[Isolation of surface antigen of hepatites B virus].

The scheme of immunoaffinity isolation of surface antigen of hepatitis B virus is developed. Selection of monoclonal antibodies was carried out and conditions for synthesis of immunoaffinity matrix were optimized; specificity of binding of HBs-antigen with a sorbent is improved; conditions of washing of columns and elution of HBs-antigen are chosen. The yield of purified HBs-antigen obtained according to the developed scheme exceeded 90% and it allows to use such HBsAg for immunization of animals and application in immunoanalysis.

[Oligodeoxyribonucleotides complementary to sections of the mollicute ribosomal operon as transcription inhibitors in vitro]. / Oligodezoksiribonukleotidy, komplementarnye uchastkam ribosomal'nogo operona mollikutov, kak ingibitory transkriptsii in vitro.

Antisense oligodeoxyribonucleotides have been studied for their effect on the transcription in vitro in mollicutes. A synthetic fragment of DNA [symbol: see text] complementary to that part of DNA which codes the 1510-1521 area of the 3'-terminal sequence 16S-pRNA of all mollicutes was used in the study as well as its modifications by imidasophenasine derivatives: [symbol: see text], [symbol: see text] [symbol: see text]. Maximal inhibition of the mollicute transcription in vitro was observed with 100 nM oligonucleotide concentration. Lower or higher concentrations were less effective. Transcription initiated by RNA-polymerase of M. fermentans PG-18 (a mollicute strain referring to AIDS disease) proved to be the most sensitive to the effect of modified oligonucleotide: it was inhibited by 75-80%. It is concluded that modified oligonucleotides exert a dual effect on transcription: firstly, they participate in nonspecific interaction with RNA-polymerase which induces insignificant inhibition of transcription and, secondly, they complementary interact with homologous sections of one-stranded DNA-matrix and block the RNA synthesis. Binding of modified oligonucleotides with DNA is rather strong.