Lipid rafts of antigen-presenting cells

Cholesterol-rich cell membranes of antigen-presenting cells (APCs), primarily known as lipid rafts, are specialized plasma membrane microdomains characterized by high concentrations of cholesterol and glycosphingolipids. These domains function as dynamic platforms that organize and concentrate signaling molecules, such as Major Histocompatibility Complex (MHC) class II and co-stimulatory molecules (e.g., CD80, CD86), which are critical for the formation of the immunological synapse and subsequent T-cell activation (Hiltbold et al., 2003). Beyond their role in physiological immune signaling, these microdomains are frequently exploited by pathogens, including viruses like HIV-1 and parasites like Leishmania, to facilitate host cell entry and intracellular trafficking (Lafont et al., 2004). Pharmacological targeting of these membranes typically involves the use of cholesterol-depleting agents or sterol-binding compounds to disrupt raft integrity, thereby modulating immune responses or blocking pathogen infection. For instance, the adjuvant QS-21 interacts with membrane cholesterol to facilitate antigen delivery, while drugs like miltefosine can alter raft-associated signaling to treat parasitic infections (Ghochikyan et al., 2006; Seifert et al., 2007). While these microdomains offer a unique site for therapeutic intervention, their ubiquitous nature across various cell types poses challenges for achieving cell-specific targeting and minimizing systemic toxicity (Pike, 2006).

Other names

Cholesterol-rich membrane microdomainsLipid raftsDetergent-resistant membranesMembrane raftsCholesterol-rich microdomains

Disruption of membrane microdomain integrity through cholesterol depletion, sequestration, or inhibition of biosynthesis, leading to the dissociation of signaling complexes and impaired antigen presentation.