Opening Remarks
Recent research conducted by Johns Hopkins Medicine has suggested a potential approach to combating the potentially deadly inflammatory reactions elicited by the novel coronavirus (SARS-CoV-2). The study indicates that curtailing the activity of a human protein known as factor D might be key in mitigating these intense responses.
Methodology and Objectives
The studies under this research were implemented with the use of normal human blood serum and three subunits of the SARS-CoV-2 spike protein. The objective was to better understand how the virus takes control of the immune system, endangering the normal cells in the process.
The research team zoomed in on two specific proteins, factor H and factor D. These are otherwise known as “complement” proteins, which contribute to the clearance of pathogens from the body through the immune system’s action.
Pivotal Discoveries
On delving deeper, it was discovered that the Covid-19 spike protein facilitates factor D in causing an overstimulation of the immune response. This overactivity subsequently inhibits factor H from moderating this heightened response.
Spike proteins can be seen on the surface of SARS-CoV-2 and act as the primary agent in attaching to cells targeted for infection. The spikes first attach to a molecule called heparan sulfate, a large, complex sugar molecule present on the surface of cells found in the lungs, blood vessels, and smooth muscle across most organs.
With the help of its initial binding with heparan sulfate, SARS-CoV-2 proceeds to utilize another cell-surface component, the protein known as angiotensin-converting enzyme 2 (ACE2), as its entryway into the targeted cell. ACE2, which sits on the surface of numerous cell types, is an enzyme that produces small proteins by breaking up the larger protein angiotensinogen. These smaller proteins then go on to control various functions in the cell.
Mechanism of Virus
When SARS-CoV-2 attacks the ACE2 receptors to multiply and infect more cells in the human body, it also prevents Factor H from using the sugar molecule to bind with cells. Factor H’s primary function is to regulate the chemical signals that trigger inflammation and keep the immune system from damaging healthy cells.
However, the research team unearthed that by blocking the action of factor D, they were able to put a halt to the harmful chain of events kick-started by SARS-CoV-2.
Significance and Implications
This understanding has provided a definite direction for future research focused on tackling Covid-19. A promising development is that there may already be drugs under development for other diseases capable of blocking the action of this protein, which is already a positive step as per the study.
