Cytomegalovirus phosphoprotein 65 and immediate-early protein 1 peptides presented by human leukocyte antigen class I and class II (CMV pp65/IE-1 pHLA complex)

Cytomegalovirus (CMV) phosphoprotein 65 (pp65, encoded by UL83) and Immediate-Early protein 1 (IE-1, encoded by UL123) are the primary immunodominant antigens recognized by the human immune system during infection (Sylwester et al., 2005). These viral proteins are processed into short peptide fragments and presented on the surface of infected cells by Human Leukocyte Antigen (HLA) Class I and Class II molecules. HLA Class I complexes are typically recognized by CD8+ cytotoxic T cells, while HLA Class II complexes are recognized by CD4+ helper T cells, both of which are essential for controlling viral replication (Wills et al., 1996). In immunocompromised individuals, such as those undergoing hematopoietic stem cell or solid organ transplantation, the failure of this T-cell-mediated control leads to CMV reactivation and severe clinical disease (Papadopoulou et al., 2014). Consequently, these peptide-HLA complexes serve as the foundational targets for adoptive T-cell therapies and CMV vaccines designed to restore or enhance the host's cellular immunity. Current therapeutic approaches include the infusion of donor-derived or off-the-shelf CMV-specific T cells (VSTs) that specifically bind these epitopes to eliminate infected cells (Blyth et al., 2013). Monitoring the frequency of T cells reactive to these specific complexes is also a critical biomarker for assessing a patient's risk of CMV-related complications.

Other names

CMV pp65/IE-1 epitopesHCMV UL83/UL123 HLA complexesCMV-specific T-cell targetspp65/IE-1 peptide-MHC complexesCMV antigen-HLA complexes

T-cell receptor-mediated recognition of the peptide-HLA complex, triggering cytotoxic granule release (perforin/granzyme) and inflammatory cytokine production (IFN-gamma, TNF-alpha) to induce apoptosis in infected cells.