In Vitro Primary Immunization of Human Peripheral Blood Lymphocytes to KLH: Evidence for HLA-D Region Restriction

Abstract

Human T cells were primed in vitro by culture for 12 days with autologous adherent monocytes and KLH. KLH-primed cells recovered from primary cultures were restimulated in a second culture containing autologous or allogeneic monocytes in the presence or absence of KLH, and proliferation was determined by incorporation of tritiated methyl-thymidine. Secondary proliferation of primed T cells requires both autologous adherent cells and KLH in the cultures. Allogeneic adherent cells work as effectively as autologous adherent cells in supporting proliferation only if the allogeneic cell shares an HLA-D region determinant in common with the autologous adherent cells used during the priming culture. Proliferative responses in cultures containing allogeneic adherent cells with no shared D-region specificities were markedly diminished or absent. This D region restriction was further confirmed by demonstrating that the addition to the secondary cultures of an anti-DR antiserum directed against the shared DR determinant abrogates proliferation whereas anti-DR antisera against the nonshared DR determinants on either primed T cell or allogeneic adherent cell do not. In conclusion, this study provides additional evidence that the genetic restrictions governing human cell-interactions of in vitro immune responsiveness are analogous to those observed in other animal models. By extension, it is likely that these in vitro techniques can also be utilized to define Ir genes, which control immune responsiveness in humans; and ultimately, to characterize better the H-linked genetic factors that contribute to the susceptibility to certain disease states that are associated with HLA-D region gene products.