FINE SPECIFICITY ANALYSIS INDICATES THAT THE PRIMARY AND SECONDARY FLUORESCEIN-SPECIFIC CYTOTOXIC T-CELL RECEPTOR REPERTOIRES ARE INDISTINGUISHABLE

Previous data from this laboratory have shown that fluorescein-specifi c cytotoxic T cells derived from naive mice are capable of distinguish ing between different isomeric forms of the fluorescein hapten, as wel l as between the iodoacetamido-, isothiocyanate- and dichlorotriazinyl amino-fluorescein derivatives. In this report, we show that T cells d erived from previously immunized animals, while demonstrating a strong er and more cross-reactive response overall, display identical fine sp ecificity patterns to those of primary T cells for a panel of fluoresc ein homologues. We interpret this finding to indicate that the antigen receptor repertoires utilized by primary and secondary cytotoxic T ce lls are indistinguishable and that the enhanced response of memory as compared with naive CTL results from factors such as a higher density of,ell surface receptors of receptor-associated molecules and/or a hig her frequency of antigen-responsive T cells.