The innate immune system is composed of various innate immune cells, which can sense, eliminate, or adapt to intra-/extracellular threats (e.g., pathogens). Thus, the fine-tuning of innate immune responses is essential for protecting the host from pathogen infection. Indeed, there are many regulators that govern innate immune responses, including metabolic regulators.

Immune cells require copious energy, metabolic intermediates, and even microbial metabolites to support biosynthesis, thus completing the proliferation, development, differentiation, and execution of physiological functions. The metabolic pattern of activated immune cells is quite different from that of resting cells, and the phenotype and function of activated immune cells are also regulated by metabolism. Additionally, pathogens can also evade the host immune responses by affecting the synthesis of several host metabolic intermediates. Therefore, the concept of metabolic flexibility in the proliferation, development, and maturation of immunocytes, and the response to pathogen infection has quickly become an important paradigm in immune cell biology. Emerging studies focus on innate immune metabolism (e.g., macrophages); however, the impact of pathogens on innate immune metabolism and the cross-talk between metabolic reprogramming and innate immune responses need further exploration.

This Special Issue aims to collate state-of-the-art research focused on the interactions between innate immunocyte biology and metabolism, especially immune responses and metabolic reprogramming during pathogen infection. We are particularly interested in studies that strengthen our understanding of the molecular and biochemical mechanisms of metabolic alterations in infectious diseases. This Special Issue welcomes review and original research articles that allow narrowing of existing gaps in knowledge. Systematic reviews are particularly encouraged.

Potential topics include but are not limited to the following:

• Metabolic modulation of immunocytes in their proliferation, development, and maturation
• Metabolic reprogramming of innate immune cells in response to pathogens
• Cross-talk between innate immune cells and metabolic/epigenetic changes
• Microbial metabolism in the modulation of immunocytes biology
• Identification and characterization of potential therapeutic targets for infectious diseases