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. They have the advantages of being applicable on all types of mice independently of the presence of a transgenic BCR and to give multiple readout of the antigen-specific immune response and affinity maturation. Although first developed more than 20 years ago, these techniques are still considered to be the gold standard for the analysis of affinity maturation in vivo.