Transformation of antibody from IgM to IgG in experimental syphylitic rabbits. I. Syphylitic serum reaction

Localization of IgM and IgG sypylitic antibodies in the sera of patients and the experimental syphylitic rabbits was examined by the gel filtration on Sephadex G.200 column. I) In the case of late syphylitic patients; OGATA test-reactive antibodies were contained in IgM and IgG fractions. On the other hand, RPCF test-reactive antibody was contained only in IgG fraction. This discrepancy may be due to the difference in antigens; Cardiolipin.resicin and T. P. Reiter protein. 2) In the case of the experimental syphylitic rabbits; The results were as follows. a) Variation in the level of the titer. The peaks of the titer were seen 3-4 weeks after inoculation of T. P. Nichols by OGATA test, VDRL test and RPCF test, thereafter titers decreased. On the other hand, the titer kept on rising up to 2 months and maintained high level during the periods of 3, 4 and 5 months by TPHA test. b)Transformation of antibody from IgM to IgG. Transformation of antibody from IgM to IgG was seen 3-4 weeks after inoculation by all four tests; OGATA test, VDRL test, RPCF test and TPHA test, and such a transformation was completed 3 months after inoculation.