Maintenance of FRC and follicular dendritic cell (FDC) networks within LTs in chronically SIV infected sooty mangabeys (SMs) but not in RMs. (A) Immunohistochemical staining of the FDC network with antibodies to desmin (left panel) and the FDC network with antibodies to CD35 (right panel) in LNs from uninfected and chronically infected SMs and RMs, showing the intact FRC and FDC network in SMs during chronic infection compared with RMs. Original magnification ×200. (B) Quantitative image analysis of the percent area of the stromal cell networks, showing the preservation of both FDC and FRC networks in SMs but not in RMs. Bars represent the mean ± SEM.