HLA class I histocompatibility antigen protein P5 (HLA complex protein P5, protein P5-1) (HCP5)

Expression

• expressed in lymphoid tissues
• detected in spleen as well as in B-cell lines, NK cell lines & activated lymphocytes Polymophism:
• variation Gly-112 is associated with low viral loads in untreated HIV patients
• the level of circulating virus in the plasma of HIV patients (viral set point) varies among individuals during the nonsymptomatic phase preceding the progression to AIDS
• this polymorphism explains 9.6% of the total variation in set point & is associated with the HLA-B*5701 allele, which has the strongest described protective impact on HIV disease progression
• however, it is possible that HPC5 polymorphism, & not HLA-B*5701 allele, plays a direct role in the control of viremia in HIV patients

Genetics

• HCP5 is localized within the MHC class I region, but is not structurally related to MHC class I genes
• HCP5 is related in sequence to human endogenous retroviruses HERV-L & HERV-16
• it has sequence homology with retroviral pol genes in HERV retroviral element; thus, it is itself a good candidate to interact with HIV-1, possibly through an antisense mechanism against retroviral transcript

More general terms

• MHC class I antigen

Database

• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:1086
• OMIM: https://mirror.omim.org/entry/604676
• UniProt: http://www.uniprot.org/uniprot/Q6MZN7.html