Parasiticidal activity of human alpha-defensin-5 against Toxoplasma

In Vitro Cell Dev Biol Anim. 2010 Feb 5. [Epub ahead of print]

Parasiticidal activity of human alpha-defensin-5 against Toxoplasma gondii

Tanaka T, Rahman MM, Battur B, Boldbaatar D, Liao M, Umemiya-Shirafuji R, Xuan X, Fujisaki K.

Laboratory of Emerging Infectious Diseases, Department of Frontier Veterinary Science, Faculty of Agriculture, Kagoshima University, 1-21-24 Korimoto, Kagoshima, 890-0065, Japan.

Human defensins play a fundamental role in the initiation of innate immune responses to some microbial pathogens. In this paper, we show that human alpha-defensin-5 displays a parasiticidal role against Toxoplasma gondii, the causative agent of toxoplasmosis. Exposure of the tachyzoite form of T. gondii to defensin induced aggregation and significantly reduced parasite viability in a concentration-dependent peptide. Pre-incubation of tachyzoites with human alpha-defensin-5 followed by exposure to a mouse embryonal cell line (NIH/3T3) significantly reduced T. gondii infection in these cells. Thus, human alpha-defensin-5 is an innate immune molecule that causes severe toxocity to T. gondii and plays an important role in reducing cellular infection. This is the first report showing that human alpha-defensin-5 causes aggregation, leading to Toxoplasma destruction.

PMID: 20135360 [PubMed - as supplied by publisher]