B1b Cells Recognize Protective Antigens after Natural Infection and Vaccination

Abstract

There are multiple, distinct B-cell populations in human beings and other animals such as mice. In the latter species, there is a well-characterized subset of B-cells known as B1 cells, which are enriched in peripheral sites such as the peritoneal cavity but are rare in the blood. B1 cells can be further subdivided into B1a and B1b subsets. There may be additional B1 subsets, though it is unclear if these are distinct populations or stages in the developmental process to become mature B1a and B1b cells. A limitation in understanding B1 subsets is the relative paucity of specific surface markers. In contrast to mice, the existence of B1 cells in human beings is controversial and more studies are needed to investigate the nature of these enigmatic cells. Examples of B1b antigens include pneumococcal polysaccharide and the Vi antigen from Salmonella Typhi, both used routinely as vaccines in human beings and experimental antigens such as haptenated-Ficoll. In addition to inducing classical T-dependent responses some proteins are B1b antigens and can induce T-independent (TI) immunity, examples include factor H binding protein from Borrelia hermsii and porins from Salmonella. Therefore, B1b antigens can be proteinaceous or non-proteinaceous, induce TI responses, memory, and immunity, they exist in a diverse range of pathogenic bacteria, and a single species can contain multiple B1b antigens. An unexpected benefit to studying B1b cells is that they appear to have a propensity to recognize protective antigens in bacteria. This suggests that studying B1b cells may be rewarding for vaccine design as immunoprophylactic and immunotherapeutic interventions become more important due to the decreasing efficacy of small molecule antimicrobials.

B‐1 lymphocytes in mice and nonhuman primates

“…B‐1a and B‐1b cells are mouse B cell populations with unique developmental, phenotypic, and functional characteristics . B‐1b cells have been studied far less frequently than B‐1a cells, and their role in the immune system has only been recently become appreciated.…”

Controlled Human Malaria Infection: Applications, Advances, and Challenges

“…Mice infected with such attenuated strains of Salmonella spp. resolve the infection over a period of 5 to 6 weeks through the induction of CD4 ϩ Th1 cells and IgG antibody (35). The defined kinetics of this Salmonella infection allows antigen-specific T cell and antibody responses to be monitored.…”

“…Early secretory antigen 6 (ESAT-6) of Mycobacterium tuberculosis was chosen as the model antigen because it is a nonnative protein which induces specific cells that can be detected ex vivo. S. Typhimurium SL3261 was chosen for delivery because it is an attenuated strain that is able to cause a sustained yet limited infection of mice and disseminates to multiple organs, such as the spleen and liver (35). Mice infected with such attenuated strains of Salmonella spp.…”

Evasion and interactions of the humoral innate immune response in pathogen invasion, autoimmune disease, and cancer

“…3). NAb interact with serum lectins and the complement cascade similar to Ab from the adaptive response [124, 127, 128]. As such, these Ab protect the host with a basal level of immunity to pathogens but as NAb recognize self antigens, an excessive response may result in pathology.…”

“…Among other functions, NAb protect the host from Ag that do not develop monoreactive Ab, such as capsular polysaccharides [128]. Pathogens will encounter these Ab almost immediately as they are constantly present in normal serum, though they degrade more quickly than monoreactive Ab [123, 127, 132].…”