Specificity of Human Lymphocytes Primed against Allogeneic Cells in vitro. II. Discrimination and Cross‐Reactivity in Repeated Priming

Abstract

When studying the specificity of human lymphocytes primed in vitro against HLA—D determinants on allogeneic cells, it was found that specific restimulation of the primed cells 10 days after the first priming did not influence their discriminatory power compared to cells primed only once. Likewise, priming to one HLA—D determinant and repeated priming against another HLA—D determinant did not change the discrimination for the first priming antigen. Neither was there any increased relative reactivity to the second priming determinant. On simultaneous priming against two HLA—D determinants carried by two different stimulating cells, a good discrimination for both antigens was obtained compared to third party cells, but if the stimulations were separated by 24 h or more, the second priming was mainly without effect. Antigeneic competition is thought to be the mechanism involved in this early restriction of specificity.

Aspects of the Primed Lymphocyte Typing (PLT) Technique

“…The primary culture conditions may be modified in many ways, e.g. the ratio between the numbers of responder and stimulator cells, the length of the culture time, separation of T-cells or blast cell separation, stimulation with lymphoblastoid cell lines and repeated stimulations of the PLT-cells in primary cultures (Hirschberg et al 1975, Crosier et al 1977, Fradelizi et al 1977, Reinsmoen et al 1977, Moen & Thorsby 1978, Baron et al 1979, DeWolf et al 1979, Moen & Thorsby 1979. We have chosen to use primary cultures with lo7 responder cells + 0.5-1.0x lo7 stimulator cells which are cultured for 10-12 days.…”