Ultrastructural studies of peripheral blood lymphocytes in T cell-depleted rabbits. A scanning and transmission electron microscopic analysis.

Density separation of purified peripheral blood leucocytes from T-cell depleted rabbits on a linear Ficoll-metrizoate gradient has been applied to obtain different leucocyte fractions. Two lymphocyte fractions separated on density seem to have different characteristics, both morphologically and immunologically. In this study these two fractions have been characterized ultrastructurally by using scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and a relationship has been established between the surface architecture (SEM), the cell size (SEM/TEM) and surface-Ig/C3-receptors (LM, light microscopy). Finally three types of lymphocytes have been described in the two lymphocyte fractions separated on density. Morphometric information such as cell size, cell shape, eu-/heterochromatin ratio in the nucleus and the nucleus-/cell ratio have been correlated to the stage of activation of the B lymphocyte in a representative density separation.