B cell memory in barrier tissues

Dr Mauro Gaya; Centre for Immunology of Marseille-Luminy

Mauro Gaya obtained his BSc degree in Molecular and Cellular Biology from the University of Buenos Aires (2011, Argentina) and his PhD from the University College London (2015, UK). He performed his PhD work at the London Research Institute in the laboratory of Dr. Facundo Batista. While there, he uncovered a role for lymph node resident macrophages in the induction of B cell responses upon infection (Gaya et al. Science 2015). Mauro Gaya performed a postdoctoral stage in between the Francis Crick Institute (London, UK)and the Ragon Institute of MIT and Harvard (Cambridge, USA) still with Dr. Batista. His work led to the discovery of how innate T cell populations initiate the seeding of germinal center reactions during infection (Gaya et al. Cell 2018). Mauro Gaya was recruited to the Luminy Center for Immunology (Marseille, France) in 2018, where he studies B cell immunity in barrier tissues (Gregoire et al. Immunity2022). During this period, Dr Gaya became a Marie Curie fellow, tenured researcher at the National Institute of Health and Medical Research (INSERM) and EMBO Young Investigator. At present, his lab is financed by the ERC Starting Grant program to study the role of the IgA BCR in shaping B cell memory responses.

During infection, the immune system unleashes protective responses to fight against the pathogen while also establishes a memory compartment that will provide protection in case of a subsequent pathogen encounters. The B cell memory compartment is composed of two layers: long-lived plasma cells (LLPCs) and memory B cells (MBCs). LLPCs mainly migrate to the bone marrow, where they continuously secrete high-affinity antibodies and provide protection against re-infection with the same pathogen for years or even for lifetime. In contrast, MBCs remain in a quiescent state in secondary lymphoid organs (spleen and lymph nodes) until a future encounter with the same pathogen or a variant. Only then, MBCs will proliferate and differentiate into antibody-secreting plasma cells to provide a rapid and effective protective response, or re-enter germinal centre reactions, where they will diversify the memory repertoire. In the last years, it became evident than LLPCs and MBCs not only remain in lymphoid organs but further take residence in barrier tissues upon mucosal infections. During my talk, I will discuss how distinct barrier tissues, such as the lungs and the gut, use different B cell memory strategies to fight recurrent pathogens.