The Antigen-Presenting Potential of Vγ9Vδ2 T Cells During Plasmodium falciparum Blood-Stage Infection.

During Plasmodium falciparum infections, erythrocyte-stage parasites inhibit dendritic cell maturation and function, compromising effective antimalarial adaptive immunity. Human Vγ9Vδ2 T cells can act in vitro as antigen-presenting cells (APCs) and induce αβ T-cell activation. However, the relevance of this activity in vivo has remained elusive. Because Vγ9Vδ2 T cells are activated during the early immune response against P. falciparum infection, we investigated whether they could contribute to the instruction of adaptive immune responses toward malaria parasites. In P. falciparum-infected patients, Vγ9Vδ2 T cells presented increased surface expression of APC-associated markers HLA-DR and CD86. In response to infected red blood cells in vitro, Vγ9Vδ2 T cells upregulated surface expression of HLA-DR, HLA-ABC, CD40, CD80, CD83, and CD86, induced naive αβ T-cell responses, and cross- presented soluble prototypical protein to antigen-specific CD8+ T cells. Our findings qualify Vγ9Vδ2 T cells as alternative APCs, which could be harnessed for therapeutic interventions and vaccine design.