AN IMPROVED AND RAPID METHOD FOR THE ISOLATION OF RAT LYMPH-NODE OR SPLEEN LYMPHOCYTES-T FOR T-CELL PROLIFERATION ASSAYS

To detect and compare the capacity of antigen presenting cells to present antigen in a T cell proliferation assay, it is necessary to obtain a pure population of antigen-primed T cells that gives low background proliferative responses. Therefore in this paper we present a newly developed isolation method of antigen-primed T lymphocytes from rat spleen or lymph nodes. This method uses a nylon wool column to deplete most of the adherent cells and B cells, followed by an indirect elimination method with magnetic beads to remove contaminating la-positive cells. We compared this method with two commonly used isolation methods, namely a 1.5 h adherence step, followed by a nylon wool column and a Sephadex G-10 column and a 1.5 h adherence step followed by a passage through two consecutive columns of Sephadex G-10. The best T cell enrichment (98% OX-19/52-positive cells) was achieved with the newly developed method, in which the contamination of la-positive cells, predominantly B cells and dendritic cells (DC), was diminished to less than 2%. The background response of this population was low and differed significantly with the common methods. Antigen-specific T cell responses induced by splenic DC, expressed as stimulation index, gave very specific responses and showed a steep rise with increasing DC concentrations compared to the common methods. Therefore we conclude that we developed an improved, rapid and reproducible method for the isolation of rat spleen or lymph node T lymphocytes suitable for T cell proliferation assays.