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.