Fig. 2

Microbiota depletion accelerated nephropathogenic IBV pathogenesis and viral replication in vivo. a Trachea, peripheral blood, and kidney of SPF or ABX chicken were harvested and tested for viral loads at 3 and 5 dpi using qRT-PCR (n = 6). b Immunohistochemical anti-N staining of hematoxylin-counterstained tracheal or kidney sections (representative images of 4 or 5 per group). Scale bar, 200 μm. c Histopathological analysis of IBV infection in SPF and ABX chickens. Histopathological analysis was performed on tracheal or kidney samples from noninfected or IBV-infected chickens (SPF or ABX chickens). Histological scoring of hematoxylin and eosin stain-colored tracheal or kidney sections (n = 7 or 8). d Consequences of ABX treatment on IBV virus replication in embryonated chicken eggs. Eleven-day-old embryonated chicken eggs (n = 6) were injected with ABX or PBS. Viral growth was analyzed by quantifying viral RNA using qRT-PCR from RNA extracted from allantoic fluids collected at 72 h post-infection. e Kidney and peripheral blood of gnotobiotic chicken (n = 6) were harvested and tested for viral loads at 3 and 5 dpi using qRT-PCR. Data are from three independent experiments. Biological replicates for each sample are three. P values were determined by an unpaired two-tailed Student’s t test. ns, not significant ; **P < 0.01