ATG5-regulated CCL2/MCP-1 production in myeloid cells selectively modulates anti-malarial CD4 Th1 responses.

Parasite-specific CD4 Th1 cell responses are the predominant immune effector for controlling malaria infection; 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 selectively enhancing parasite-specific CD4 Th1 cell responses. This effect was independent of ATG5-mediated canonical and non-canonical autophagy. Mechanistically, ATG5 deficiency suppressed FAS-mediated apoptosis of LY6G ITGAM/CD11b ADGRE1/F4/80 cells and subsequently increased CCL2/MCP-1 production in parasite-infected mice. LY6G ITGAM ADGRE1 cell-derived CCL2 selectively interacted with CCR2 on CD4 Th1 cells for their optimized responses through the JAK2-STAT4 pathway. The administration of recombinant CCL2 significantly promoted parasite-specific CD4 Th1 responses and suppressed malaria infection. Conclusively, our study highlights the previously unrecognized role of ATG5 in modulating myeloid cells apoptosis and sequentially affecting CCL2 production, which selectively promotes CD4 Th1 cell responses. Our findings provide new insights into the development of immune interventions and effective anti-malarial vaccines.: ATG5: autophagy related 5; CBA: cytometric bead array; CCL2/MCP-1: C-C motif chemokine ligand 2; IgG: immunoglobulin G; IL6: interleukin 6; IL10: interleukin 10; IL12: interleukin 12; MFI: mean fluorescence intensity; JAK2: Janus kinase 2; LAP: LC3-associated phagocytosis; MAP1LC3/LC3: microtubule-associated protein 1 light chain 3; pRBCs: parasitized red blood cells; RUBCN: RUN domain and cysteine-rich domain containing, Beclin 1-interacting protein; STAT4: signal transducer and activator of transcription 4; Th1: T helper 1 cell; Tfh: follicular helper cell; ULK1: unc-51 like kinase 1.