Density and size distributions of the intramembranous particles in the cytoplasmic membrane of human peripheral blood lymphocytes.

A freeze-fracture study has been carried out on human peripheral blood lymphocytes (hPBL) from healthy donors. Lymphocytes were frozen either from 37 degrees C or 4 degrees C. Quantitative analysis performed on density and size of intramembranous particles (IMPs) present on both fracture faces of the plasma membrane has revealed: a) a difference in size between IMPs on the external face (EF) and those on the protoplasmic face (PF); b) a remarkable influence of temperature either on size or density of the IMPs; c) the existence at 4 degrees C of two lymphocyte populations differing in IMP density.