Development and Differentiation of Lymphocytes

Histogenesis of mouse cerebellum in microwell cultures. Cell reaggregation and migration, fiber and synapse formation.

“…Genetic endowment ultimately controls both the production of the signalling molecules and the receptor mechanisms. Among the model systems suitable for analysis of such events, the immunological system serves as one prototype, in which undifferentiated precursor cells migrate via the circulation and assemble in specific organs after induction of differentiation (15,26,48,65). Reaggregation systems provide another model, especially suitable for analysis of the events that come after migration, when dif-ferent classes of cells interact to construct an organ (for review, see reference 38).…”

Some Endocrine Aspects of the Thymus Gland

“…In the case of cytotoxicity, thymosin antiserum is specific for thymic cells and probably shows no cross-reactivity with spleen or lymph node lymphocytes (Hardy et al, 1968). However, recent findings that thymosin stimulates synthesis of T cell antigens on the surface of nonimmunocompetent cells argues against this objection (Komuro and Boyse, 1973b Miller, 1975;Claman, 1975;Raff, 1974 (Singhal and Wigzell, 1971), and the specific antigen stimulates the cell to secrete this specific immunoglobulin (antibody). The actual signal for activation may be a structure other than the Ig receptor (Moller and Coutinho, 1975).…”

“…The actual signal for activation may be a structure other than the Ig receptor (Moller and Coutinho, 1975). The receptor on the T lymphocyte cell surface is uncertain, but it reacts specifically to recognized antigen, producing non-specific factors (lymphokines), which mobilize macrophages and other elements seen in the cell-mediated responses (Raff, 1974). While B and T lymphocytes can be distinguished immunologically, morphologically they have been found to be indistinguishable by the light microscope, transmission E/M and probably scanning E/M (Alexander and Wetzel, 1975).…”