[Study the capacity of recombinant HCV core+1 protein to induce immune responses in combination with different adjuvants]

Hepatitis C virus [HCV] genome contains a large open reading frame coding for a polyprotein that is cleaved into ten proteins. Recently, a new protein, named core+1, has been described to be expressed through a ribosomal frame shift within the capsid-encoding sequence. To address these possibilities, core+1 was produced in E.coli and the purified protein was evaluated for the immunological properties. The core+1 corresponding nucleotide sequence was created by PCR-based induction of a +1 frame shift mutation within the core gene template. The amplicon was cloned into the pET-24a vector and expressed in E.coli host. The expressed protein was purified under denaturing condition and after refolding steps was characterized by SDS-PAGE and Western Blotting. The immunization potential of core+1 with various adjuvant [Freunds [C/IFA], Montanide ISA 206 and IMS 1312, pluronic acid [F127] and imiquimod [IMIQ] was assessed in Balb/c mice. ELISA-based assays were used to analyze the humoral immune responses. The yield of E.coli-derived core+1 was 5 mg/ L of culture media and antigenicity of this protein was confirmed by western blotting. All the core+1/adjuvant formulations significantly developed the anti-core+1 IgG responses in the immunized mice but C/IFA and ISA206 elicited the highest antibody titers. ISA 206 and IMS 1312 formulation of core+1 induced strong Th1/Th2 responses. Our results indicated that core+1 formulation with various adjuvants may elicit the different immune response profiles [Th1/Th2]. Thus core+1 might be a potential component of future HCV vaccine too

[Isolation of shigatoxin-producing Escherichia coli [STEC] from meat samples by PCR in Tehran and evaluation of antibacterial patterns of isolated strains]

Shigatoxin-producing Escherichia coli [STEC] is an emerging foodborne pathogen of worldwide public health importance. This bacterium has been reported as an etiological agent of many outbreaks and sporadic cases. Studies in different countries have shown that food items maybe contaminated by this pathogen. The present study was carried out to determine the frequency of STEC contamination of meat samples, collected in Tehran, as well as defining genotype and antibiotic susceptibility patterns of isolated bacteria. In a period of one year [from 1 July 2004 to 30 June 200, 250 beef samples were collected from different markets of Tehran city. For detection and isolation of STEC from beef samples, conventional culture and PCR were applied. Then, Antibacterial resistance patterns of isolated strains were determined by standard disk diffusing method. Among 250 beef samples, 47[18.8%] were positive for stx genes by PCR. However, only 30[12%] successful isolations of bacteria were made. Of the 30 STEC isolates, 24 [80%] carried the stx2 gene only, while 2 [6.7%] isolates gave positive results for both stx1and stx2. Four isolates [13.3%] possessed stx2 and eae genes. According to the antibiotic resistance tests, all isolates were susceptible to Gentamicin, Imipenem, Norfluxacin, Enrofloxacin, Nalidixic acid, Ciprofluxacin and Ceftazidime. The percentages of isolates that were resistance to the other antibacterial agents were as following: Olendeomycin:100, Erythromycin:100, Cephalothin:67, Amoxycillin-Clavulanic acid: 46.6, Chlortetracycline: 13.3, Tetracycline: 10 and Streptomycin: 6.6. Results of this study indicate that retail raw meats may often be contaminated with antimicrobial-resistant STEC and cautionary efforts are necessary in order to prevent them from contaminating with this bacterium