Heparan Sulfate Glycosaminoglycans Are Involved in Adenovirus Type 5 and 2-Host Cell Interactions

Abstract

Gene therapy vectors derived from subgroup C adenoviruses of the serotype 5 (Ad5) and 2 (Ad2) resulted in inefficient infection of well differentiated respiratory cells, both in vitro and in vivo. The level of expression and localization of the primary receptor for Ad5 and Ad2, termed CAR, do not completely explain why the infection efficiency varies greatly in different experimental conditions. The possibility that additional receptors like proteoglycans are involved in the infection of Ad5 and Ad2 was investigated, because several pathogenic microorganisms use heparan sulfate-glycosaminoglycans (HS-GAGs) as coreceptors for multistep attachment to target cells. The HS-GAG analog heparin decreased Ad5- and Ad2-mediated infection and binding starting from the concentration of 0.1 microgram/ml, up to a maximum of 50%. A similar reduction in Ad5 binding and infection was obtained by treatment of cells with heparin lyases I, II, and III but not with chondroitin ABC lyase. The effect of heparin on Ad5 binding has not been observed in surface GAG-defective Raji cells and after treating A549 cells with heparin lyases I, II,and III. The binding of Ad5 was completely abolished when both CAR was blocked with RmcB antibody and HS-GAGs were competitively inhibited by heparin. Parallel experiments demonstrate that HS-GAGs are irrelevant to binding and infection of the subgroup B adenovirus type 3. Collectively, these results demonstrate for the first time that HS-GAGs expressed on the cell surface are involved in the binding of Ad5 and Ad2 to host cells.

Influence of adenoviral fiber mutations on viral encapsidation, infectivity and in vivo tropism

“…This was unexpected but could be explained by the fact that heparan sulfate-glycosaminoglycans expressed on the cell surface may be involved in the binding of Ad5 to host cells. 31 Our results demonstrate that the combination of the Ser408Glu mutation in the AB loop and the addition of the polylysine ligand allows specific retargeting towards heparan sulfate proteoglycans in vitro.…”

Wild-type adenoviruses from groups A–F evoke unique innate immune responses, of which HAd3 and SAd23 are partially complement dependent

“…50 and the lone member of group E, HAd4, which was recently vectorized and characterized in our lab. 30 In addition, first generation 16 MHC class I, 55 heparin sulfate proteoglycan-binding, 56 and sialic acid-containing receptors, 15 as well as differing interactions with blood factors such as opsonins, or other pathogen sensors of innate immunity, for example complement. 41,57 For example, CAR-ablated Ads seem to retain their liver targeting capabilities in vivo.…”

Enhanced apoptosis of glioma cell lines is achieved by co-delivering FasL-GFP and TRAIL with a complex Ad5 vector

“…This process requires the presence of both primary and secondary receptors for the Ad5 virion (i.e., CAR and a 3 b V or a 5 b V integrins) on the cell surface at levels sufficient to allow binding by the vector. 46,47 As most of the clinical tumor cell isolates are heterogeneous, we have tested all our cell lines for susceptibility to Ad5 vector infection by titrating the replication competent rcAd/ CMV-GFP vector on each of the cell lines (Fig 4). The ability of rcAd/CMV-GFP to replicate in all human cell lines allows for an easy detection of transduced cells, since vector genome amplification boosts GFP expression levels many fold.…”

“…46,47 We determined cell surface levels of FasR and DR4 and DR5 (functional TRAIL receptors) for each cell line using flow cytometry (Fig 5). The majority of cell lines had levels of FasR comparable to or greater than those of HeLa.…”