Accessory cell response to rye grass pollen extract in mice, guinea pigs and man

The ability of murine, guinea-pig and human accessory cells to function in antigen presentation has been assayed by a T-cell proliferative response to adherent cells pulsed with rye grass pollen extract. A population of phagocytic, esterase-positive, plastic-adherent splenocytes from non-immune Balb/c mice briefly incubated with solubilized rye antigen were capable of stimulating syngeneic T lymphocytes from immune mice in an antigen-specific manner. Accessory cell function was H-2 restricted and required Ia-positive cells. Treatment with a monoclonal anti-Ia antibody impaired proliferation, whereas the presence of polyclonal rabbit anti-rye antibody increased activity. Guinea-pig peritoneal and alveolar adherent cells pulsed with up to 1 mg/ml antigen increased the response of rye-immune lymph node T cells in vitro. Proliferation was dose-dependent, despite less than 0.1% of the available antigen being cell-associated, and could be inhibited by treating the accessory cells with trypsin, sodium iodoacetate and chloroquine. Adherent human peripheral blood cells treated with rye antigen supported the proliferation of non-adherent and nylon wool-enriched mononuclear cells obtained from both grass pollen-sensitive donors and from individuals lacking either detectable serum IgE antibody or a positive skin test to rye antigen.