AEGiS-11IAC: HIV-1 gene expression in members of the dendritic cell family depends upon their microenvironment.

11th International AIDS Conference

Vancouver, British Columbia — July 7-12, 1996

HIV-1 gene expression in members of the dendritic cell family depends upon their microenvironment.

Int Conf AIDS 1996 Jul 7-12; 11:23 (abstract no. LB.A.6009)
Tenner-Racz K, von Stemm A, Raschdorff B, Dietrich M, Racz P; Bernhard-Nocht-Institut fur Tropenmedizin, Hamburg, Germany. Fax: 49 60 31182309.

OBJECTIVE: DCs from peripheral blood support HIV-1 replication in vitro but data concerning the in vivo role of these cells as targets for HIV-1 are controversial and it was therefore our aim to evaluate whether or not members of the dendritic cell (DC) family are productively infected by HIV-1.

METHODS: Surgical specimens (25 lymph nodes with follicular hyperplasia, 52 skin, 3 benign lymphoepithelial cysts of the parotid gland consisting of intraparotid lymph node with follicular hyperplasia and cystic dilatation of the duct) were obtained from seropositive patients, fixed in fomalin and embedded in paraffin. Sections were immunostained (S-100 protein, HLA-DR, CD1a, CD83, CD68, CD3, CD8) and subjected to in situ hybridization with an (35)S-labeled antisense RNA probe of HIV-1.

RESULTS: Interdigitating cells (IDC) of the lymph nodes as well as Langerhans cells of the skin and of the squamous epithelium lining the benign lymphoepithelial cysts (BLC) did not express viral RNA. In contrast, parts of the epithelial lining of BLC which are identified as lymphoepithelium (LE) contained HIV-1 RNA+ cells. The majority of these cells were T lymphocytes but productively infected DC, including S-100+ multinucleated giant cells in one case, and macrophages were also present. In the lymphoid compartment of the BLC no productively infected DC or macrophages were found, not even in a case in which HIV-1 RNA positive cells were present not only in the germinal centre but also in the extrafollicular parenchyma. The number of CD8+ T cells were markedly elevated. The density of these cells were high in the extrafollicular parenchyma and relatively low in the LE and the germinal centres.

CONCLUSION: HIV-1 gene expression in DC depends upon the immunologic microenvironment of these cells. In situ DNA amplification is needed to determine whether they are latently infected and the different environments lead to induction or suppression of viral gene expression or they can only be infected in a surrounding that contains many infected cells. The distribution of CD8+ lymphocytes strongly suggest, that these cells regulate viral gene expression.

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LBA6009