BACKGROUND Various mechanisms contribute to the loss of human leukocyte antigen (HLA) class I expression that is frequently observed in cancers. Although some single allele losses have been ascribed to mutations in HLA class I genes, direct evidence for this phenomenon in vivo is still lacking. Thus, we investigated whether HLA class I gene mutations could account for the loss of allele-specifi...

The transporter associated with antigen processing (TAP), which is composed of two subunits (TAP1 and TAP2) that have different biochemical and functional properties, plays a key role in peptide loading and the cell surface expression of HLA class I molecules. Three cases of HLA class I deficiency have previously been shown to result from the absence of a functional TAP2 subunit. In the present...

We studied by immunohistochemistry the HLA-allelic, beta 2-microglobulin, and TAP-1 expression in primary breast carcinomas and related lymph node metastases. Thirty-three of the primary tumors and 44% of the lymph node metastases had a complete HLA class I loss. The higher incidence of antigenic loss in metastatic tumors suggests that recognition of HLA class I antigens by the host immunity co...

OBJECTIVE We report here genotyping data and type 1 diabetes association analyses for HLA class I loci (A, B, and C) on 1,753 multiplex pedigrees from the Type 1 Diabetes Genetics Consortium (T1DGC), a large international collaborative study. RESEARCH DESIGN AND METHODS Complete eight-locus HLA genotyping data were generated. Expected patient class I (HLA-A, -B, and -C) allele frequencies wer...

background: hepatitis b is an important infectious disease.  since several years ago, mass vaccination against this viral infection has become as part of routine vaccination schedule of iran.  however, some healthy neonates, children and adults fail to generate a protective antibody response after vaccination. objectives: to investigate distribution of hla class-i and class-ii antigens in healt...

The alloreactive human T cell clone MBM15 was found to exhibit dual specificity recognizing both an antigen in the context of the HLA class I A2 molecule and an antigen in the context of the HLA class II DR1. We demonstrated that the dual reactivity that was mediated via a single clonal T cell population depended on specific peptide binding. For complete recognition of the HLA-A2-restricted spe...

Downregulation of MHC class I expression is a widespread phenomenon used by tumor cells to escape antitumor T-cell-mediated immune responses. These alterations may play a role in the clinical course of the disease. The aim of our study was to investigate the molecular mechanism underlying the absence of HLA-class I molecule expression in bladder cancer cells. Microdissected tumor tissues were c...

The HLA class I genes are located within a 2-million-base pair (2-Mbp) region constituting the telomeric half of the human major histocompatibility complex. The large majority of the class I sequences, including the HLA-A, -E, -F, and -G genes, is found within the telomeric 1 Mbp. We report here the isolation and characterization of yeast artificial chromosome (YAC) clones that span a contiguou...