Serologic Cross Reactions among Leptospirae Observed with Sera from Animals Infected with Leptospira Pomona

Sera from sheep, goats, pigs and guinea pigs infected with Leptospira pomona were examined for cross agglutination lysis reactions with Leptospira icterohaemorrhagiae AB, L. icterohaemorrhagiae A, Leptospira canicola, Leptospira sejroe and Leptospira hebdomadis antigens L. icterohaemorrhagiae AB, L. icterohaemorrhagiae A, and L. canicola antigens were consistently agglutinated by sera from infected sheep, goats and pigs. Guinea pig sera containing antibodies for either strain O or W did not agglutinate L. icterohaemorrhagiae AB, cells to an observable level but did react with L. icterohaemorrhagiae A, and L. canicola. Reactions for L. sejroe or L. hebdomadis were not regularly demonstrated with sera from L. pomona infected animals. Generally the levels of cross reactivity coincided with the persistence and fluctuations of homologous titers. The possible significance of differences in the degree of cross reaction observed with sera from several animal species and differences within a single animal species is pointed out. An anamnestic response was obtained in guinea pigs infected with L. pomona strain O but not strain W upon challenge with any of the three cross reactive serotypes. Serum adsorptions were conducted on one sheep serum and two pig sera.