Exogenous OVA can be presented on MHC-I molecules throughcross-presentation,a process by which internalized antigens are either translocated intothe cytosol for proteasomal degradation or processed within specializedendosomal compartments before entering the MHC-I presentation pathway. Cross-presentation is essential for the initiationof CD8+ T-cell responses against tumors or infections that do notdirectly infect antigen-presenting cells. The gene discussed is CD8A; the disease is infection.