B lymphocytes are central players in the immune response; canonically, they have been recognized as precursors of antibody-producing cells: plasma cells. Recent findings have shown that the role of B lymphocytes goes far beyond the production of antibodies. There are different subtypes of B lymphocytes with different participations in innate and adaptive responses that include the recognition of the antigen, its processing, and its presentation to T lymphocytes, as well as the production of cytokines that impact and modulate the response toward the pathogen. Traditionally, it has been considered that B lymphocytes do not have phagocytic abilities that allow them to internalize, to process, or even to be infected by bacterial pathogens. The new information has shown that B lymphocytes can be readily infected by bacterial pathogens like Salmonella, Francisella, Moraxella, and Mycobacterium, among others, and respond to those infections. Some of the recent advances on these topics will be presented in this chapter
