Antigen processing of vesicular stomatitis virus in situ. Interdigitating dendritic cells present viral antigens independent of marginal dendritic cells but fail to prime CD4(+) and CD8(+) T cells
Rp. Ciavarra et al., Antigen processing of vesicular stomatitis virus in situ. Interdigitating dendritic cells present viral antigens independent of marginal dendritic cells but fail to prime CD4(+) and CD8(+) T cells, IMMUNOLOGY, 101(4), 2000, pp. 512-520
Acute macrophage (M phi) depletion, using a liposome-mediated 'suicide tech
nique', markedly suppressed priming of splenic CD4(+) and CD8(+) T-cell res
ponses to vesicular stomatitis virus (VSV). However, phagocytic marginal de
ndritic cells (MDC), but not interdigitating dendritic cells (IDC), are now
known to be also depleted by this technique. To clarify the role splenic d
endritic cell(DC) subsets and M phi play in priming for a virus-specific T-
cell-mediated immune response, DC and M phi were purified from VSV-infected
mice and assayed for the presence of epitopes recognized by VSV helper T (
Th) cells and cytotoxic T lymphocytes (CTL). Antigen pulse experiments perf
ormed in situ demonstrated that VSV Th cell and CTL epitopes became transie
ntly associated only with DC, but not M phi or B cells, indicating that DC
represent the critical antigen-presenting cell (APC) population in vivo for
this virus. The failure of MDC/M phi -deficient mice to become primed was
not due to the complete elimination of antigen-presenting DC because VSV pe
ptide/class I and II complexes were detected on IDC following lipsome-media
ted elimination of phagocytic cells. However, the VSV-induced chemokine res
ponse was dramatically suppressed in these mice. Thus, despite the expressi
on of VSV peptide/class I and II complexes, IDC are not sufficient to prime
VSV Th cells in the absence of MDC and/or splenic M phi.