The histology of local streptococcus immunity.

Abstract

The two most significant results of our studies over several years on localized streptococcus infections in the rabbit would seem to be, first: That, under properly controlled conditions, local infection is followed by a local form of immunity; 1 , 2 and second, that local protection in the pleural cavity, whether in a form of increased resistance (broth) or of specific active or passive immunity, is associated with an increase in the number of clasmatocytes or tissue macrophages there present. 2 , 3 A third study would associate clasmatocytes with the formation of antibodies. 4

Repeated attempts to simulate conditions in the body by the action of clasmatocyte exudates outside the body have been confusing. The transfer of the entire pleural exudate of a clasmatocyte type, from a broth-protected to a normal animal, transfers no protection. Exudates of both polymorphonuclear and clasmatocyte type do not in their entirety destroy even a minimal number of streptococci in the test tube, although it may be shown that the supernatant fluids of both exudates are bactericidal, and furthermore, that the acid cell extracts of both types of cell will destroy streptococcus. (Unpublished observations.) But these extracorporeal phenomena do not account for the occurrences in the animal body, since they are much slower in effect, and, since the polymorphonuclear exudate yields more highly bactericidal substances (owing to the greater number of cells present) than does the clasrnatocyte exudate. The former, however, as it occurs in the body, is associated with no protection of the animal.