EN
White rats (10) were infected with RH Toxoplasma gondii strain administering a Toxoplasma suspension on 7 occasions at 3-day intervals (2 ml of the peritoneal exudate from infected mice, at the dilution of 1:10). The obtained rat sera gave a positive reaction in the complement fixation test with Toxoplasma antigen (1:10-1:160). The electroproteinograms of immune sera (paper electrophoresis, staining according to Grassman-Hannig, photodensitometric measurements) were found to contain albumins and globulins α₁ and α₂, β, γ; as compared with the sera from non-infected rats there were hyperproteinemia and increase in β- and γ- globulins. The inactivation of sera at 56° did not affect the electroproteinogram pattern. Similar results were obtained by electrophoresis of immune sera on gel agar, with the difference that the γ-globulin fraction was extended to γ₁ and γ₂ subfractions. Immunoelectrophoresis (according to Grabar-Williams' and Scheideger's methods) of immune sera, as compared with those of non-infected rat sera, showed more conspicuous precipitation lines in the zones α₂, β and γ as well as a more clear-cut line corresponding to β₂M subfraction. The inactivated sera: gave a smaller number of precipitation lines. Preliminary studies by microdiffusion and agar gel techniques revealed the presence of 5 precipitation lines in the immune sera and only 3 lines in the normal ones. The inactivation of sera diminished the number of precipitation lines to 2 in immune sera, and to 1 in those of non-infected rats. Quantitative determinations of the fractions are under way.