Serial recombinant expression and anti-tumor activity in vitro of antibiotic peptide Alloferon-1 / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To generate a recombinant expression system of repeated serial antibiotic peptide Alloferon-1 DNA segment with trypsin digestion site and to determine its anti-tumor activity in vitro.</p><p><b>METHODS</b>A 14 repeated serial DNA segment of Alloferon-1 with a lysine residual at the C-end that acts as the trypsin digestion site was constructed. pET42a vector and E.coli BL21DE3 were applied to generate the prokaryotic expression system of the repeated serial DNA segment of Alloferon-1. The yield of target recombinant product was measured by SDS-PAGE and Bio-Rad Gel image system. Ni-NTA affinity column, trypsin digestion and Sephadex G-50 column were used to purify 14 rAlloferon-1-K fusion protein and rAlloferon-1-K monomer. By using the co-cultivation of BALB/c mouse splenocyte with K562, KB or SGC tumor cells and CCK-8 detection method, the effects of rAlloferon-1-K, chemosynthetic Alloferon-1 (cAlloferon-1) and Alloferon-1-K (cAlloferon-1-K) on the growth and proliferation of tumor cells were detected.</p><p><b>RESULTS</b>The prokaryotic expression system E.coli BL21DE3pET42a-14 Alloferon-1-K efficiently expressed 14 rAlloferon-1-K fusion protein under inducement of IPTG,and the yield of fusion protein was approximate 30% of the total bacterial proteins. 0.1≊10 ng/ml rAlloferon-1-K remarkably increased the effect of mouse splenocytes to inhibit the growth and proliferation of K562, KB and SGC cells (P<0.05), and there was no statistically significant difference of the anti-tumor ability of rAlloferon-1-K compared to that of cAlloferon-1 or cAlloferon-1-K (P>0.05).</p><p><b>CONCLUSION</b>A prokaryotic expression system of repeated serial Alloferon-1 DNA segment has been successfully constructed with high yield of rAlloferon-1-K, which maintains anti-tumor activity in vitro.</p>

Avian influenza virus infection in people occupied in poultry fields in Guangzhou city / 中华流行病学杂志

Objective To conduct serological investigation on H5N1/H9N2/H7N7 infection among people occupied in poultry fields. Methods Serum samples were collected from people working in live poultry and none-poultry retailing food markets, poultry wholesaling, large-scale poultry breading factories and in small-scale farms, wide birds breeding, swine slaughtering houses and from normal population. Antibodies of H5, H9 and H7 with hemagglutination inhibition and neutralization tests were tested and analyzed. Logistic regression and χ2 test were used. Results Among 2881 samples, 4 were positive to H5-Ab(0.14%), 146 were positive to H9-Ab (5.07%) and the prevalence of H9 among people from live poultry retailing (14.96%) was the highest. Prevalence rates of H9 were as follows: 8.90% in people working in the large-scale poultry breading factories, 6.69% in the live poultry wholesaling business, 3.75% in the wide birds breeding, 2.40% in the swine slaughtering, 2.21% in the non-poultry retailing, 1.77% in the rural poultry farmers and 2.30% in normal population. None was positive to H7-Ab among 1926 poultry workers. Conclusion The H5 prevalence among people was much lower than expected, but the H9 prevalence was higher. None of the populations tested was found positive to H7-Ab. There was a higher risk of AIV infection in live poultry retailing, wholesaling and large-scale breading businesses, with the risk of live poultry retailing the highest. The longer the service length was, the higher the risk existed.