Limiting dilution comparison of the repertoires of high and low responder MHC-restricted T cells

• Format: Text
• Language: English
• Published: The Rockefeller University Press 1988
• Subjects: Articles; Sperm whale
• Online Access: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2188878; http://www.ncbi.nlm.nih.gov/pubmed/2450949

To approach the mechanism that determines Ir gene-controlled high or low responsiveness to whole proteins, such as sperm whale myoglobin (SWMb), we compared the repertoires of high and low responder haplotype- restricted T cells for different myoglobin epitopes by limiting dilution frequency analysis. Poisson analysis was performed using long- term limiting dilution cell lines of (B10.BR [low] X B10.D2[high])F1 T cells maintained on high or low responder APCs. The cell lines were tested with SWMb peptides and fragments for T cell repertoire fine specificities and Ia restrictions. The frequency of SWMb-specific F1 T cells responsive on B10.BR (H-2k) APCs was 2.5-3.6-fold lower than on B10.D2 (H-2d) APCs. Strikingly, all of the H-2k-restricted T cells used I-Ek as a restriction element, whereas both I-Ad- and I-Ed-restricted T cells were found among the H-2d-restricted lines. The I-Ad-restricted T cells were dominant, and the majority was specific for the synthetic peptide 102-118. T cells specific for peptide 132-146, dominant in association with I-Ed, were less frequent. However, no detectable H-2k- restricted T cells were specific for either of these peptides, but instead they were specific for fragment 1-55 or peptide 59-80. Fragment 1-55 also stimulated a similar number of H-2d-restricted T cells. Therefore, the low response of F1 T cells on H-2k-presenting cells may be due to the failure to see myoglobin plus I-Ak, in particular the immunodominant site around Glu 109, in contrast to the dominant response of high responder mice (both H-2d and H-2s) focused on the I-A molecule and the site around residue Glu 109. The I-E- low responder B10 strain also failed to respond to peptide 102-118, supporting the idea that the low responder status results from a limited repertoire lacking response to 102-118 plus I-A. In those strains that respond to the immunodominant site 102-118, the frequency of T cells in the repertoire specific for this site was always considerably greater than that for other sites. These results ...