Leishmaniasis caused by Leishmania major is a neglected, emerging disease that produces open sores, scarring and disfigurement. As a paradigmatic skin infection, it is an excellent model for the study of dermal immunity.

Susana Mendez and colleagues, Baker Institute for Animal Health, Cornell University, USA, previously reported that vaccination of mice with live L. major plus the adjuvant CpG DNA prevents disease and provides long-term immunity.
Here, Wenhui Wu, Lu Huang, and Susana Mendez further characterize the components of adaptive immunity that are unique to this successful live vaccine.
The authors demonstrate that vaccination of mice with live L. major plus CpG DNA causes the specific induction of Th17 cells, which enhances the development of a protective cellular immunity against the parasite. This contrasts with the highly polarized Th1 response caused by L. major alone.

Their findings suggest that vaccines combining live pathogens with immunomodulatory molecules may strikingly modify immunity to infection in a different manner to killed or subunit vaccines.

• A live Leishmania major vaccine containing CpG motifs induces the de novo generation of Th17 cells in C57BL/6 mice,
  Wenhui Wu, Lu Huang, Susana Mendez
  Eur. J. Immunol. 2010, 40, 2517–2527.
  DOI: 10.1002/eji.201040484