Immunization with the DNA-encoding N-terminal domain of proteophosphoglycan of Leishmania donovani generates Th1-type immunoprotective response against experimental visceral leishmaniasis.

Abstract

Leishmania produce several types of mucin-like glycoproteins called proteophosphoglycans (PPGs) which exist as secretory as well as surface-bound forms in both promastigotes and amastigotes. The structure and function of PPGs have been reported to be species and stage specific as in the case of Leishmania major and Leishmania mexicana; there has been no such information available for Leishmania donovani. We have recently demonstrated that PPG is differentially expressed in sodium stibogluconate-sensitive and -resistant clinical isolates of L. donovani. To further elucidate the structure and function of the ppg gene of L. donovani, a partial sequence of its N-terminal domain of 1.6 kb containing the majority of antigenic determinants, was successfully cloned and expressed in prokaryotic as well as mammalian cells. We further evaluated the DNA-encoding N-terminal domain of the ppg gene as a vaccine in golden hamsters (Mesocricetus auratus) against the L. donovani challenge. The prophylactic efficacy to the tune of approximately 80% was observed in vaccinated hamsters and all of them could survive beyond 6 mo after challenge. The efficacy was supported by a surge in inducible NO synthase, IFN-gamma, TNF-alpha, and IL-12 mRNA levels along with extreme down-regulation of TGF-beta, IL-4, and IL-10. A rise in the level of Leishmania-specific IgG2 was also observed which was indicative of enhanced cellular immune response. The results suggest the N-terminal domain of L. donovani ppg as a potential DNA vaccine against visceral leishmaniasis.

• Authors: Mukesh Samant, Reema Gupta, Shraddha Kumari, Pragya Misra, Prashant Khare, Pramod Kumar Kushawaha, Amogh Anant Sahasrabuddhe, Anuradha Dube
• Journal: Journal of immunology (Baltimore, Md. : 1950) (J Immunol) Vol. 183 Issue 1 Pg. 470-9 (Jul 01 2009) ISSN: 1550-6606 [Electronic] United States
• PMID: 19542458 (Publication Type: Journal Article)

Chemical References

• DNA, Protozoan
• Leishmaniasis Vaccines
• Membrane Proteins
• Peptide Fragments
• Ppg1 protein, Leishmania
• Proteoglycans
• Protozoan Proteins
• Vaccines, DNA

Topics

• Animals
• Cell Line
• Cell Polarity (genetics, immunology)
• Cricetinae
• DNA, Protozoan (administration & dosage, genetics, immunology)
• Escherichia coli (genetics, immunology)
• Humans
• Leishmania donovani (genetics, immunology)
• Leishmaniasis Vaccines (administration & dosage, genetics, immunology)
• Leishmaniasis, Visceral (immunology, prevention & control)
• Male
• Membrane Proteins (administration & dosage, genetics, immunology)
• Mesocricetus
• Peptide Fragments (administration & dosage, chemistry, immunology)
• Protein Structure, Tertiary
• Proteoglycans (administration & dosage, genetics, immunology)
• Protozoan Proteins (administration & dosage, genetics, immunology)
• Th1 Cells (immunology, metabolism, parasitology)
• Vaccines, DNA (administration & dosage, genetics, immunology)