Requirement of Ia-positive nylon wool adherent cells for activation of cytotoxic T-lymphocytes specific to melanocyte-associated antigens in patients with Vogt-Koyanage-Harada's disease.

Involvement of Ia-positive nylon wool adherent cells (AC) for the expression of cytotoxic T-lymphocyte (CTL) activity specific to melanocyte-associated antigens (MAA) was studied. Although unseparated peripheral blood lymphocytes (PBL) from several patients with Vogt-Koyanagi-Harada's (VKH) disease showed significant cytotoxic activity against SK-MEL-28 (P-36) human melanoma cells which carried cross-reactive surface antigens with normal melanocytes, the cytotoxic activity of nylon wool column passed nonadherent cells (NAC) against the same target cells markedly decreased in the absence of Ia-positive nylon wool AC. The reduced cytotoxic activity of the NAC was reconstituted not only by the addition of Ia-positive AC from the same VKH patient, but also by the addition of allogeneic IA-positive AC mismatched with human leukocyte antigen (HLA) complex-DR region haplotype. Moreover, the cytotoxic activity of nylon wool NAC was augmented by the addition of interleukins instead of DR-positive AC. The data indicate that the primed CTL in patients with VKH would be stimulated nonspecifically by factors from Ia-positive cells, presumably to differentiate the precursor CTL (CTL in memory state) into mature CTL (effector cells).