Major Histocompatibility Complex Class II and T-cell receptor complex (SARS-CoV-2 Receptor Binding Domain peptide) (MHC-II:TCR:RBD)

The 'Major Histocompatibility Complex Class II and T-cell receptor complex (SARS-CoV-2 Receptor Binding Domain peptide)' refers to the molecular assembly formed during the adaptive immune response to SARS-CoV-2. In this process, the Receptor Binding Domain (RBD) of the viral Spike protein is captured by professional antigen-presenting cells, processed into short peptide fragments, and presented on the cell surface via Major Histocompatibility Complex Class II (MHC-II) molecules (Grifoni et al., 2020, Cell). These peptide-MHC complexes are then recognized by specific T-cell receptors (TCRs) on the surface of CD4+ T helper cells (Mateus et al., 2020, Science). This recognition event is critical for the induction of high-affinity neutralizing antibodies and the establishment of long-term immunological memory (Sahin et al., 2020, Nature). In the context of pharmaceutical development, this complex is the functional target of RBD-based and Spike-based vaccines, which aim to elicit a robust T-cell response to provide protection against COVID-19 (Tay et al., 2020, Nature Reviews Immunology). Understanding the stability and diversity of these complexes across different human leukocyte antigen (HLA) alleles is essential for the design of effective and equitable vaccines that remain potent against emerging viral variants.

Other names

HLA-DR/TCR/RBD complexMHC-II/TCR/Spike-peptide complexpMHC-TCR complexAntigen-MHC-TCR synapseMHC-II-presented SARS-CoV-2 RBD peptides

The complex facilitates the presentation of viral RBD peptides to CD4+ T cells, leading to their activation, proliferation, and subsequent help for B-cell antibody production and CD8+ T-cell recruitment (Grifoni et al., 2020; Sahin et al., 2020).