Antigen-specific proliferative human T-lymphocyte clones with specificity for Chlamydia trachomatis.

Blast-enriched suspensions of T cells primed for Chlamydia trachomatis antigen were cloned by a limiting dilution technique. A cloning efficiency of 20-25% was obtained. T-lymphocyte clones (TLC) with high proliferative responses were selected for further studies. Kinetic studies showed a peak response between 60 and 84 h after antigen stimulation. The TLC were OKT4+. They were specific for the chlamydial antigen and did not respond to other antigens when non-T cells were used as antigen-presenting cells (APC). Antigen-specific proliferation of the TLC required that the responding TLC and the APC shared class-II HLA determinants--that is, HLA-D/DR molecules. The true clonal nature of the TLC was confirmed by subcloning experiments.