B cell epitopes within VP1 of type O foot-and-mouth disease virus for detection of viral antibodies.
In this study, the coding region of type O FMDV capsid protein VP1 and a series of codon optimized DNA sequences coding for VP1 amino acid residues 141-160 (epitope1), tandem repeat 200-213 (epitope2 (+2)) and the combination of two epitopes (epitope1-2) was genetically cloned into the prokaryotic expression vector pP(RO)ExHTb and pGEX4T-1, respectively. VP1 and the fused epitopes GST-E1, GST-E2 (+2) and GST-E1-2 were successfully solubly expressed in the cytoplasm of Escherichia coli and Western blot analysis demonstrated they retained antigenicity. Indirect VP1-ELISA and epitope ELISAs were subsequently developed to screen a panel of 80 field pig sera using LPB-ELISA as a standard test. For VP1-ELISA and all the epitope ELISAs, there were clear distinctions between the FMDV-positive and the FMDV-negative samples. Cross-reactions with pig sera positive to the viruses of swine vesicular disease virus that produce clinically indistinguishable syndromes in pigs or guinea pig antisera to FMDV strains of type A, C and Asia1 did not occur. The relative sensitivity and specificity for the GST-E1 ELISA, GST-E2 (+2), GST-E1-2 ELISA and VP1-ELISA in comparison with LPB-ELISA were 93.3% and 85.0%, 95.0% and 90%, 100% and 81.8%, 96.6% and 80.9% respectively. This study shows the potential use of the aforementioned epitopes as alternatives to the complex antigens used in current detection for antibody to FMDV structural proteins.
National Foot-and-mouth Disease Reference Laboratory, Key Laboratory of Animal Virology of Ministry of Agriculture, State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730046, China.
Shan-dian
SD
Gao
Jun-zheng
JZ
Du
Hui-yun
HY
Chang
Guo-zheng
GZ
Cong
Jun-Jun
JJ
Shao
Tong
T
Lin
Shuai
S
Song
Qing-ge
QG
Xie
D000818:Animals; D000914:Antibodies, Viral / Q000097:blood*; D000956:Antigens, Viral / Q000235:genetics / Q000276:immunology*; D036022:Capsid Proteins / Q000235:genetics / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D018985:Epitopes, B-Lymphocyte / Q000235:genetics / Q000276:immunology*; D004926:Escherichia coli / Q000235:genetics; D005536:Foot-and-Mouth Disease / Q000175:diagnosis*; D029544:Foot-and-Mouth Disease Virus / Q000235:genetics / Q000276:immunology*; D015870:Gene Expression; D006168:Guinea Pigs; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology; D012680:Sensitivity and Specificity; D013552:Swine
D000914:Antibodies, Viral; D000956:Antigens, Viral; D036022:Capsid Proteins; D018985:Epitopes, B-Lymphocyte; D011993:Recombinant Fusion Proteins; C442501:VP1 protein, Foot-and-mouth disease virus