Inhibition of anti-HLA-B7 alloreactive CTL by affinity-purified soluble HLA.
The objective of this study was to elucidate the interaction of naturally occurring soluble MHC class I molecules with alloreactive CTL and to discuss its possible relevance to graft acceptance. An anti-HLA-B7 specific CTL-line, BV.B7, was generated in vitro. On phenotyping the cells after 6 weeks, 80% were found to be CD8+, 14% CD4+ and 6% CD8+CD4+. CD4+ CTL were depleted using immunomagnetic beads precoated with an anti-CD4 antibody. Of the recovered CTL greater than 96% were CD8+. A total of 12 HLA-B7 target cell lines and PHA blasts tested were specifically lysed in a 51Cr-release assay. Soluble HLA class I molecules were isolated on affinity chromatography columns using the anti-HLA-B7 ME 1 and the anti-heavy chain W6/32 monoclonal antibodies. Antigen purity was confirmed by analysis on SDS-PAGE gels. CTL were preincubated with 0.1-1.8 micrograms/ml soluble HLA for 30 min at 37 degrees C and subsequently tested for cytotoxicity in the 51Cr-release assay; 1.1 micrograms/ml HLA-B7 molecules reduced CTL cytotoxicity by 50% whereas non-B7 HLA had no effect. Further, CTL cytotoxicity was reduced by preincubation with anti-CD8, anti-TcR, and anti-CD3 antibodies. We anticipate a possible down-regulatory role of soluble HLA on CTL in allogeneic transplantation.
Zavazava
N
N
Department of Immunology, University of Kiel, Federal Republic of Germany.
Hausmann
R
R
Müller-Ruchholtz
W
W
D000906:Antibodies / Q000037:antagonists & inhibitors*; D000911:Antibodies, Monoclonal / Q000276:immunology; D006680:HLA Antigens / Q000502:physiology*; D015793:HLA-B7 Antigen / Q000276:immunology*; D006801:Humans; D012995:Solubility; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D014407:Tumor Cells, Cultured
D000906:Antibodies; D000911:Antibodies, Monoclonal; D006680:HLA Antigens; D015793:HLA-B7 Antigen