The Agglutinating and Bactericidal Activity of IgM and IgG Antibodies to the 9 and 12 Factors of Salmonella Typhi O 901

[摘要] By the methods of absorption, elution and column chromatography separation, IgM and IgG antibodies to either one or both 9 and 12 O factors of S. typhi O 901 were isolated. On a molar basis IgM antibodies were always more active than IgG. IgM antibodies directed against the 12 antigenic sites were more active in both agglutination and complement-dependent bactericidal killing. Mixture of preparations containing antibodies to different specific sites of the bacterial cell wall did not react synergistically in bactericidal reactions. In all tests the different antibody preparations reacted more strongly with the homologous antigen than with the cross-reacting organisms. A prozone, i.e., a pronounced inhibition of the bactericidal activity, was elicited by both types of immunoglobulins at higher concentrations, and was attributed to antibodies specifically attached to either one or both antigenic sites.

[学科分类] 生物科学（综合）