T cell recognition of QA-1b antigens on cells lacking a functional Tap-2 transporter

Carla J. Aldrich, Robert Waltrip, Evan Hermel, Michelle Attaya, Kirsten Fischer Lindahl, John J. Monaco, James Forman

Research output: Contribution to journalArticlepeer-review

52 Scopus citations


MHC class Ia H chains and β2-microglobulin assemble with appropriate peptides to form stable cell surface molecules that serve as targets for Ag- specific CTL. The structural similarities of class Ia and the less polymorphic Q/T/M (class Ib) molecules suggest that class Ib molecules also play a role in antigen presentation, although the origin of the peptides they present remains mostly unclear. The cell line RMA-S has a defect in class I Ag presentation, presumably due to a mutation in a peptide transporter gene. This defect can be overcome by transfection of RMA-S cells with the Tap-2 gene (formerly Ham-2) that encodes an ATP-binding transporter protein. We now show that a substantial portion of alloreactive CTL specific for Qa-1 class Ib molecules recognize Qa-1b on RMA-S cells and thus differ from most class Ia specific CTL. Those anti-Qa-1b CTL that do not recognize untransfected RMA-S do lyse RMA-S transfected with Tap-2. We also examine the effects of Qdm, a gene that maps to the D region and alters recognition of Qa-1. Qdm(k) strains lack an epitope(s) recognized by some (Qdm dependent) anti-Qa-1 CTL whereas Qdm+ strains express this epitope. Thus, Qdm-dependent CTL do not recognize Qa-1 on Qdm(k) targets whereas Qdm-independent CTL recognize Qa-1 epitopes in all strains. Although Qdm-independent CTL varied as to whether they recognized RMA-S vs RMA, all nine Qdm-dependent clones only recognized Qa-1b on RMA and not RMA-S. This result is consistent with Qdm encoding a peptide dependent upon the TAP transporter for cell membrane expression.

Original languageEnglish (US)
Pages (from-to)3773-3777
Number of pages5
JournalJournal of Immunology
Issue number12
StatePublished - 1992

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology


Dive into the research topics of 'T cell recognition of QA-1b antigens on cells lacking a functional Tap-2 transporter'. Together they form a unique fingerprint.

Cite this