Integrins are members of a ubiquitous membrane receptor family which includes 18 different α subunits and 8 β subunits forming more than 20 α/β heterodimers. Integrins play key functions in vascular endothelial cell and tumour cell adhesion, lymphocyte trafficking, tumor growth and viral infection. Current understanding of the molecular basis of integrins as viral receptors has been achieved through many decades of study into the biology of transmembrane glycoproteins and their interactions with several viruses. This review provides a summary of the current knowledge on the molecular bases of interactions between viruses and integrins, which are of potential practical significance. Inhibition of virus-integrin interactions at the points of virus attachment or entry will provide a novel approach for the therapeutic treatment of viral diseases.
Shan-dian GAO Jun-zheng DU Jian-hua ZHOU Hui-yun CHANG Qing-ge XIE
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 （epitopel）, tandem repeat 200-213 （epitope2 （＋2）） and the combination of two epitopes （epitopel-2） was genetically cloned into the prokaryotic expression vector PPRoExHTb 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.
Shan-dian GAO Jun-zheng DU Hui-yun CHANG Guo-zheng CONG Jun-jun SHAO Tong LIN Shuai SONG Qing-ge XIE
