Expression of immunoglobulin isotypes by lymphoid cells of mouse intestinal lamina propria

At the time of their ablation, human tonsils contained some lymphocytes which incorporated [³H]thymidine during short-term culture. The extent of proliferation seemed to be a characteristic of the individual organ pairs. Tonsil cells also secreted during culture at least three soluble factors. One factor suppressed proliferation of human PBL treated with Con A, another factor augmented the proliferation, and the third factor was mitogenic for unstimulated PBL. Mitogenic factor was demonstrable in the presence of supernatants which expressed suppressor activity, but the augmentor could not be demonstrated in such supernatants until it was physically separated from the suppressor by gel filtration or by anion-exchange chromatography. The dose-response curves for the augmentor and mitogenic factor, both of which were simultaneously present in the supernatant, were different. The expression of one of these activities, however, did not require expression of the other. Both augmentor and mitogenic factor were nondialyzable. The augmentor had a molecular weight of about 30,000 and eluted from DEAE-cellulose in 150–250 mM NaCl.