In vivo cross-priming of MHC class I-restricted antigens requires the TAP transporter

Immunity. 1996 Apr;4(4):349-55. doi: 10.1016/s1074-7613(00)80248-4.


Recent in vitro evidence suggests two alternative mechanisms by which bone marrow-derived APCs may process exogenous antigens for presentation to CTL in vivo, a phenomenon termed cross-priming. Although in vitro studies have suggested that both TAP-dependent and TAP-independent pathways exist, we have now demonstrated an absolute requirement for a functional TAP for cross-priming to occur in vivo. Bone marrow chimeras reconstituted with marrow from TAP-defective donors develop functional CD8+ CTL, but have APCs with disrupted TAP function. In such chimeras, in vivo priming of naive CTL was observed when antigen was targeted to the ER in a TAP-independent fashion, but cross-priming could not be demonstrated. These results support the TAP-dependent mechanism of cross-priming.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • ATP-Binding Cassette Transporters / immunology*
  • Animals
  • Antigen Presentation*
  • Female
  • H-2 Antigens / metabolism
  • Histocompatibility Antigens Class I / metabolism*
  • Male
  • Mice
  • Mice, Inbred BALB C
  • Mice, Inbred DBA
  • Radiation Chimera / immunology
  • T-Lymphocytes, Cytotoxic / immunology


  • ATP-Binding Cassette Transporters
  • H-2 Antigens
  • Histocompatibility Antigens Class I