What's new for 'Trypanosomatids' in PubMed

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Sent on Thursday, 2010 Dec 30
Search kinetoplastids OR kinetoplastid OR Kinetoplastida OR "trypanosoma brucei" OR leishmania OR brucei OR leishmaniasis OR "African trypanosomiasis"
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PubMed Results

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1.	Infect Immun. 2010 Dec 28. [Epub ahead of print] The differential microbicidal effects of human histone proteins H2A and H2B on Leishmania promastigotes and amastigotes. Wang Y, Chen Y, Xin L, Beverley SM, Carlsen ED, Popov V, Chang KP, Wang M, Soong L. College of Veterinary Medicine, China Agricultural University, Beijing, China, 100193; Department of Microbiology and Immunology, and Department of Pathology, Center for Biodefense and Emerging Infectious Diseases, Sealy Center for Vaccine Development, Institute for Human Infections and Immunity, Sealy Center for Cancer Cell Biology, University of Texas Medical Branch, Galveston, Texas 77555; Washington University School of Medicine, St. Louis, Missouri 63110; and Department of Microbiology/Immunology, Chicago Medical School, Rosalind Franklin University, 3333 Green Bay Road, North Chicago, IL 60064. Abstract Recent studies have shown that histone proteins can act as antimicrobial peptides in host defense against extracellular bacteria, fungi, and Leishmania promastigotes. In this study, we used human recombinant histone proteins to further study their leishmaniacidal effects and the underlying mechanisms. We found that the histones H2A and H2B (but not H1(0)) could directly and efficiently kill promastigotes of L. amazonensis, L. major, L. braziliensis, and L. mexicana in a treatment dose-dependent manner. Scanning electron microscopy revealed surface disruption of histone-treated promastigotes. More importantly, the pre-exposure of promastigotes to histone proteins markedly decreased the infectivity of promastigotes to murine macrophages (MΦs) in vitro. However, axenic and lesion-derived amastigotes of L. amazonensis and L. mexicana were relatively resistant to histone treatment, which correlated with the low levels of intracellular H2A in treated amastigotes. To understand the mechanisms underlying these differential responses, we investigated the role of promastigote surface molecules in histone-mediated killing. Compared with the corresponding controls, transgenic L. amazonensis promastigotes expressing lower levels of surface gp63 proteins were more susceptible to histone H2A, while L. major and L. mexicana promastigotes with targeted deletion of the lipophosphoglycan 2 (lpg2) gene (but not the lpg1 gene) were more resistant to histone H2A. We discuss the influence of promastigote major surface molecules in the leishmaniacidal effect of histone proteins. This study provides new information on host innate immunity to different developmental stages of Leishmania parasites.
	PMID: 21189319 [PubMed - as supplied by publisher]