Biomedical subjects

S V Shirshev

Publications and source records attributed to S V Shirshev.

43 records · Page 3Linked to original sources

PubMedDate not supplied

[Regulation of oxidative activity of neutrophils by chorionic gonadotropin. The role of female steroid sex hormones].

We studied the effect of the main sex hormone, chorionic gonadotropin, on the production of the active forms of oxygen and nitrogen by human neutrophils and the control of its effects by female steroid sex hormones. Gonadotropin proved to inhibit both total production of oxygen metabolites and NO synthesis by the cells. Gonadotropin-dependent regulation of oxidative activity of the neutrophils is controlled by female steroid sex hormones. At the same time, progesterone completely or partially inhibits the suppressive effects of gonadotropin, while estradiol has antagonistic, sensibilizing, or permissive effect on gonadotropin depending on the dose, incubation conditions, and activation status of the cells.

Cells, Cultured↗

PubMedDate not supplied

[The role of chorionic gonadotropin in regulating the humoral immune response].

A study was made of the effect of chorionic gonadotropin (CG) on the formation of a primary immune response and generation of antigen-specific T-suppressors in normal and ovariectomized female mice. CG at doses of 40 or 200 U. strongly suppressed the generation of suppressor cells in noncastrated animals, and significantly raised the level of a humoral immune response at a small dose (40 U.). In ovariectomized mice CG at various doses made a selective stimulating effect on T-suppressor generation which depended on the synthesis of endogenous prostaglandins. A CG effect resulted in a significant decrease in the level of a primary immune response in castrated animals. Choriogonin was assumed to cause an immunostimulating effect in normal female mice as a result of raised secretion of sex steroids by the ovaries. The hormone proper produced an immunosuppressive effect which was implemented at the level of suppressor cells.

Animals↗

PubMedDate not supplied

[Chorionic gonadotropin as a modulator of cell interaction in the induction of the primary immune response].

The authors studied the effect of chorionic gonadotropin (CG) on the formation of a primary immune response and interactions of T- and B-lymphocytes in the realization of a humoral response to sheep erythrocytes in CBA and E1 (CBA X C57BL/6) mice. CG at a dose of 40 U. significantly increased the amount of antibody forming cells (AFC) whereas at a dose of 200 U. it made no significant effect on a primary immune response. The injection of chorionic gonadotropin (40 or 200 U.) to mouse donors of T-cells did not influence their ability for cooperative interactions. At the same time administration of the hormone to donors of B-cells reduced their ability for cooperation in the system of syngeneic transfer. CG injection of lymphoid cells to recipient mice caused an increase in AFC formation and the dose of 40 U. was more effective than the dose of 200 U. Possible mechanisms of the CG effect on immunogenesis were discussed.

Animals↗

PubMedDate not supplied

[Relationship between the immunomodulating effects of chorionic gonadotropin and the initial functional activity of the splenocytes mediating the adoptive immune response].

CBA and (CBA x C57BL/6)F1 male mice were used in experiments. One h incubation of splenocytes with chorionic gonadotropin (CG) in doses 10 or 50 MU/ml statistically significantly reduced the count of antibody-producing cells detectable in the syngeneic transfer system. Addition of conA or recombinant human interleukin 2 to the splenocyte culture did not alter the processes of the formation of antibody-producing cells. Addition of CG simultaneously with conA resulted in discontinuation of the immunosuppression induced by a low hormone dose, whereas 50 MU/ml of CG in the presence of conA had a marked immunodepressant effect. Combination of interleukin 2 with CG lead either to immunosuppression cessation (10 MU/ml) or to more than twofold stimulation of the adoptive immune response (50 MU/ml). Voltaren, a cycloxygenase inhibitor, was used in some experiments to elucidate the degree of endogenic prostaglandin relationships with the mechanisms of CG immunomodulating effects. Cycloxygenase activity was found to be related to the immunosuppressive effect of CG low dose, whereas the costimulating effect of a high dose of the hormone in the presence of interleukin 2 was unrelated to endogenic prostaglandin synthesis.

Adjuvants, Immunologic↗

PubMedDate not supplied

[Effect of female sex steroids on the ability of splenocytes to form an adoptive immune response. Role of prostaglandin F2alpha in the mechanisms of hormonal immunoregulation].

Male CBA mice were used in experiments. Splenocytes were incubated for an hour in macrocultures with estradiol (E2) or progesterone (P), then the cells were transferred (together with the antigen) to lethally irradiated syngeneic recipients, and on day 4 the count of antibody-producing cells (APC) was estimated. Prostaglandin F2 alpha (PGF2 alpha) concentrations were radioimmunoassayed in cell culture supernatants. E2 and P concentrations corresponded to these hormones levels in blood sera during pregnancy. E2 and P in the tested concentrations were found to reliably stimulate the processes of APC formation, their effects being dose independent. Both E2 and P statistically reliably increased PGF2 alpha level in splenocyte culture. Fractionation of splenocytes helped reveal the highest PGF2 alpha level in the cultures devoid of adhesive cells and rich for T lymphocytes. Hence, E2 and P stimulated the processes of antigen-independent differentiation of splenocytes producing APC either by directly stimulating T lymphocytes or via macrophages by blocking their negative effects. Stimulation of adoptive immune response by sex steroids is closely connected with PGF2 alpha production by immunocompetent cells under the effects of these hormones.

Adjuvants, Immunologic↗

PubMedDate not supplied

[Effect of chorionic gonadotropin on formation of secondary immune response].

Experiments were carried out in vivo and in vitro. Secondary immune response to sheep red cells was assessed on day 5 after repeated immunization by IgM and IgG antibody-producing cells. Chorionic gonadotropin was injected after reimmunization to intact and ovariectomized animals in doses compatible to those in normal pregnancy. In vitro chorionic gonadotropin was added for one h into sensitized splenocyte cultures and then its effects were assessed in syngeneic transfer system by the same parameters. Experiments have demonstrated that in dose 40 MU chorionic gonadotropin cannot influence secondary immune response formation. All hormonal effects are related to 200 MU dose extrapolated from the maximal level of this hormone during pregnancy. In this dose gonadotropin reduced splenocyte counts and inhibited the formation of IgG-antibody-producing cells. Ovarian sex steroids do not mediate chorionic gonadotropin immunomodulating effects. An hour's contact of sensitized splenocytes with the hormone in a high dose resulted in a statistically significant inhibition of the formation of IgM-antibody-producing cells. Hence, if chorionic gonadotropin interacted with immunocompetent cells before their repeated contact with the antigen, IgM-antibody-producing cells suffer, and if this exposure occurs after this contact, IgG-antibody-producing cells decrease in number. The role of chorionic gonadotropin in development of normal pregnancy and that complicated by immunopathologic processes is discussed.

Adjuvants, Immunologic↗

PubMedDate not supplied

[Second messengers in the realization of immunomodulating effects of chorionic gonadotropin].

The mechanisms of the molecular action of chorionic gonadotropin (CG) at different doses have been studied in splenocyte culture on the level of secondary messengers. It has been demonstrated that in the dose of 40 IU CG suppresses the splenocyte ability to form plaque-forming cells (PFC) only in the presence of macrophages through the eicosanoid system. The dose of 200 IU produced an analogous effect using Ca2+ as the secondary messenger. Transduction of the hormonal signal, leading to immunosuppression does not depend on the inositide system. It is established that in a low dose CG selectively stimulates PFC formation on the condition that there are no macrophages in the cell culture. This effect depends on Ca2+ and inositol phosphates, which are synergists. The dose of 200 IU in the absence of macrophages does not show an immunomodulating effect. We propose the presence of high-affinity receptors for CG on macrophages an B-lymphocytes and low-affinity receptor on T-lymphocyte suppressors, which are associated with "slow" Ca2+ channels.

Adjuvants, Immunologic↗