MULTIPLICATION OF BRUCELLA IN CULTURED LYMPHOID AND NONLYMPHOID CELLS.

Richardson, Marvis (Michigan State University, East Lansing), and Jane N. Holt. Multiplication of Brucella in cultured lymphoid and nonlymphoid cells. J. Bacteriol. 88:1163-1168. 1964.-Growth curves were established for the multiplication of Brucella abortus in cultured bovine cells. The number of viable brucellae was determined by colony count after lysis of the parasitized tissue cells. It was found that the number of brucellae dropped during the first 3 to 6 hr. This was followed by intracellular growth. Brucellae multiplied in uterine mucosal and fetal skin cells at an exponential rate with a 4-hr generation time. In contrast, only limited multiplication occurred in spleen cell cultures, usually approaching the stationary phase by 20 to 30 hr. Preliminary results indicated an average generation time of 8 hr in calf spleen cells. Differences were apparent in the ability of spleen cells from individual calves to support intracellular growth. This suggests that a relationship may exist between the establishment of intracellular pathogens in vitro and the natural resistance of the animal. By the use of fluorescein-labeled antisera, some insight was gained into the fate of brucellae in lymphoid cells. Fluorescent antisera stained intact brucellae and also revealed soluble antigen in the cytoplasm of reticularlike cells.