Investigation on monoclonal antibodies against two serovars of the icterohaemorrhagiae serogroup of Leptospira.

By means of the cell fusion technique, two hybridoma cell lines, V-1 and H2-1 have been obtained. V-1 cells secrete monoclonal antibody against serovars icterohaemorrhagiae and dakota. The H2-1 cell line secretes serovar-specific monoclonal antibody against serovar H2. These monoclonal antibodies have been successfully used in serovar-typing of leptospires isolated in China. The results of identification of leptospires by using monoclonal antibodies showed total coincidence with that by the traditional cross agglutinin absorption test and factor antiserum method. It was confirmed by using monoclonal antibody that the serological agglutination totally paralleled with animal protection. On the basis of the study, a concept was proposed that the agglutination in vitro and the protection in vivo are different manifestations in different reaction systems from the same antibody (antibodies) stimulated by a component(s) of the surface antigen of leptospires.