Eosinophils function as antigen presenting cells
Objective To examine the capacity of HLA DR expressing eosinophils to serve as antigen presenting cells (APC) for presenting antigen tetanus toxoid to autologous T lymphocytes. Methods Freshly isolated eosinophils were cultured in vitro for 24 hours with granulocyte macrophage colony factor to induce HLA DR expression, and then exposed to different concentrations of tetanus toxoid. The capacity of HLA DR + eosinophils to function as APC was evaluated with the response of T cell proliferation induced by eosinophils. Results HLA DR +eosinophils stimulated T cell proliferation in the presence of tetanus toxoid in a dose dependent manner. It was also found that the T cell proliferation response elicited by eosinophils was inhibited by anti HLA DR monoclonal antibody. Conclusion Human eosinophils can uptake and process antigen and function as HLA DR dependent APC in stimulating T lymphocyte response.