The Activation State of CD4 T Cells Alters Cellular Peptidase Activities, HIV Antigen Processing, and MHC Class I Presentation in a Sequence-Dependent Manner.

CD4 T cell activation is critical to the initiation of adaptive immunity. CD4 T cells are also the main targets of HIV infection, and their activation status contributes to the maintenance and outcome of infection. Although the role of activation in the differentiation and proliferation of CD4 T cells is well studied, its impact on the processing and MHC class I (MHC-I) presentation of epitopes and immune recognition by CD8 T cells are not investigated.