Peptide transporter-independent, stress protein-mediated endosomal processing of endogenous protein antigens for major histocompatibility complex class I presentation

Eur J Immunol. 1994 Jul;24(7):1478-86. doi: 10.1002/eji.1830240704.


The peptide transporter-defective cell line RMA-S expressing the wild-type simian virus 40 large T antigen (wtT-Ag) from a transfected gene did not present two well-defined, H-2 class I (Db)-restricted epitopes of T-Ag to cytotoxic T lymphocytes (CTL). Hence, "endogenous" processing and presentation of the wtT-Ag depended on a functional peptide transporter heterodimer. In contrast, both T-Ag epitopes were efficiently presented to CTL by transfected RMA-S cells expressing a truncated, cytoplasmic T-Ag variant (cT-Ag) or a karyophilic, amino-terminal 272-amino acid T-Ag fragment. Transporter-independent "endogenous" processing of mutant T-Ag molecules correlated with their association with the constitutively expressed heat shock protein 73 (hsp73). Class I-restricted presentation of both epitopes processed from these hsp73-associated protein antigens was sensitive to NH4Cl and chloroquine. These data indicate that selected intracellular proteins access an alternative, hsp73-mediated pathway for class I-restricted presentation that operates independent of peptide transporters in an endosomal compartment.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ATP Binding Cassette Transporter, Subfamily B, Member 3
  • ATP-Binding Cassette Transporters*
  • Amino Acid Sequence
  • Animals
  • Antigen Presentation / physiology*
  • Antigens, Polyomavirus Transforming / immunology*
  • Biological Transport / physiology
  • Carrier Proteins / physiology
  • Cell Line
  • Cytotoxicity Tests, Immunologic
  • H-2 Antigens / physiology*
  • Heat-Shock Proteins / physiology*
  • Mice
  • Mice, Inbred C57BL
  • Molecular Sequence Data
  • Mutation
  • Recombinant Proteins / immunology
  • T-Lymphocytes, Cytotoxic / immunology
  • Transfection
  • Tumor Cells, Cultured


  • ATP Binding Cassette Transporter, Subfamily B, Member 3
  • ATP-Binding Cassette Transporters
  • Antigens, Polyomavirus Transforming
  • Carrier Proteins
  • H-2 Antigens
  • Heat-Shock Proteins
  • Recombinant Proteins
  • Tap2 protein, mouse