Production and characterization of monoclonal antibodies to Tyzzer's organism 'Bacillus piliformis'

Two cell clones producing monoclonal antibodies (MAb) to the RT strain of Tyzzer's organism ('Bacillus piliformis'), of rat origin, were established by fusion of immunized BALB/c mouse splenocytes and NSl1 cells. Western blotting and immunofluorescence (IF) revealed that one of the MAb recognized an bacterial antigen having a molecular weight (M.W.) of 54, 000 and combined with the bacterial flagella, while the other recognized another antigen with M.W. of 73, 000 and combined with the bacterial cell surface but not with flagella. The former reacted also with antigens of mouse derived bacterial strain MSK of B. piliformis the latter did not. Both MAb were protective for the challenge infection with B. piliformis, reducing the number of necrotic foci in the liver of infected mice as well as that of cytopathic plaques on mouse hepatocyte culture.