Major Histocompatibility Complex class I and II antigen presentation pathways (MHC-I/II pathways)

The MHC class I and II antigen-presenting pathways in dendritic cells (DCs) are fundamental processes for initiating and regulating adaptive immune responses (Janeway et al., Immunobiology, 2001). Dendritic cells, as professional antigen-presenting cells, capture antigens from the environment or produce them internally, processing them into peptides that are loaded onto MHC molecules (Roche & Furuta, Nat Rev Immunol, 2015). MHC class I molecules typically present endogenous or cross-presented exogenous peptides to CD8+ cytotoxic T cells, while MHC class II molecules present exogenous peptides to CD4+ helper T cells (Neefjes et al., Nat Rev Immunol, 2011). These pathways are critical for the detection of pathogens and malignant cells, as well as the maintenance of peripheral tolerance to self-antigens. In many diseases, such as cancer, these pathways are often downregulated or subverted to evade immune detection, making them a focal point for immunotherapeutic strategies like vaccines and checkpoint modulators (Garrido et al., Cancer Immunol Immunother, 2016). Conversely, overactivity in these pathways can lead to autoimmune disorders, where self-peptides are inappropriately presented, triggering an attack on healthy tissues (Rock et al., Annu Rev Immunol, 2016).

Other names

Antigen processing and presentationMHC-restricted antigen presentationCross-presentation pathwayExogenous and endogenous antigen pathways

Modulation of antigen processing through proteasome inhibition (MHC I), alteration of endosomal/lysosomal pH (MHC II), or interference with the assembly and transport of MHC-peptide complexes to the cell surface (Blum et al., Annu Rev Immunol, 2013).