Abstract
Monoclonal antibodies were produced by hybridoma cell lines derived by fusion of mouse NS-1 myeloma cells with splenocytes from mice immunized with Leptospira interrogansserovar pomona. One hybridoma (A3) produced an lgG2a antibody which agglutinated all leptospires of the Pomona serogroup but not leptospires representative of serovars of any other serogroup. The antibody precipitated in immunodiffusions with either alkali- or phenol-extracted lipopolysaccharide and also with theTM antigen of Yanagawa et al., indicating a common determinant on both antigens. A3 antibody opsonized viable leptospires for phagocytosis by mouse macrophages in vitro.