Preparation and Application on the Inactivated Bacterins of Yellow and White Scour of Piglets

Pathogenic Escherichia coli strains were isolated from yellow and white scour samples in pig farms. The strains were used to make autologous inactivated bacterins,and the bacterins were applied to multiple infected farms. The results showed that in the group of inactivated bacterins,the infected piglet number was less,the course of disease was shorter and the symptoms was milder. The piglet E. coli inactivated bacterins could significantly reduced morbidity of yellow and white scour of piglets,the preventive effects of E. coli autologous inactivated bacterins against yellow and white scour of piglets were much better than that of genetically engineered vaccines.

Genetically engineered bacterial-like particles induced specific cellular and humoral immunity as effective tick-borne encephalitis virus vaccine

Tick-borne encephalitis(TBE)is a natural focal disease with fatal encephalitis induced by tick-borne encephalitis virus(TBEV),seriously threatening human and public health.Protection of TBE depends on vaccination with inactivated vaccine,which requires high cost and multiple immunizations.Here,we construct genetically engineered bacterial-like particles(BLPs)as an effective TBEV vaccine with simplified immunizations and improved immune efficacy.The TBEV BLPs involve the combination of the gram-positive enhancer matrix from Lactococcus lactis,and TBEV envelope(E)protein expressed by genetically engineered recombinant baculovirus.The prepared TBEV BLPs can effectively stimulate the activation of dendritic cells to present the TBEV E proteins to T and B cells,leading to strong and durable cellular and humoral immune responses in mice.Surprisingly,the serum levels of specific IgG antibodies in mice remain about 10^(6)at 6 months after the secondary immunization.Overall,the TBEV BLPs can be used as a potent vaccine candidate,laying the foundation for developing novel TBEV genetically engineered vaccines.

Immunity induced by DNA vaccine of plasmid encoding the rhoptry protein 1 gene combined with the genetic adjuvant of pcIFN-γ against Toxoplasma gondii in mice

Objective To construct the eukaryotic expression recombinant plasmid, pcIFN γ, as a genetic adjuvant and observe the immune responses elicited by pcDNA3 rhoptry protein 1 (pc ROP1) combined with pcIFN γ against Toxoplasma gondii (T gondii) infection in mice Methods A fragment of the IFN γ gene was directly inserted into the pcDNA3 plasmid and identified by two restriction endonucleases digestion pcIFN and pcROP1 DNA was injected into the left leg muscle of mice at a dosage of 100?μg, and a booster vaccination was given at the same dosage after two weeks Control groups were injected with pcDNA3 blank plasmid or normal saline At 30, 50 and 70 days after booster injection, kinetic tests were carried out: MTT assay for the proliferation response of T lymphocyte cells and the activity of NK cells, sandwich ABC ELISA for the determination of IFN γ, IL 2 and IL 10; a serum enzymetic aassay for nitric oxide (NO) in sera and ELISA for the titer of IgG antibody in sera Results The recombinant plasmid, pcIFN γ was constructed The proliferation response of spleen T lymph cells, NK cell killing activity, and serum levels of IFN γ, IL 2 and NO in mice injected with pcROP1 and pcIFN γ were higher than in those injected with pcROP1 alone There was no difference in IgG antibody levels between the two groups Conclusion The genetic adjuvant, pcIFN γ, could enhance the cellular immune response induced by DNA vaccine of pcROP1 in mice against Toxoplasma gondii infection