Expression of HLA class I antigens in transporter associated with antigen processing (TAP)-deficient mutant cell lines

Neil Thomas Young, A Mulder, V Cerundolo, F H Claas, K I Welsh

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)


Cells lacking expression of the transporter associated with antigen processing (TAP) are deficient in surface HLA class I, yet express reduced levels of HLA-A2 antigen through TAP-independent processing pathways. We have analysed the expression of HLA-A, -B and -C antigens on the 721.174 and T2 TAP-deficient mutant cell lines using a panel of monoclonal antibodies specific for the HLA antigens encoded by the genotype of these cells. Our study has shown the constitutive expression of HLA-Cw1 molecules on the cell surface of both T2 and 721.174 cells and has confirmed that HLA-A2 and HLA-B51 are expressed at low levels. Transfection of 721.174 cells with cDNAs encoding TAP1 and TAP2 proteins did not fully restore HLA class I antigen expression on these cells, which appeared to be mainly due to a deficiency in expression of the HLA-B51-associated Bw4 epitope. This suggests that additional antigen-processing genes may be required for optimal generation of HLA-B-binding peptides. Our results indicate that TAP-independent pathways of antigen-processing provide peptides for functional expression of all three classical HLA class I molecules.
Original languageEnglish
Pages (from-to)368-373
Number of pages6
JournalTissue Antigens
Issue number4
Publication statusPublished - 1 Oct 1998


  • ATP-Binding Cassette Transporters
  • Alleles
  • Animals
  • Antibodies, Monoclonal
  • Cell Line
  • Flow Cytometry
  • Genotype
  • HLA Antigens
  • Humans
  • Major Histocompatibility Complex
  • Mice


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