?? T Cells Are Required for the Induction of Sterile Immunity during Irradiated Sporozoite Vaccinations.

ABSTRACT: Whole-sporozoite vaccines confer sterilizing immunity to malaria-naive individuals by unknown mechanisms. In the first PfSPZ Vaccine trial ever in a malaria-endemic population, V?2 ?? T cells were significantly elevated and V?9/V?2 transcripts ranked as the most upregulated in vaccinees who were protected from Plasmodium falciparum infection. In a mouse model, absence of ?? T cells during vaccination impaired protective CD8 T cell responses and ablated sterile protection. ?? T cells were not required for circumsporozoite protein-specific Ab responses, and ?? T cell depletion before infectious challenge did not ablate protection. ?? T cells alone were insufficient to induce protection and required the presence of CD8?+ dendritic cells. In the absence of ?? T cells, CD8?+ dendritic cells did not accumulate in the livers of vaccinated mice. Altogether, our results show that ?? T cells were essential for the induction of sterile immunity during whole-organism vaccination.

SUBMITTER: Zaidi I 

PROVIDER: S-EPMC5698172 | biostudies-literature | 2017 Dec

REPOSITORIES: biostudies-literature