Six macaques, apparently uninfected, following low-dose exposure to the pathogenic SIV(mac251) and SIV(SME650) by the mucosal route, were used in a pilot study to investigate whether infectability of ex viva lymph nodes could predict resistance and/or susceptibility to SIV infection in viva. Of six macaques exposed to the less-pathogenic virus SIV(MNE), four resisted viral infection, Analysis of the susceptibility of the PBMC of these four animals before SIV(MNE) challenge indicated that all of them were resistant to infection by the SIV(BK28) isolate and, in three of them, this resistance was dependent on CD8+ T cells. Blocks of lymph nodes of these four macaques were resistant to SIV(MNE) infection ex vivo following SIV(MNE) viral challenge exposure, However, the same blocks from the same animals were permissive to the more virulent SIV251(32H). Accordingly, three of these macaques were readily infected following challenge exposure with SIV251(32H). Lymphoproliferative responses in blood or lymph nodes, local C-C chemokine production in the lymph-node explants, and cytotoxic T-cell activity measured throughout the study did not correlate with ex viva resistance or susceptibility to in viva infection. In conclusion, PBMC and lymph-node resistance or susceptibility to infection ex viva appeared to correlate with in viva infectivity and, thus, these approaches should be further tested for their predictive value for in viva infection. (C) 2000 Academic Press.
ASJC Scopus subject areas
- Infectious Diseases