Modulation of HIV transcription in and release from human monocytic cells following phagocytosis of Mycobacterium tuberculosis.

The consequence of phagocytosis of Mycobacterium tuberculosis by human monocytic cells on transcription and release of human immunodeficiency virus (HIV) is unknown. In order to investigate the effects of phagocytosis of M. tuberculosis on HIV transcription, human monocytic THP-1 cells were transfected with constructs of the long terminal repeat of HIV1 or 2 linked to the chloramphenicol acetyl transferase gene (HIV LTR CAT). Following phagocytosis of M. tuberculosis by THP-1 cells maintained in non-adherent conditions, there was enhanced transcription of HIV LTR CAT. This enhancement was further potentiated when such THP-1 cells adhered to tissue culture plastic. Phagocytosis of M. tuberculosis by HIV-infected THP-1 cells in non-adherent conditions had no effect on intact HIV release. However in adherent conditions, phagocytosis of M. tuberculosis reduced release of intact virus even in the face of enhanced HIV transcription. Phagocytosis of M. tuberculosis by THP-1 cells affects HIV replication at both the transcriptional level (upregulates) and the level of viral release (down-regulates) and is modified by cellular adhesion.