Structural and functional convergence and divergence of myeloid dendritic cells and conventional dendritic cells

Dendritic cells (DCs) are essential regulators of immune responses, acting as a bridge between innate and adaptive immunity. They play a critical role in recognizing and responding to microbial threats and malignant transformations, ensuring appropriate immune activation. However, DCs can also contribute to immunosuppression, creating conditions that favor infections and tumorigenesis. Among the major subsets of DCs in mammals, conventional dendritic cells (cDCs) and plasmacytoid dendritic cells (pDCs) exhibit both striking similarities and distinct differences in their origins, phenotypic characteristics, functional roles, and tissue distribution. This review provides a comprehensive analysis of pDCs and cDCs, exploring their classification based on cellular lineage, migration potential, and immunological functions. It delves into their morphological and structural features, comparing their cell surface and cytosolic receptor profiles and the key signaling pathways expression; the roles of both subsets in orchestrating immune defense against microbial invasion and neoplasia are discussed, highlighting their contributions to both innate and adaptive immunity. Furthermore, we examine how these subsets influence immune homeostasis and disease progression, including their involvement in immunosuppressive environments. Additionally, the review explores the therapeutic potential of targeting pDCs and cDCs in cancer immunotherapy, vaccine development, and disease prevention strategies. Understanding the nuanced differences between these DC subsets could pave the way for novel immunotherapeutic approaches, offering new insights into enhancing immune responses while mitigating immune evasion mechanisms exploited by pathogens and tumors.