Generation And Immunogenicity Of Cow Escherichia Coli O14 Ghost Vaccine

Escherichia coli is an important zoonotic pathogen.The bacteria is Widespread in the environment,and some strains have strong pathogenicity.The Bacterial ghost(BGs)are Gram-negative bacteria that are controlled by the phiX174 cleavage gene E to produce bacterial shells with no cell contents.In addition to a vaccine,the bacteria can be used as adjuvants,exogenous protein antigens,bioactive substances and DNA vaccine carriers,etc.Preparation of BGs by gene E cleavage may also have the risk of gene transfer of pathogenic island or antibiotic resistance gene level.Therefore,BGs as a vaccine or vaccine carrier should be safer.In order to minimize or completely eliminate the vitality of the bacteria after cleavage and remove the residual genetic material,this study will Introduce the assisted dying gene into the lysis of the expression system SNA,and construct a new temperature-controlled expression plasmid pBVE-CIP-SNA(pBVES),and the plasmid was successfully imported into the E.coli O14 wild strain from cattle.Furthermore,we analyzed Salmonella ghost by bacteriolytic dynamics test with more times.And the agglutination kinetics of plasmid Escherichia coli was up to 99.65%,Electron microscopic observation Salmonella ghosts showed that the contents of the stool were complete,and the morphology and surface structure were complete,compared with the control group.In order to verify the immunogenicity of the BGs,the decay group,inactivated group and inactivated adjuvant group was established for the experiment,and the control group is PBS,and then the immunogenicity of the four groups was measured by different immune indicators.The results showed that the serum IgG content in the experimental group was significantly higher than that in the control group with the increase of the immunization times.The results of the mouse lymphocyte subsets showed that the bacteria could stimulate the mice to produce Th1 cell immune response.The results of main cytokines determination showed that the levels of IFN-γ and IL-12 in the BGs group were significantly higher than those in control group,but the secretion level of IL-4 in experimental group has no obvious different from that of the control group.The results showed that the protection rate of BGs group for mice was 70%.The clinical symptoms showed that the mice of BGs group were better than other immunized groups after the challenge,and the pathological results showed that the lesion of BGs group was lighter than the other immunization groups.In summary,the plasmid Escherichia coli bacteria has a good immunogenicity.The result of this study provides a basis for development of new vaccines,which can be applied widely.