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Biomedical subjects

M C Raff

Publications and source records attributed to M C Raff.

At least 145 records · Page 8Linked to original sources

Direct demonstration of theta-positive antigen-binding cells, with antigen-induced movement of thymus-dependent cell receptors.

Anti-thetaAKR antibody conjugated to fluorescein has been used in direct immunofluorescence tests to identify spleen theta(+) (T) sheep erythrocyte rosette-forming cells in AKR mice. Specificity studies involving A and cogenic A/thetaAKR mice clearly demonstrated that the cell surface fluorescence and cytotoxicity produced by the antiserum is directed solely toward the thetaAKR alloantigen. Approximately (3/8) of rosette-forming and non-rosette-forming spleen cells were found to be theta(+). The tendency for T cells to bind less antigen and the tendency for antigen-binding T cells to bear less theta than other spleen T cells, first suggested by other studies involving rosette-elimination by anti-thetaC3H plus complement, were confirmed by direct immunofluorescence. All AKR rosettes are specifically inhibitable by anti-immunoglobulin, including T rosettes. Antigen-induced redistribution of T cell receptors, analogous to that previously described for B cell receptors (16), occurs as readily in theta(+)RFC as in theta(-) RFC, without altering the symmetrical ring distribution of thetaAKR antigen.

Animals↗

Studies on the differentiation of thymus-derived lymphocytes.

The development pathway from embryonic thymus-stem cell to peripheral thymus-derived lymphocyte has been demonstrated using the alloantigens theta (theta) and TL as surface markers of cell differentiation. On the basis of cytotoxicity tests carried out on CBA.H or A embryo thymus cultured in diffusion chambers and on CBA.H embryo thymus grafts and peripheral lymphocytes derived from them in AKR hosts, it has been concluded that two differentiation stages take place during the maturation of thymus-derived cells, namely a first step from stem cell to thymocyte and a second step from thymocyte to peripheral lymphocyte.

Animals↗