Abstract
Immunization with dead vaccine activates phagocytosis by RE cells. Increase of 0 antibody also plays a role in effective opsonizing. Marked effect is found especially when challenge is done at the same area of immunization. Usually, growth of intracellular bacteria and subsequent death of challenged mice is not inhibited after the immunization with dead vaccine. In the case of immunization with live vaccine, on the other hand, clearance of challenged bacteria seems to be rather weak, but intraceelluler growth of bacteria or re sultingsepsis is inhibited.
These cellular immunity is found only in some group of RE cells. In the case of subcutaneous challengeethe first infiltration and phagocytosis by polymorphnuclear cells never suppress the grow th of bacteria, and only after the appearance of largemonuclear cells, the course of infection is interrupted. Principal participants in cellular immunity with live vaccine are larger mononuclear cells and are not polymorphnuclear cells.
