A high-dimensional cytometry atlas of peripheral blood over the human life span.

Age can profoundly affect susceptibility to a broad range of human diseases. Children are more susceptible to some infectious diseases such as diphtheria and pertussis, while in others, such as coronavirus disease 2019 and hepatitis A, they are more protected compared with adults. One explanation is that the composition of the immune system is a major contributing factor to disease susceptibility and severity. While most studies of the human immune system have focused on adults, how the immune system changes after birth remains poorly understood. Here, using high-dimensional spectral flow cytometry and computational methods for data integration, we analyzed more than 50 populations of immune cells in the peripheral blood, generating an immune cell atlas that defines the healthy human immune system from birth up to 75 years of age. We focused our efforts on children under 18 years old, revealing major changes in immune cell populations after birth and in children of schooling age. Specifically, CD4⁺ T effector memory cells, Vδ2⁺ gamma delta (γδ)T cells, memory B cells, plasmablasts, CD11c⁺ B cells and CD16⁺ CD56^bright natural killer (NK) cells peaked in children aged 5-9 years old, whereas frequencies of T helper 1, T helper 17, dendritic cells and CD16⁺ CD57⁺ CD56^dim NK cells were highest in older children (10-18 years old). The frequency of mucosal-associated invariant T cells was low in the first several years of life and highest in adults between 19 and 30 years old. Late adulthood was associated with fewer mucosal-associated invariant T cells and Vδ2⁺ γδ T cells but with increased frequencies of memory subsets of B cells, CD4⁺ and CD8⁺ T cells and CD57⁺ NK cells. This human immune cell atlas provides a critical resource to understand changes to the immune system during life and provides a reference for investigating the immune system in the context of human disease. This work may also help guide future therapies that target specific populations of immune cells to protect at-risk populations.

Ontogenetic Transfer of Microplastics in Bloodsucking Mosquitoes Aedes aegypti L. (Diptera: Culicidae) Is a Potential Pathway for Particle Distribution in the Environment

The uptake and accumulation of microplastics (MPs) by bloodsucking mosquitoes Aedes aegypti L., carriers of vector-borne diseases, were investigated in the laboratory. In the experimental group, polystyrene (PS) particles were registered in insects of all life stages from larvae to pupae and adults. Ae. aegypti larvae readily ingested MPs with food, accumulating on average 7.3 × 106 items per larva in three days. The content of PS microspheres significantly decreased in mosquitoes from the larval stage to the pupal stage and was passed to the adult stage from the pupal without significant loss. On average, 15.8 items were detected per pupa and 10.9 items per adult individual. The uptake of MPs by Ae. aegypti did not affect their survival, while the average body weight of mosquitoes of all life stages that consumed PS microspheres was higher than that of mosquitoes in the control groups. Our data confirmed that in insects with metamorphosis, MPs can pass from feeding larvae to nonfeeding pupae in aquatic ecosystems and, subsequently, to adults flying to land. Bloodsucking mosquitoes can participate in MP circulation in the environment.

Immunoregulatory role of nucleated erythroid cells

Nucleated erythroid cells (NEC) are the precursors of the most massive population of human cells – erythrocytes, for which functions of hemo- and immunoregulation have been shown at various stages of ontogenesis and in various organs and tissues of the human body. NEC perform this function by secreting cytokine proteins, growth factors, enzymes such as arginase-2, ROS, and by surface molecules PD-L1 and PD-L2. Their important regulatory role has been shown for the formation of fetoplacental immunosuppression, immunosuppression during pregnancy, suppression of the response against commensals in the gastrointestinal tract, in the pathogenesis of bacterial and viral infections in adults, in the pathogenesis of tumor growth and autoimmune diseases, as well as participation in the recognition of pathogen-associated molecular patterns using Toll-like receptors in fish and birds. Such qualities, together with their number and width of distribution, represent NEC as active participants in hemo- and immunoregulation, which makes it important to study their regulatory role in health and disease.

Diet and Lifestyle Guidelines for Immunomodulation with Reference to Corona Virus Pandemic: A Scientific Statement of the International College of Nutrition

The immune system is comprised of lymph glands, lymph nodes, thymus gland, spleen, bone marrow, lymphocytes, and molecules such as antibodies and cytokines. It has a vast array of functionally different cells such as T and B lymphocytes, macrophages, neutrophils and mast cells. The ontogenesis of the immune system is comprised of the innate immune cells and the adaptive immune cells, where innate immune cells are the first defense mechanisms to respond to pathogenic environmental factors. There are multiple components of the adaptive immune cells, including immunoglobulins (Igs), T-cell receptors (TCR), and major histocompatibility complex (MHC) responsible for adaptive immunity. However, many elements of both the innate and adaptive immune systems are conserved in our bodies. The adaptive immunity is a type of immunity that develops when a person’s immune cells respond to a pathogen such as microorganism or vaccination. Environmental factors such as pathogenic bacteria or viruses, solar exposure, age, exercise, stress, diet, sleep quality and air pollutants can influence the immune system. There may be marked decline in the immune function due to attack of COVID-19. Most patients with mild COVID-19 develop an appropriate immune response that culminates with viral clearance. However, severe disease manifestations have been linked to lymphopenia and immune hyper-responsiveness leading to cytokine storm. It has been observed that in COVID-19, alveolar macrophages are epigenetically altered after inflammation, leading to long-term lung immune-paralysis. Western diets are known to have adverse effects on the immune function. However, Mediterranean-type diets rich in short-and long-chain polyunsaturated fatty acids (PUFA), vegetables, nuts and fruits, dairy products and fish and red wine, due to high content of vitamins, minerals and flavonoids may be useful in boosting immunity. Moderate physical activity may also cause an extensive increase in numerous and varied lipid super-pathway metabolites, including oxidized derivatives called oxylipins. Emerging evidence suggests that dietary supplements containing flavonoids, carotenoids, coenzyme Q10 (CoQ10), vitamins, minerals and antioxidants modulate gene and protein expression and thereby modify endogenous metabolic pathways, and consequently enhance the immunity. Mediterranean-type diet and multiple bioactive nutrients, fatty acids, amino acids, vitamins and minerals as well as moderate physical activity may be crucial for enhancing immunomodulation.