A lymphocytosis stimulating factor in the plasma of chronic lymphatic leukaemic patients

Tribute to Donald Metcalf

A collection of tributes and remembrances from esteemed colleagues, mentees, and friends on the life and work of "the father of hematopoietic cytokines".

Miller's seminal studies on the role of thymus in immunity

The thymus is one of the two primary lymphoid organs. It is responsible for the provision of T lymphocytes to the entire body, and provides a unique microenvironment in which T cell precursors (thymocytes) undergo development, differentiation and clonal expansion. This review article summarizes the seminal work of the Australian scientist Francis Albert Pierre Miller concerning the description for the first time of the crucial role of the thymus for normal development of the immune system.

Studies on lymph humoral factor. Evidence for a lymphocytopoietic factor in rat thoracic duct lymph

Normal rats were injected with the partially purified material extracted from the thoracic duct lymph which was collected from normal syngeneic rats. The cellular changes in the peripheral lymphoid tissues and thymus were examined cytologically and histologically. The intravenous injection of the lymph extract into normal syngeneic rats resulted in increase in weight of lymphoid tissues. Histologically, a massive proliferation of large pyroninophilic lymphoid cells and an increase in mitotic index was detected predominantly in the thymus-dependent areas and thymic cortex. In spleens from rats injected with lymph extract, the marginal zone bridging channel was shown as one route for the translocation or mobilization of newly borne lymphoid cells to the venous circulation. Similar lymphocytopoietic activity, but to a lesser extent than lymph extract, was also detected in lymph plasma, serum and serum extract. The lymph extract was shown to be non-immunogenic in syngeneic rats. It is suggested that the effects of the lymph extract on lymphoid cell proliferation are due to the presence of a lymphocytopoietic factor in body fluid, particularly in the lymph.

A hypocalcemic and lympnocyte-stimulating substance isolated from thymus extracts, and its physicochemical properties

Two kinds of active protein fraction, TP1 and TP2, were isolated from bovine thymus extracts. Both these fractions showed a single band in polyacrylamide gel disc electrophoresis. Though these two fractions showed a difference in potency, they both lowered serum calcium in rabbits and increased lymphocytes in mice. Molecular weight determination by SDS polyacrylamide gel electrophoresis gave the values of 68,000 for TP1 and 57,000 for TP2. Amino acid composition of TP1 did not show marked characteristics but was clearly different from that of bovine serum albumin. Isoelectric focusing showed the isoelectric point at pH 5.65 for TP1 and pH 5.4 for TP2. Dose-response relation in serum calcium-lowering activity was examined with a sample purified from the extracts, and a linear dependence of the response to log dose was recognized over a moderate range of doses. The time-course measurement of the hypocalcemic activity showed that the action of TP1 is somewhat different from that of calcitonin.

Fine structural evidence for hormone secretion by the human thymus

The epithelial cells of the Hassall's corpuscles in 11 human thymus glands (nine cases of myasthenia gravis and two glands from patients undergoing surgical correction of congenital heart disease) have been examined by electron microscopy. In every instance the epithelial cells have the cytoplasmic organelle complex necessary for ;export'-type secretory activity and in addition contain large numbers of membrane-limited small spheroidal secretion granules.Hassall's corpuscles are avascular anatomical units and a pericorpuscular zone, at least 50 mum broad, is also without blood vessels. It is therefore suggested that the secretory product(s) of the corpuscular epithelial cells has a purely intrathymic function.

Isolation and characterization of a thymic factor

A protein was isolated from bovine thymus that was shown to accelerate the appearance of hemolysin to sheep erythrocytes in neonatal mice. The isolation procedure consisted of saline homogenization, ammonium sulfate precipitation, and methanol precipitation, followed by chromatography on diethylaminoethyl-cellulose and two chromatographies on Sephadex G-150. The protein was shown to be homogeneous by polyacrylamide gel electrophoresis and by sedimentation velocity and sedimentation equilibrium analytical ultracentrifugation. The molecular weight was determined to be 79,950. Additional physical and chemical characteristics were also determined.

A buffy coat stimulating effect in serum from cattle with persistent lymphocytosis

A stimulating effect on bovine buffy coat cells was demonstrated in blood samples from cattle with persistent lymphocytosis. The stimulation was a function of the serum and not the cells used. It was not altered by filtration or inactivation of the serum. When buffy coat cells were grown in homologous serum, the resulting growth was moderate to abundant when the donor animal had persistent lymphocytosis and was usually poor when the donor animal had a consistently normal hemogram.