Effect of mycobacterial infection on virus loads and disease progression in simian immunodeficiency virus-infected rhesus monkeys

The effect of a mycobacterial infection on AIDS disease was studied in the simian model. Monkeys were infected with the primary virulent isolate SIV/D eltaB670 and inoculated 90 days later with BCG, an attenuated strain of Myc obacterium bovis. All monkeys experienced a dramatic transient increase in plasma viremia and CCR5 expression on T lymphocytes after BCG inoculation. Only two of the four SIV+ animals had substantial proliferative responses t o PPD, with poor responders developing disseminated BCG during the course o f the experiment. BCG inoculation of SIV-infected long-term nonprogressor ( LTNP) monkeys was also performed. Similar to the acutely infected animals, two of three LTNPs experienced increases in plasma viral levels and CCR5 ex pression. In the majority of animals studied, there was no accelerated prog ression to AIDS despite the concomitant transient stimulation of virus repl ication and CCR5 expression on T lymphocytes.