Shogo Kano

Stimulation of Human Lymphocyte Subpopulations by Protein A from Staphylococcus aureus

Protein A from Staphylococcus aureus is known to stimulate human lymphocytes. Using 3H-thymidine incorporation, virus plaque assay and induction of cytotoxic T lymphocytes (CTL), this study showed that soluble or insoluble protein A stimulated different lymphocyte subpopulations. Soluble protein A is highly mitogenic to T lymphocytes. In both 3H-thymidine incorporation and virus plaque assay, its maximum stimulation was as high as the stimulation by the nonspecific mitogens phytohemagglutinin and concanavalin A, and a higher CTL response than that induced by phytohemagglutinin or concanavalin A was induced. Mitogenic activity to B lymphocytes was negligible. S. aureus (Cowan I strain) is itself considered to be an insoluble form of protein A and is 3--4 times more mitogenic to B lymphocytes than pokeweed mitogen without any increase in virus plaque-forming cells. No mitogenicity was noted to T lymphocytes. Sepharose CL-4B-protein A, also known as insoluble protein A, stimulated both T and B lymphocytes effectively, but its mitogenicity to T lymphocytes was considered to be due to the soluble protein A released from the Sepharose CL-4B beads.

Hemopoietic Stem Cells in Experimental Hypoplastic Marrow Failure of the Mouse

Aplastic anemia is a syndrome characterized by a failure of the supply of erythrocytes, leukocytes, and platelets to the peripheral blood, owing to a decreased production of these cells. In this disease, the number of hemopoietic cells in the bone marrow usually fall, and they are replaced by fatty cells.