Planned immunization of human volunteers with HLA-DR incompatible lymphocytes

Aiming at the production of anti HLA-DR test sera, eight healthy human volunteers were immunized by repeated intradermal injections of lymphocytes which were selected to be incompatible for one HLA-DR antigen, and matched as well as possible for HLA-A,-B,-C antigens. One out of 3 recipients immunized exclusively against HLA-DR produced lyrnphocytotoxic HLA-DR antibodies. The remaining 5 recipients were immunized against 1 or more HLA-A,-B,-C antigens in addition to one HLA-DR antigen. After 3 immunizations, 3 of these reacted with strong HLA-A or -B antibody production; however, only one showed a parallel anti HLA-DR antibody response detectable by complement dependent lymphocytotoxicity.
Testing of the recipient sera in the antibody dependent cell-mediated cytotoxicity (ADCC) assay revealed that 6 of the 8 recipients did react early to the immunizations with HLA specific antibody production. However, in spite of repeated booster injections it was not possible to obtain more than the above-mentioned 2 sera with HLA-DR antibodies strong enough to react in the lymphocytotoxicity microtechique.