[DNA, RNA and protein synthesis in hepatitis A virus-infected cells].

Synthesis of DNA, RNA, and protein macromolecules was observed in cells infected with a strain of HA virus which had undergone 11 passages in the same culture. At 24-hour intervals the infected and uninfected cells were pulse-labeled with 1 microCi/cc 3H-thymidine, 3H-uridine, and 14C-valine. In 6-9 days after cell inoculation, inhibition of DNA, RNA, and protein synthesis was observed, being most marked in DNA synthesis.

[Clinical and immunological studies of an experimental series of vaccines against hepatitis B].

Two experimental lots of hepatitis B vaccine were prepared by purification of HBsAg from human plasma, inactivation at 100 degrees C for 2 min and at 37 degrees C for 72 hours with formalin in a concentration of 1:4000. The former lot comprises purified HBsAg (40 mg/ml) adsorbed with 0.32 mg % Al(OH)3, the latter consists of purified HBsAg stabilized with 0.

[Antibody formation in type A viral hepatitis].

Immune response to hepatitis type A antigen (HAAg) was measured by the passive hemagglutination test (PHA) and by the immune adherence test (IAHA). Specific antibodies found by PHA are of the IgM class which indicates a recent exposure to hepatitis A virus. The antibodies found by IAHA reflect the level of postinfectious immune status.

[Development of cellular immunity in patients with viral hepatitis].

The development of cell-mediated immunity (CMI) to the surface antigen of hepatitis B virus (HBSAg) and Botevgrad antigen (BA) was traced in 50 hepatitis patients. Migration inhibition test (MIT) was performed with purified HBSg and AB. Blood samples from every hepatitis patient were obtained at the beginning of the icteric phase, 10 days later and during convalescence.

[Serologic studies in viral hepatitis].

Comparative studies of sera from 710 patients with viral hepatitis and contacts were made during the 1958-1973 period for hepatitis antigens (Au antigen and the Botevgrad antigen). The percentage of virus hepatitis in patients positive for the Au and the Botevgrad antigens varied in different years. The percentage of those positive for the Au antigen ranged from 50 in 1958 to 8.