Leishmania mexicana Gp63 cDNA Using Gene Gun Induced Higher Immunity to L. mexicana Infection Compared to Soluble Leishmania Antigen in BALB/C

BACKGROUND: Leishmaniasis is a worldwide disease prevalent in tropical and sub tropical countries. Many attempts have been made and different strategies have been approached to develop a potent vaccine against Leishmania. DNA immunisation is a method, which is shown to be effective in Leishmania vaccination. Leishmania Soluble Antigen (SLA) has also recently been used Leishmania vaccination. METHODS: The immunity generated by SLA and L. mexicana gp63 cDNA was compared in groups of 6 mice, which were statistically analysed by student t- test with the P-value of 0.05. SLA was administered by two different methods; intramuscular injection and injection of dendritic cells (DCs) loaded with SLA. L. mexicana gp63 cDNA was administered by the gene gun. RESULTS: Immunisation of BALB/c mice with L. mexicana gp63 resulted in high levels of Th1-type immune response and cytotoxic T lymphocytes (CTL) activity, which were accompanied with protection induced by the immunisation against L. mexicana infection. In contrast, administration of SLA, produced a mixed Th1/Th2-type immune responses as well as a high level of CTL activity but did not protect mice from the infection. CONCLUSION: The results indicate higher protection by DNA immunisation using L. mexicana gp63 cDNA compared to SLA, which is accompanied by a high level of Th1 immune response. However, the CTL activity does not necessarily correlate with the protection induced by the vaccine. Also, gene gun immunisation is a potential approach in Leishmania vaccination. These findings would be helpful in opening new windows in Leishmania vaccine research.