Surface immunoglobulins of tonsil lymphocytes.

Human tonsillar lymphocytes bound 14C-labelled homologous IgG, IgA, and IgM at 5 degrees C and released them at 35 degrees C. B cells were found to be more active in this type of Ig binding. The amount of lymphocytes which could be labelled with fluoresceinated anti-human Ig-s decreased during preincubation of the cells at 35 degrees C. Intrinsic Ig-s (determinants of lymphocytes) were demonstrated by immunofluorescent staining preceded by preincubation of the cells at 35 degrees C for 60 min. The ratios of IgG, IgA, and IgM bearing cells in the human tonsillar lymphocyte population were 16.0, 8.0 and 7.4% respectively. The weak binding of Ig-s to the surface of lymphocytes is discussed with regard to the demonstration of surface Ig determinants of lymphocytes.