Rat Memory T Lymphocytes: in Vitro Proliferation Induced by Antigens of Actinomyces viscosus

Abstract

Peripheral T [thymus-derived] lymphocytes from RIC-Sprague-Dawley rats primed in vivo several months earlier with A. viscosus Ny 1 reacted with a strong proliferative response upon antigenic challenge in vitro. Two different antigen preparations from A. viscosus Ny 1, a broken cell supernatant (BCS) and an extracellular fraction (EXC) gave maximum responses as measured by the uptake of [3H]thymidine at a concentration of 10 .mu.g at day 4 of culture. Phytohemagglutinin (PHA) used as a control provoked a maximum proliferation in the same order of magnitude. T lymphocytes from unprimed, germfree and conventional animals showed a similar stimulation to PHA, but only a marginal reaction to BCS, and were not at all activated by EXC. There apparently is efficient removal of cells responding non-specifically to B[bone marrow-derived]-cell mitogens.