Kinetics of primary SIV infection in lymph nodes

The very early stages of SIV infection in lymph nodes of rhesus monkeys were characterized by in situ hybridization. Massive viral replication was detected in macrophages and lymphocytes during the first week of infection. In a second phase, SIV RNA concentrated in the developing germinal centers, and colocalized with the follicular dendritic cells. The down-regulation of the viral load in lymph nodes varied depending on the animal, indicating early differences in the susceptibility to SIV infection.