Induction of PHA response in mouse bone marrow cells by thymic extracts as studied by changes in the structuredness of cytoplasmic matrix.

The specificity and cross-species activity of thymic extracts and some non-specific agents on some alleged properties of T cells and their precursors in the bone marrow cells of normal, nude and thymectomized mice was studied in vitro. The phenomenon of changes in the structuredness of cytoplasmic matrix (SCM) was used to assess the maturation and responses of cells treated with the extracts to mitogens, i.e. phytohaemagglutinin and concanavalin A. We found that thymic extracts of calf and mouse origin induce functional 'maturation' which can be abrogated by cycloheximide, an inhibitor of protein synthesis. The nonspecific agents used (spleen extracts, PPD, dBcAMP and endotoxin) had no effect on bone marrow cells, as measured by changes in the SCM. The method of measuring SCM using the technique of fluorescence polarization is described.