Previous Article | Next Article ![]()
Infection and Immunity, December 2006, p. 6940-6948, Vol. 74, No. 12
0019-9567/06/$08.00+0 doi:10.1128/IAI.02032-05
Copyright © 2006, American Society for Microbiology. All Rights Reserved.
Department of Biochemistry and Health Graduate Program, Federal University of Rio Grande do Norte, Natal, RN, Brazil,1 Department of Biochemistry, University of Iowa,2 Departments of Internal Medicine, Microbiology, and Epidemiology, University of Iowa and Veterans' Administration Medical Center, Iowa City, Iowa 522423
Received 17 December 2005/ Returned for modification 21 January 2006/ Accepted 15 September 2006
Control of human visceral leishmaniasis in regions where it is endemic is hampered in part by limited accessibility to medical care and emerging drug resistance. There is no available protective vaccine. Leishmania spp. protozoa express multiple antigens recognized by the vertebrate immune system. Since there is not one immunodominant epitope recognized by most hosts, strategies must be developed to optimize selection of antigens for prevention and immunodiagnosis. For this reason, we generated a cDNA library from the intracellular amastigote form of Leishmania chagasi, the cause of South American visceral leishmaniasis. We employed a two-step expression screen of the library to systematically identify T-cell antigens and T-dependent B-cell antigens. The first step was aimed at identifying the largest possible number of clones producing an epitope-containing polypeptide by screening with a pool of sera from Brazilians with documented visceral leishmaniasis. After removal of clones encoding heat shock proteins, positive clones underwent a second-step screen for their ability to cause proliferation and gamma interferon responses in T cells from immune mice. Six unique clones were selected from the second screen for further analysis. The corresponding antigens were derived from glutamine synthetase, a transitional endoplasmic reticulum ATPase, elongation factor 1
, kinesin K39, repetitive protein A2, and a hypothetical conserved protein. Humans naturally infected with L. chagasi mounted both cellular and antibody responses to these proteins. Preparations containing multiple antigens may be optimal for immunodiagnosis and protective vaccines.
Published ahead of print on 25 September 2006.
Copyright © 2009 by the American Society for Microbiology. For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»