[Study of Salmonella cultures. IV. Immunogenicity of Salmonella resistant to antibiotics].

Three avirulent and 5 slightly virulent for birds mutants of Salmonella enteritidis and Salmonella braenderup, resistant to streptomycin (S), chlorteracyclin (CT), and chloramphenicol (Ch) were used in the production of live vaccines. The latter were tested for immunogenicity on albino mice and birds. On the eighth and 15th day following vaccination the protein fractions in the blood serum of the birds were followed up through electrophoresis on agar gel, while the agglutinin titer was determined by means of test tube agglutination. The experimental results were mathematically processed with the use of statistical methods. All slightly virulent and resistant to antibiotics mutants showed strong immunogenic properties and gave protection (preventing death) to 76.2-81.82 per cent of the mice. Of the avirulent mutants one showed moderate virulence giving protection to 71.43 per cent of the animals. Tested on 110-day-old chickens the avirulent mutants gave protection to 80 per cent of them. The average titers of the blood serum antibodies of birds vaccinated with immunogenic mutants, and the average percent values of the gamma-globulin fractions were higher on the eighth than on the 15th day. The protein fractions showed changes in the albumin and the gamma-globulin. The rate of correlation between these indices, as shown by the coefficient of correlation, is high (rxy = - 0.843). In this case the negative value of rxy in the equation points to the negative link between the characters.