Mucosal B cells and their function
Phillip D. Smith, Richard S. Blumberg, Thomas T. MacDonald in Principles of Mucosal Immunology, 2020
The structure of GALT is similar throughout the gastrointestinal tract with prominent B-cell follicles with intervening T-cell zones. CD4+ T cells in the outermost zone intermingle and interact with antigen-exposed B cells. GALT contains a marginal zone that resembles the splenic marginal zone and is surrounded by and merged with the memory B-cell population (Figure 10.1). Splenic and GALT marginal zone B cells are similar morphologically and are medium-sized cells with cleaved nuclei. These B cells are CD27+IgM+ and do not express high levels of IgD. Splenic marginal zone B cells have mutations in their IgHV genes that are acquired in the germinal centers of GALT. The GALT marginal zone also contains B cells with mutations in IgHV. Internal to and overlapping with the marginal zone is the mantle zone of IgD high naive B cells. The broadest aspect of the often narrow, crescent-shaped mantle zone faces the antigen-exposed FAE. Memory B cells expressing predominantly IgA or IgM (but not IgD) are located on the periphery of the B-cell area of GALT. At the center of the follicle is the germinal center. B cells proliferate and mutate in the cell-dense dark zone of the germinal center and are selected for further antigen-driven mutation and maturation by T-follicular-helper (TFH) cells in the light zone.
Cutaneous Lymphomas
Ayşe Serap Karadağ, Lawrence Charles Parish, Jordan V. Wang in Roxburgh's Common Skin Diseases, 2022
Laboratory studies: Histopathologically, PCMZL shows nodular to diffuse infiltrates of atypical marginal zone B-cells (small lymphocytes with irregular nuclei and abundant pale cytoplasm), reactive T-cells, and plasma cells. The infiltrate may be seen in the dermis and subcutis and may be accompanied by surrounding lymphoid follicles and germinal centers. Reactive plasma cells can be found at the periphery of the infiltrate (Figure 22.11). If plasma cells predominate, it is classified as a PCMZL plasmacytic variant. Immunophenotypically, marginal zone B cells express positivity for CD20 and Bcl-2. Additionally, they are Bcl-6−, CD10−, CD79a+, MUM1−, and CD5−. The reactive germinal centers are Bcl-6+, CD10+, and Bcl-2−, and plasma cells are CD138+ and CD79a+. Immunoglobulin light chain restriction or B-cell monoclonality is observed in malignant marginal zone B cells.
Orders Norzivirales and Timlovirales
Paul Pumpens, Peter Pushko, Philippe Le Mercier in Virus-Like Particles, 2022
Moreover, the Qβ VLPs as a standard antigen contributed markedly to the solution of basic immunological problems. Thus, the in vivo response of marginal zone and follicular B cells to the Qβ VLPs was compared (Gatto et al. 2004; Gatto and Bachmann 2005). The role of the CD21-CD35 complement receptors in the generation of the B-cell memory was elucidated by the immunization of the appropriate deficient mice with the Qβ VLPs (Gatto et al. 2005). It was shown that the early B-cell proliferation and development of B-cell memory in mice were highly antigen-dependent, whereas persisting antigen was not essential for the maintenance of B-cell and antibody memory in the late phase of the response (Gatto et al. 2007b). The heterogeneous antibody repertoire of the marginal zone B-cells was evaluated after immunization of mice with the two different VLPs, namely Qβ and AP205 (Gatto et al. 2007a).
B cells targeting therapy in the management of systemic lupus erythematosus
Published in Immunological Medicine, 2020
Immature B cells exiting from bone marrow enter a transitional phase during which further maturation events occur to produce mature cells. B cells migrate to secondary lymphoid organs (spleen or lymph nodes) where may encounter antigen through interact with dendritic cells or macrophages. B cells can enter in a germinal center or differentiate into a short-lived plasma cell. Within the germinal center, B cells undergo clonal expansion, class switch recombination or somatic hypermutations resulting in antibody-secreting cells, including plasmablasts and plasma cells, and memory cells [17]. B cells can also be divided in marginal zone B cell subsets found in the marginal zone of the spleen, or follicular zone B cell subsets circulating in the periphery. Memory cells generated in the germinal center persist and differentiate into plasma cells in a secondary immune response to provide rapid antibody production [18].
B cells and upper airway disease: allergic rhinitis and chronic rhinosinusitis with nasal polyps evaluated
Published in Expert Review of Clinical Immunology, 2021
Harsha H Kariyawasam, Louisa K James
Early B-cell development occurs in bone marrow where the immunoglobulin variable gene is generated by somatic recombination of V (variable) D (diversity) J (joining) segments at the heavy-chain locus and VJ segments at the light-chain locus. The breath-taking diversity of the variable regions is created through the random rearrangement of these gene segments and is further increased by deletion or insertion of nucleotides at the junctions during recombination. It is estimated that the antigen-naïve repertoires could theoretically exceed 1016 variants [35] and in practical terms means that each newly generated B cell has an entirely unique antigen-binding site. Positive selection of immature B cells expressing a functional BCR on their surface permits their exit out of the bone marrow and into the periphery. Further maturation of immature B cells through two distinct transitional stages occurs prior to their commitment to either the follicular or marginal zone B fate, thought to depend in part on the strength of signaling through the BCR [36]. Marginal zone B cells largely reside within discrete spatial regions of secondary lymphoid tissue such as the spleen. They are innate-like B cells important for generating immunity to blood-borne bacterial antigens through rapid production of antibody [37]. The majority of immature B cells become follicular B cells which recirculate through SLOs until they become activated following antigen encounter.
Splenic marginal zone B-cell lymphoma associated with ruptured breast implants: case report and review of the literature
Published in Case Reports in Plastic Surgery and Hand Surgery, 2021
Mark G. Evans, Melissa A. Mueller, Frederik Chen, Larry S. Nichter
Splenic marginal zone B-cell lymphoma is a rare malignancy, accounting for less than 2% of all lymphoma cases [12]. It was first described in 1992 and is now considered a separate entity in the World Health Organization (WHO) classification [13]. The three types of marginal zone B-cell lymphomas are splenic marginal zone lymphoma (SMZL), nodal marginal zone lymphoma (NMZL), and extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma). The diagnosis of SMZL is made based on lymphocyte morphology, immunophenotype, cytogenetic abnormalities, bone marrow histology, and spleen histology if available. When microscopic examination of the spleen is not possible, clinical splenomegaly and typical morphologic and immunophenotypic blood and bone marrow findings are sufficient to make a diagnosis.
Related Knowledge Centers
- B Cell
- Cd1
- Complement Receptor 2
- Immunoglobulin D
- Immunoglobulin M
- Spleen
- Lymphatic System
- Marginal Zone
- B-Cell Receptor
- Toll-Like Receptor