Marginal-zone B cell

[6] In humans, but not rodents, marginal zone B cells are also located in the inner wall of the subcapsular sinus of lymph nodes, the epithelium of tonsillar crypts, and the sub-epithelial area of mucosa-associated lymphoid tissues including the sub-epithelial dome of intestinal Peyer's patches.

[2] In specimens where the tyrosine kinase for Pyk-2 has been knocked-out, marginal zone B-cells will fail to develop while B-1 cells will still be present.

[9] The MZ B cells are especially well-positioned as the first line of defense against systemic blood-borne antigens that enter the circulation and become trapped in the spleen.

It is believed that MZ B cells are especially reactive to microbial polysaccharide antigens of encapsulated bacteria such as Streptococcus pneumoniae, Haemophilus influenzae and Neisseria meningitidis.

[5] They are important for antibody-response toward invading pathogens and maintaining homeostasis via opsonization of dead cells and cellular debris.

[2][7] Deficiencies of MZ B cells are associated with a higher risk of pneumococcal infection, meningitis and insufficient antibody response to capsular polysaccharides.

On the other hand, aiding in the clearance of self-antigens is considered an important mechanism to prevent the development of autoimmune diseases.

The role of expanded self-reactive MZ B cells has been observed on mice models of lupus, diabetes and arthritis.