Efficient Plasma Cell Differentiation and Trafficking Require Cxcr4 Desensitization.

CXCR4 plays a central role in B cell immune response, notably by promoting plasma cell (PC) migration and maintenance in the bone marrow (BM). Gain-of-function mutations in CXCR4 affecting receptor desensitization have been reported in the rare immunodeficiency called WHIM syndrome (WS). Despite lymphopenia, patients mount an immune response but fail to maintain it over time.

Assessing T follicular helper cell function in vivo: antigen-specific B cell response to hapten and affinity maturation.

The mechanisms controlling affinity maturation have been extensively studied over the last 20 years and the central role of T follicular helper cells (Tfh) in this process has now been clearly established. In order to analyze how Tfh impact on affinity maturation several models have been developed. This chapter aims to present three different techniques to evaluate antigen-specific B cell response and affinity maturation using the NP system: Flow cytometric single cell sorting and sequence analysis, ELISA and ELISpot.