[Lymphocytes HLA antigens expressivity after neuraminidase treatment (author's transl)]

Neuraminidase treatment of lymphoid cells increases the cytotoxic action of antibodies and complement on these cells. We have studied the action of 25 human alloantisera on lymphocytes of 26 healthy subjects by the Trypan blue lymphocytotoxicity technic, before and after neuraminidase treatment of cells. The results show, as a rule, an increased cytotoxicity of sera, with a higher titer and/or a more important number of positive cells. In some sera a specific cytotoxic activity is found only with neuraminidase treated cells. The antibodies often reveal an anti-HLA specificity: that specificity was previously known in the serum or, in several cases, has been found only with neuraminidase treated cells. But in some cases the new specificity does not seem to be related to the HLA system. Different hypotheses are discussed in order to explain these results and the action of neuraminidase on membranes; lastly, applications of our neuraminidase treatment method to practical problems are presented.