Inhibition of Lymphocyte-Mediated Cytotoxicity (⁵¹Cr-Release) by Antisera Preabsorbed With Various Cells

Summary

Immunologic specificities of lymphocytemediated cytotoxicity (LMC) were studied with the use of the in vitro ⁵¹Cr-releasing method. When compared with inhibition of LMC by unlabeled cells or by antiserumpretreated cells, inhibition of LMC by antisera preabsorbed with test cells was more sensitive and specific in detecting minor antigenic differences. The inhibitory effects of antiserum-pretreated cells were unexpectedly strong, showing very weak blocking effects of antiserum on unlabeled inhibiting cells. Cell-free antigens alone or cellfree antigen-antibody complexes did not inhibit LMC within the system used, while cell-free antigens neutralized the inhibiting activity of antiserum.