Abstract
Purpose: :
To test if an HSV gene delivery vector (hrR3) up–regulates IL–6 expression in ARP–19 cells and establish requirements for induction.
Methods: :
Human ARPE–19 cells were transduced with hrR3 and infected with HSV–1 KOS. Replication was tested by plaque assay. At various times, changes in IL–6 expression were analyzed by immunolot, ELISA, and RT–PCR. Acyclovir (ACV) and UV–inactivated virus were used to test the requirement for replication. NFΚB nuclear translocation was measured by immunofluorescence. To confirm activation of NFΚB was needed a dominant negative IΚB Adenovirus vector was constructed.
Results: :
IL–6 induction was seen in hrR3 transduced and KOS infected cells at both the mRNA and protein levels beginning 3–4 hours after viral addition. The hrR3 vector replicated in the ARPE–19 cells. Acyclovir blocked induction and UV–inactivated virus failed to induce IL–6. Translocation of NFΚB to the nucleus occurred 3–4 hours after viral addition concomitant with IL–6 induction. Chemical inhibitors of NFΚB activation and the DN IΚB vector blocked translocation and IL–6 induction.
Conclusions: :
The results indicate that induction of IL–6 by HSV in human RPE cells requires viral replication and NFΚB activation.Since the hrR3 vector does not replicate in primate eyes, IL–6 induction is not involved in triggering inflammatory responses by the vector in vivo. The delayed IL–6 induction and requirement for viral replication may be an additional mechanism for suppressing inflammation in the retina.
Keywords: herpes simplex virus • cytokines/chemokines • retinal pigment epithelium