Identification of factors interacting with a subset of T8+ cells.

In a previously work we have reported that T8+ lymphocytes decrease can be obtained by incubation of lymphocytes from normal blood donors with serum taken from patients in the acute phase of the disease. In this paper is described a partial characterization of the masking serum factor present in the acute phase of the disease. It displays a m.w. of approximately 640,000 d and its effect disappears either after heating 60 min. at 37 degrees C or 30 min. at 56 degrees C, after dialysis against 1M NaCl or lyophilization. Another serum factor, insoluble at 50% ammonium sulphate final saturation, resistant to heating and lyophilization, able to remove (in vitro) the former masking factor from the T8+ cells, is present in the remission phase.