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Leishmania chagasi T-cell antigens identified through a double library screen
Journal article   Open access   Peer reviewed

Leishmania chagasi T-cell antigens identified through a double library screen

Daniella R A Martins, Selma M B Jeronimo, John E Donelson and Mary E Wilson
Infection and immunity, Vol.74(12), pp.6940-6948
12/2006
DOI: 10.1128/iai.02032-05
PMCID: PMC1698060
PMID: 17000724
url
https://doi.org/10.1128/iai.02032-05View
Published (Version of record) Open Access

Abstract

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 1gamma, 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.
Amino Acid Sequence Immune Sera - immunology Epitopes, T-Lymphocyte - biosynthesis Antigens, Protozoan - immunology Gene Library Antibodies, Protozoan - immunology Humans DNA, Complementary - genetics Molecular Sequence Data Epitopes, T-Lymphocyte - genetics Recombinant Proteins - genetics Epitopes, T-Lymphocyte - isolation & purification Recombinant Proteins - biosynthesis Leishmania - immunology Blotting, Northern Immune Sera - analysis Animals Recombinant Proteins - immunology Antigens, Protozoan - isolation & purification Antigens, Protozoan - genetics Mice Leishmania - genetics

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