Innate Lymphoid Cells, their Biological Characteristic and Role in Immunopathological Processes
Milan BUC
Institute of Immunology, Comenius University Faculty of Medicine, Bratislava, Slovakia
Innate lymphoid cells (ILCs) are among the most recently identified cell populations that contribute to immune responses. ILCs lack antigen-specific receptors that characterise T and B lymphocytes. In contrast to cells of adaptive immunity, ILCs lack somatic rearrangement of antigen-specific receptors and do not express T-cell or B-cell receptors (TCRs or BCRs). ILCs arise from hematopoietic common lymphoid progenitors in the bone marrow; however, full ILC maturation occurs in non-lymphoid tissues, where immature ILCs take up residence. ILCs are under-represented in lymphoid tissues, but parenchymal tissues, especially mucosal surfaces, show substantial enrichment for ILCs. In the mucosa of the intestine and lungs, ILCs seem to be particularly important regulators of epithelial barriers. Because of their strategic location, ILCs are among the first immune cells to respond to pathogens, inducing infection-related responses and shaping the adaptive immune response. Innate lymphoid cells are divided into three groups, ILC1, ILC2, and ILC3, each of which performs specific functions and cooperates with other cells of the immune system, thereby supporting immune defence and homeostasis. ILC cells also contribute to the inflammation and tissue damage in some diseases by producing cytokines that drive inflammatory responses.
DOI: 10.29245/2578-3009/2026/1.1268 View / Download PdfSkin mucus N-glycolylneuraminic acid relates to mucous cell parameters in Atlantic salmon
Grigory V. Merkin1*, Anette Sauve2, Mearge A. Okubamichael1, Trond-Inge Kvernevik3, Karin Pittman1,4**
1QuantiDoc AS, 5006 Bergen, Norway
2Vitas AS, 0349 Oslo, Norway
3Caligen Holding AS, 6700 Måløy, Norway
4University of Bergen, 5006 Bergen, Norway.
Sialic acids (Sias) in fish skin mucus play a crucial role in mediating interactions with the surrounding environment, serving as key components of the protective mucus that coats the fish. Sias contribute to the physical and chemical barriers that protect fish from pathogens and support mutualistic relationships with bacteria. In Atlantic salmon (Salmo salar), N-Glycolylneuraminic sialic acid (Neu5Gc) concentration in skin mucus and skin mucous cell (MC) parameters such as size, abundance, and volumetric density were monitored during the transition from freshwater to seawater across five sampling dates. A significant positive regression was observed between Neu5Gc concentration (free Neu5Gc and total Neu5Gc, encompassing both free and bound forms) and MC parameters in four of the five sampling points, suggesting a relationship between mucous barrier characteristics and Neu5Gc concentration in the mucus. Moreover, the transition to seawater resulted in a significant decrease in both MC parameters and Neu5Gc concentration (p < 0.05). Together, these findings support the interpretation that MCs represent a source of Neu5Gc in the skin mucus and that both Neu5Gc levels and MC characteristics appear to change during the transition to seawater.
DOI: 10.29245/2578-3009/2026/1.1264 View / Download Pdf