To evaluate the importance of receptor 1 of TNF in the resistance of mice during the infection by N. caninum, WT and Tnfr1-/- mice were infected with a lethal dose of N. caninum for 50% of the animals (DL50, 1x107 tachyzoites), and were monitored for 30 days for survival (Figure 1). This evidence concerns the gene TNF and infection.