Virus load and sequence variation in simian retrovirus type 2 infection

The natural history of type D simian retrovirus (SRV) infection is poorly c haracterized in terms of viral load, antibody status, and sequence variatio n. To investigate this, blood samples were taken from a small cohort of mos tly asymptomatic cynomolgus macaques (Macaca fascicularis), naturally infec ted with SRV type 2 (SRV-2), some of which were followed over an 8-month pe riod with blood taken every 2 months. Provirus and RNA virus loads were obt ained, the samples were screened for presence of antibodies to SRV 2 and ne utralizing antibody titers to SRV-2: were assayed. env sequences were align ed to determine intra- and intermonkey variation over time. Virus loads var ied greatly among cohort individuals but, conversely, remained steady for e ach macaque over the 8-month period, regardless of their initial levels, No significant sequence variation was found within an individual over time. N o clear picture emerged from these results, which indicate that the variabl es of SRV-2 infection are complex, differ from those for lentivirus infecti on, and are not distinctly related to disease outcome.