CD46 is a cellular receptor for all species B adenoviruses except types 3 and 7

Abstract

The 51 human adenovirus serotypes are divided into six species (A to F). Adenovirus serotypes from all species except species B utilize the coxsackie-adenovirus receptor for attachment to host cells in vitro. Species B adenoviruses primarily cause ocular and respiratory tract infections, but certain serotypes are also associated with renal disease. We have previously demonstrated that adenovirus type 11 (species B) uses CD46 (membrane cofactor protein) as a cellular receptor instead of the coxsackie-adenovirus receptor (A. Segerman et al., J. Virol. 77:9183-9191, 2003). In the present study, we found that transfection with human CD46 cDNA rendered poorly permissive Chinese hamster ovary cells more permissive to infection by all species B adenovirus serotypes except adenovirus types 3 and 7. Moreover, rabbit antiserum against human CD46 blocked or efficiently inhibited all species B serotypes except adenovirus types 3 and 7 from infecting human A549 cells. We also sequenced the gene encoding the fiber protein of adenovirus type 50 (species B) and compared it with the corresponding amino acid sequences from selected serotypes, including all other serotypes of species B. From the results obtained, we conclude that CD46 is a major cellular receptor on A549 cells for all species B adenoviruses except types 3 and 7.

FIG. 1.

All species B adenoviruses except Ad3 and Ad7 infect CHO-CD46 cells more efficiently than CHO cells. (A) CHO or CHO-CD46 cells were infected with purified virions, stained with homotypic rabbit anti-CD46 polyclonal sera and fluorescein isothiocyanate-conjugated anti-immunoglobulin G antibodies, and analyzed for infected cells as described in Materials and Methods. (B) Quantification of infected cells.

FIG. 1.

All species B adenoviruses except Ad3 and Ad7 infect CHO-CD46 cells more efficiently than CHO cells. (A) CHO or CHO-CD46 cells were infected with purified virions, stained with homotypic rabbit anti-CD46 polyclonal sera and fluorescein isothiocyanate-conjugated anti-immunoglobulin G antibodies, and analyzed for infected cells as described in Materials and Methods. (B) Quantification of infected cells.

FIG. 2.

Rabbit anti-CD46 serum inhibits the infectivities of all species B adenoviruses in A549 cells, except Ad3 and Ad7. (A) A549 cells were preincubated with rabbit anti-CD46 (α-CD46) serum, infected with purified virions, stained with homotypic rabbit anti-CD46 polyclonal sera and fluorescein isothiocyanate-conjugated anti-immunoglobulin G antibodies, and analyzed for infected cells as described in Materials and Methods. (B) Quantification of infected cells. CTRL, control.

FIG. 2.

Rabbit anti-CD46 serum inhibits the infectivities of all species B adenoviruses in A549 cells, except Ad3 and Ad7. (A) A549 cells were preincubated with rabbit anti-CD46 (α-CD46) serum, infected with purified virions, stained with homotypic rabbit anti-CD46 polyclonal sera and fluorescein isothiocyanate-conjugated anti-immunoglobulin G antibodies, and analyzed for infected cells as described in Materials and Methods. (B) Quantification of infected cells. CTRL, control.

FIG. 3.

Phylogenetic tree of the knob domains of species B adenovirus fibers. The length of each pair of branches represents the distance between sequence pairs, while the units at the bottom of the tree indicate the number of substitution events. The sequences were aligned from the TLWT hinge to the translational stop codon, as described in Materials and Methods.

FIG. 4.

Alignment of the knob domains of selected adenovirus serotypes. The amino acid sequences of the knob domains of multiple adenovirus serotypes were aligned using ESPript 2.2 software, as described in Materials and Methods. Secondary structure elements and numbering, according to the Ad3 fiber amino acid sequence and three-dimensional structure (20), are shown above the alignment (arrows represent beta-strands). Completely conserved residues are marked with a red background, and highly conserved residues are red letters surrounded by blue boxes. The three-amino-acid inserts in the AB loop of the knobs of species B adenoviruses are boxed in green. The two hydrophobic residues (240 and 296) that are unique for the knobs of Ad3 and Ad7 are marked with a green background. Residues in the knob of Ad12 that are of importance for the interaction with CAR (10) are marked with a yellow background. Residues in the knob of Ad5 that are of importance for the interaction with CAR according to Roelvink et al. (31) are marked with an orange background. Residues in the knob of Ad5 that are of importance for the interaction with CAR according to Kirby et al. (25) are boxed in black. The two key residues (Y256 and K295) that form the sialic acid-binding site in the knob of Ad37 (11) are marked with a blue background, whereas the two other sialic acid-interacting residues (forming weaker hydrogen bonds) are boxed in cyan. The two residues that differ between Ad37 and Ad19p (a serotype that does not use sialic acid as a cellular receptor [3, 4]) are marked with a cyan background.