Characteristics of Splenic CD8αβ+ γδT Cells in Plasmodium yoelii Infection.

Abstract

γδT cells are a subset of innate lymphocytes that play an essential role in anti-infection immunity. However, the functional role of CD8αβ⁺ γδT cells, a distinct subset of γδT cells, remains poorly characterized during malaria infection. Female C57BL/6 mice were intraperitoneally injected with 1 × 10⁶ Plasmodium yoelii-infected red blood cells (iRBCs). At 12 days post-infection (12 dpi, the peak of parasitemia), spleens were harvested and lymphocytes were isolated. Fluorescence-activated cell sorting (FACS) was performed to determine the frequency, phenotypic features and functional properties of CD8αβ⁺ γδT cells. Meanwhile, CD45⁺ lymphocytes were sorted for single-cell RNA sequencing (scRNA-seq) to compare differentially expressed genes between CD8αβ⁺ γδT and CD8αα⁺ γδT cell subsets. FACS analysis revealed a significant increase in CD8αβ⁺ γδT cells following P. yoelii infection. These cells exhibited elevated expression of activation-related molecules, enhanced effector functions, preferential polarization towards an IFN-γ-producing (γδT1) phenotype, and reduced expression of exhaustion markers. scRNA-seq further demonstrated that CD8αβ⁺ γδT cells upregulated genes involved in DNA replication and repair. Our findings indicate that CD8αβ⁺ γδT cells upregulate molecules associated with activation and function during P. yoelii infection, suggesting that they may play a more prominent role in host defence against malaria.