IDENTIFICATION AND COMPARISON OF MACROPHAGE-INDUCED PROTEINS AND PROTEINS INDUCED UNDER VARIOUS STRESS CONDITIONS IN BRUCELLA-ABORTUS

Brucella abortus is a facultative intracellular pathogen of cattle and humans that is capable of survival inside macrophages. In order to un derstand how B. abortus copes with the conditions during intracellular growth in macrophages, the protein synthesis pattern of the bacteria growth inside bovine macrophages has been compared with that of bacter ia grown in the cell culture medium by two-dimensional polyacrylamide gel electrophoresis. Approximately 24 new proteins that are not detect ed in the bacteria grown in the cell culture medium have been induced during intracellular growth in macrophages. In contrast, approximately 50 proteins that were expressed during growth in cell culture medium were completely repressed during intracellular growth. The level of ex pression of 19 proteins increases while that of 54 proteins decreases during intracellular growth. To understand these results, the protein synthesis pattern of B. abortus during intracellular growth was compar ed with those during other stress conditions. Under each stress condit ion studied, several new proteins were induced that were not present d uring regular growth conditions. Comparison of the protein synthesis p attern of B. abortus during intracellular growth with those obtained u nder various stress conditions has indicated that the response to intr acellular growth was not just a simple sum of stress conditions studie d so far.