Identification of a CD8alpha(+) dendritic cell subpopulation in rat spleen and evaluation of its OX-62 expression

Rat spleen DC and bone marrow-derived DC were isolated and characterized by morphology and flow cytometry. We found a CD8alpha(+) DC subpopulation representing 19-48% (27.4 +/- 12.0) of total spleen DC. The OX-62 expression on total spleen DC was 41-59% (51.8 +/- 7.5). Myeloid bone marrow-derived DC were negative for CD8alpha and OX-62. We demonstrated the coexpression of CD8alpha and OX-62 molecules, at least in a portion CD8alpha(+) spleen DC. Both CD8alpha(+) and CD8alpha(-) spleen DC subpopulations separated by MACS were able to induce an in vivo primary immune response to OVA. The immune response induced by the CD8alpha(-) DC subpopulation was higher (P < 0.05). We identified a CD8alpha(+) DC subpopulation in rat spleen less effective in inducing an immune response than CD8alpha(-) DC. Moreover, our results suggest the presence of DC subpopulations with different lineages in DC preparations based on OX-62 expression.