[Microlymphocytotoxic test with T lymphocytes: positivity by 3 hrs incubation (author's transl)]

Some human anti-HLA-DR and anti-HLA-A,B-sera contain cytotoxins reacting with T lymphocytes in the cytotoxic test by the prolongation of the incubation time to 3 hrs, whereas in the normal cytotoxic test of 1 1/2 hr incubation antibodies are not proved. These results suggest that simultaneous testing of sera with B and T lymphocytes not always give a true image of the actual occurrence of antibodies in the serum. The cause of the phenomen and the problem of the serological character of cytotoxins are discussed.