Interactions Between Mononuclear Phagocytes and Brucella abortus Strains of Different Virulence.

Abstract

Studies on the in vitro interactions between S and R strains of Brucella abortus and monocytes from normal or immune guinea pigs have indicated: (1) intracellular multiplication of S bacteria and a lack of, or insignificant extent of, multiplication of R bacteria in normal monocytes; (2) differences in the rate of ingestion of S and R bacteria; (3) differences in the rate of destruction of monocytes by S and R types; (4) differences in the rate of intracellular multiplication among S strains; (5) a significant modification of these events in immune monocytes; and (6) an apparently unique behavior of immunogenic, relatively avirulent strain 19-S bacteria in normal monocytes. The relation of these observations to some problems of host-parasite interactions is discussed. It was also shown how these observations may provide the basis for a new technic of rapid assessment of the homogeneity or heterogeneity of bacterial populations in regard to properties associated with virulence.