Anti-CD40 (aa 100-200) polyclonal antibody

PI3K plays multiple roles throughout the life of a B cell. As such, its signaling is tightly regulated. The importance of this is illustrated by the fact that both loss- and gain-of-function mutations in PI3K can cause immunodeficiency in humans. PIK3IP1, also known as TrIP, is a transmembrane protein that has been shown to inhibit PI3K in T cells. Results from the ImmGen Consortium indicate that PIK3IP1 expression fluctuates throughout B cell development in a manner inversely correlated with PI3K activity; however, its role in B cells is poorly understood. In this study, we define the consequences of B cell-specific deletion of PIK3IP1. B cell development, basal Ig levels, and T-independent responses were unaffected by loss of PIK3IP1. However, there was a significant delay in the production of IgG during T-dependent responses, and secondary responses were impaired. This is likely due to a role for PIK3IP1 in the extrafollicular response because germinal center formation and affinity maturation were normal, and PIK3IP1 is not appreciably expressed in germinal center B cells. Consistent with a role early in the response, PIK3IP1 was downregulated at late time points after B cell activation, in a manner dependent on PI3K. Increased activation of the PI3K pathway was observed in PIK3IP1-deficient B cells in response to engagement of both the BCR and CD40 or strong cross-linking of CD40 alone. Taken together, these observations suggest that PIK3IP1 promotes extrafollicular responses by limiting PI3K signaling during initial interactions between B and T cells.

Aim: Tumor-derived small extracellular vesicles (TEVs) are considered for use in inducing tumor antigen-specific immune responses as they contain tumor antigens. The delivery of tumor antigens to the antigen presentation cells (especially dendritic cells [DCs]), and the activation of DCs are the main challenges of TEV therapy.Materials & methods: TEVs were modified with CD40 ligand (CD40L), which can target CD40 expressed on the surface of DCs and can activate them via CD40L-CD40 interactions.Results: It was found that CD40L-TEVs were efficiently taken up by DCs and also activated them. Moreover, tumor antigens were efficiently presented to the T cells by DCs treated with CD40L-TEVs.Conclusion: This study proved that CD40L-modification of TEVs will be helpful for further development of TEV-based tumor vaccination.