Leptospires colonial variations.

Six of 12 relatively freshly isolated and museum strains representing serovars mozdok, monjakov, kazakhstanica I and patoc were heterogeneous in colonia morphology. Recloned colonial variants of one and the same heterogeneous population did not exhibit any differences in antigenic properties in cross reactions of microagglutination and absorption of agglutinins. Along with it among the clones with various colonial types of the two relatively freshly isolated strains of serovar mozdok distinctions in virulence (LD50) for hamsters were marked. Moreover for the clones one of them differences in the level of renal infection (ID50) and in morphology of the cells (hooked and straight) were found. In a solid Tween-80 albumin medium in populations of two colonial variants (serovars monjakov and kazakhstanica I) colonial mutants appeared without any changes in antigenic properties, virulence and cell morphology with frequency of 10-9-10-8 per one bacterium per one generation.

Potential variability of Leptospira serovars belonging to the same group.

3 clone strains of monjakov and pomona serovars were cultured with prolongation in a medium containing homologous immune sera. Separate subcultures were cloned in a solid medium, while isolated clones were typed in microagglutination test with whole and absorbed immune sera and in some cases in an absorption test. The results showed that the mutants of subcultures with the minimal and maximal time of contact with the immune serum turned out to differ greatly from each other in antigenic properties. While antigenic mutants of earlier subcultures were constantly connected with serovars of Pomona serogroup, mutants of subcultures adapted to immune serum were serologically more related to butembo serovar of Cynoptery serogroup. The results obtained showing potential variability of serovars belonging to Pomona serogroup could be significant from the viewpoint of classification and phylogeny of Leptospira.

The dynamics of IgM- and IgG-antibodies in leptospiral infection in man.

The dynamics of specific agglutinating antibodies belonging to different classes of immunoglobulins in 1047 blood sera of 669 patients and persons who had recovered from leptospirosis was studied. 19S and 7S antibodies were found in sera of patients with simultaneous presence of Pomona and Grippotyphosa. The character of syntesis of specific leptospiral IgM and IgG antibodies correlated, but the concentration of the IgG was much lower. As a rule, IgM antibodies had a wide range of cross-reactions with leptospires of heterologous serogroups. However, IgG-antibodies in 85% of cases reacted with homologous leptospires only.

Formation of antibodies and immunoglobulins of various classes in persons vaccinated with warm antileptospirosis polyvalent vaccine.

The results of the observations of 2 groups of 372 persons during 10 months showed that a twofold inoculation of corpuscular heated 6-valent antileptospiral vaccine ensures the formation of 19S-antibodies. The ratio 19S/7S antibodies was determined by inactivation of IgM agglutinins with the help of 2-mercaptoethanol. Quantitative content of immunolglobulins (G, A and M) was determined in parallel with the reaction of agglutination by the method of simple radial diffusion. Immunoglobulins of the class M in the serum of vaccinated persons increased as compared with control, whereas the content of IgG did not rise and that of IgA decreased.

Dependence of pathogenic properties of leptospires on animal subspecies.

1. Leptospires of mozdok serotype of the Pomona serogroup possessed specific pathogenic properties for a definite subspecies of Apodemus agrarius. They caused carriership in rodents of a European population, but were unable to cause such a process in Far East mice. However, leptospires of monjakov and pomona types were also unable to provoke leptospiruria in these small mammals. 2. The intensity of the formation of antibody to leptospires in different subspecies of Apodemus agrarius was dependent on the degree of their susceptibility, determined by the presence of renal leptospirosis. Leptospira-carriers among animals reacted by antibody formation 6-40 times more intensive than in those not susceptible to the infection. 3. Leptospires of pomona, monjakov and mozdok serotypes of the Pomona group taxonomically can be designated as separate subspecies, on the basis of differences in biological properties as related to their natural animal reservoirs.