ATG5-regulated MCP-1 production in myeloid cells selectively modulates anti-malarial CD4+ Th1 responses

Induction of parasite-specific CD4+ Th1 cell responses is a promising strategy for designing effective blood-stage malaria vaccines; however, the underlying regulatory mechanisms remain largely unknown. This study demonstrated that ATG5 deficiency in myeloid cells can significantly inhibit the growth of rodent blood-stage malarial parasites by enhancing parasite-specific CD4+ Th1 cell responses. This effect was independent of ATG5-mediated canonical and non-canonical autophagy. Mechanistically, ATG5 deficiency promoted myeloid cell (Ly6G-CD11b+F4/80-) survival and subsequently increased MCP-1 production in parasite-infected mice. Ly6G-CD11b+F4/80- cell-derived MCP-1 interacted with CCR2 on CD4+ Th1 cells for their optimized responses through the JAK2/STAT4 pathway. Notably, recombinant MCP-1 significantly improved parasite-specific CD4+ Th1 responses of the whole-killed blood-stage vaccine. Conclusively, our study highlights the previously unrecognized role of ATG5 in modulating myeloid cell survival via MCP-1 production, which selectively promotes CD4+ Th1 cell responses. Our findings provide new insights into the development of effective antimalarial vaccines. scRNA-seq analysis of CD11b+ cells isolated from splenocytes of P. yoelii 17XNL-infected mice at day 0 and day 3 post-infection.