A subset of splenic macrophages process and present native antigen to naive antigen-specific CD4+ T-cells from mice transgenic for an alpha beta T-cell receptor.

The progeny of individual macrophage precursors from mouse spleen were examined for their ability to constitutively process and present native pigeon cytochrome c or a peptide fragment of this antigen to naive CD4+ T-cells from mice transgenic for a V alpha 11/V beta 3 TCR that recognizes an epitope in the antigen fragment. The results show that constitutive Ag processing and presentation is a stable characteristic restricted to the progeny of approximately 20% of splenic macrophage precursors. This property does not appear to be randomly acquired, but to reflect the ability of certain macrophages to produce IL-12.