FIG. 3.

T cells from OMP-19-immunized mice proliferated and produced IFN-γ in response to specific antigens. (a) T cells were purified by negative magnetic selection from spleens of C57BL/6 mice after 10 days following IOE OMP-19 immunization. Cells were cultured with or without APCs from unimmunized mice in the presence or absence of IOE OMP-19 (10 μg/ml). Concanavalin A was used as positive control. Cells from three immunized mice were pooled and were cultured in duplicate. Proliferative responses using T cells from unimmunized mice were less than 2 × 10³ cpm. (b) The frequencies of IFN-γ-producing OMP-19-specific CD4 T cells in spleens and draining brachial lymph nodes (dLN) from IOE OMP-19-immunized mice were determined by ELISPOT assay. Cells from three OMP-19-immunized mice were pooled and cultured in triplicate in the presence of OMP-19 (10 μg/ml). Data were obtained following subtraction of background from cells cultured in the absence of added antigen. Responses using CD4 T cells from unimmunized mice were at background levels. Horizontal lines indicate means. SFC, spot-forming cells.