High levels of viral replication in lymph nodes during primary SIVagm infection contrasts with lack of morphological changes

We previously reported data on the dynamics of acute SIVagm infection in AG Ms showing remarkable similarities with viral replication patterns observed in peripheral blood during the first two weeks of pathogenic SIVmac infect ion. We therefore compared these early events occuring in peripheral blood of infected AGMs with those taking place in the lymph nodes of distinct ana tomical sites (cervical, axillary, inguinal and mesenteric lymph nodes). Th e lymph node RNA and DNA viral load patterns were similar to those in blood with peaks ranging from 5.10(4)-1.10(8) RNA copies/10(6)LNC and 10(3)-6.10 (4) DNA copies/10(6)LNC between day 7 and day 14 followed by rapid and sign ificant decreases as early as 21 days post-infection. The lymph node archit ecture and the FDC network was conserved during the course of infection, an d neither follicular hyperplasia nor CD8(+) cell infiltration into LN germi nal centers were detected in acute and chronic phases of infection.