Complement Suppresses the Initial Type 1 Interferon Response to Ocular Herpes Simplex Virus Type 1 Infection in Mice

Abstract

The complement system (CS) contributes to the initial containment of viral and bacterial pathogens and clearance of dying cells in circulation. We previously reported mice deficient in complement component 3 (C3KO mice) were more sensitive than wild-type (WT) mice to ocular HSV-1 infection, as measured by a reduction in cumulative survival and elevated viral titers in the nervous system but not the cornea between days three and seven post infection (pi). The present study was undertaken to determine if complement deficiency impacted virus replication and associated changes in inflammation at earlier time points in the cornea. C3KO mice were found to possess significantly (p 2-fold increased levels (p t-test) in the cornea of WT mice at 12 h pi. C3KO mouse resistance to HSV-1 infection at the early time points correlated with a significant increase in type I interferon (IFN) gene expression including IFN-α1 and IFN-β and downstream effector genes including tetherin and RNase L (p < 0.05, Mann–Whitney rank order test). These results suggest early activation of the CS interferes with the induction of the type I IFN response and leads to a transient increase in virus replication following corneal HSV-1 infection.

Keywords

• complement
• herpes simplex virus type 1
• cornea
• cytokines
• chemokines
• interferon