Wound macrophages express MHC Class I and II, express costimulatory molecules, and induce antigen‐specific T cell proliferation

This study further investigated the phenotype of wound macrophages, specifically focusing on the capacity of wound macrophages to present antigen. Studies were conducted in the polyvinyl alcohol (PVA) sponge wound model in mice. Wound cell suspensions were obtained 7 days after PVA sponge insertion, stained, and evaluated by flow cytometry. Wound macrophages expressed MHC Class I and Class II antigens and the costimulatory molecules CD80 and CD86. Day 7 wound macrophages from C57BL/6 mice were isolated by negative selection using magnetic beads, and exposed to antigen (ovalbumin peptides 257–264 or 323–339). After removal of unbound antigen by washing, the macrophages were cocultured with splenic T cells (T cell to macrophage ratio of 50:1). T cell proliferation was determined by incorporation of 3 H‐thymidine. Wound macrophages induced antigen specific proliferation of CD8 + T cells from OT‐I/Rag1 mice and CD4 + T cells from OT‐II.2a/Rag1 mice. Macrophages isolated 2 days after sponge insertion also induced antigen specific proliferation of splenocytes. Thus, wound macrophages should be considered capable antigen presenting cells. This research was supported by funds from the National Institutes of Health (GM79227, T35HL94308, T32GM65085, GM42859) and funds allocated to the Department of Surgery by Rhode Island Hospital, a Lifespan partner.