Should COVID Vaccines Engage T-Cells?

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Should COVID Vaccines Engage T-Cells?

 

Leading immunology researchers suggest the answer is YES. In the case of existing COVID vaccines, immunity comes from B-cells, which are immune cells that produce antibodies.  But there is another arm to our immune system – the underrated T-cell – that that is too often overlooked in vaccine development, according to recent research.  Evidence suggests T-cell immunity may confer longer lasting protection and may explain why some people fare better when infected with the COVID virus than others.

An American team of researchers on T-cell immunity states unequivocally that “antibodies alone may not protect sufficiently” against COVID-19 and point to the role of other immune mechanisms for recovery, namely T-cell immunity. 

The human immune system has two arms that work together:  humoral immunity (via B-cells) and cell-mediated immunity (via T-cells).   Humoral immunity is so named because it involves cells that move in the “humors” of the body, which is to say the fluid part of our bodies.  (In Latin, ‘’humor’ means wet or fluid).  Thus, humoral immunity refers to cells that create proteins (antibodies) that travel throughout our blood searching for things to bind to with the intent of neutralizing them.  In this way, humoral immunity refers to protection that arises from antibodies.  

However, there is another arm of our immune system that may be more important to long lasting immunity against pathogens.  This is the cell-mediated immune system and as the name suggests, it occurs when special cells (T-cells) interact directly with viruses to destroy or inactivate them.  Further, T-cells interact directly with infected host cells, halting the ability of that host cell to be used as a viral reproduction factory. 

Although a subtle difference, B cells create antibodies, and these antibodies are what interact directly with the virus, while T-cells themselves will interact with virus or infected cells.  Although there is some crossover between the function of T-cells and B-cells, in general the T-cell has a much bigger role in cell to cell communications (i.e. cell mediated immunity) during an infection.

In order for T-cells to protect us, they must be able to multiply efficiently (basically cloning themselves), AND they must be able to remember what a virus looks like so they can fight it in the future.  In this way, T-cells hold a memory of viruses, which we call immunity.

Interestingly, the vaccines for COVID generally focus on the B-cell response to a virus.  However, in most patients, antibody responses were relatively short lived lasting about 1-2 years, based on data from the SARS-CoV1 virus, which is the closest in structure to SARS-Cov2.  In contract, the researchers state that T-cell memory in survivors was long lived lasting about 6-17 years. 

This suggests T-cell immunity may confer much longer protection than B-cells.  

One possible reason may be that T-cells tend to recognize more sections of the virus than a B-cell.  Compared to an antibody, the T-cell holds a more complete memory of the virus structure.  As a result, T-cell immunity may provide broader protection even if the virus mutates, because the T-cells remembers more about the whole virus, as opposed to only remembering one very specific antibody binding site.  If the virus mutates and one section of its structure changes, the T-cell can still recognize the virus.  However, if the section of the virus that mutated was the target of the vaccine antibody, immunity is compromised.  

T-cell immunity against the COVID virus can, and often does, exist even in the absence of antibodies and may persist longer than humoral (antibody) immunity.  A healthy T-cell is one that functions well, meaning it can clone itself as needed as well as respond to cellular signals in the biological environment, whether or not these signals up or down regulate an inflammatory response.  T-cells that function optimally is imperative to building T-cell immunity.  An adaptable T-cell is a healthy T-cell.

SpectraCell measures T-cell function in a test called the Immunidex, which is part of its more comprehensive Micronutrient Test. Beginning in 2021, the Immunidex can be ordered as a standalone test called the Immunidex Screen.

 

(Frontiers in Immunology, September 2020)

LINK to FREE FULL TEXT An Effective COVID-19 Vaccine Needs to Engage in T Cells