Lopez, DanielSamino, YKoszinowski, U HVal, Margarita del2020-07-152020-07-152001-10-15J Immunol . 2001 Oct 15;167(8):4238-440022-1767http://hdl.handle.net/20.500.12105/10777CTL recognize peptides that derive from viral protein Ags by proteolytic processing and are presented by MHC class I molecules. In this study we tested whether coexpression of viral Ags in the same cell leads to competition between them. To this end, two L(d)-restricted epitopes derived from HIV-1 envelope gp160 (ENV) and from CMV pp89 phosphoprotein were coexpressed. HIV ENV strain IIIB, but not MN variant, impaired recognition by specific CTL of CMV pp89 epitope 9pp89. Susceptibility to inhibition after ENV coexpression was inversely related to the amount of antigenic 9pp89 peptide processed from different antigenic constructs. In line with it, competition decreased the yield of naturally processed antigenic 9pp89 peptide bound to MHC class I molecules in coinfected cells. Also, point mutants of the presenting MHC class I molecule differed in their competition pattern. Collectively, the data imply that competition operates at the step of MHC-peptide complex assembly or stabilization. We conclude that, although not the rule, in certain combinations there is interference between different Ags expressed in the same cell and presented by the same MHC class I allele. These studies have implications for vaccine development and for understanding immunodominance.engAMhttp://creativecommons.org/licenses/by-nc-sa/4.0/Antigen PresentationAnimalsHIV Envelope Protein gp120HIV Envelope Protein gp160HIV-1Histocompatibility Antigens Class IImmediate-Early ProteinsMiceMice, Inbred BALB CPeptide FragmentsPoint MutationAtribución-NoComercial-CompartirIgual 4.0 Internacional1159174516784238-4410.4049/jimmunol.167.8.4238Journal of immunology (Baltimore, Md. : 1950)open access