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CTL responses to Leishmania mexicana gp63-cDNA vaccine in a murine model
S A Ali1, H Rezvan, S E McArdle
1School of Science and Technology, Nottingham Trent University, Clifton, Nottingham, UK. selman.ali@ntu.ac.uk
Insights
Gene gun immunization with Leishmania mexicana gp63 DNA induced higher protection against infection than intramuscular injection. This study also established a cytotoxicity assay to measure cytotoxic T lymphocyte (CTL) activity, revealing its presence in immunized mice.
Area of Science:
- Immunology
- Parasitology
- Molecular Biology
Background:
- Immunity to Leishmania is primarily linked to Th1 responses.
- The specific role of cytotoxic T lymphocytes (CTLs) in Leishmania immunity requires further elucidation.
Purpose of the Study:
- To develop a reliable cytotoxicity assay for measuring CTL activity against Leishmania.
- To compare the efficacy of gene gun versus intramuscular DNA immunization using Leishmania mexicana gp63 cDNA in BALB/c mice.
Main Methods:
- Established a 51Cr-release cytotoxicity assay.
- Utilized CT26 tumor cells transfected with L. mexicana gp63 cDNA and dendritic cells (DCs) loaded with soluble Leishmania antigen (SLA) as target cells.
- Evaluated CTL activity in splenocytes from immunized and infected BALB/c mice.
Main Results:
- Gene gun DNA immunization conferred superior protection against L. mexicana infection compared to intramuscular injection.
- Significant CTL activity was detected in splenocytes of mice immunized with L. mexicana gp63 DNA or SLA.
- Long-lived CTL activity was observed in immunized and/or re-challenged mice, but not in naive infected mice.
Conclusions:
- Gene gun immunization is a more effective strategy for inducing protective immunity against Leishmania via CTL activation.
- The developed cytotoxicity assay is suitable for assessing Leishmania-specific CTL responses.
- CTLs play a crucial role in the adaptive immune response to Leishmania infection.
Abstract:
Immunity to Leishmania is believed to be strongly dependent upon the activation of Th1 immune responses, although the exact role of cytotoxic T lymphocytes (CTLs) has not yet been determined. The aims of this study were to establish a suitable cytotoxicity assay to measure CTL activity and to compare immunity induced by Leishmania mexicana gp63 cDNA via i.m. injection and gene gun immunization in the BALB/c mouse model. The CTL activity was evaluated by short-term (51)Cr-release cytotoxicity assays against CT26 tumour cells transfected with L. mexicana gp63 cDNA and dendritic cells (DCs) loaded with soluble Leishmania antigen (SLA) as targets. The results clearly demonstrated that higher protection to L. mexicana infection was induced by gene gun DNA-immunization vs. i.m. injection. Cytotoxic T lymphocyte activity of splenocytes was observed in mice immunized either with L. mexicana gp63 cDNA or SLA and long-lived CTL activity was observed in immunized and/or re-challenged mice but not naïve mice infected with the parasite.
