| Abstract: |
Alloreactivity against micromismatches in MHC class I molecules is difficult to measure. Here, we describe an in vitro model with which it is possible to examine alloreactivity against a single HLA class I allotype. The HLA class I- and class II-negative myelocytic leukemia cell line K562 was transfected with a genomic DNA clone carrying B*4403 to express a single allotype. CTL lines were generated from normal individuals carrying B*4402, B*4403, or unrelated HLA-B alleles by stimulation with B*4403-transfected K562. The bulk CTL lines generated from B*4402+ T cells against B*4403 that carry a single amino acid disparity at position 156 were specific for B*4403+ targets and did not react with targets carrying any other HLA allotype. However, the CTL lines generated from B44-negative individuals exhibited killing of the targets bearing not only B44, but also B44 CREG and a few other B alleles. Reverse transcriptase-PCR analysis of TCRs, expressed in the CTL clones uniquely specific for B*4403, showed that TCR Vβ usage of alloreactive T cells directed against B*4403 was diverse but nonrandom and was affected by the HLA background of the responder. Thus, the K562-HLA transfectant system provides a useful in vitro tool to analyze alloreactivity against a single class I allele and to aid in the prediction of alloreactivity in unrelated marrow transplantation. |
| Keywords: |
human cell; t-lymphocytes; phenotype; alleles; tumor cells, cultured; transfection; chronic myeloid leukemia; immunoreactivity; prediction; molecular cloning; lymphocyte culture test, mixed; hla matching; dna; leukemia, myeloid; cytotoxic t lymphocyte; t-lymphocytes, cytotoxic; hla antigen class 1; isoantigens; hla-b antigens; multigene family; epitopes; variation (genetics); genes, mhc class i; humans; human; priority journal; article
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