Discovery of an ancient MHC category with both class I and class II features

Two classes of major histocompatibility complex (MHC) molecules, MHC class I and class II, play important roles in our immune system, presenting antigens to functionally distinct T lymphocyte populations. However, the origin of this essential MHC class divergence is poorly understood. Here, we discovered a category of MHC molecules (W-category) in the most primitive jawed vertebrates, cartilaginous fish, and also in bony fish and tetrapods. W-category, surprisingly, possesses class II–type α- and β-chain organization together with class I–specific sequence motifs for interdomain binding, and the W-category α2 domain shows unprecedented, phylogenetic similarity with β2-microglobulin of class I. Based on the results, we propose a model in which the ancestral MHC class I molecule evolved from class II–type W-category. The discovery of the ancient MHC group, W-category, sheds a light on the long-standing critical question of the MHC class divergence and suggests that class II type came first.

DNA/RNA heteroduplex oligonucleotide technology for regulating lymphocytes in vivo

Manipulating lymphocyte functions with gene silencing approaches is promising for treating autoimmunity, inflammation, and cancer. Although oligonucleotide therapy has been proven to be successful in treating several conditions, efficient in vivo delivery of oligonucleotide to lymphocyte populations remains a challenge. Here, we demonstrate that intravenous injection of a heteroduplex oligonucleotide (HDO), comprised of an antisense oligonucleotide (ASO) and its complementary RNA conjugated to α-tocopherol, silences lymphocyte endogenous gene expression with higher potency, efficacy, and longer retention time than ASOs. Importantly, reduction of Itga4 by HDO ameliorates symptoms in both adoptive transfer and active experimental autoimmune encephalomyelitis models. Our findings reveal the advantages of HDO with enhanced gene knockdown effect and different delivery mechanisms compared with ASO. Thus, regulation of lymphocyte functions by HDO is a potential therapeutic option for immune-mediated diseases.

RELATIONSHIP OF LYMPHOCYTE SUBPOPULATIONS IN BREAST CANCER PATIENTS WITH TREATMENT RESULTS

Introduction. Breast cancer (BC) is an immunogenic tumor. Immune cells infiltration of tumor tissue can affect the clinical course of the disease. The immunogenicity of breast cancer varies depending on the molecular subtype.The aim of this work was to study the main indicators of systemic and local immunity before patient’s treatment and to determine their relationship with the immediate neoadjuvant chemotherapy results.Materials and methods. Patients with stage II–III BC received standard neoadjuvant chemotherapy in accordance with the molecular subtypes. The percentage of the main effector and regulatory lymphocytes populations of systemic and local immunity was determined by flow cytometry.Results. A decrease in the level of effector CD8 and CD4 lymphocyte populations and an increase in the level suppressor populations in tumor tissue in comparison with peripheral blood indicate an immunosuppressive state of local immunity in BC patients. In tumor tissue, a high level of CD8+ PD-1+ and CD4+ PD-1+ cells were associated with a high level of regulatory CD4+ CD25highCD127–/low and CD8+ CD11b– CD28– lymphocytes. Differences were found in the significance of individual lymphocyte populations for the immediate results of treatment between patients with different subtypes of breast cancer.Conclusion. Determination of lymphocyte subpopulations correlating with the level of PD-1 cells, and the results of treatment in patients with different molecular BC subtypes, will help a clearer understanding of the antitumor immune response in this pathology, and will also serve as a basis for identifying immune biomarkers that can be used as additional predictive factors in various treatment options for BC patients.

Computational systematics of nutritional support of vaccination against viral and bacterial pathogens as prolegomena to vaccinations against COVID-19

A total of 6,628 PUBMED-registered publications on the relationships between the effects of vaccination and the provision of micronutrients have been studied by methods of topological analysis of text data. In case of insufficient intake of certain micronutrients, the functioning of the acquired immunity is disrupted resulting in an imbalance of populations of T-cells CD4+/CD8+ and of B-lymphocytes. Nutritional supplements of folate, vitamins A, D and B12, which are recognized regulators of cell division, support a wide range of lymphocyte populations. Trace elements zinc, iron, selenium, manganese and omega-3 polyunsaturated fatty acids are also important for supporting the mechanisms of acquired immunity. The data presented show that a course intake of these micronutrients by patients planning vaccination can significantly improve its effectiveness. In particular, these micronutrients can increase the titers of antibodies to pathogens, and to reduce the percentage of patients who still contract infection after vaccination. Supplements of these micronutrients can also contribute to the safety of vaccination: to prevent malaise and, in the unfortunate case of contracting infection despite the vaccine, to reduce the severity of the course and the mortality from the corresponding infection.

Flow cytometry evaluation of the rhesus monkey cellular immunity following the Zaire ebolavirus (Filoviridae; Ebolavirus: Zaire ebolavirus) experimental infection

Introduction. The outbreaks of the Zaire ebolavirus (ZE) disease (ZED) that have arisen in the last decade determine the need to study the infection pathogenesis, the formation of specific immunity forming as well as the development of effective preventive and therapeutic means. All stages of fight against the ZED spread require the experimental infection in sensitive laboratory animals, which are rhesus monkeys in case of this disease .The aim of the study is to evaluate the rhesus monkey cellular immunity following the ZE experimental infection by the means of flow cytometry (cytofluorimetry).Material and methods. Male rhesus monkeys were intramuscularly infected by the dose of 15 LD50 (dose of the pathogen that causes 50% mortality of infected animals) of the ZE, the Zaire strain (ZEBOV). Levels of 18 peripheral blood lymphocyte populations of the animals before the ZE experimental infection and at the terminal stage of the disease were assessed using flow cytometry.Results and discussion. The certain changes in the levels of the lymphocyte populations were observed following infection, indicating simultaneous activation and suppression of the immune system during ZED. The increase in content was observed for T-lymphocytes, T-helper and cytotoxic T-lymphocytes expressing the corresponding markers of early activation. The decrease was recorded for T-lymphocytes and double-positive T-lymphocytes expressing corresponding markers of late activation, as well as natural killer cells expressing CD8 (p < 0.05).Conclusion. For the first time in the Russian Federation, the rhesus monkey cellular immunity before and after the ZE experimental infection was assessed using flow cytometry.

Differential DNA Damage Response of Peripheral Blood Lymphocyte Populations

DNA damage occurs constantly in every cell triggered by endogenous processes of replication and metabolism, and external influences such as ionizing radiation and intercalating chemicals. Large sets of proteins are involved in sensing, stabilizing and repairing this damage including control of cell cycle and proliferation. Some of these factors are phosphorylated upon activation and can be used as biomarkers of DNA damage response (DDR) by flow and mass cytometry. Differential survival rates of lymphocyte subsets in response to DNA damage are well established, characterizing NK cells as most resistant and B cells as most sensitive to DNA damage. We investigated DDR to low dose gamma radiation (2Gy) in peripheral blood lymphocytes of 26 healthy donors and 3 patients with ataxia telangiectasia (AT) using mass cytometry. γH2AX, p-CHK2, p-ATM and p53 were analyzed as specific DDR biomarkers for functional readouts of DNA repair efficiency in combination with cell cycle and T, B and NK cell populations characterized by 20 surface markers. We identified significant differences in DDR among lymphocyte populations in healthy individuals. Whereas CD56+CD16+ NK cells showed a strong γH2AX response to low dose ionizing radiation, a reduced response rate could be observed in CD19+CD20+ B cells that was associated with reduced survival. Interestingly, γH2AX induction level correlated inversely with ATM-dependent p-CHK2 and p53 responses. Differential DDR could be further noticed in naïve compared to memory T and B cell subsets, characterized by reduced γH2AX, but increased p53 induction in naïve T cells. In contrast, DDR was abrogated in all lymphocyte populations of AT patients. Our results demonstrate differential DDR capacities in lymphocyte subsets that depend on maturation and correlate inversely with DNA damage-related survival. Importantly, DDR analysis of peripheral blood cells for diagnostic purposes should be stratified to lymphocyte subsets.

Protective Immunity Induced by TgMIC5 and TgMIC16 DNA Vaccines Against Toxoplasmosis

Toxoplasma gondii is an obligate intracellular parasite, which is responsible for a widely distributed zoonosis. Effective vaccines against toxoplasmosis are necessary to protect the public health. The aim of this study is to evaluate the immune efficacy of DNA vaccines encoding TgMIC5 and TgMIC16 genes against T. gondii infection. The recombinant plasmid pVAX-MIC5 and pVAX-MIC16 were constructed and injected intramuscularly in mice. The specific immune responses and protection against challenge with T. gondii RH tachyzoites were evaluated by measuring the cytokine levels, serum antibody concentrations, lymphocyte proliferation, lymphocyte populations, and the survival time. The protection against challenge with the T. gondii RH tchyzoites and PRU cysts was examined by evaluation of the reduction in the brain cyst burden. The results indicated that immunized mice showed significantly increased levels of IgG, IFN-γ, IL-2, IL-12p70, and IL-12p40 and percentages of CD4+ and CD8+ T cells. Additionally, vaccination prolonged the mouse survival time and reduced brain cysts compared with controls. Mouse groups immunized with a two-gene cocktail of pVAX-MIC5 + pVAX-MIC16 were more protected than mouse groups immunized with a single gene of pVAX-MIC5 or pVAX-MIC16. These results demonstrate that TgMIC5 and TgMIC16 induce effective immunity against toxoplasmosis and may serve as a good vaccine candidate against T. gondii infection.