Stimulation of peripheral lymphocytes by allogeneic and autochthonous mononucleosis lymphocyte cell lines.

Cultures of peripheral lymphocytes obtained during the acute phase of infectious mononucleosis (IM) were established. Mitomycin C-inhibited cells of these cultures caused abnormally high transformation rates in mixed cultures (MLR) with allogeneic peripheral lymphocytes and to a lesser degree they also stimulated autochthonous peripheral lymphocytes obtained from the same persons 3 to 9 months after their acute disease. This stimulation seems not to be caused by Epstein-Barr virus (EBV), present in the IM-cultures, because concentrated EBV preparations did not stimulate the convalescent lymphocytes and allogeneic lymphocytes from infants with and without circulating EBV antibodies responded equally well in the MLR with cultured IM lymphocytes. Circulating antibodies against surface antigens of autochthonous acute phase IM lymphocytes, stored in liquid nitrogen or cultured, were demonstrated in convalescent IM sera by the indirect membrane fluorescence technique. Blastogenic activity for both allogeneic and autochthonous lymphocytes was found in the cell-free supernatants of these IM lymphocyte cultures and was probably associated with cell membrane fragments.