PIF2024 - RESPUESTAS IGM E IGD DE MUCOSAS EN PECES: CINETICA, INTERACCIONES, RESPUESTAS SECUNDARIAS/MEMORIA Y QUIMIOTAXIS (PID2023-148142NB-I00)

Although jawed vertebrates contain an adaptive immune system based on immunoglobulins (Ig) and T cell receptors, teleost fish have a singular B cell system that challenges established paradigms on the roles of vertebrate B cells in adaptive immunity. As the adaptive immune response and the consequent generation of immunological memory constitute the basis for vaccination, until we have a complete understanding of how the adaptive immune system works in fish, the generation of vaccines for aquaculture will be a mere trial-and-error process. Specifically, understanding how adaptive responses are induced and regulated in mucosal surfaces that are continuously exposed to the external media, will be essential for the optimization of highly demanded mucosal vaccines. Teleost contain different B cell subsets according to the surface expression of Igs. Some B cells, exclusively express IgT (a fish-specific Ig) on their surface. While these cells have been associated with mucosal responses, there are many aspects of their response to mucosal and systemic antigens that remain unknown. In most systemic compartments, cells co-expressing IgM and IgD constitute the main cell type. Interestingly, these cells are rare in teleost mucosal compartments, where most IgM+ B cells have lost IgD expression. Although these IgM+IgD- B cells have a profile of cells that have experienced a differentiation to plasmablasts/plasma cells, a further differentiation seems feasible in response to mucosal immun