Distinguishing B and T lymphocytes by scanning electron microscopy

This work demonstrates differences between B lymphocytes and T lymphocytes as seen in the scanning electron microscope (SEM). Slides of routinely prepared benign and malignant lymphoid tissues were viewed in the SEM. The location of prominent populations of T lymphocytes and B lymphocytes was verified by immunocytochemical staining respectively with CD3 and CD20 antisera. Benign tissues, including infant thymus and adult hyperplastic lymph node, were compared with malignant lymphomas of T-cell and B-cell types. The SEM appearance of benign B and T lymphocytes is compared utilizing the backscattered electron (BSE) mode and secondary electron (SE) mode in adult hyperplastic lymph node and infant thymus, respectively. The BSE and SE modes reveal that the sectioned T-lymphocyte nucleus has a more complex configuration than that of the B lymphocyte. T lymphocytes appear more discrete and separated one from another, while B lymphocytes exhibit close cellular association to form a syncytial array. These features are noted also in malignant lymphomas of B-lymphocyte and T-lymphocyte types, respectively. The SEM can distinguish between B and T lymphocytes by studying the differences in nuclear and chiefly the cell to cell appearances. The syncytial configuration of B lymphocytes may reflect prominent expression of cell adhesion molecules, e.g., ICAM-1. as noted in the literature.