Distribution Characteristics Of Influenza Virus Sialic Acid Receptors In Partridge

Objective With the improvement of living standards in recent years,the demand of partridge is numerous. On farms and live bird markets,people mix the partridge and land birds (chickens, quail and so on),waterfowl duck and goose to cultivate and sell. These hosts provide theenvironment for avian influenza virus to spread and repeated infections.After a long time, the HA receptor binding sites of avian influenza virusare likely to change. Even more, a new subtype of virus will form by theway of genetic recombination. Therefore, the new subtype of virus canobtain the ability to infect human. Through molecular epidemiology, itfound that some avian influenza virus epidemic in partridge and haveestablished stable lineages. These phenomena suggest that partridge mayalso play the role of intermediate host in influenza virus ecosystem.However, the molecular mechanism has not been reported at home and abroad. This study determine the Distribution characteristics of influenzavirus SAα-2，3and SAα-2，6sialic acid receptors in partridge. This studycan probe the role of partridge in cross-species transmission of influenzaviruses and evolution and provide a basis for the selection of monitoringinfluenza virus host.Methods1. Determine sialic acid receptors of SAα-2，3andSAα-2，6Lectin histochemical staining: paraffin dewaxing to water,MAA-Ⅱ(1.25μg/ml)and SNA（0.25μg/ml）were dropping on the tissuesections, the former is a specific markers of SAα-2,3Gal receptor, thelatter is a specific marker of SAα-2,6Gal receptor.4oC freezer overnight,wash3x5min with PBS,drop R.T.U. Horseradish PeroxidaseStreptavidin, Incubate30minutes at room temperature, wash3x5minwith PBS, drop the fresh DAB, tap water, dyeing, dehydration,transparent, seting, see the results under optical microscope. Positivecontrol: duck colon tissue for MAA-Ⅱ, human tracheal tissue for SNA;Negative control: human tracheal tissue for MAA-Ⅱ, duck colon tissuefor SNA. Determine results: under optical microscope, the surface ofepithelial cells shows the color of brown is positive signals.2. Influenzavirus markers and binding experiments amplicate avian influenza virusH9N1by Chicken embryos; Culture human influenza virus (H1N1) byMDCK cells, with0.03%formaldehyde inactivated virus liquid72h,centrifuged at speeding to purified virus, buffer exchange, use fluorescein Alexa48to mark virus, shaker shake1h, the labeled virus were shiftedto Microcon YM-100, wash3x5min with PBS. Positive control: duckcolon tissue for avian influenza virus H9N2; human tracheal tissue forhuman influenza virus H1N1. Negative control: duck colon tissue forhuman influenza virus H1N1, human tracheal tissue for avian influenzavirus H9N2.Determine results: under fluorescence microscopy, greenfluorescent are found at membrane is Positive signal.Results1. Lectin histochemical staining and virus binding test were used andresults showed that both the SAα-2,3Gal receptors and SAα-2,6Galreceptors were expressed in respiratory tract, but only the SA α-2,3Galreceptors were expressed in partridge alimentary tract. The SAα2,3Galreceptors were general presence in the trachea, bronchus, secondbronchus, parabrochus, and colon of partridge. The SAα2,6Galreceptors was prevalent in the trachea, bronchus and second bronchus,but was infrequent in parabrochus and colon of partridge.2. Alexa488labelled avian influenza H9N1virus could bind to epithelial cells inrespiratory tract and alimentary tract of partridge. Human influenzaH1N1virus could only bind to the trachea, bronchus and secondbronchus, but not to the parabrochus and colon of partridge.Conclusions1. The SAα2,3Gal receptors were strongly expressed in the trachea, bronchus, secondary bronchi, vice bronchial and gastrointestinal colon ofpartridge.The SAα2,6Gal receptors were strongly expressed in thetrachea, bronchus and secondary bronchi of partridge, but not in vicebronchial and gastrointestinal colon of partridge2. the trachea, bronchus, secondary bronchi, vice bronchial andgastrointestinal colon of partridge are easily combined with H9N1avianinfluenza virus, the trachea, bronchus, secondary bronchi of partridge areeasily combined with H1N1human influenza virus,but vice bronchial andgastrointestinal colon not easily combined with H1N1human influenzavirus.3. Taken together, these results indicate that partridge, which carry bothSAα2,3Gal and SAα2,6Gal receptors compatible with binding of avianand human influenza viruses, could provide an environment ofreassortants between avian and human influenza viruses and act aspotential intermediate hosts for avian influenza virus transmission tohumans and could generate new influenza viruses with pandemicpotential.