Résumé
The distribution of glycosylation sites in HA proteins was various among H5 subtype avian influenza viruses (AIVs), however, the role of glycosylation sites to the virus is still unclear. In this study, avian influenza H5N1 viruses with deletion of the glycosylation sites in HA were constructed and rescued by site direct mutation and reverse genetic method, and their biological characteristics and virulence were determined. The result showed that the mutants were confirmed to be corrected by HA gene sequencing and Western blot analysis. The EID50 and TCID50 tested in SPF chick embryo and MDCK cells of a mutant rSdelta158 with deletion of glycosylation site at position 158 were slight lower than that of wild type rescued virus rS, and the plaque diameter of rSdelta158 was significant smaller than that of rS. The EID50 and TCID50 of mutants rSdelta169 and rSdelta290 with deletion of glycosylation sites at position 169 and 290, respectively, were slight higher than that of wild type rescued virus rS, the plaque diameters of rSdelta169 and rSdelta290 were similar as that of rS, but the plaque numbers of rSdelta169 and rSdelta290 were 10-fold higher than that to rS. On the other hand, the rSdelta158, rSdelta169 and rSdelta290 showed similar growth rate in chicken embryo fibroblast as rS. All viruses remained high pathogenicity to SPF chickens. Therefore, the growth of AIV can be affected by changes of glycosylation sites in HA protein, by which the effect is variable in different cells.
Sujets)
Animaux , Embryon de poulet , Motifs d'acides aminés , Lignée cellulaire , Poulets , Glycosylation , Glycoprotéine hémagglutinine du virus influenza , Chimie , Génétique , Métabolisme , Sous-type H5N1 du virus de la grippe A , Chimie , Génétique , Métabolisme , Grippe chez les oiseaux , Virologie , Maladies de la volaille , VirologieRésumé
<p><b>OBJECTIVE</b>To study the changes of red cell immune function and T-lymphocyte subsets in children with bronchiolitis and their possible roles in the pathogenesis of bronchiolitis.</p><p><b>METHODS</b>Forty-five children with bronchiolitis and 30 healthy controls were enrolled. Red cell immune complex rosette (RBC-ICR) and red cell C3b receptor rosette (RBC-C3bRR) were detected. The percentages of CD3+, CD4+ and CD8+ cells were assayed by flow cytometry.</p><p><b>RESULTS</b>RBC-C3bRR［(13.6 ± 6.2)% vs (18.0 ± 7.4)%] and the percentage of CD8+ cells [(21.6 ± 4.4)% vs (25.6 ± 5.2) %］ in the bronchiolitis group were lower than those in the control group (P<0.01). The percentage of CD3+ cells ［(59.9 ± 6.7)% vs (52.1 ± 8.3)%］ and CD4+ cells [(53.5 ± 6.2)% vs (46.8 ± 4.9)%] and RBC-ICR [(8.3 ± 3.5)% vs (6.1 ± 2.5)%] in the bronchiolitis group were higher than those in the control group (P<0.01). The percentage of CD4+ cells was positively correlated with RBC-ICR (r=0.63,P<0.05) and negatively correlated with RBC-C3bRR (r=-0.82,P<0.01).</p><p><b>CONCLUSIONS</b>There are dysfunctions of red cell immune and T-lymphocyte subsets in children with brochiolitis, which may play a role in the pathogenesis of brochiolitis.</p>