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Target screening among microbial products resulted in isolation of hypolipidemic compounds tested for activity against HIV in culture of transferable lymphoblastoid cells MT-4. The majority of the compounds showed antiviral activity. The highest antiviral effect was observed when before exposure to the virus the cells were preincubated for 1 hour in the presence of the isolated compounds. The compounds showed no effect when added to the cell culture preliminarily infected by HIV.

Interferons obtained on induction of human lymphocytes with Newcastle viruses and staphylococcal enterotoxin A and diploid fibroblast cells of human embryos with poly (I).poly (C), as well as translation products of interferon mRNA obtained from these cells were analysed serologically. It was shown that the main type of interferon produced by the cells depended on the cell culture and inductor nature. It was defined at the level of the respective gene depression. Effective translation of mRNA of the interferons of the 3 types makes possible production of cDNA and creation of bacterial plasmids coding the genetic information for the synthesis of human interferon.

The results of using human interferon of types I (alpha- and beta-interferons) and II (gamma-interferon) in combination with chemotherapeutic drugs, such as remantadin and ribavirin for the study in human cell cultures are presented. Moderate doses of the drugs (25 microgram/ml) did not eliminate the interferon production. In higher doses (50 microgram/ml) they lowered the interferon production levels 2--3 times. In the presence of ribavirin the level of the interferon production lowering was higher. On the whole the effect of the drugs on production of interferons of types I and II was of a similar character despite the different means of interferon induction. The combined use of interferons of types I and II with the chemotherapeutic drugs in human embryo cultures infected with Semiliki forest virus (SFV) revealed an additive character of the antiviral effect in all combinations tested. The level of the antiviral activity of alpha-, beta- and gamma-interferons against the SFV was practically the same.

The specific activity of diagnostic preparations based on monoclonal IgM MAK-14-7 interacting with the antigens of the Venezuela equine encephalomyelitis virus, monoclonal IgG KAMA-51 interacting with the antigens of the forest spring encephalitis virus and monoclonal IgA OKA and IgM OKA binding to the antigens of the vaccine virus was studied by the enzymatic immunological and immunofluorescent tests. Both the ascitic preparations of the antibodies and the fluorescein isothiocyanate-conjugated reagents such as MAK-FITC, KAMA-FITC and OKA-FITC were characterized by high specificity and activity. The specific sensitivity and activity of the monoclonal immunoglobulins was completely maintained in the mixed and combined preparations.

Preparation of highly active rabbit antisera (AS) to human recombinant alpha 2-interferon and their use for studying biological properties of natural and plasmid alpha-interferons are described. By exhaustion of AS by alpha 3-interferon there were prepared practically monospecific AS not reacting with antigenic determinants of alpha 3-interferon. It was found that alpha 3-interferon represented a significant portion of human lymphoblastoid interferons and was included in PH-labile alpha-interferon from serum of patients with Kaposi carcinoma. AS to alpha 2-interferon completely neutralized antiviral and antiproliferative activity of the homologous subtype alpha-interferon and stimulation of cytotoxicity of human natural killer cells induced by it. It neutralized also the same effects of the heterologous subtypes (alpha 3 and alpha F/D) and leukocytic interferon, but the neutralization level was lower. The results of the study confirmed the polyfunctional nature of the interferon molecule.