Abstract
Leishmaniasis is a major health problem and itis estimated that 12 million people are currently infected.A vaccine which could cross-protect people against different Leishmania spp. would facilitate control ofthis disease as more than one species of Leishmania may be present. In this study the ability of a DNA vaccine, using the full gene sequence for L. donovani gamma glutamyl cysteine synthetase (GCS) incorporated in the pVAX vector (pVAXGCS), and a protein vaccine, using the corresponding recombinant L. donovani GCS protein (LdGCS),to protect against L. major or L. mexicana infection was evaluated. DNAvaccination gave transient protection against L. major and no protection against L. mexicana despite significantly enhancing specific antibody titres in vaccinated infected mice compared to infected controls. Vaccination with the LdGCS protected against both species but only if the protein was incorporated into non-ionic surfactant vesicles for L. mexicana. The results of this study indicate that a L. donovani GCS vaccine could be used to vaccinate against more than one Leishmania species but only if the recombinant protein is used. arabic 30 English 176