[A two-step method of purifying the surface antigen of the hepatitis B virus and its use in the passive hemagglutination reaction for indicating antibodies to the surface antigen of the hepatitis B virus].

A simple and economic scheme for the purification of HBsAg has been developed: step I--immunosorption with the use of a cellulose suspension with immobilized purified anti-HBs, and step II--isopycnic ultracentrifugation through CsCl. This method yields a 300-fold purified HBsAg, its harvest being 75%. An erythrocytic immunodiagnosticum for the passive hemagglutination test has been prepared on the basis of this purified HBsAg; the sensitivity of the test with this immunodiagnosticum is but slightly inferior to that of radioimmunoassay.

[Cross reactivity of cytotoxic T-lymphocyte immune receptors immune to antigens of the H-2 complex studied by lymphocyte fractionation on target cell monolayers].

In vivo induced d anti-b spleen cytotoxic T-lymphocytes (CTL) display the cross lysis of H-2f and T-2a target cells (TC) which is about 4 to 6 per cent of the H-2b TC lysis as judged by comparison of CTL doses required for the same lysis. d anti-b CTL fractions cross-reacting (CR) to H-2f and H-2a TC are not identical and can be separated one from another by a selective adherence to the corresponding TC monolayer. The preliminary CTL absorption onto the syngeneic TC monolayer and the 3-step elution of the adherent CTL by pronase in two concentrations and EDTA gave rise to the optimizations of the CTL enrichment conditions and to the fractionation of CTL on the basis of stability of their contact with monolayer cells.