[The experimental efficacy of vaccination with a recombinant yeast vaccine against hepatitis B in combination with immunomodulators].

Experiments in BALB/c mice were carried out to study a number of immunomodulators in combination with vaccination using a recombinant yeast hepatitis B vaccine. The use of poludan, ridostine, amixine, larifan, myekonide significantly enhanced specific antibody production and at least doubled cell-mediated immune response by 14 and 28 days postvaccination. The above-mentioned immunomodulators are planned to be used in vaccination with the recombinant yeast vaccine against hepatitis B.

[The detection of hepatitis B virus DNA in the blood serum of children with chronic HBsAg-positive hepatitis].

The presence of HBV DNA in the blood serum of 50 children with HBsAg-positive chronic hepatitis (36 with chronic hepatitis B, 14 with chronic hepatitis delta) was determined by molecular hybridization method. No significant differences were observed between the frequency of HBV DNA detection and clinicomorphological type of chronic HBsAg-positive hepatitis. In chronic HBV infection, HBV DNA was shown to be detected more frequently than in chronic hepatitis delta.

[Optimization of expression of hepatitis B surface antigen gene in yeasts].

A series of recombinant plasmids has been constructed for expression of the hepatitis B viral surface antigen gene (HBsAg) under the control of the regulatory elements of the yeast acidic phosphatase gene (PHO5). The obtained plasmids possess the high mitotic and structural stability in the transformant yeast cells. The effect of different structural modifications of the vector on the level of HBsAg synthesis in yeasts has been studied.

[Properties of the HBsAg gene expression product in yeast cells].

The Saccharomyces cerevisiae DBY 746/pNMVG-20 strain produces HBsAg similar in its properties to HBsAg from hepatitis B patients' plasma. The paper analyses variants of extraction of HBsAg from yeast cells, presents data on immunogenic potency of yeast HBsAg in mice, and describes gel filtration of yeast extracts containing HBsAg.