CROSS-REACTIVITY OF T-CELL LINES AND CLONES TO BETA-LACTAM ANTIBIOTICS

To clarify on a molecular level the specific T cell response to hapten s like penicillin G, we generated T cell lines and clones from penicil lin-allergic patients, Two types of beta-lactam reactivity of T cells could be delineated: one group of patients showed a rather restricted specificity, as the penicillin-elicited T cell lines generated from su ch donors proliferated only to the stimulating penicillin, but not to other beta-lactam antibiotics nor to cephalosporines, even if the side chain was identical, This indicates that the penicilloyl structure to gether with the side chain was recognized by these T cells, The second group comprised patients with more broadly reactive T cells, as they were restimulated by penicillin G as well as by related penicillins li ke amoxicillin or ampicillin, but not cephalosporines. This indicates that the penicilloyl structure, a common motif of penicillins, was imp ortant for T cell recognition, Clones generated from a broadly reactiv e patient confirmed this heterogeneity, as either monospecific or broa dly specific T cell clones could be identified, This broad or very res tricted pattern of T cell reactivity was reflected in the use of TCR V beta-chains: while the broadly reactive T cell lines showed a heterog enous TCR usage, the highly restricted T cell lines showed an up regul ation of one TCR V beta-chain, Thus, our data suggest that the outgrow th of T cells bearing a certain TCR V beta may be a sign of a limited cross-reactivity.