Monoclonal antibodies against etiological agents of
Weil's disease were produced by cell fusion technology. Twenty hybridomas were produced through the fusion of P3X63Ag8 .653 cells with spleen cells from BALB/c mice immunized against Leptospira interrogans serovar icterohaemorrhagiae RGA strain and serovar copenhageni Shiromizu and M20 strains. Reactivities of the
antibodies produced by the hybridomas were determined by the microscopic agglutination test. Among the five hybridoma
antibodies to the RGA strain, two reacted specifically to serovar icterohaemorrhagiae, two reacted to serovar icterohaemorrhagiae at a high titer and serovar copenhageni at a low titer, and one reacted to serovars icterohaemorrhagiae, copenhageni,
pyrogens, and canicola. Of the ten hybridoma
antibodies to the Shiromizu strain, one reacted specifically to serovar copenhageni, seven reacted to both serovars copenhageni and icterohaemorrhagiae at almost the same titer, and two exhibited intermediate properties. Of the five hybridoma
antibodies to the M20 strain, three reacted to both serovars copenhageni and icterohaemorrhagiae at almost the same titer, one reacted to serovar copenhageni at a low titer and serovar icterohaemorrhagiae at a high titer, and one reacted to serovars copenhageni, icterohaemorrhagiae, and
pyrogens. The results revealed that each serovar has its own
antigen(s) and their common
antigens. In addition, 20 strains of leptospires were recently isolated and tested with three
monoclonal antibodies characterized by different reactivities. Twenty strains were clearly identified by their
antibodies, i.e., 16 strains were identified as serovar icterohaemorrhagiae and three strains were identified as serovar copenhageni. The remaining strain, which was not agglutinated by three
antibodies, was identified as serovar autumnalis by an agglutination test with immune rabbit sera.