title: Evaluation of humoral and cellular immune responses to BP26 and OMP31 epitopes in the attenuated Brucella melitensis vaccinated sheep.
abstract: In recent years, the number of cases of human brucellosis has been increasing by approximately 10% per year in China. Most cases were caused by Brucella melitensis through contacts with infected sheep, goats or their products. An attenuated B. melitensis vaccine M5-90 is currently used to vaccinate both animals in China. This vaccine has not been investigated for critical parameters such as immune response and its association with protective efficacy. In this study, humoral and cellular immune response to the periplasmic protein BP26 and the outer membrane protein OMP31 were evaluated in M5-90 vaccinated Chinese merino and Kazak sheep. Antibodies to BP26 or OMP31 were detected at low levels, and specific IFN-γ response was quantified. Strongly reactive peptides derived from BP26 and OMP31 identified five T-cell epitopes (BP26-6, -8, -11, -12 and OMP31-23) common to both sheep species, five species-specific epitopes (BP26-10, -18, -21 and -22 and OMP31-12) and four animal-specific epitopes (BP26-15, -23, OMP31-6 and -21), which stimulated specific IFN-γ response in vaccinated sheep. Among those T-cell epitopes, reactivity to BP26-18 and -21 epitopes was significantly associated with MHC-I B allele (P=0.024). However, a specific T-cell response induced by the M5-90 vaccine was relatively week and did not sustain long enough, which might be suppressed by rapid activation of T-regulatory (Treg) cells following vaccination. These findings provide an insight in designing a safer and more effective vaccine for use in animals and in humans.
authors.affiliation: Department of Transfusion Medicine, Southern Medical University, Guangzhou, China.
authors.forename: Wenjing
authors.initials: W
authors.lastname: Wang
authors.affiliation: Department of Transfusion Medicine, Southern Medical University, Guangzhou, China.
authors.forename: Jingbo
authors.initials: J
authors.lastname: Wu
authors.affiliation: School of Animal Science and Technology, Shihezi University, Shihezi, Xinjiang, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Qiao
authors.affiliation: Department of Transfusion Medicine, Southern Medical University, Guangzhou, China.
authors.forename: Yunceng
authors.initials: Y
authors.lastname: Weng
authors.affiliation: School of Animal Science and Technology, Shihezi University, Shihezi, Xinjiang, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Department of Transfusion Medicine, Southern Medical University, Guangzhou, China.
authors.forename: Qingyu
authors.initials: Q
authors.lastname: Liao
authors.affiliation: Department of Transfusion Medicine, Southern Medical University, Guangzhou, China.
authors.forename: Jinlang
authors.initials: J
authors.lastname: Qiu
authors.affiliation: School of Animal Science and Technology, Shihezi University, Shihezi, Xinjiang, China.
authors.forename: Chuangfu
authors.initials: C
authors.lastname: Chen
authors.affiliation: Department of Transfusion Medicine, Southern Medical University, Guangzhou, China; Department of Haematology, University of Cambridge, Cambridge, UK.
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Allain
authors.affiliation: Department of Transfusion Medicine, Southern Medical University, Guangzhou, China. Electronic address: chengyaoli@hotmail.com.
authors.forename: Chengyao
authors.initials: C
authors.lastname: Li
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D001425:Bacterial Outer Membrane Proteins / Q000276:immunology*; D002004:Brucella Vaccine / Q000276:immunology*; D017347:Brucella melitensis; D002006:Brucellosis / Q000276:immunology* / Q000517:prevention & control / Q000662:veterinary; D018984:Epitopes, T-Lymphocyte / Q000276:immunology; D005260:Female; D007111:Immunity, Cellular; D056724:Immunity, Humoral; D007371:Interferon-gamma / Q000276:immunology; D008565:Membrane Proteins / Q000276:immunology*; D012756:Sheep / Q000276:immunology; D012757:Sheep Diseases / Q000276:immunology* / Q000382:microbiology / Q000517:prevention & control; D034561:Sheep, Domestic / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; C106040:BP26 protein, Brucella; D001425:Bacterial Outer Membrane Proteins; D002004:Brucella Vaccine; D018984:Epitopes, T-Lymphocyte; D008565:Membrane Proteins; C101108:Omp31 protein, Brucella melitensis; D007371:Interferon-gamma
keywords: B. melitensis; BP26; Epitopes; Immune Response; OMP31; Vaccine