Here, mice carrying a T cell specific deletion of Notch1 (N1ΔCD4Cre), Notch2 (N2ΔCD4Cre) or both Notch1 and Notch2 (N1N2ΔCD4Cre) on a resistant C57BL/6 genetic background were infected with L. major to study the importance of Notch receptors in Th1 differentiation and resolution of the infection. The gene discussed is NOTCH1; the disease is infection.