An APCA which included CD4+ T cells (responders) and irradiated PBMC (stimulators) from uninfected and infected animals during the early and late stage of the infection (G3, G4 and G5) was performed to assess efficiency of antigen presentation to CD4+ T cell following stimulation with rFhCB3 and rFhCL2. The gene discussed is CD4; the disease is infection.