Objective To screen B and T cell antigen epitopes on Acinetobacter baumannii outer membrane protein 33×103-36×103 (OMP33-36).Methods B and T cell epitopes on OMP33-36 of Acinetobacter baumannii were predicted by bioinformatics methods and synthesized.Recombinant expression plasmid pET-30a-OMP33-36 was cloned and used to express OMP33-36 in a prokaryotic expression system.The expressed OMP33-36 was used to immunize BALB/c mice after purification.Serum sample was collected from each mouse in immunization and negative control groups, and then analyzed by indirect ELISA with synthesized peptides to identify B cell epitopes.Splenocytes were separated from every mouse and then cultured with each of the synthesized peptides, respectively.Double sandwich ELISA was performed to detect IFN-γ secretion in the supernatant of cell cultures for screening of T cell epitopes.Results Candidates of B and T cell epitopes were constructed, which were PB1, PB2, PB3, PT1, PT2 and PT3.Results of the indirect ELISA showed that peptides PB1 and PB2 reacted with the serum samples collected from immunized mice and A450 values of the immunization group were significant higher than those of the negative control group.Compared with the negative control group, enhanced secretion of IFN-γ following peptide PT3 stimulation was observed in the immunization group as indicated by the double sandwich ELISA.Conclusion Two B cell epitopes PB1 and PB2, and one T cell epitope PT3 on the OMP33-36 of Acinetobacter baumannii were successfully constructed and screened out.

Objective To investigate the clinical features and prognostic factors of Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis (EBV-HLH) in adults.Methods Clinical data of 40 adult patients with EBV-HLH admitted in the First Affiliated Hospital of Nanjing Medical University during January 2010 and September 2013 were retrospectively analyzed.The patients were divided into fatal group or survival group based on the results of 1-month follow-up.Logistic regression analysis was performed to identify risk factors of early death.Results EBV-HLH in clinic were characterized by fever,hepatosplenomegaly and lymphadenopathy.The incidences of peripheral blood cytopenias in 2 or 3 lines,hepatic dysfunction and hyperferritinemia in EBV-HLH patients were 60.0％ (24/40),95.0％ (38/40) and 94.9％ (37/39),respectively.Hemophagocytic phenomenon in bone marrow was observed in 83.8％ patients (31/37).Soluble CD25 (sCD25) was detected in 12 patients,and all were higher than 2 400 pg/mL.Nineteen patients died 1 month after fiual diagnosis with a fatality rate of 47.5％.Univariate logistic regression analysis indicated that EBV-DNA ＞ 105 copies/mL (OR =4.85,95％ CI:1.14-25.83,P ＜ 0.05),PLT ＜ 50 × 1012/L (OR =6.81,95 ％ CI:1.41-32.83,P ＜ 0.05),total bilirubin ＞ 50 μmol/L (OR =6.91,95％ CI:1.24-38.52,P ＜0.05),albumin ＜ 30 g/L (OR =7.50,95％ CI:1.80-31.28,P ＜ 0.01),serum ferritin ＞5 000 μg/L (OR =8.75,95％ CI:2.03-37.67,P ＜0.01) and polyserositis (OR =5.40,95％ CI:1.18-24.64,P ＜0.05) were risk factors of death within 1 month after final diagnosis,while chemotherapy was a protective factor of early death (OR =0.15,95％ CI:0.03-0.81,P ＜ 0.05).Conclusions EBV-HLH in adult has a poor prognosis.Significant elevated EBV-DNA,total bilirubin or serum ferritin,and notable decrease of peripheral blood platelet count or albumin level may indicate a poor prognosis,while chemotherapy may reduce the risk of early death.