To compare immunological characteristics of Extracellular fibrinogen-binding protein (Efb) and Clumping factor A (CfA) of Staphylococcus aureus, we constructed two prokaryotic expression vector pET28a-Efb and pET28a-ClfA. After prokaryotical expression and purification, Efb and ClfA were used to immunize experimental animal. After the second immunization the antisera were collected and the antibody titers, the bacteria binding activity and adhesion inhibition activity of these antisera were detected by enzyme linked immunosorbent assay, adhesion inhibition assay and challenge. Both Efb and ClfA had Fibrinogen binding activity whereas the former had better Fibronectin binding activity. The bacteria binding capability of antisera of rabbits immunized with ClfA was better than that with Efb (P < 0.01). Both antisera of Efb and ClfA could inhibit adherence activity of Staphylococcus aureus to Fibrinogen and Fibronectin adherence compare to the control group (P < 0.01), and Efb had better adhesion inhibition activity than ClfA. The antibody titer of immunized group could reach 1:40 500. After the second immunization, both Efb and ClfA had good protective efficacy. This result constitutes a good foundation for Staphylococcus aureus subunit vaccine development.
Animals ; Antibodies, Bacterial ; blood ; Bacterial Adhesion ; Bacterial Proteins ; immunology ; Cattle ; microbiology ; Coagulase ; immunology ; Enzyme-Linked Immunosorbent Assay ; Fibrinogen ; metabolism ; Genetic Vectors ; Immune Sera ; immunology ; Immunization ; Rabbits ; Staphylococcal Infections ; immunology ; Staphylococcus aureus

Objective To observe the incidence of spontaneous clearance of hepatitis B virus (HBV) DNA in chronic hepatitis B (CHB) patients ,and to investigate the related factors of the spontaneous clearance of HBV DNA and to determine the time to start antiviral therapy .Methods Patients who met the inclusion criteria were recruited from the follow-up cohort of chronic HBV infection from January 2008 to August 2017 for observation .The liver function including alanine aminotransferase (ALT) levels ,HBV DNA load and serum markers of HBV were measured at baseline ,month 1 ,month 3 and month 6 of follow-up . Evaluation index included cumulative HBV DNA negative conversion rate and cumulative HBeAg negative conversion rate .Multivariable analysis was used to analyze the factors associated with the spontaneous clearance of HBV DNA .Results A total of 116 patients were recruited in this study .All the patients showed ALT level elevation at baseline .Without antiviral treatment ,the cumulative HBV DNA negative conversion rate was 12 .9％ after 6-month observation .HBeAg negative conversion rate was 22 .5％ .Multivariable analysis showed that patients without a family history of HBV infection ,baseline ALT level >3 times the upper limit of normal (ULN) and HBV DNA level <6 lg copies/mL had higher cumulative HBV DNA spontaneous clearance rate .HBV DNA negative conversion rate in patients whomet all the above three conditions was up to 75％ .Conclusions In CHB patients and ALT level elevation for the first time , some patients could achieve spontaneous clearance of HBV DNA without antiviral therapy .Patients without a family history of HBV infection ,baseline ALT level >3 ULN and HBV DNA level <6 lg copies/mL have higher rate of cumulative HBV DNA spontaneous clearance .

To analyze the immunogenicity and protective ability of recombinant IgG-binding protein (EAG) of Streptococcus equi subspecies equi and to evaluate its value when used as equine vaccine antigen, EAG gene was amplified by PCR and inserted into pET-28a vector. The EAG recombinant proteins were expressed and purified to immune mice. The serum antibody and challenge protection were tested. The purified recombinant protein of EAG was 26 kDa, and the protein reacted specifically with positive serum of Streptococcus equi subspecies equi. The mice antibody level for EAG immunization group was 1∶8 100. The immunological protection result showed that the protection rate of the EAG recombinant protein was 90%. The results suggested that the EAG protein has good immunogenicity and immunological protection, and it can effectively increase the humoral immune response and immunological protection of mice.
Animals ; Antibodies, Bacterial ; blood ; Antigens, Bacterial ; immunology ; Bacterial Proteins ; immunology ; Bacterial Vaccines ; immunology ; Immunity, Humoral ; Immunoglobulin G ; blood ; Mice ; Polymerase Chain Reaction ; Protein Binding ; Recombinant Proteins ; immunology ; Streptococcal Infections ; prevention & control ; Streptococcus equi ; Vaccination