Quantitative image analysis of simian immunodeficiency virus replication in macrophages coinfected with Mycobacterium avium complex.

Mycobacterium avium is the most frequent cause of disseminated bacterial infection in patients with human immunodeficiency virus type 1 infection and in rhesus macaques with simian immunodeficiency virus (SIV) infection. This animal model of AIDS was used to test the hypothesis that this frequent association is the result of reciprocal enhancement of replication of both microorganisms. The replication of M. avium and SIV was analyzed in lymphatic tissues obtained from rhesus macaques experimentally inoculated with SIVmac who developed or remained free of overt M. avium infection. In situ hybridization, quantitative image analysis, and staining of M. avium and of macrophages were used to assess the effects of coinfection on the replication of SIV and M. avium in vivo. There was no correlation between virus load and M. avium load in coinfected lymph nodes, and, with one exception, there was no evidence that M. avium coinfection of macrophages increased SIV replication.