Studies of rabbit testes infected with Treponema pallidum. II Local synthesis of antibodies.

Samples of serum and testicular fluid from normal rabbits and those infected with Treponema pallidum were examined for total protein, albumin, IgG, and IgM concentrations. Total protein concentrations were similar in testicular fluid from normal and infected animals but were lower than in serum. The concentrations of individual proteins in serum did not differ substantially between infected and non-infected rabbits. In testicular fluid, however, the concentrations of all three proteins, especially IgM, were greater in infected rabbits. A significantly (p less than 0.02) raised testis-IgM index, together with a higher concentration of anti-treponemal IgM in the infected testicular fluid than in autologous serum, suggests local synthesis of IgM antibodies.