These mutants were unable to survive in vitro in human macrophages and animals vaccinated with LdCEN-/- mutants were protected against homologous as well as heterologous challenge.[73] Our group has recently demonstrated that L. major phosphomannomutase (PMM) deficient mutants were able to protect susceptible mice against infection via an increased magnitude of T cell responses and suppression of IL-10 and IL-13 production early during infection.[74] These parasites are viable in vitro, but do not survive in macrophages or in vivo in mice, similarly to LdCEN-/- parasites. The gene discussed is IL10; the disease is infection.