Immunology research update from www.immunopaedia.org.za
As of today, January 31, 2021, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has infected over 375 million individuals globally and lead to more than 5,5 million deaths. Today the virus has been known to cause a variety of symptoms resembling flu and in certain circumstances may progress to death.
To date, the function of interferon-λ (IFN-λ) in SARS-CoV-2 infection and subsequent disease pathology remains unknown. Patients with the disease, COVID-19, have higher amounts of pro-inflammatory cytokines and chemokines in their circulation and they have lower levels of type I and III IFN. This is suggestive of virus-induced antagonism or skewing of antiviral responses.
It has been reported that elevated levels of IFN-λ in serum and were linked to a reduction in viral infection within the respiratory tract and efficient viral clearance in one human trial. In addition, a higher ratio of IFN-λ to type I IFN was linked to a better survival outcome.
In a recent paper, Chong, et al., investigated the effect of IFN-λ on SARS-CoV-2 infection in mice. In this present study, the authors found that IFN-λ conferred protection against the SARS-CoV-2 B.1.351 (Beta variant) and the newer SARS-CoV-2 B.1.1.529 (Omicron variant). The authors also decided to test exogenous intranasally administered IFN-λ2 and its role in protecting mice against SARS-CoV-2 infection for which they had similar findings. IFN-λ2 treatment resulted in decreased viral RNA levels in the nasal turbinates, nasal washes, and lungs, but not in the brain. Testing therapeutic efficacy of IFN-λ2, showed that in the nasal turbinates, lungs, and brains of IFN-λ2 treated mice, viral RNA levels were lower, as were infectious virus titers in the nasal turbinates and lungs.
In their own words:
“In summary, we present evidence that nasal administration of IFN-λ confers pre- and post-exposure protection against infection by several SARS-CoV-2 strains including key variants of concern without causing extensive inflammation. In the lung, IFN-λ is induced in a MAVS and MyD88-dependent manner primarily in ECs that are likely infected, and acts upon radio-resistant cells to control infection. Additional treatment studies are warranted to evaluate further the potential of IFN-λ as a broadly-acting antiviral agent against SARS-CoV-2 and its emerging variants.”
NB to note: bioRxiv is a preprint server which publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, or guide clinical practice or treated as established information.
Journal article: Chong, Z, et al., 2022. Nasally-delivered interferon-λ protects mice against upper and lower respiratory tract infection of SARS-CoV-2 variants including Omicron. bioRxiv.