EBV-specific cytotoxic T cells can be generated in vitro in a secondary response. Several previous studies with bulk cultures provided evidence that cytotoxicity was restricted by HLA-A,B-related antigens. In the present family study, the EBV-specific cytotoxic T-cell response of a normal EBV-seropositive donor was analysed in detail by T-cell colony formation. Peripheral blood mononuclear cells were stimulated by the gamma-irradiated autologous lymphoblastoid cell line (LCL) and 3 days later seeded into agarose. Colonies were harvested, amplified by addition of interleukin-2 (IL-2), and analysed for T-cell markers and specificity in 51Cr-release assays. Twenty-two colonies were studied: all colonies were OKT3+, five were predominantly OKT4+, 9 were OKT8+ and 8 were mixtures. As expected from previous work, the OKT8+ colonies were cytotoxic for the autologous LCL target and cytotoxicity was blocked by monoclonal antibody (W6/32) to the nonpolymorphic determinants of HLA-A,B,C antigens. Significantly, the OKT4+ colonies tested also showed specific cytotoxicity, but lysis of the autologous LCL was blocked by the monoclonal antibody (OKlal) to the non-polymorphic determinants of HLA-DR antigens. Two interesting patterns of specificity were seen in cytotoxicity tests on sibling LCL targets. In one pattern, targets bearing the A11, B5, DR7 haplotype were lysed, while those bearing the A1, B8, DR3 were not, indicating haplotype preference. In the other pattern, there was lysis of the autologous cell line but not of the sibling targets. These results including HLA-DR-associated restriction, haplotype preference and strict self-preference, further illustrate the complexity of the EBV-cytotoxic T-cell response.

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SUMMARYThere are two lypes, A and B, of Epstein-Barr virus (EBV) and B95-8 represents the common lype A laboratory strain. Herein, we show in a family study thai paternal EBV-specific cyiotoxie T lymphocytes (CTL) generated in short-term cultures following stimulation with the autologous B95-8-lransformed lymphoblastoid cell line (LCL) or B cells freshly infected wilh the B95-8 isolate did not Iyse haptoidentiati B95-8 LCL expressing the HLA-AL -B8. -DR3 paternal haplotype. In contrast, the haploiUentical B95-8 LCL expressing the HLA-Al I, -B5i, -DR? paternal haplotype was sirongly lysed. Moreover, paternal CTL generated in response lo stimulation with the B95-8 LCL expressing the haploidentical HLA-Al. -B8, -DR3 paternal haplotype included an allogeneic response against the maternal haplotype but no EBV-specific response as shown by the poor lysis ofthe autologous LCL target cells. However, stimulation with the hapioidentieal HLA-Al I. -B51. -DR7 paternal haplotype resulted in the generation of both an allogeneic and an EBV-specific response. CTL clones were generated from two HLA-B8' donors in response to stimulation wilh the aulologous type A LCL transformed wiih wildlype EBV. The clones were cross-reactive for an immunodominant B95-8-associalcd peplide epitope ihat interacted with the HLA-B8 allcie but failed to Iyse B95-8-transfomied LCL largets unless the targets were prc-coated with ihe exogenous peptide. A CTL clone that was inilially stimulated wilh the autologous BL74 LCL lysed the spontaneous autologous LCL and spontaneous LCL from an HLA-B8 * donor, but failed to Iyse the B95-8 LCL from that donor. The observed haplotype preference can be explained in terms of sequence variation between the B95-8 and the corresponding wildlype epitope. Our findings may help lo clarify the role of EBV in the pathogenesis of primary Sjogren's syndrome which is closely associated with HLA-B8.

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