Relationship between the cellular distribution of the alpha(v)beta3/5 integrins and adenoviral infection in salivary glands.

This study compared the localization of the alpha(v)beta3/5 integrins in the different cell types of the rat submandibular gland with the susceptibility of these cells to infection by an intraductally administered replication-deficient recombinant type 5 adenovirus coding for rat aquaporin 5 (termed AdrAQP5). We used a panel of antibodies and immunohistochemical procedures to determine the luminal membrane distribution of the integrins. The alpha(v)beta3/5 integrin subunits were present in luminal membranes of all ductal cell types and acini; however, the alpha(v) subunit was found to a lesser extent in the acini. After AdrAQP5 infection, the expression of AQP5 exhibited a similar, though not identical, cellular localization to that seen for alpha(v)beta3/5 integrins. AdrAQP5 infected all cell types in these glands, except excretory ducts, after intraductal administration, directing the transient expression of AQP5. In addition, the localization of alpha(v)beta3/5 integrins was examined in rabbit, monkey, and human submandibular and parotid glands. Although there were some interspecies differences, glands generally displayed the presence of these integrin subunits on luminal membranes of ductal cells and most acinar cells. These findings show that the presence of alpha(v)beta3/5 integrins on the luminal membranes of rat salivary epithelial cells is associated with the susceptibility of these cells to act as targets for adenoviral-mediated gene transfer. However, the abundance of alpha(v)beta3/5 integrin expression was not necessarily predictive of the extent of transgene expression in a particular cell type. Furthermore, because the salivary glands of rabbits, monkeys, and humans show a similar luminal membrane distribution of these integrins, it is likely that recombinant type 5 adenoviruses may be able to mediate in vivo gene transfer to salivary glands in these species.