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Biomedical subjects

V G Galaktionov

Publications and source records attributed to V G Galaktionov.

At least 19 recordsLinked to original sources
PubMed1997

The functional transformation of cytotoxic lymphocytes into T-suppressors under the influence of two mediators.

A set of CTL-lines in the system differing in the whole H-2 complex, as well as in distinct subregions of H-2, was established. These lines were routinely tested in Cr51-release assay to insure that they retained lytic activity and antigen-specificity. The result of the interaction of CTL with H-2Kb-molecule and alpha1-thymosine was transition of CTL into a reversible state of anergy. A high concentration of alpha1-thymosine is necessary for this transition. Anergic CTL caused specific suppressor activity that is functional if transformation of CTL into T-suppressors took place.

Animals↗
PubMed1995

The costimulatory and differentiating activity of soluble class I MHC antigens for an autologous thymocyte population.

Combined cultivation of macrophages with syngeneic thymocytes resulted in accumulation of soluble H-2Kk antigens in culture medium. Incubation of intact autologous thymocytes with these soluble class I MHC molecules was shown to induce functional maturation of thymocytes assayed in local graft-vs-host reaction. Similar thymocyte costimulating activity was detected for the papain-solubilized purified H-2Kk antigens. Soluble class I antigens were shown to costimulate IL2 production by thymocytes in response to submitogenic doses of exogenous IL2 and to increase PHA-induced thymocyte proliferation. Soluble class I molecules were shown to increase the level of expression of function-associated membrane antigens, H-2Kk, CD8 and CD4, and to trigger thymocyte differentiation. The expression of I-Ak antigens remained invariable. It was also shown that soluble autologous class I molecules may function as direct amplifiers of thymocyte proliferation in autologous, but not allogeneic, mixed leukocyte reactions. It is concluded that soluble MHC class I molecules are capable of triggering functional and phenotype differentiation of syngeneic thymocytes and acting as restricted coaccessory molecules when thymocyte activation is induced by a submitogenic dose of different stimuli.

Animals↗
PubMed1994

[Immunobiologic characteristics of hybrid proteins consisting of tumor necrosis factor alpha and thymosin alpha 1].

The preparations of alpha 1-thymosin (T), alpha-tumor necrotic factor (TNF) and their based hybrid proteins: T-TNF, TNF-T, and T-TNF-T were studied by using a wide spectrum of immunobiological tests. In the L-929 cells, T-TNF preserved cytotoxicity unique to TNF; TNF-T preserved it 10 times less, and T-NTF-T was completely inactive. TNF-T inhibited the growth of Molt-4, Jm-9, Raji cells by 63 = 84%, and TNF suppressed only Raji cells by 50%. Hybrid proteins caused cell proliferation of the thymus, spleen, and lymph nodes; H-2K, CD4, and CD8 differently increased the expression of thymocytic antigens. The authors found the different effects of the drugs on phagocytosis, the production of antibody-forming cells, delayed reaction, and activation of natural killer cells. The protein T-TNF-T produced the most pronounced action.

Animals↗
PubMed1992

Nonapeptide corresponding to the sequence 27-35 of the mature human IL-2 efficiently competes with rIL-2 for binding to thymocyte receptors [corrected].

Previously it was shown [1] that amino acid substitutions at the region of the first alpha-helix of IL-2 specifically inactivate its reactivity with the intermediate-affinity receptor p70, and mutations in the fifth alpha-helix specifically inactivate the binding to the low-affinity receptor p55. We have synthesized the peptides corresponding to the putative binding site of IL-2 with the intermediate-affinity receptor p70 and found that the nonapeptide corresponding to the sequence 27-35 of the mature IL-2 [2] effectively competes with human rIL-2 for binding to thymocyte receptors. Two types of nonapeptide receptors were revealed: those with Kd1 = 1.84 x 10(-8) M and Kd2 = 1.6 x 10(-7) M. The rIL-2 provides a 100% inhibitory effect on the binding of the 125I-labeled nonapeptide to thymocyte receptors, Ki = 3.5 x 10(-8) M. Low immunoproliferative activity of the peptide allows one to recommend it as a specific antiproliferation drug, IL-2 inhibitor [corrected].

Animals↗
PubMed1991

The octapeptide corresponding to the region of the highest homology between alpha-interferon and thymosin-alpha 1 effectively competes with both cytokines for common high-affinity receptors on murine thymocytes.

The octapeptide corresponding to human interferon-alpha 2 (Hu IFN-alpha 2) sequence 131-138 has high affinity to murine thymocyte receptors (Kd = 4.2 x 10(-12) M, about 700 receptors per cell). The peptide receptor binding is inhibited by both Hu rIFN-alpha 2 (Ki = 8.6 x 10(-10) M) and thymosin-alpha 1 (TM-alpha 1) (Ki = 3 x 10(-7) M) as well as by the octapeptide homologous to the TM-alpha 1 sequence 16-23 (Ki = 4.5 x 10(-7) M). The peptide from IFN-alpha 2 (131-138) activates murine thymocyte blast transformation at a concentration of 10(-11) M in the presence of 2.5 micrograms/ml of concanavalin A.

Amino Acid Sequence↗
PubMed1991

[The dependence of the functional activity of "immune" macrophages on T-cells].

The dependence of the functional activity of the peritoneal macrophages of mice immunized with Francisella tularensis vaccine strain on the presence of T-cells in the culture has been studied. The elimination of "immune" macrophages and sensitized T-lymphocytes by means of anti-Thy-1-2-serum has been shown to lead to a sharp decrease in both ingestive and digestive functions of the phagocytic mononuclears of peritoneal exudate to the level of the activity of macrophages isolated from intact animals.

Animals↗
PubMed1990

[The comparative characteristics of the immunomodulating properties of protein A from Staphylococcus aureus of different origins].

The immunomodulating properties of highly purified staphylococcal protein A and its analog obtained by gene engineering techniques have been compared with those of commercial preparations. The comparison has shown that the differences observed in this investigation may be explained by the presence of admixtures of staphylococcal nature in commercial preparations. The preparations of highly purified staphylococcal and recombinant protein A stimulate humoral immune response and the processes of phagocytosis and do not show mitogenic activity with respect to T cells. The conclusion on the identity of the immunomodulating activity of the preparations of natural and recombinant protein A has been made.

Adjuvants, Immunologic↗
PubMed1989

[Effect of recombinant human alpha-interferon (reaferon) on macrophage functional activity in mice].

The influence of human recombinant alpha 2-interferon (reaferon) on the parameters of the phagocytic activity of mouse peritoneal macrophages (migration, spreading, adhesion and absorption of corpuscular antigen) has been studied. Reaferon in doses of 5-5 X 10(2) I. U./ml has been found to produce a stimulating effect on all parameters under study. The data obtained in this study suggest that a stimulating effect on the functional activity of macrophages is the same for recombinant (alpha 2) interferon and natural alpha-interferon.

Absorption↗
PubMed1989

[The immunoregulatory properties of reaferon].

The influence of human recombinant alpha-interferon (reaferon) on cell-mediated and humoral immune response has been studied. Experimental facts on the blast transformation of lymphocytes, humoral immune response and the reaction of delayed hypersensitivity are presented. The study has shown that reaferon possesses the main immunoregulatory properties, characteristic of natural human leukocytic alpha-interferon. Manifestation of these properties depends on the dose of preparation and the time of its use.

Adjuvants, Immunologic↗
PubMed1987

[The role of major histocompatibility complex genes in the reaction of macrophages and thymocytes during induction of T-effectors of the graft vs host reaction. III. Effect of antisera against H-2 complex antigens on the realization of the process].

The data are presented on the influence of antisera to different products of the histocompatibility gene complex on the interaction between macrophages and thymocytes during the formation of T-cell GVH effectors. The intensity of the local GVH reaction was evaluated by the index of the lymph nodes enlargement. The close physical contact between cells was necessary for the induction of T-effectors GVH. Treatment of macrophages or thymocytes with anti-H-2 and anti-H-2K antibodies, prior to the beginning of combined incubation, or addition of these antisera to the cultural media suppressed the formation of T-cell inducing GVH. Anti-H-2 I and anti-H-2 D sera did not affect the formation of GVH T-effectors.

Animals↗
PubMed1986

[Control by major histocompatibility complex genes of macrophage interaction with thymocytes during induction of T-effectors of graft vs host reaction. I. Genetic control on the cellular level].

H-2 complex control of interaction between macrophages and thymocytes during induction of T-cell effectors GVH was studied. Intensity of the local GVH reaction was evaluated by the index of the lymph nodes enlargement. Genes of the H-2 system control interaction of macrophages with thymocytes during the formation of T-cell effectors GVH. H-2K subregion genes identity of interacting cells was necessary and sufficient for the effective induction of T-effectors GVH. I and D region differences did not affect the formation of T-cells inducing GVH.

Animals↗
PubMed1986

[Control by genes of the major histocompatibility complex of macrophage-thymocyte interaction during induction of T-effectors of graft versus host reaction. II. Analysis at the level of humoral factor activity].

The data are presented on the genetic restriction of interaction between humoral factors and intact thymocytes during the formation of T-cell effectors GVH from thymus cells. The source of humoral factors was a cultural medium from combined cultivation of macrophages and syngeneic thymocytes during 18 h. The intensity of the local GVH reaction was evaluated by the index of the lymph nodes enlargement. Genes of the H-2 system control interaction of mediators with thymocytes during the formation of T-cell effectors. H-2 region genes identity of supernatant generative cells and intact thymocytes was necessary for the effective induction of T-effectors GVH. I and D region differences did not affect the formation of T-cells inducing GVH.

Animals↗