Immunity to syphilis. I. Passive transfer in rabbits with hyperimmune serum.

Passive transfer of humoral immunity to experimental syphilis in rabbits was accomplished with large doses of hyperimmune serum. When the serum was administered before inoculation of Treponema pallidum, the onset of chancres was delayed; when it was given early in the course of infection, a transient period of arrest and healing of the chancres was imposed.