Individuals with nonfunctional transporters associated with antigen processing (TAP) complexes are not particularly susceptible to viral infections or neoplasms. Therefore, their immune system must be reasonably efficient, and the present, though reduced, cytolytic CD8+ αβ T subpopulation specific for TAP-independent antigens may be sufficient to establish an immune defense protecting against viral infections in these individuals. The objective of the present study was to identify TAP-independent ligands from HIV gp160 protein. An analysis and comparison of complex human histocompatibility complex (HLA)-bound peptide pools isolated from large quantities of healthy or HIV gp160-expressing human cells was performed using mass spectrometry and bioinformatics tools. A conserved TAP-independent HLA peptide ligand endogenously processed and presented in infected human cells was identified. This ligand originates from the envelope protein bound to the HLA-Cw1 class I molecule with high affinity. It was concluded that HLA class I peptides derived from a large fraction of the N-terminal HIV envelope protein could be presented even in the absence of the TAP complex.
aUnidad de Procesamiento Antigénico, Israel
bDepartment of Biology, Technion-Israel Institute of Technology, Haifa, Israel
cUnidad de Proteómica, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Madrid, Spain.
Received 12 July, 2010
Revised 13 September, 2010
Accepted 23 September, 2010
Correspondence to Dr Daniel López, Unidad de Procesamiento Antigénico/Proteómica, Centro Nacional de Microbiología, Instituto de Salud Carlos III, 28220 Majadahonda, Madrid, Spain. Tel: +34 91 822 37 08; fax: +34 91 509 79 19; e-mail: firstname.lastname@example.org