From: Lymphocytes and the Cellular Basis of Adaptive Immunity
NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.

(A) A resting lymphocyte, which could be a T cell or a B cell, as these cells are difficult to distinguish morphologically until they have been activated to become effector cells. (B) An effector B cell (a plasma cell). It is filled with an extensive rough endoplasmic reticulum (ER), which is distended with antibody molecules. (C) An effector T cell, which has relatively little rough ER but is filled with free ribosomes. Note that the three cells are shown at the same magnification. (A, courtesy of Dorothy Zucker-Franklin; B, courtesy of Carlo Grossi; A and B, from D. Zucker-Franklin et al., Atlas of Blood Cells: Function and Pathology, 2nd edn. Milan, Italy: Edi. Ermes, 1988; C, courtesy of Stefanello de Petris.)
From: Lymphocytes and the Cellular Basis of Adaptive Immunity
NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.