Transitory or long-lasting immunity to Leishmania major infection: the result of immunogenicity and multicomponent properties of histone DNA vaccines.

The present studies were designed to analyze the immunization against cutaneous leishmaniosis with plasmids encoding Leishmania histones either individually or genetically linked in tandem, or with cocktails encoding the four nucleosomal histones (H2A, H2B, H3 and H4). Genetic immunization of BALB/c mice with the individual histones only resulted in a delay in lesion development, whereas the immunization with any one of the plasmids encoding a pair of histones provided stronger, though still partial protection against Leishmania major infection compared to the combination of the four histones. These results provide direct evidence that all four nucleosomal histones of Leishmania are necessary to maintain complete protection against L. major reinfection.