PubMed Health⌕ Search

Biomedical subjects

G Di Sabato

Publications and source records attributed to G Di Sabato.

17 recordsLinked to original sources
PubMed1988

Purification and characterization of two forms of rat interleukin-2.

Rat IL-2 produced by spleen cells in culture with concanavalin A was purified using gel filtration, hydrophobic chromatography, and ion-exchange chromatography. At least two forms of rat IL-2 were found to be separable by ion-exchange chromatography. These two forms have been designated form I and form II. Form I of rat IL-2 was purified by a factor of 1297 and found to have a pI of 6.4. Form II was purified by a factor of 669 and found to have a pI between 5.4 and 6.1. Lectin chromatography was used to demonstrate that these two forms most likely differ in the extent of glycosylation. In the presence of tunicamycin the production of form II was significantly reduced. The two forms of rat IL-2 differ in their abilities to promote a mixed-lymphocyte reaction. Their differences in glycosylation may be the reason for these differences in activity.

Animals↗
PubMed1982

Purification and initial characterization of rat interleukin 2.

With the sequential use of dialysis, chromatography on Sephadex G-100, reactive red 120-agarose, p-hydroxymercuribenzoate-agarose, phenyl-Sepharose, poly(L-lysine)-agarose, and isoelectrofocusing, the thymocyte stimulatory factor activity of interleukin 2 from rat spleen was purified about 8,000-fold. By the same procedures, the T cell growth factor activity of interleukin 2 was purified about 6,000-fold. The major peaks of thymocyte stimulatory factor activity and T cell growth factor activity cochromatographed in the various systems used, but T cell growth factor activity without significant thymocyte stimulatory factor activity was sometimes present. Both activities were found to have a pI between pH 5.50 and 6.30. Detectable thymocyte stimulatory factor activity was found at concentrations as low as 0.1-0.2 ng of protein per 0.2 ml. Dose--response plots were linear up to at least 1 ng of protein. Preparations of interleukin 2 labeled with 125I-containing Bolton--Hunter reagent and purified by the procedure mentioned above were electrophoresed on a polyacrylamide gel under denaturing and reducing conditions. The 125I-labeled material migrated in one major band with a molecular weight under 20,000 and three smaller bands with molecular weights of about 20,000, 60,000, and 90,000. Material with thymocyte stimulatory factor activity did not bind to a number of lectin-gels.

Animals↗
PubMed1977

Effect of serum and serum components on the mitogen-induced proliferation of murine lymphocytes.

By increasing the concentration of human serum, the dose-response profile of the Concanavalin A-induced proliferation of murine spleen lymphocytes becomes broader and the optimal cell proliferation takes place at higher concentrations of mitogen. It is shown that this behavior is due to the globulin fraction of serum which greatly decreases the binding of Concanavalin A to lymphocytes. Cohn fractions III and IV have a similar effect. On the other hand, cell proliferation takes place also in the absence of Pooled Human Serum at appropriate concentrations of Concanavalin A and within a very narrow range of cell concentrations. In the presence of the albumin fraction of serum, proliferation takes place over a wider range of mitogen and cell concentrations. As a result of these phenomena, the mitogenic effect of Concanavalin A varies greatly in function of the concentration of serum. Analogous results were obtained with fetal calf serum.

Animals↗
PubMed1977

Some immunological effects of penicillamine.

Immunological effects of D- and D,L-penicillamine (PA) were studied in efforts to develop assays for synthetic D or D,L analogs and to contribute to the understanding of the mechanism(s) of action of D-PA in rheumatoid arthritis. At the highest doses tolerated by mice, D,L-PA did not significantly inhibit the development of haemagglutinating antibodies in vivo. In studies in vitro with T lymphocytes, D-PA at 1 mM concentration inhibited both concanavalin A- and phytohaemagglutinin-induced transformation as assayed by [3H]thymidine incorporation, but D-PA concentrations of 5 mM were required to inhibit concanavalin A-induced amino acid uptake. No effect of D-PA was observed either on the induction of cytotoxic T cells or on the attack of specifically sensitized T cells on target cells. It is of interest that D-PA at 1 mM concentration did inhibit lipopolysaccharide-induced transformation, which predominately stimulates B lymphocytes. The effects of PA on the induced transformation of T and B cells deserve further attention for studies with analogs of PA.

Animals↗