Survival of virulent and attenuated strains of Brucella abortus in normal and gamma interferon-activated murine peritoneal macrophages.

Virulent Brucella abortus 2308 was phagocytized more readily than attenuated strain 19 following opsonization and survived at significantly higher levels in normal murine peritoneal macrophages and in macrophages treated with gamma interferon. Activation of macrophages with gamma interferon greatly inhibited intracellular replication of strain 2308 but did not result in its elimination. These data support the hypothesis that persistent infection of the host requires the ability of antibody-opsonized B. abortus to survive in activated macrophages.