Detection of allo-HLA cross-reactivity by virus-specific memory T-cell clones using single HLA-transfected K562 cells

The ability to directly measure virus-specific lymphocytes using fluorochrome-labeled tetrameric complexes has proven a great advancement for the transplantation field. Viral peptide/HLA tetrameric complexes allow the rapid generation of virus-specific clones using single cell sorting apparatus, permitting the determination of alloreactivity from a single TCR with known specificity. When combined with new target "detector" cells called single HLA antigen-transfected K562 cells (SALs), the human alloresponse can for the first time be examined specifically and reliably. Here we describe a method for detection of "heterologous immunity" from virus-specific memory T-cells using single HLA expressing cell lines as allogeneic targets.