Internalization and replication of Mycobacterium tuberculosis and M. avium complex within type II alveolar epithelial cell line

Abstract

Profiles of internalization and replication of Mycobacterium tuberculosis (MTB) or M. avium complex (MAC) within A-549 human type II alveolar epithelial cell line (A-549 cells) were studied and the results were compared with the mode of internalizing and proliferative behaviors of the organisms within murine peritoneal macrophages (M phi s) and various M phi-like cell lines (murine J774A. 1, human THP-1, and human MONO-MAC-6). First, MTB and MAC internalized not only in peritoneal M phi s and M phi-like cell lines but also in A-549 cells. Secondly, MTB and MAC replicated within A-549 cells and these organisms displayed much more vigorous intracellular multiplication in A-549 cells than in murine peritoneal M phi s and J774A. 1 M phi-like cell line. Human M phi-like cell lines (THP-1, MONO-MAC-6) allowed the growth of MTB and MAC equally or occasionally more rapidly, as compared to the case of A-549 cells.