissolved or suspended in a sterile medium prior to use. Carriers such as solvents or dispersants containing, e.g., water, ethanolpolyols, vegetable oils and the like can also be added. Coatings such as lecithin and tensides can be used to maintain suitable fluidity of the preparation. Isotonic substances such as sugar or sodium chloride can also be added, as well as products intended to retard absorp- tion of the active ingredients, such as aluminum monostearate and gelatin. Sterile injectable solutions are prepared in the famili¬ ar way and filtered before storage and/or administration. Sterile powders can be vacuum-dried or freeze-dried from a solution or suspension.

All substances added to the preparation must be pharmaceutically acceptable and essentially nontoxic in the quantities used. The preparation and formulations that produce a delayed release are also part of the invention.

The preparation is supplied in dosage units for a uniform dosage and to facilitate administration. Each dosage unit contains a predetermined quantity of active components to produce the desired therapeutic effect, along with the requisite quantity of pharmaceutical carriers.

IFN-α can be administered in a quantity of around 1000 to 300,000 U/kg/day, preferably around 3000 to 100,000 U/kg/day and best of all around 10,000 to 50,000 U/kg/day.

The biogenic amines histamine and serotonin can be administered in a quantity of around 0.1 to 10 mg/day, preferably around 0.5 to 8 mg/day and best of all around 1 to 5 mg/day. However other quantities can be administered with IFN-α, as decided by the treating physician. For substances other than biogenic amines with corresponding receptor activity, doses producing an equi- valent pharmacological effect shall be used.

Although it is stated in the examples that the administration was given in a single dose, it is obvious that the compounds can be distributed over longer periods of time for treatment of virus infections or tumors. The daily dose can be administered as a single dose or it can be divided into several doses, should negative effects occur.

EXAMPLES

In Vitro Studies of IFN-α and histamine/serotonin.

The example illustrates the effect of human recombinant IFN-α and histamine/serotonin, separately and in combination, on the NK cell cytotoxicity (NKCC) of human mononuclear cells (MNC).

MNC are obtained from peripheral venous blood from healthy human blood donors by Ficoll-Hypaque centrifuging, followed by Percoll density-gradient fractionation (Timonen and Saksela, 1980, J. Immunol. Methods 36, 285-291; Hellstrand and Hermodsson, 1990, Scand. J. Immunol. 31, 631-645).

In the respective Percoll fractions, the high-density MNC (Per¬ coll fractions 1-4) were small lymphocytes with low baseline cytotoxicity against K562 target cells. After removal of the monocytes, the low-density fractions 6-10 displayed high NKCC, consistent with earlier studies. (Timonen and Saksela, 1980, J. Immunol. Methods 36, 285-291)

The target cells used in these experiments were K562, an NK-cell- sensitive erythroleukemic cell line, or Daudi, a relatively NK-insensitive EBV-transformed B-cell lymphoblastoid cell line.

The NKCC was determined six times as the specific ⁵¹Cr-release for a MNC:target-cell ratio of between 30:1 and 3.8:1 in two¬ fold dilution gradients. The suspensions of MNC/target cells were incubated in microplates at 37 C for 6 hours (Daudi) or 16 hours (K562). The supernatant solution was then collected and examined for radioactivity in a gamma counter. The maximum ⁵¹Cr-release was measured in target cell cultures treated with Triton X-100. The NKCC was calculated as the cell lysis % by the formula 100 x (experimental release - spontaneous release/maximum release - spontaneous release) = cell lysis %.

A low-density Percoll fraction was separated by counterflow centrifuge elution (CCE) in a monocyte and in a lymphocyte fraction. The monocyte fraction was concentrated to >90% purity whereupon the contaminating cells consisted of large lymphocytes. The lymphocyte fractions obtained by CCE contained <3% monocytes, determined by morphology and Leu-M3 (CD14) antigen expression. The lymphocytes were CD3^"/16756^* T cells (45-50%), CD3"/16"/56" NK cells (35-40%) , CD37l6^~/56^" T cells (45-50%) , CD3⁺/16⁺/56^* cells (1-5%), determined by flow cytometry.

The eluted monocytes and/or the NK cell-concentrated low-density lymphocytes were treated with IFN-α and histamine/serotonin. The compounds were added, separately or in combination, to mixtures of MNC and K562 target cells at the start of a 16-hour ⁵¹Cr-rele- ase assay. The cytotoxicity against K562 in the NK cell-concentr¬ ated lymphocyte fraction was increased by IFN-α and unaffected by histamine or serotonin. The eluted monocyte fraction exhibited a low baseline cytotoxicity and was slightly induced by histami- ne/IFN-α or serotonin/IFN-α; this cytotoxicity resulted from the low fraction of contaminating lymphocytes (data not given). The addition of eluted monocytes to the NK cell-concentrated lympho- cytes suppressed the baseline cytotoxicity to K562. Furthermore, the eluted monocytes almost totally inhibited the activation of the cytotoxicity of the NK-cell-concentrated lymphocytes by means of IFN-α (Table 1).

Histamine and serotonin restored the basal cytotoxicity of lymphocytes in mixtures of monocytes and lymphocytes. Further¬ more, both histamine and serotonin eliminated the monocyte induced inhibition of the NK cell response to IFN-α. Hence, IFN-α plus histamine or serotonin synergistically enhance the cytotoxi- city in mixtures of monocytes and NK cell-enriched lymphocytes (Table 1).

In the experiments reported in Table 1, eluted lymphocytes were mixed with monocytes as shown in the table, in a total volume of 150 μl. The data are NKCC (cell lysis %; mean ±SEM of six deter¬ minations). Serotonin 10'*M and/or IFN-α (25 U/ml) were added at the start of a 16-hour microcytotoxicity test against 10⁴ K562 target cells.

TABLE 1: Suppression of NK Cell Cytotoxicity by Monocytes and Elimination of This Effect with Serotonin

NK CELL CYTOTOXICITY AFTER TREATMENT WITH

Table 2 shows the synergistic activation of NK cells by combined treatment with IFN-α and histamine. Monocytes were recovered along with NK cells in low-density Percoll fractions. In the experiment shown in Table 2, IFN-α and/or histamine were added to MNC obtained from these monocyte-containing Percoll fractions. As was the case with mixtures of eluted monocytes and low-density lymphocytes, IFN-α was relatively ineffective in these cell frac- tions, while histamine increased the cytotoxicity. Treatment of monocyte-containing cells with histamine (10^"4 - 10^"6 M) and IFN-α (25 U/ml) produced a synergistic NK-boosting response against K562 and against Daudi target cells. A similar result was obtained when histamine was replaced by serotonin.

In the result shown in Table 2, MNC from five different donors were used. All compounds were added to mixtures of MNC and target cells at the start of a 6 h (Daudi) or 16 h (K562) effector and target cell incubation. The effector cells were obtained from Percoll fractions 7-8, containing 33-55% monocytes.

Figure 1 shows the synergistic NK cell activation by IFN-α and histamine/serotonin for different concentrations of IFN-α (0-100 U/ml). Cells from the monocyte-containing Percoll fraction 8 were incubated with culture medium, histamine (10^~4 M) or serotonin (10^"4 M) in the presence of IFN-α (0-lOOU/ml). The data shown are NKCC (cell lysis %; mean ±SEM of six determinations). The com¬ pounds were added at the start of a 16 h microcytotoxicity test against K 562 target cells. TABLE 2: Synergistic Activation of NK Cells by Histamine and IFN-α

NKCC (cell lysis % ±SEM)

target Histamine concentration

Exp. cell MNC/target treatment 0 10^"4 M 10^'° M 10^"6 M cell ratio

K 562 15:1 Medium 33.1±0.5 55.5±1 54.7±1 39.2±1

IFN 25 U/ml 33.1±1 76.4±3 74.1±1 66.0±2

K 562 15:1 27.4±1 23.2±2 66.2±1 55.4±1

K 562 15:1 38.6±1 29.4±1 66.5±2 56.3±2

Daudi 30:1 3.5±1 1.1±0.3 28.3±1 14.1±1

5. Daudi 30:1 9.7±1 2.5±1 52.3±2 31.7±1

The effect of histamine on monocyte-induced suppression of resting and IFN-α-activated NK cells was completely blocked by simultaneous treatment with the specific H₂R antagonist ranitidi- ne and imitated by the H₂R agonist dimaprit, which is shown in Table 3. This means that the effect of histamine on the NK cell's response to IFN-α is H₂R-specific.

TABLE 3: Effects of Histamine and H₂R Agonist Dimaprit and H₂-Antagonist Ranitidine on NK Cells

NKCC (Cell Lysis %)±SEM After Treatment With

Treatment Control Ran IFN Ran + IFN Control O.l±O.l O.O±O.l O.l±O.l O.O±O.l Histamine 9.4±0.3 1.5±0.3 31.7±0.3 1.6±0.2 Dimaprit 6.4±1 0.4±0.4 32.6±1 0.5±0.5

In the experiment shown in Table 3, culture medium (control), histamine ( 10^"4 M), dimaprit ( 10^"4 M), ranitidine (ran) ( 10^"4 M) and/or IFN-α (25 U/ml) were added at the start of a 6-hour ⁵¹Cr- release assay using Daudi target cells. The data are representa¬ tive of three similar experiments. NKCC is given as mean cell lysis %+SEM of six determinations. The effector cells were recovered from a low-density Percoll fraction 8, containing around 40% monocytes.

Serotonin acted synergistically with IFN-α and had an effect corresponding to that of histamine. Ranitidine (10^~4 M) did not alter the effect of serotonin. The specific synthetic 5-HT_1A- receptor (5-HT_1AR) agonists 8-OH-DPAT and (+) - ALK-3, which lack activity for 5-HT₁₈R, 5-HT₁₀R, 5-HT₂R or 5-HT₃R, intensified the baseline NKCC and restored the NK cell's response to IFN-α with a potency and effect comparable to that of serotonin. This is shown by Table 4. Ketanserin and ondansetron, which are antagon¬ ists of 5-HT₂R and 5-HT₃R, respectively, did not influence the effect of serotonin in equimolar concentrations.

TABLE 4. The Effect of Serotonin and 5-HT^R Agonists on NK Cells

NKCC After Treatment With

Treatment Medium IFN

Medium l.l±l 0.5±0.3

Serotonin 10^"4 M 10.4±1 44.3±1 Serotonin 10^"5 M 4.5±0.3 33.2±1

Serotonin 10^" M 2.2±0.4 12.3±1

8-OH-DPAT 10^"4 M 8.8±1 43.3±1

(+) -ALK-3 10 —4 M 9.1±1 40.4±1 In the experiment shown in Table 4, culture medium (control), serotonin, 8-OH-DPAT (+)-ALK-3 and/or IFN-α (25 U/ml) were added at the start of a 6-hour ⁵¹Cr-release assay against Daudi target cells. The NKCC is given as cell lysis %±SEM of six determina¬ tions. The effector cells were recovered from the low-density Percoll fraction 7, containing around 36% monocytes.

Similar experiments were then performed using freshly recovered human tumor cells as target cells, rather that the cultured tumor cell lines used as target cells in the experiments described above.

MNC were obtained from peripheral venous blood by Ficoll-Hypaque centrifuging and the mononuclear cells were separated into monocytes and NK-cell-enriched lymphocytes (Hellstrand et al., J. Interferon Res. , 12, 199-2061992). Seventy thousand NK-cell- enriched lymphocytes were mixed with 70,000 monocytes and 20,000 ⁵¹Cr-labeled leukemic target cells (97% pure acute myelogenous leukemic cells) in a total volume of 150μl. The cells were treated with culture medium (control) or histamine dihydro- chloride at a final concentration of 10^"4 M, during a 16 hour ⁵¹Cr-release assay to determine killed target cells.

The results are shown in Figure 2. The data are the mean percent cell lysis of six determinations ±SEM. The recorded cytotoxicity was completely depleted after removal of NK-cells using Dynabeads coated with anti-CD56, but not by removal of T-cells using beads coated with anti-CD3 (using the method described by Hellstrand et al., Scand. J. Immunol., 37:7-18 (1993). As seen in Figure 2, treatment with interferon alone does not induce killing of leukemic target cells unless histamine is present. In addition, it has been shown that the cytotoxic effects obtained with histamine and interferon-α are seen not only in cultured tumor cells, but in freshly recovered human leukemic cells as well. Thus, in conclusion, it can be affirmed that the above-described in vitro experiments demonstrate that the biogenic amines hista¬ mine, through H₂-type receptors, and serotonin, through 5-HT_1A- type receptors, abolish the monocyte-induced suppression of resting and IFN-α activated NK cells. Treatment with IFN-α and compounds with H₂ or HT_1A receptor agonist activity thus produces a synergistic activation of NK cells, which can be used in connection with tumor treatment or treatment of virus infections.

Claims (20)

1. Pharmaceutical preparation or system for activation of natural killer cells (NK cells), for example in order to treat tumors or virus infections, characterized in that a first compo¬ sition containing interferon-α or analogues thereof along with another composition containing at least one biogenic amine with H₂ or 5-HT_1A receptor agonist activity or another substance with corresponding receptor activity, whereby said first and second compositions are either mixed in a preparation or furnished in separate doses in a quantity sufficient for the intended treat¬ ment.

2. Pharmaceutical preparation or system according to claim 1, c h a r a c t e r i z e d t h e r e i n , that the daily dose of interferon-α is between 1000 and 300,000 U/kg, preferebly between 3000 and 100,000 U/kg and best of all between 10,000 and 50,000 U/kg.

3. Pharmaceutical preparation or system according to claim 1 or 2, c h a r a c t e r i z e d t h e r e i n , that the daily dose of the biogenic amines is between 0.1 and 10 mg, preferably between 0.5 and 8 mg and best of all between 1 and 5 mg, whereas doses which produce an equivalent pharmacological effect are used for other substances with corresponding receptor activity.

4. Pharmaceutical preparation or system according to one or more of the foregoing claims, c h a r a c t e r i z e d t h e r e i n, that the compounds are selected from the group consisting of histamine, serotonin, dimaprit, clonidine, tolazoline, impro¬ madine, 4-methylhistamine, betazole, histamine congener deriva- ives such as

CH₃ Q CH₃ O

(CH₂)₅-CH₃ CH-(CH₂)₃-C-NH ■•-Q- CH₃ CH-( CH₂ )₄-C-NH -Q- CF₃ 8-OH-DPAT, ALK-3, BMY 7378, NAN 190, lisuride, d-LSD, flesoxinan, DHE, MDL 72832, 5-CT, DP-5-CT, ipsapirone, WB 4101, ergotamine, buspirone, metergoline, spiroxatrine, PAPP, SDZ (-) 21009, and butotenine.

5. Pharmaceutical preparation or system according to one or more of the foregoing claims, c h a r a c t e r i z e d t h e r e i n , that it contains one or more pharmaceutically acceptable carrier, such as a solvent, dispersant, coating, antimicrobial agent, isotonic or absorption-retarding agent or the like.

6. Application of a first composition containing interferon-α or analogues thereof, together with a second composition contai- ning at least one biogenic amine with H₂, or 5-HT_1A receptor agonist activity or another substance with corresponding receptor activity, for production of a pharmaceutical preparation or system for activation of natural killer cells (NK cells), for example, in order to treat tumors or virus infections, whereby said first and second compositions are either mixed in a prep¬ aration or furnished in separate doses in a quantity sufficient for the intended treatment.

7. Application according to claim 6, c h a r a c t e r i z e d t h e r e i n, that the daily dose of interferon-α is between 1000 and 300,000 U/kg, preferably between 3000 and 100,000 U/kg and best of all between 10,000 and 50,000 U/kg.

8. Application according to claim 6 or 7, c h a r a c t e r i z e d t h e r e i n , that the daily dose of the biogenic amines with H₂ or 5-HT_1A receptor agonist activity is between 0.1 and 10 mg, preferably between 0.5 and 8 mg and best of all between 1 and 5 mg, whereas doses which produce an aquivalent pharmacological effect are used for other substances with corresponding receptor activity.

9. Application according to one or more of claims 6-8, c h a r a c t e r i z e d t h e r e i n , that the compounds with H₂ or 5-HT_1A receptor agonist acitivity are selected from the group consisting of histamine, serotonin, dimaprit, clonidine, tolazoline, impromadine, 4-methylhistamine, betazole, histamine congener derivatives such as

C CHH₃₃ OO C CHH,, I ³

(CH₂),-CH₃ CCHH--((CCHH₂₂))₃₃--CC--NNHH O-Q"- CCHH₃₃ C CHH--((CCHH₂₂)) ₄₄--δC--NNHH -- - CF₃

8-OH-DPAT, ALK-3, BMY 7378, NAN 190, lisuride, d-LSD, flesoxinan, DHE, MDL 72832, 5-CT, DP-5-CT, ipsapirone, WB 4101, ergotamine, buspirone, metergoline, spiroxatrine, PAPP, SDZ (-) 21009, and butotenine.

10. Application according to one or more of claims 6-9, c h a r a c t e r i z e d t h e r e i n , that the preparation or system contains one or more pharmaceuti- cally acceptable carrier, such as a solvent, dispersant, coating, antimicrobial agent, isotonic or absorption-retarding agent or the like.

11. A method for the activation of natural killer cells (NK cells) comprising: administering a first composition containing interferon-α and administering a second composition containing at least one biogenic amine having affinity and agonist activity for histamine H₂ - or serotonin 5-HT_1A-receptors or a compound having affinity and agonist activity for histamine H₂ or serotonin 5-HT_1A recep¬ tors.

12. The method of claim 11, wherein said administering steps are performed in vitro.

13. The method of claim 11, where in said administering steps are performed in vivo.

14. The method of claim 11, wherein said first and second compo¬ sitions are administered together.

15. The method of claim 11, wherein said first and second compo- sitions are administered separately.

16. The method of claim 11, wherein said compound is selected from the group consisting of serotonin, histamine, dimaprit, clonidine, tolazoline, impromadine, 4-methylhistamine, betazole, histamine congener derivatives such as

CH, CH,

(CH₂)₅-CH₃ CH-(CH₂)₃ X-C-NH -Q- CH₃ CH-(CH₂)₄-C-NH -Q- CF₃

8-OH-DPAT, ALK-3, BMY 7378, NAN 190, lisuride, d-LSD, flesoxinan, DHE, MDL 72832, 5-CT, DP-5-CT, ipsapirone, WB 4101, ergotamine, buspirone, metergoline, spiroxatrine, PAPP, SDZ (-) 21009, and butotenine.

17. The method of Patent Claim 11, wherein said interferon-α is administered in a daily dose of between 1000 and 300,000 U/kg.

18. The method of Patent Claim 11, wherein said compound is administered in a daily dose of between 0.1 and 10 mg.

19. Use of interferon-α in preparation of a medicament for treatment of viral or neoplastic disease by coadministration with an H₂ receptor agonist or a 5-HT_1A receptor agonist.

20. Use of an H₂ receptor agonist or a 5-HT_1A receptor agonist in the preparation of a medicament for treatment of viral or neo¬ plastic disease by coadministration with interferon-α.