Induction of high level specific immune response and of pre-challenge multipotent CD4+ T cells, partial protection of genetically susceptible BALB/c mice from high dose infection with L. major, recognition by CL and VL patient samples as well as its predominant expression in amastigote stage of the parasite make Peroxidoxin-1 one of the promising anti-leishmanial vaccine candidates. The gene discussed is CD4; the disease is infection.