title: Identification and characterization of common B cell epitope in bovine leukemia virus via high-throughput peptide screening system in infected cattle.
abstract: BACKGROUND
  Bovine leukemia virus (BLV) is the causative agent of enzootic bovine leukosis, the most common neoplastic disease of cattle. BLV is closely related to human T cell leukemia virus. B cell epitopes are important for the use of antibodies as therapeutic agents, the epitope-driven vaccine design, and immunological assays. A common B cell epitope for BLV has not yet been found due to individual differences in disease susceptibility.
  
  
  RESULTS
  We used a peptide microarray with 156 synthetic 15-mer peptides covering the envelope glycoprotein gp51 and the Gag proteins p15, p24, and p12 to map B cell epitope and one B cell epitope, gp51p16, was recognized by all four cattle experimentally infected with BLV. A newly developed high-throughput peptide ELISA system revealed 590 (91.2%) of 647 cattle naturally infected with BLV, carrying 25 different bovine leukocyte antigen class II DRB3 (BoLA-DRB3) alleles, responded to a 20-mer gp51p16-C peptide containing a C-terminal cysteine and gp51p16. Alanine mutation and comparison of the sequences at 17 amino acid positions within gp51p16-C revealed that R7, R9, F10, V16, and Y18 were the common binding sites to BLV antibodies, and two of these sites were found to be highly conserved. Transient expression in the cells of five infectious molecular clones of BLV with a single alanine mutation at five common antibody binding sites had no effect syncytia formation of the gp51 protein. In addition, the mutant proteins, R7A and R9A had no effect on the expression of gp51 protein; the gp51 protein expressions of F10A, V16A and Y18A were lower than that of the wild type protein.
  
  
  CONCLUSIONS
  This is the first report to identify a common B cell epitope in BLV by comprehensive screening of BLV-infected cattle with varied genetic backgrounds in BoLA-DRB3. Our results have important implications for disease control and diagnosis.
authors.affiliation: Viral Infectious Diseases Unit, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan. lanlan.bai@riken.jp.|Laboratory of Animal Microbiology, Department of Microbial Biotechnology, Graduate School of Agricultural Science, Tohoku University, Sendai, Miyagi, 981-8555, Japan. lanlan.bai@riken.jp.
authors.forename: Lanlan
authors.initials: L
authors.lastname: Bai
authors.affiliation: Viral Infectious Diseases Unit, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan. hiroyuki.otsuki@riken.jp.|Bovine Leukemia Virus Vaccine Laboratory, RIKEN Innovation Center, RIKEN, Wako, Saitama, 351-0198, Japan. hiroyuki.otsuki@riken.jp.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Otsuki
authors.affiliation: Viral Infectious Diseases Unit, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan. hirotaka.sato@riken.jp.|Bovine Leukemia Virus Vaccine Laboratory, RIKEN Innovation Center, RIKEN, Wako, Saitama, 351-0198, Japan. hirotaka.sato@riken.jp.
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Sato
authors.affiliation: Animal Research Center, Hokkaido Research Organization, Shintoku, Hokkaido, 081-0038, Japan. kohara-junko@hro.or.jp.
authors.forename: Junko
authors.initials: J
authors.lastname: Kohara
authors.affiliation: Laboratory of Animal Microbiology, Department of Microbial Biotechnology, Graduate School of Agricultural Science, Tohoku University, Sendai, Miyagi, 981-8555, Japan. homeiso2006@yahoo.co.jp.
authors.forename: Emiko
authors.initials: E
authors.lastname: Isogai
authors.affiliation: Viral Infectious Diseases Unit, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan. takesima@riken.jp.|Bovine Leukemia Virus Vaccine Laboratory, RIKEN Innovation Center, RIKEN, Wako, Saitama, 351-0198, Japan. takesima@riken.jp.
authors.forename: Shin-nosuke
authors.initials: SN
authors.lastname: Takeshima
authors.affiliation: Viral Infectious Diseases Unit, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan. aida@riken.jp.|Bovine Leukemia Virus Vaccine Laboratory, RIKEN Innovation Center, RIKEN, Wako, Saitama, 351-0198, Japan. aida@riken.jp.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Aida
mesh_terms: D000409:Alanine / Q000235:genetics; D000483:Alleles; D000818:Animals; D000956:Antigens, Viral / Q000276:immunology*; D001665:Binding Sites; D002417:Cattle; D016583:Enzootic Bovine Leukosis / Q000276:immunology* / Q000821:virology; D004797:Enzyme-Linked Immunosorbent Assay; D018985:Epitopes, B-Lymphocyte / Q000737:chemistry / Q000276:immunology*; D015683:Gene Products, gag / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D057166:High-Throughput Screening Assays; D000949:Histocompatibility Antigens Class II / Q000235:genetics / Q000276:immunology; D001909:Leukemia Virus, Bovine / Q000737:chemistry / Q000235:genetics* / Q000276:immunology*; D009154:Mutation; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry / Q000276:immunology*; D040081:Protein Array Analysis; D014759:Viral Envelope Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology
chemical_list: D000956:Antigens, Viral; C423282:BoLA-DRB3 antigen; D018985:Epitopes, B-Lymphocyte; D015683:Gene Products, gag; D000949:Histocompatibility Antigens Class II; D010455:Peptides; D014759:Viral Envelope Proteins; D000409:Alanine