Caspases are an evolutionarily conserved family of aspartate-specific cystein-dependent proteases with essential functions in apoptosis and normally exist in ceils as inactive proenzymes.In addition to the inflammatory caspases,the initiator and effector caspases have been shown to have an important role in regulating the immune response,but are involved in different ways.We give a brief introduction on the benefit of apoptosis on the clearance of invasive pathogens,and the caspase functions involved in the immune response.Then we construct a working model of caspases during pathogen invasion.A detailed description of the three modes is given in the discussion.These three modes are regulated by different inhibitors,and there may be a novel way to treat intracellular pathogen and autoimmune diseases based on the specific inhibitors.

Three encoding sequence genes (Lab, 3C, 3D) from 19 isolates of O-serotype of foot and mouth disease virus(FMDV) were down-loaded from GenBank. And the coding and amino acid sequences of 3 FMDV proteases (Lpro, 3Cpro, 3Dpol) were compared with the FMDV OA/58 serotype Lab, 3C, 3D sequences abstracted in our laboratory and qualified by variance analysis and multiple analysis(Duncan method). The experimental results revealed that the Lab, 3C and 3D genes had similar nucleotide mutation rates(P>0.05). However, overall analysis of the amino acid substitutions revealed that the Lpro- coding region was more prone to amino acid alterations than 3Cpro and 3Dpol- coding regions(P<0.01), but via multiple comparison, at the amino acid mutation, both 3Cpro and 3Dpol showed no significant difference. Depending on Swiss--pdb-Viewer sofe to simulate amino acid alterations at mutation hotspots, the findings showed that these alterations at hotspots failed to ruin the spatial structures of these 3 proteases. This result presents that the nucleotide mutation just acts on dynamics related to FMDV mutation, but the real evolutionary power must depend on the infected host cells to select functions with each viral proteases.

To develop a safe and efficient recombinant subunit vaccine to foot-and-mouth disease virus(FMDV)type Asia 1 in sheep,a tandem repeated multiple-epitope gene consisting of residues 137-160 and 197-211 of the VP1 gene of FMDV was designed and artificially synthesized.The biologically functional molecule,the ovine IgG heavy constant region(oIgG)as a protein carrier was introduced for design of the multiple-epitope recombinant vaccine and recombinant expression plasmids pET-30a-RE and pET-30a-RE-oIgG were successfully constructed.The recombinant proteins,RE and RE-oIgG,were expressed as a formation of inclusion bodies in E.coli.The immune potential of this vaccine regime in guinea pigs and sheep was evaluated.The results showed that IgG could significantly enhance the immune potential of antigenic epitopes.The recombinant protein RE-oIgG could not only elicit the high levels of neutralizing antibodies and lymphocytes proliferation responses in the vaccinated guinea pigs,but confer complete protection in guinea pigs against virus challenge.Although the recombinant protein RE could not confer protection in the vaccinated animals,it could delay the appearance of the clinical signs and reduce the severity of disease.Inspiringly,the titers of anti-FMDV neutralizing antibodies elicited in sheep vaccinated with RE-oIgG was significantly higher than that for the RE vaccination.Therefore,we speculated that this vaccine formulation may be a promising strategy for designing a novel vaccine against FMDV in the future.

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.

The potency of an improved recombinant multi-epitope vaccine against FMDV type Asia1 was evaluated in this study .A multi-epitope gene based on FMDV type Asia1 was designed and a recombinant expression plasmid (pRE-oIgG) was constructed .The proteins ,RE-oIgG and 3D were expressed in E .coli cells and purified with Ni-NTA agarose resin by affinity chromatography .The proteins ,RE-oIgG ,3D and RE-oIgG plus 3D ,were emulsified in an oil adjuvant ISA 206 .Twenty-five female guinea pigs were randomly divided into five groups and intramuscularly vaccinated for with RE-oIgG ,3D ,RE-oIgG plus 3D ,an inactivated FMDV vaccine (type Asia1) ,and PBS .All animals were vaccinated for two times .Anti-FMDV specific an-tibodies ,neutralization antibodies ,protection potency ,and lymphoproliferation assay were detected by ELISA ,virus neutrali-zation assay ,challenge test ,and flow cytometry ,respectively .Results showed that RE-oIgG plus 3D elicited significant high-level anti-FMDV specific antibodies compared to RE-oIgG alone (P<0 .05) .All the vaccinated animals induced higher level lymphoproliferation responses in vitro except PBS .Both 3D alone and PBS produced the negligible neutralizing antibodies and anti-FMDV specific antibodies .RE-oIgG plus FMDV 3D not only elicited high levels of anti-FMDV neutralizing antibodies ,but also induced significant lymphoproliferation responses .More importantly ,RE-oIgG plus 3D conferred complete protection to guinea pigs against challenge with 1 000 GPID50 .Interestingly ,two of five vaccinated animals with 3D alone were full protected against challenge ,and other three animals significantly showed a delay of 2-3 days in the onset of clinical signs .Therefore ,we considered that RE-oIgG plus 3D induces strong humoral and cellular immune responses ,which may be used for control and prevention of FMD in the future .

In order to develop an anti-FMDV A Type monoclonal antibo by (mAb),BABL/c mice were immunized with FMDV A type.Monoclonal antibodies (mAbs) 7B11 and 8H4 against Foot-and-mouth disease virus (FMDV) serotype A were produced by fusing SP2/O myeloma cells with splenocyte from the mouse immunized with A/AV88.The microneutralization titer of the mAbs 7B11 and 8H4 were 1024 and 512,respectively.Both mAbs contain kappa light chains,the mAbs were IgG1.In order to define the mAbs binding epitopes,the reactivity of these mAbs against A Type FMDV,were examined using indirect ELISA,the result showed that both mAbs reacted with A Type FMDV.These mAbs may be used for further vaccine studies,diagnostic methods,prophylaxis,etiological and immunological research on FMDV.Characterization of these ncindicated that prepared anti-FMDV A mAbs had no cross-reactivity with Swine Vesicular Disease (SVD) or FMDV O,Asial and C Type antigens.Their titers in abdomen liquor were 1:5×106 and 1:2×106,respectively.7B11 was found to be of subtype IgG1,8H4 was classified as IgG2b subtype.The mAbs prepared in this study,are specific for detection of FMDV serotype A,and is potentially useful for pen-side diagnosis.

To identify linear epitopes on the non-structural protein 3AB of foot-and-mouth disease virus (FMDV),BABL/c mice were immunized with the 3AB protein and splenocytes of BALB/c mice were fused with myeloma Sp2/0 cells.Two hybridoma monoclonal antibodies (mAbs) cell lines against the 3AB protein of foot-and-mouth disease virus (FMDV) were obtained,named C6 and E7 respectively.The microneutralization titer was 1∶1024 for mAb C6,and 1∶512 for E7.Both mAbs contain kappa light chains,and were of subclass IgG2b.In order to define the mAbs binding epitopes,the reactivity of these mAbs against FMDV were examined by indirect ELISA.The results showed that both mAbs can react with FMDV,but had no cross-reactivity with Swine Vesicular Disease (SVD) antigens.The titers in abdomen liquor were 1∶5×106 for C6 and 1∶2×106 for E7.In conclusion,the mAbs obtained from this study are specific for the detection of FMDV,can be used for etiological and immunological researches on FMDV,and have potential use in diagnosis and future vaccine designs.

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(epitope1-2)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 Asial 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.

In order to develop an anti-FMDV Asial type monoclonal antibody (mAb), BABL/c mice were immunized with recombinant FMDV VP1 protein. Three mAbs, 1B8, 5E1 and 5E2, were then further optimized. The result indicated that prepared anti-FMDV Asial mAbs had no cross-reactivity with Swine vesicular disease (SVD) and FMDV O, A and C type antigen. Their titers in abdomen liquor were l:5×106, l:2×106 and l:5×l06, respectively. 1B8 was found to be of IgGi subtype, 5E1 and 5E2 belonged to IgG2b subtype. In this study, the prepared mAbs are specific for detecting FMDV type Asial, and is potentially useful for pen-side diagnosis.

To investigate the security of semen biologically, 15 bull semen samples were collected (of which 5 exhibited clinical signs of Foot-and-mouth disease) and identified by RT-PCR and virus isolation. The results indicated that the semen of the infected bulls were contaminated by Foot-and-mouth disease virus (FMDV), but FMDV was not detected in semen samples from those bulls not showing clinical signs of Foot-and-mouth disease (FMD). This is the first report of the presence of FMDV in bull semen due to natural infection in China. The analysis of the partial sequence of the VP1 gene showed that the virus strain isolated from semen has 97.9% identity with the virus isolated from vesicular liquid of infected bulls showing typical signs of FMD and belonged to the same gene sub-group.