Scientists at the University of Washington School of Medicine in St. Louis (USA) called the cornea an invulnerable part of the human body for the SARS-CoV-2 coronavirus, which prevents the pathogen from replicating. This is reported in an article published in the journal Cell Reports.
The researchers evaluated the ability of various viruses to infect cells in the cornea of the human eye, including Zika virus, herpes simplex virus type 1 and the causative agent of COVID-19. It turned out that the Zika virus can be transmitted through corneal transplantation in mice, but it is not able to multiply effectively in the human cornea. SARS-CoV-2, at the same time, did not replicate at all.
The invulnerability of the cornea to viruses is explained by the fact that epithelial cells produce type III interferon (IFN-λ) and its receptor IFNλR1. Treatment of cells with eye drops containing IFN-λ activates antiviral genes. If the receptor is blocked, the replication of the Zika virus and herpes is enhanced, but this did not affect SARS-CoV-2 in any way. These results indicate that despite the presence of ACE2, which the coronavirus uses to enter cells, the cornea remains immune to infection.
