Characterization of a recombinant herpes simplex virus 1 designed to enter cells via the IL13Rα2 receptor of malignant glioma cells

Malignant glioma tumor cells in situ exhibit on their surfaces the interleukin 13 (IL-13) receptor designated IL13R alpha 2. To target herpes simplex virus 1 to this receptor, we constructed a recombinant virus (R5111) in which the known heparan sulfate binding sites in glycoproteins B and C were deleted and IL-13 was inserted into both glycoproteins C and D. We also transduced a baby hamster kidney cell line lacking the known viral receptors (J1-1) and Vero cells with a plasmid encoding IL13R alpha 2. The J1-1 derivative (J-13R) cell line is susceptible to and replicates the R5111 recombinant virus but not the wild-type parent virus. We report the following. (i) Expression of IL13R alpha 2 was rapidly lost from the surface of transduced cells grown in culture. The loss appeared to be related to ligands present in fetal bovine serum in the medium. None of the malignant glioma cell lines cultivated in vitro and tested to date exhibited the IL13R alpha 2 receptor. (ii) Soluble IL-13 but not IL-4 or IL-2 blocked the replication of R5111 recombinant virus in J-13R cells. (iii) The endocytosis inhibitor PD98059 blocked the replication in J1-1 cells of a mutant lacking glycoprotein D (gD(-/-)) but not the replication of R5111 in the J-13R cells. We conclude that R5111 enters cells via its interaction with the IL13R alpha 2 receptor in a manner that cannot be differentiated from the interaction of wild-type virus with its receptors.