Binding of rabbit hemorrhagic disease virus to antigens of the ABH histo-blood group family

Abstract

The ability of rabbit hemorrhagic disease virus to agglutinate human erythrocytes and to attach to rabbit epithelial cells of the upper respiratory and digestive tracts was shown to depend on the presence of ABH blood group antigens. Indeed, agglutination was inhibited by saliva from secretor individuals but not from nonsecretors, the latter being devoid of H antigen. In addition, erythrocytes of the rare Bombay phenotype, which completely lack ABH antigens, were not agglutinated. Native viral particles from extracts of infected rabbit liver as well as virus-like particles from the recombinant virus capsid protein specifically bound to synthetic A and H type 2 blood group oligosaccharides. Both types of particles could attach to adult rabbit epithelial cells of the upper respiratory and digestive tracts. This binding paralleled that of anti-H type 2 blood group reagents and was inhibited by the H type 2-specific lectin UEA-I and polyacrylamide-conjugated H type 2 trisaccharide. Young rabbit tissues were almost devoid of A and H type 2 antigens, and only very weak binding of virus particles could be obtained on these tissues.

FIG. 1

(A) Agglutination of human erythrocytes from cord blood or from adults of A, B, and O and O_h (Bombay) phenotypes by an RHDV liver extract. Cord blood and Bombay erythrocytes have small amounts of ABH antigens and no ABH antigens, respectively. Hemagglutination assay titers were defined as the reciprocal of the last serial two-fold dilutions that gave detectable agglutination. (B) Inhibition of agglutination of adult blood group O erythrocytes by saliva from a nonsecretor [OLe(a+b−)] or a secretor [OLe(a−b+)]. As a control, PBS was used in place of saliva. Inhibition titers correspond to the reciprocal of the last dilution that completely inhibited agglutination.

FIG. 2

Adsorption of native RHDV on immobilized blood group-active oligosaccharides. (A) After incubation of an RHDV liver extract on oligosaccharide-conjugated beads (structures 3, 4, 16, 17, 18, and 19 as given in Table 1), the presence of virus particles was detected using a capture ELISA. (B) Direct binding of native RHDV particles from a liver extract (open symbols) or of VLPs (closed symbols) on a series of blood group-related oligosaccharides conjugated to polyacrylamide (structures 1 through 14). Binding was revealed by an ELISA using the anti-VP60 MAb 10C5. (C) Binding of VLPs to decreasing amounts of the H type 2 (#4), the Le^b (#12), and the Le^y (#13) polyacrylamide probes, measured by an ELISA using MAb 10C5. O. D. 405 nm, optical density at 405 nm.

FIG. 3

Histochemical staining of rabbit tracheae. Adult rabbit trachea sections (A through D) were incubated with either native RHDV particles from liver extract (A and B) or VLPs (C and D). RHDV liver extract or VLPs were coincubated with either the UEA-I lectin (B), Le^x-polyacrylamide conjugate structure 15 (C), or the H type 2-polyacrylamide conjugate (D). Binding of peroxidase-labeled UEA-I lectin to epithelial cells from adult and 6-week-old rabbits is shown in panels E and F, respectively.