FOLLICULAR DENDRITIC CELLS RETAIN HIV-1 PARTICLES ON THEIR PLASMA-MEMBRANE, BUT ARE NOT PRODUCTIVELY INFECTED IN ASYMPTOMATIC PATIENTS WITHFOLLICULAR HYPERPLASIA

During HIV-1 infection, extensive alterations can be observed in the g erminal centers (GCs) of lymphatic tissue. The initial hyperplasia of GCs is followed by disintegration and involution of these structures. The process is accompanied by progressive destruction of the network o f follicular dendritic cells (FDCs). We investigated whether or not th e destruction of GCs is caused by HIV-1 infection of FDCs in vivo. FDC s were purified by FACS or magnetic cell sorter (MACS) from enlarged l ymph nodes (LNs) of four asymptomatic HIV-1-infected patients with per sistent generalized lymphadenopathy. In situ hybridization demonstrate d positive signals for HIV-1 RNA on the cell membrane of FDCs. Virus p articles attached to the dendritic network could be demonstrated by el ectron microscopy, but budding was not seen. Furthermore, proviral DNA was detected by nested PCR (NPCR) in limiting dilution assays of FACS -purified FDCs (up to 1.0 X 10(4) cells) in only one cell fraction. In comparison, proviral DNA could be found in 5.0 x 10(3) to 2.5 x 10(5) FACS-purified Th cells obtained from peripheral blood and in 7.5 x 10 (2) to 2.5 X 10(4) Th cells from LN of the same patients. In conclusio n, FDCs retain HIV-1 particles on their cell membrane during HIV-1 inf ection, but the progressive destruction of FDC in vivo is probably not caused by a productive infection of FDCs with HIV-1.