RACK1 and malaria: Given that the newly described subpopulation of follicular T cells, named T follicular regulatory (Tfr) cells, play an essential role in suppressing Tfh-dependent GC formation and protective immunity to blood-stage malaria [57,58], we then assessed whether the impaired Tfh-dependent GC reaction in RACK1 KO mice was associated with Tfr response elicited by P. yoelii 17XNL.