CD4+ and CD8+ T cell- and IL-17-mediated protection against Entamoeba histolytica induced by a recombinant vaccine.

Abstract

Amebiasis in the murine model can be prevented by vaccination with the Gal/GalNAc lectin through a T cell-dependent mechanism. In this work we further decipher the mechanism of this protection. Mice vaccinated with the recombinant "LecA" fragment of the Gal/GalNAc lectin with alum were capable of transferring protection to naïve recipients by both CD4+ T cells and surprisingly CD8+ T cells. We then examined the cytokine profile of these cells. CD4+ T cells from PBMC of LecA-alum vaccinated mice were observed to be a major source of IFN-γ, known to be a protective cytokine with this vaccine. In contrast, CD8+ T cells produced relatively little IFN-γ but more IL-17 than the CD4 compartment. We thus examined the role of IL-17 in vaccine mediated protection and found through neutralization experiments that this cytokine contributed to LecA-alum vaccine protection. In addition we examined whether these cells exhibited direct amebicidal activity in vitro and found that both populations had amebicidal activity at high concentrations (1000:1) but CD8+ T cells appeared more potent, capable of cytotoxicity at a 100:1 ratio. In conclusion, both CD4 and CD8 T cells exert protection with this amebiasis vaccine. The mechanism of CD8 T cell-mediated protection may include direct amebicidal activity and/or IL-17 production. Both IL-17 and IFN-γ are useful surrogates for immune protection.

• Authors: Xiaoti Guo, Lisa Barroso, David M Lyerly, William A Petri Jr, Eric R Houpt
• Journal: Vaccine (Vaccine) Vol. 29 Issue 4 Pg. 772-7 (Jan 17 2011) ISSN: 1873-2518 [Electronic] Netherlands
• PMID: 21095257 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)
• Copyright: Copyright © 2010 Elsevier Ltd. All rights reserved.

Chemical References

• Interleukin-17
• Protozoan Vaccines
• Vaccines, Synthetic
• Interferon-gamma

Topics

• Animals
• CD4-Positive T-Lymphocytes (immunology)
• CD8-Positive T-Lymphocytes (immunology)
• Cell Survival
• Entamoeba histolytica (immunology, physiology)
• Entamoebiasis (immunology, prevention & control)
• Interferon-gamma (metabolism)
• Interleukin-17 (immunology)
• Male
• Mice
• Protozoan Vaccines (immunology)
• Vaccines, Synthetic (immunology)