Fig. 2.

Proliferative responses of T cell lines following initial isolation, and following in vitro expansion. The ability of T cell lines cultured from endarterectomy material to respond to PPD, tetanus toxoid (TT) and Chlamydia trachomatis (Ct) was evaluated by proliferation assay. Examples from this initial screen are shown in (a–e). Lines that showed a response to chlamydial antigens were expanded through non-specific (phytohaemagglutinin (PHA)) re-stimulation and subsequently re-tested to (i) ensure chlamydial specificity was maintained, and (ii) evaluate defined antigenic responses using recombinant antigens from Ct and Chlamydia pneumoniae (Cpn). Human hsp60 prepared in the same Escherichia coli expression vector was used as a control. These results for each line are shown in the adjacent panel, i.e. (g–k). PPD and TT lines were also expanded by PHA restimulation. Specificity could also be maintained and enhanced as shown by the examples in (f,l). □, The initial screen; ▪, the secondary screen. Results are depicted as ct/min and represent triplicate means with standard error bars.