Lymphocyte proliferation in vitro induced by soluble protein antigens. II. Cellular requirements.

Immune guinea pig lymph node cells were fractionated on Ig anti-Ig or HSA anti-HSA affinity columns or on plastic surface in medium containing carbonyl iron. These techniques selectively removed B lymphocytes, K lymphocytes or adherent cells. The residual cells (Fc receptor-negative T lymphocytes) responded to soluble antigen in vitro in the same way or even better compared with nonfractionated cells. In addition, there was no indication that antigen-antibody complexes were superior to antigen in triggering lymph node cells or purified lymph code T lymphocytes into DNA synthesis. The results obtained suggested that memory T lymphocytes can be stimulated by antigen autonomously.