Effect of Short Peptides of Pregnancy-Specific ß1-Glycoprotein on Differentiation of Human Regulatory T Cells In Vitro and on Their Cytokine Profile.

Pregnancy-specific ß1-glycoprotein (PSG), one of the most important proteins of pregnancy, has a pronounced immunosuppressive effect. Short peptides of PSG, the so-called SLiMs (short linear motifs), are promising molecules for mild immunosuppression. We studied in vitro effect of short PSG peptides (YACS, YQCE, YVCS, and YECE) on differentiation and cytokine profile of human T-regulatory lymphocytes (Treg). T helpers isolated from the peripheral blood and polarized into the Treg phenotype with a T-cell activator (anti-CD2/3/28) and the cytokines IL-2 and transforming grown factor ß (TGFß) were used. PSG peptides were shown to have no direct modulatory effect on Treg differentiation in a culture of CD4+ cells polarized to the Treg phenotype. At the same time, PSG peptides had no effect on the viability and number of CD4+ cells in the in vitro culture. PSG peptides also had no effect on the levels of TNFα, IL-8, IL-2, macrophage inflammatory protein 1ß, IL-17, IL-10, IL-6, granulocyte-macrophage CSF, monocyte chemoattractant protein 1, IL-13, IL-5, IL-7, IL-12(p70), IL-1ß, granulocyte CSF, IL-4, but decreased IFNγ levels. The observed ability of the YQCE peptide to reduce the production of this proinflammatory Th1 cytokine by T helper cells can be interpreted as a positive effect. Our findings can be used for further development of safe peptide drugs based on SLiMs sequences.

In HIV-Infected Immunological Non-Responders, Hepatitis C Virus Eradication Contributes to Incomplete Normalization of Systemic Inflammation Indexes, but Does Not Lead to Rapid CD4+ T-Cell Count Recovery.

In HIV-positive individuals taking antiretroviral therapy, coinfection with hepatitis C virus (HCV) increases systemic inflammation, which interferes with the CD4+ T-cells regeneration. This study evaluated the effect of HCV eradication on systemic inflammation and CD4+ T-cell regeneration in patients who gave poor response to antiretroviral therapy, the so-called "immunological non-responders" (INRs). HIV-infected patients who received a course of direct-acting antivirals for treating hepatitis C were examined. The control groups included HIV/HCV-coinfected INRs and relatively healthy volunteers. It was established for the first time that HCV eradication is not accompanied by a complete suppression of systemic inflammation, but improves the T-cell pool composition: in INRs, the blood CD4+/CD8+ T-lymphocyte ratio increases and approaches those of healthy individuals. Apparently, in INRs treated for hepatitis C, the immune system recovery takes time and may be incomplete.

Effect of PEGylated Graphene Oxide Nanoparticles on the Metabolism of Jurkat Cells.

The effect of graphene oxide (GO) nanoparticles of 100-200 nm in size coated with linear (LP-GO) and branched (BP-GO) polyethylene glycol at concentrations of 5 and 25 µg/mL on the metabolism of Jurkat tumor cells was studied. It was found that LP-GO nanoparticles at a concentration of 25 µg/mL can enhance basal glycolysis of Jurkat T-lymphocyte tumor cell line cells, while LP-GO and BP-GO at the same concentration can reduce the indicators of compensatory glycolysis. Despite this, GO nanoparticles coated with linear and branched PEG at a concentration of 5 µg/mL do not have pronounced effects on oxidative phosphorylation and glycolysis of Jurkat cells and could therefore be safe for activated T cells.

Alpha-Fetoprotein as a Factor of Differentiation and Functional Activity of Myeloid-Derived Suppressor Cells.

We studied the role of alpha-fetoprotein (AFP) in regulation of differentiation and functional activity of human myeloid-derived suppressor cells (MDSC) in vitro. To obtain MDSC, CD11b+ cells were isolated from the peripheral blood of healthy donors followed by cytokine induction (IL-1ß+GM-CSF) into the MDSC phenotype. The cell functions were assessed by the expression of indoleamine 2,3-dioxygenase (IDO) and arginase-1 (Arg1) and cytokine profile of the cell cultures. Native AFP did not affect the total number of MDSC and the percentage of polymorphonuclear MDSC (PMN-MDSC), but increased the number of monocytic MDSC (M-MDSC). AFP did not change the expression of Arg1, but in low concentrations (10 and 50 U/ml) increased the number of IDO-containing cells. AFP modulated the cytokine profile of CD11b+ cells: it reliably decreased the level of IL-19 (50 and100 U/ml) and showed a tendency to decrease the levels of IL-34, MMP-2, sCD163, CHI3L1, OPN and to increase the levels of IL-29, IL-32, APRIL, PTX3, and sTNF-R1. Thus, we have demonstrated a regulatory effect of native AFP at the level of MDSC generated from CD11b+ cells under conditions of cytokine induction in vitro.

Effect of Glycodelin on the Cytokine Profile of Rats during Allogeneic Bone Marrow Cell Transplantation.

The protein glycodelin (PP14, PAEP) is associated with pregnancy and exhibits pronounced immunotropic properties. We studied the effect of glycodelin on the cytokine profile of blood serum during transplantation a suspension of allogeneic red bone marrow cells to Wistar rats. Recombinant glycodelin was administered to the animals 4 times (14 µg each time). Against the background of bone marrow cell transplantation, the levels of proinflammatory (IL-1α, IL-1ß, and IL-18) and regulatory (IL-7, IL-12) cytokines and CSF (M-CSF) increased in blood serum, which indicates a systemic inflammatory response to the allograft. Glycodelin administration against the background of bone marrow cell allotransplantation led to a significant decrease in the proinflammatory cytokine IL-17A on day 21 of the experiment; the concentrations of the other cytokines remained unchanged. In general, glycodelin can suppress the level of IL-17A, a marker of graft rejection, which opens perspectives for its further investigation as a potential drug.

The Role of Recombinant Glycodelin in the Differentiation of Regulatory T-Lymphocytes.

The effect of recombinant glycodelin (GdA) on the number of T-regulatory lymphocytes (Treg) in a culture of activated CD4+ lymphocytes was investigated, while simultaneously assessing the proliferative status of the cells. Recombinant GdA from E. coli and from HEK293 cells were used in the study at concentrations of 0.2; 2 and 10 µg/mL. It was found that only a low concentration (0.2 µg/mL) of recombinant GdA of bacterial origin reduced the number of proliferating CD4+ lymphocytes as well as the number of Treg (CD4+CD25highCD127-/low) in the experimental system in vitro.

Interaction of Human Dendritic Cells with Graphene Oxide Nanoparticles In Vitro.

We studied the effect of graphene oxide nanoparticles on the differentiation of human dendritic cells and uptake of nanoparticles by these cells in vitro. The objects of the study were mononuclear cells from healthy donors induced into the phenotype of dendritic cells by cytokines (IL-6 and GM-CSF). We used graphene oxide nanoparticles of different sizes functionalized with linear or branched PEG (P-GO or bP-GO) in concentrations of 5 and 25 µg/ml. It was found that graphene oxide nanoparticles did not affect the viability and percentage of dendritic cells in the culture. However, P-GO nanoparticles (25 µg/ml) suppressed the expression of CD83 on the surface of dendritic cells in cultures, thereby suppressing cell differentiation. Dendritic cells internalized P-GO nanoparticles, particles in high concentration were more actively engulfed, but the size of the particles and the type of PEG did not affect the intensity of this process. In general, P-GO nanoparticles in a concentration of 25 µg/ml can regulate differentiation of dendritic cells by suppressing their maturation.

Effect of Alpha-Fetoprotein on Differentiation of Myeloid Supressor Cells.

The effect of recombinant alpha-fetoprotein (AFP) on human myeloid suppressor cell (MDSC) differentiation was studied in vitro in the presence of cytokines IL-6 (10 ng/mL) and GM-CSF (10 ng/mL). It was found that AFP at concentrations of 50 and 100 IU/mL increased the number of MDSC (CD33+ HLA-DR-/lowCD11b+) in culture. Analysis of MDSC subpopulations showed that the increase was due to monocytic M-MDSC (HLA-DR-/lowCD33+CD11b+CD14+CD66b-). There was no modulating effect of AFP on granulocytic PMN-MDSC (HLA-DR-/lowCD33+CD11b+CD14-CD66b+). The effects of recombinant AFP on MDSC differentiation were thus demonstrated for the first time.

Effect of Graphene Oxide Nanoparticles on Differentiation of Myeloid Suppressor Cells.

We studied the effect of graphene oxide (GO) nanoparticles on differentiation of human myeloid suppressor cells (MDSC) in an in vitro system. Separated mononuclear cells of healthy donors were induced with cytokines (IL-6 and GM-CSF) into the MDSC phenotype (both polymorphonuclear (PMN-MDSC) and monocyte (M-MDSC) subsets of these cells were taken into account). Pegylated GO nanoparticles (GO-PEG; mean size 569±14 nm, PEG content ~20%) were used. GO-PEG in low concentrations (2.5 and 5 µg/ml) increased the percentage of MDSC in cultures, but reduced their content in high concentration (10 µg/ml). After exposure to GO-PEG (2.5 and 5 µg/ml), the MDSC content increased at the expense of M-MDSC, while the level of PMN-MDSC did not change. The decrease in MDSC levels after exposure to high doses of GO-PEG (10 µg/ml) was due to a decrease in PMN-MDSC. Thus, GO-PEG nanoparticles can oppositely regulate differentiation of MDSC by inhibiting or stimulating differentiation of these cells depending on the concentration.