Human cytomegalovirus phosphoprotein 65 (pp65)

**Human cytomegalovirus phosphoprotein 65** (pp65) is the most abundant tegument protein in the human cytomegalovirus (HCMV) virion and plays a major role in virion assembly and morphogenesis[1][3]. It acts as an optional scaffold for packaging other viral proteins into the tegument layer of the virus particle[1]. Functionally, pp65 is also a dominant target antigen for both CD8+ and CD4+ T cell responses during HCMV infection; it is presented via MHC class I molecules on infected cells, making it central to immune recognition by cytotoxic T lymphocytes[2][4][5]. The strong immunogenicity of pp65 has led to its use in diagnostic assays and research tools for monitoring cellular immunity against HCMV[7].\n\nThe term "Cytomegalovirus phosphoprotein 65 antigen-presenting pathway" is not itself a canonical molecular target but rather describes the process by which peptides derived from **pp65** are processed intracellularly and presented on MHC class I molecules. Therefore, this entry should be flagged as **incorrect** because it refers to an immunological process/pathway rather than a discrete molecule or receptor.\n\nKey points about **pp65** include:\n\n- It shapes both CD8+ and CD4+ T cell repertoires in individuals exposed to CMV; up to 83% of seropositive individuals have detectable CD8+ responses against this protein[5].\n- Peptides from pp65 are processed by proteasomes and various peptidases before being loaded onto MHC class I molecules for presentation at the cell surface—this underlies its role as an immunodominant CTL epitope source during infection[4].\n- There are no approved drugs that directly target or interact with pp65; however, peptide pools derived from this protein are widely used experimentally for immune monitoring purposes.\n- The presence or magnitude of anti–pp65 T-cell responses serves as a biomarker for protective cellular immunity against CMV reactivation or disease in clinical settings such as transplantation.\n\nIn summary, while "Cytomegalovirus phosphoprotein 65 antigen-presenting pathway" does not refer to a single molecular entity but rather an immunological mechanism involving **human cytomegalovirus phosphoprotein 65**, all structured information should be mapped specifically to **Human cytomegalovirus phosphoprotein 65 (pp65)** when extracting data about therapeutic targets.

Other names

CMV pp65HCMV pp65UL83 protein65 kDa lower matrix phosphoprotein