Browsing by Author "Morsy, Deyaa El Deen"
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- ItemOpen AccessFunctional characterization of murine cd20(2012) Morsy, Deyaa El Deen; Deans, JulieCD20 is a tetraspanning membrane protein that is expressed on B lymphocytes, and functions in B cell receptor (BCR)-mediated calcium entry. The effect of murine CD20 deficiency on calcium mobilization was examined in two previous studies, with inconsistent findings. Humoral immunity induced in the context of murine CD20 deficiency was characterized by a reduction in T -independent responses, but normal TĀdependent (TD) immune responses. In the current study, I examined the in vitro calcium responses of murine CD20-1- B cells, and the in vivo TD immune responses of CD20-1- mice. I confirmed that BCR-mediated calcium mobilization was reduced in CD20-1- B cells following BCR stimulation. However, calcium responses following CD 19 ligation, and following BCR-CD 19 co-ligation were enhanced, suggesting an indirect role for CD20 in calcium entry rather than direct involvment as a calcium channel. TD immune responses against adeno-associated virus (AA V) and sheep red blood cells (SRBC) were characterized by reduced neutralizing antibody response to AA V, and reduced primary (IgM) and secondary (IgGl and IgG2b) responses to SRBC. The anti-SRBC response was associated with reduced germinal center B cell numbers. Further evaluation of B cells from unimmunized CD20-1- mice revealed increased CD20-1- B cell adhesion, enhanced LF A-1 expression and activation, and enhanced transmigration. The current data characterize a new phenotype for murine CD20 deficiency, and support a role for CD20 in in vivo B cell function.