The Distribution Of SIV/SHIV In SAIDS Rhesus Macaques Model

SIV is the pathogen of SAIDS (Simian acquired immune deficiency syndrome). SIV- rhesus macaque is widely used in HIV research and vaccine evaluation as animal model. Chinese-origin rhesus macaques have been used with increasing frequency in studies of the disease. Recent studies have shown that India and Chinese rhesus macaques exhibit genetic differences, therefore, the sensitivity, pathogenesis and viral locations in tissues from infected rhesus macaques with SIV or SHIV may be different.Virus localization is an important aspect in virology research. To investigate the localization and viral loads of SIVs in tissues from the SAIDS rhesus macaque when their plasma virus loads declined to the lowest level or nearly negative, 4 Rhesus macaques were inoculated with SIVmac251 and SHIV-KB9, respectively. Viral loads in plasma were measured at intervals of 3-5 days in the first month and the inguinal nodes were collected at day 14 post-infection (p.i.). Four macaques whose viral loads in plasma were kept at very low level or undetectable at 18 months p.i. were sacrificed and their tissue samples were collected. The presence of SIV in various tissues was determined and quantified by in suit hybridization and real-time quantitative PCR.According to the results, virus loads got peaks at about 14 days ( the highest 10~7copies/ml in plasma and 10~5-10~8copies/g in inguinal lymph nodes) and cells expressing SIV RNA were detected in inguinal lymph nodes. At 18 months p.i., very low virus load was detected in blood, but SIV was demonstrated distributed positively and even had high level in mesenteric lymph node, suprarenal gland, brain tissue, jejunum, spleen and testis. It is indicated that the SIV may be distributing in some tissues when the plasma virus load is nearly negative. These findings were very meaningful in SIV/SHIV/SAIDS macaques involved in screening and evaluation of therapeutic compounds and vaccines for HIV/AIDS.