Some infected animals (n = 5/group) were administered anti-IFN-γ neutralizing antibody or recombinant IFN-γ (rIFN-γ) or isotype over an 8-day period (days 52 to 60 p.i.)before heterologous challenge with P. chabaudi AJ at day 60 post-primary infection (Fig. 5A). The gene discussed is IFNG; the disease is infection.