Time is of the essence with SARS-CoV-2 and COVID-19. In order to end this pandemic, we need a faster immune response against SARS-CoV-2 because our adaptive immune system can not respond quickly enough to a SARS-CoV-2 infection.
Our Faster Innate Immune Response
Our immune system is separated into two major components: an innate immune system and an adaptive immune system. Whereas our adaptive immune system responds after a delay of 4–7 days, our innate immune system is our first line of defense at preventing infection responding quickly within minutes to hours! This fast response is key to a timeline that can end this pandemic.
Innate immunity is the host’s first line of defense and is intended to prevent infection and attack the invading pathogens. This nonspecific mechanism is fast (minutes to hours) while the adaptive response takes longer (days to weeks).
Innate immune system
https://www.ncbi.nlm.nih.gov/books/NBK459455/
Including our innate immune response results in a much better timeline. Unlike our adaptive immune system (tortoise) which is slow to win the race, our innate immune system can respond immediately to prevent a SARS-CoV-2 infection before the infectious period even begins! Our innate immune system is like the hedgehog which says to the hare, “I’m already here!”
If we can prepare our innate immune system to respond immediately against SARS-CoV-2, then the coronavirus will have very little time to reproduce. Less coronavirus helps prevent our innate immune system from being overwhelmed. “Only when the innate host defenses are bypassed, evaded, or overwhelmed is an induced or adaptive immune response required.”
Only when the innate host defenses are bypassed, evaded, or overwhelmed is an induced or adaptive immune response required.
The front line of host defense
Immunobiology: The Immune System in Health and Disease
https://www.ncbi.nlm.nih.gov/books/NBK27105/
Our innate immune system can be powerful against SARS-CoV-2
Scientists found early on in this pandemic that even “without adaptive immunity, innate immunity may still be powerful enough to eliminate SARS‐CoV‐2” when one patient successfully cleared the coronavirus without any SARS-CoV-2 antibodies.
One COVID‐19 patient who did not produce any SARS‐CoV‐2–bound IgG [Immunoglobulin (Ig) is a scientific term for antibody so IgG is a type of antibody] successfully cleared SARS‐CoV‐2 after 46 days of illness, revealing that without antibody‐mediated adaptive immunity, innate immunity alone may still be powerful enough to eliminate SARS‐CoV‐2.
Long‐term coexistence of SARS‐CoV‐2 with antibody response in COVID‐19 patients
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7267623/
Clearing a SARS-CoV-2 infection without any antibodies demonstrates how important it is for us to use our innate immune system! After all, it’s already there! Having one immune system ready is better than none. And two immune systems are even better than one!
Clearly, our innate immune system is key to ending this pandemic because it can respond immediately to and clear a SARS-CoV-2 infection.
How do we use our innate immune system against SARS-CoV-2?
Let’s look at how we our immune systems are activated. Vaccines train our adaptive immune system to create antibodies to recognize a pathogen, in this case, the SARS-CoV-2 coronavirus. When antibodies recognize pathogens, a part of our innate immune system called the Complement System is activated to destroy the pathogens using phagocytes that literally eat the pathogens in a process known as phagocytosis.
Phagocytosis is a process wherein a cell binds to the item it wants to engulf on the cell surface and draws the item inward while engulfing around it. The process of phagocytosis often happens when the cell is trying to destroy something, like a virus or an infected cell, and is often used by immune system cells.
Phagocytosis (Khan Academy MCAT Test-Prep)
https://www.khanacademy.org/test-prep/mcat/cells/transport-across-a-cell-membrane/a/phagocytosisPhagocytosis, or “cell eating”, is the process by which a cell engulfs a particle and digests it. The word phagocytosis comes from the Greek phago-, meaning “devouring”, and -cyte, meaning “cell”. Cells in the immune systems of organisms use phagocytosis to devour bodily intruders such as bacteria, and they also engulf and get rid of cell debris.
https://biologydictionary.net/phagocytosis/
Thus, the goal of a vaccine is to train our adaptive immune system to create antibodies that recognize SARS-CoV-2 so that our complement system can use phagocytes to gobble up the coronaviruses. (Wow, that’s a mouthful!)
Here’s a good diagram for how our complement system is activated by our innate and adaptive immune systems. (You might even remember parts of this from your study books!) There are three activation pathways: Classical Pathway, Lectin Pathway, and Alternative Pathway.
Regardless of which pathway is used to activate the complement system, “all three activation pathways initiates the opsonization pathway of complement”. Opsonization is key because that’s the step where phagocytes eat the pathogen!
Opsonization is the process of recognizing and targeting invading particles for phagocytosis.
Physiology, Opsonization
https://www.ncbi.nlm.nih.gov/books/NBK534215/Opsonization refers to the process or molecular mechanism that uses opsonins to make a molecule (e.g. antigen) palatable to the phagocyte. For instance, opsonins (e.g. antibodies) bind to the surface of the bacterial cell. This makes the phagocytes (e.g. NK cells and macrophages) interact strongly with the opsonins coating the bacterial cell. Thus, opsonins serve as marks or tags that designate an antigen or a molecule for ingestion and elimination through phagocytosis.
https://www.biologyonline.com/dictionary/opsonization
Just as the adaptive immune system creates antibodies to recognize pathogens and activate the Classical Pathway, the innate immune system uses Mannose Binding Lectin (MBL) to activate the Lectin Pathway. “The lectin pathway starts with mannose-binding lectin (MBL)”.
Even more interestingly, after the previous 2002–2004 SARS outbreak in Asia where a previous strain of SARS Coronavirus (SARS-CoV or SARS-CoV-1) infected thousands of people, scientists learned that people with less MBL were more likely to get sick from SARS. This suggests that MBL protects people from SARS infections by recognizing and targeting the coronavirus very quickly upon exposure.
MBL is a serum C-type lectin, and, here, we have demonstrated that MBL binds SARS-CoV per se or infected cells and inhibits the infectivity of the virus on rhesus monkey kidney cells. These findings therefore support the possible role of MBL in the host defense against SARS-CoV infection by targeting the S protein of SARS-CoV before production of specific antibody. Taken together, our findings suggest that MBL-deficient individuals are more susceptible to SARS, and they provide insight into the possible mechanisms of the innate immune response to SARS-CoV infection.
Mannose-Binding Lectin in Severe Acute Respiratory Syndrome Coronavirus Infection
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7199483/
Recent research has confirmed that Mannose Binding Lectins may similarly prevent SARS-CoV-2 infection.
Based on prior studies on coronaviruses, mannose-specific plant lectins offer potential applications to prevent SARS-CoV-2 infection in COVID-19.
Status of mannose-binding lectin (MBL) and complement system in COVID-19 patients and therapeutic applications of antiviral plant MBLs
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7981598
So, if we can find a Mannose Binding Lectin that recognizes SARS-CoV-2, we can activate our innate immune system immediately against the SARS-CoV-2 coronavirus.
Where can we find these Mannose Binding Lectins?
Plants and many vegetables have these mannose binding lectins. More in another article.
Disclaimer: Opinions are my own and not those of Google.
