Identification of endogenous peptides recognized by in vivo or in vitro generated alloreactive cytotoxic T lymphocytes: distinct characteristics correlated with CD8 dependence.
We studied the molecular basis for CD8 independence of in vivo generated (BM3.3) versus CD8 dependence of in vitro sensitized (KB5.C20/Des) alloreactive H-2K(b)-specific cytotoxic T lymphocytes (CTL). Using microcapillary high-performance liquid chromatography fractionation of H-2K(b) eluates, mass spectrometry and CTL reconstitution assays, we determined that BM3.3 and KB5.C20 recognize, respectively, a single peptide (pBM1) expressed on 8,000 H-2K(b) molecules per allogeneic cell, and three distinct peptides (pKB1, 2, 3), each expressed on around 200 H-2K(b) molecules per allogeneic cell. CD8 (in)dependence was intrinsic to the respective TCR/H-2K(b)-peptide interactions. KB5.C20 and BM3.3 TCR illustrate the correlation that appears to exist between CD8 dependence/low affinity and in vitro sensitization as opposed to low dependency on CD8 and high TCR affinity observed after in vivo sensitization. The results suggest that CD8-dependent alloreactive CTL obtained in vitro with high frequency correspond to low-affinity TCR from the MHC-biased TCR repertoire unpurged by negative selection and have implications for cellular immunotherapeutic approaches.
Guimezanes
A
A
Centre d'Immunologie INSERM-CNRS de Marseille-Luminy, Marseille, France. guimezan@ciml.univ-mrs.fr
Barrett-Wilt
G A
GA
Gulden-Thompson
P
P
Shabanowitz
J
J
Engelhard
V H
VH
Hunt
D F
DF
Schmitt-Verhulst
A M
AM
Engelhardt
V H
VH
D000818:Animals; D016827:CD8 Antigens / Q000502:physiology*; D018604:Epitope Mapping; D051379:Mice; D008810:Mice, Inbred C57BL; D010455:Peptides / Q000276:immunology*; D051381:Rats; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*
D016827:CD8 Antigens; D010455:Peptides; D011948:Receptors, Antigen, T-Cell