Understanding the Immune Response: PRRs, Cytokine Stimulation, and Phagocytosis in Candida albicans Infections

Human immunity consists of two main systems: the innate and adaptive immune systems. The innate immune system relies on myeloid cells that express Pathogen Recognition Receptors (PRRs), crucial for identifying Pathogen Associated Molecular Patterns (PAMPs) from microorganisms. Key innate immune cells, including monocytes, macrophages, neutrophils, and dendritic cells, utilize various PRRs such as Toll-like receptors and C-type lectin receptors to detect pathogens like Candida albicans. This recognition triggers signaling pathways that activate immune responses, leading to the secretion of pro-inflammatory cytokines and the maturation of dendritic cells, ultimately enhancing protective immunity. The recognition of Pathogen Associated Molecular Patterns (PAMPs) by Pattern Recognition Receptors (PRRs) activates signaling pathways in immune cells, resulting in the secretion of cytokines that indicate immune activation and promote dendritic cell maturation and naïve T-cell activation. Candida albicans masks its inner cell wall layers with glycosylated mannoproteins, but heat treatment or mutations can expose β-1,3-glucan, facilitating recognition by Dectin-1. Phagocytic receptors, including Dectin-1 and the Mannose Receptor (MR), mediate the uptake of C. albicans, leading to its destruction through oxidative mechanisms. Toll-like receptors (TLRs) are crucial for cytokine production and regulating inflammatory responses.