Long-term follow-up study on SIV intestinal proviral load in rhesus macaques

After experimental infection with simian immunodeficiency virus (SIV), inte stinal endoscopy proved to be an easily tolerated, minimal invasive procedu re to obtain biopsies from the gastrointestinal tract of rhesus macaques du ring all stages of disease. As the GI tract is affected by many opportunist ic infections and immunological impairment after SIV/human immunodeficiency virus (HIV) infection, knowledge on the proviral load is an important para meter for a better understanding of disease pathogenesis. In this paper, we describe the set-up and evaluation of a quantitative competitive polymeras e chain reaction (PCR) and the quantification of SIV intestinal proviral lo ad in a long-term follow-up study of eight rhesus monkeys (Macaca mulatta) after two different routes of virus inoculation. A SIV-specific signal coul d be detected as early as day 3 after infection. Of 143 biopsies from the f ollow-up study, 85.3% showed a positive PCR. DNA copy numbers ranged from 3 00 to 15,000 molecules per 100,000 cells. No significant influence of the i noculation route could be shown on either proviral load or survival time, b ut higher SIV proviral load was associated with a more rapid progression to disease. Therefore, the amount of proviral load in intestinal biopsies may be an important prognostic value for the further course of the disease.