Overall, our data employing a blocking monoclonal anti-ICOSL antibody in the context of the acute MCMV infection revealed a high importance of the ICOSL:ICOS axis in the formation of Tfh cells and subsequent GC B-cell development in spleens and lymph nodes follicles, consistent with what has been previously observed in other in vivo experimental models of infection (Wikenheiser and Stumhofer, 2016). This evidence concerns the gene ICOS and infection.