Destruction of the vascular viral receptor in infectious salmon anaemia provides in vivo evidence of homologous attachment interference
Fig 1
Vascular endothelial cells in ISAV-infected fish become refractory to further ISAV attachment.
(A) Tissue expression of the ISAV receptor was mapped by virus histochemistry using ISAV antigen as the primary probe. Binding of the probe was detected by an antibody targeting the virus, a secondary HRP-labelled antibody, and DAB. The illustration was created in Biorender.com. (B-C) Cumulative mortality (black dots and lines) and ISAV binding (open circles, stippled line, data points show median scores +/- 95% confidence intervals) after infection with two different ISAV isolates: (B) High-virulent NO/Glesvaer/2/90 and (C) low-virulent CA/F679/99. Mortality data from this trial have been published before [35], but are included for context. The loss of ISAV binding was calculated by virus histochemistry on tissue sections from fish harvested 1, 2, 3, 4, 5, 6, 7, 8, 10, 12, 14, 19, and 23 d.p.i. (n = 4 fish per group). (D) Representative micrographs of virus histochemistry in hearts from infected fish at given time points. (E) Representative images of virus histochemistry in hearts from moribund fish collected during Norwegian infectious salmon anaemia outbreaks and non-infected fish (n = 3 fish per group). (D-E) Positive binding is identified by DAB (ISAV binding, brown).