To test the role of DAG-mediated signaling in T cell activation during the acute phase of chronic viral infection, we infected WT and DGKζ KO mice with LCMV CL13 and examined the phenotype and function of LCMV-specific T cells against two immunodominant epitopes (GP33 and GP276 peptides) at Days 7 and 10 post infection. The gene discussed is DGKZ; the disease is infection.