Immunogenicity of Cork and Loop Domains of Recombinant Baumannii acinetobactin Utilization Protein in Murine Model.

BACKGROUND: Acinetobacter baumannii (A. baumannii) is a bothersome fatal pathogen, particularly in healthcare system. Persistence and successful invasion of A. baumannii in vertebrate host cells largely depends on iron acquisition methods. Siderophore molecules and Iron-Regulated Outer Membrane Proteins (IROMPs) are the two essential members of iron acquisition system. Siderophores are secreted by bacteria to bind peripheral ferric iron and the IROMPs are expressed at the bacterial outer membrane as the receptor of ferric-siderophore complex. BauA is the corresponding siderophore receptor of A. baumannii. In this study, an attempt was made to assess the immunogenicity of antigenic domains of BauA which could be effective in iron uptake restriction and protection against bacterial invasion of the host cells. METHODS: The antigenic domains of bauA were amplified from A. baumannii ATCC-19606. The PCR products were ligated into pET32a and expressed in Escherichia coli (E. coli) BL21 (DE3). Purification of recombinant domains was done by Nickel-Nitri-lotriacetic Acid (Ni-NTA) affinity chromatography. The recombinant domains were injected into BALB/C mice separately and in combination. Sero-reactivities of the recombinant proteins and mouse challenge tests were carried out. RESULTS: The antibodies raised in mice could successfully recognize and bind antigenic domains. Passive immunization studies accomplished by immune rabbit serum inhibited the establishment of infection in mice. CONCLUSION: The results adapted from the present study disclose the protective role of functional domains of BauA, especially the cork domain, suggesting a novel recombinant immunogen candidate.

Elevation of HPV-18 and HPV-16 DNA in the plasma of patients with advanced cervical cancer.

OBJECTIVE: Cervical cancer (CC) is one of the main problems in women's health in which the pathologic role of the human papilloma virus, HPV, is undeniable. Molecular methods have shown viral DNA in affected tissues, related to the disease progression. PATIENTS AND METHODS: We here studied 100 patients with abnormal Pap test results. HPV DNA loads in the plasma samples were measured by quantitative real time PCR, using specific primers and probes for the E6 genes of HPV types 16, 18, 33 and 52. Another 50 women with no obvious malignancy were enrolled as controls. RESULTS: Pathological studies revealed 81 patients with CC and 19 with cervical intraepithelial neoplasia. Only 19 of the cancer patients (15 with squamous cell carcinomas and 4 with adenocarcinomas) had detectable genetic material of HPV-16 (N = 4) and HPV-18 (N = 15) in their plasma; genetic material of other types was absent. HPV DNA copies increased with advanced disease in both types. Significantly smaller amounts of HPV DNA of types 16 and/or 18 were detected in the plasma of 16% of the controls while other types were negative. CONCLUSION: The evidence of HPV DNA of high risk types in the plasma of women with CCs strongly emphasizes the necessity of more longitudinal comprehensive studies to determine its role as a possible biomarker in cervical cancer.