How Your Immune System Eliminates Viruses: Overview
Because of the unique characteristics of viruses, the immune system uses several types of defenses to eliminate them from your body. Let’s consider four, that for simplicity, I’ll call mop-up, altruistic suicide, inflammation, and homemade drugs.
Viruses are Nonliving Gene Containers
Everything actually alive has a metabolism — every living cell in your body, in a tree’s body, a blade of grass, every bacterial cell; to name just a few. Simply stated, metabolism means continually obtaining and using energy and materials to conduct any cell’s biological business. (For a more in-depth look, see https://medium.com/@vinlopresti/the-anthropo-centric-distortion-and-life-science-re-education-everything-alive-is-intelligent-4dc4dcf17c62 )
But not viruses. Viruses coming at you in the liquid droplets or aerosols in the sneeze/cough of an infected person don’t have a metabolism. They’re mobile gene-containers or information carriers. They’re not alive; at best we can call them latent life. Life (metabolism as its indicator) only occurs after they’ve stuck to the surface of your cells then worked their way inside; at which point they seize control of those cells’ metabolism. The end result of that metabolic takeover is fatal reproduction — those cells die and release hundreds to thousands of new viruses (gene-containers) into your blood and other body fluids. Those newly produced viruses can then stick to and infect many many more of your cells.
Immediately, we see the need for at least a two-pronged approach by your immune system to defend your body against this attack. First, something needs to be done about all those viruses (gene-containers) circulating around your body in your bloodstream (and other body fluids). Second, something needs to be done about the newly infected cells that serve as reproduction sites and new-virus production centers. Both strategies are necessary to slow down the inner epidemic.
Mop-Up
This first function, I’m simply calling mop-up and it’s carried out by antibodies. You might have some usable antibodies in your blood if you’ve been infected by a particular virus or some of its close relatives in the past. But you won’t have any antibodies if it’s a brand new strain like the SARS-CoV-2, the virus that causes COVID-19, so there will be a delay in this immune defense until your system revs up against this new virus and produces some specific anti-SARS-CoV-2 antibodies. This typically requires around10 days to two weeks on first encounter. Faster during subsequent exposures (immunological memory).
This emphasizes that antibody defenses are specific. So, for example, antibodies made by your immune system to defend against measles virus won’t likely do you much good against a SARS Coronavirus.
Mop-up is itself a two-pronged defense: First the antibodies chemically stick to the viruses, thereby preventing them from sticking to the surfaces of more of your cells. In this way, additional cell infections are blocked. Your antibodies effectively block the gene-containers from becoming alive and killing more cells in the process. And no more infections means no additional reproduction centers for more viruses.
Even more potently, the antibodies and viruses stick together in a molecular clump that’s recognized by certain white blood cells. It’s like setting out a dinner plate. These white blood cells eat (phagocytosis) the clump and once eaten, use potent enzymes to chop it up into smaller substances. The structure of the viruses in the clump is destroyed, and so is their ability to do further damage.
So in the inner epidemic, antibodies are analogous to the masks and other PPE in the outer epidemic. In both cases, they’re used to block additional infections.
Altruistic Suicide
But what about cells that are already infected and under viral control. In most cases, these cells are treated as expendable. They need to die for the good of the whole body to prevent them from becoming viral-reproduction factories.
This is the province mostly of the immune system’s T cells. By conducting a detailed examination of the surface your other body cells, T cells are slickly able to recognize which of those other cells are currently virus infected, currently serving as virus reproduction centers. Upon such recognition, one action these T-cells can take is to send emergency messages to an infected cell. The messages say: “kill yourself (and recycle your materials)” — altruistically, for the good of the whole body. By dying, these cells can no longer serve as virus-reproduction factories. And any viruses (gene containers) released in the process can be mopped-up by antibodies before they get a chance to infect other cells. And in most cases, enough new cells will be made to replace the altruists.
But beware: too much damage can lead to organ failure in some patients. And note that some of that damage is instigated by the potency of your own immune system.
Inflammation
Almost all immune responses are accompanied by inflammation, which can originate in any of several different ways. Without going into details, what’s important to know is that inflammation that’s short-lived or has a definite end-point (acute) is useful to your immune system, allowing both its antibodies, T Cells, and other white blood cells better access to just about all tissues and organs, except perhaps your brain. Access between blood and tissues is key for the free body-wide movement of all the defenses we’ve taken a look at. Sadly, inflammation that becomes chronic (long-lasting) is very often destructive and usually indicates an ongoing underlying problem.
Homemade Drugs: Interferon and Anti-viral Proteins
There are other anti-vital defenses, such as several different types of interferon made by a variety of cells (including certain T cells). In general, these are signaling substances that can change the pattern of gene expression in cells — thereby changing some aspect of their metabolism. For example, some cells can be tweaked to produce an enzyme making them more resistant to virus reproduction by damaging or destroying a virus’s DNA (or in the case of Corona and other viruses, their RNA).
Please note that this overview is not designed to be biologically accurate in every detail, but merely to provide a general idea of some of your important viral defenses. Some might see it differently, but in my view, it also reveals altruism as one cornerstone of human cell biology.
COVID-19 Vaccine
The April 3, 2020 issue of the journal Science outlines various vaccine studies aimed at different strategies for developing a vaccine against SARS Co-V2, putting the number of such studies at 52. As I’d anticipate, one noted researcher opined that a vaccine eliciting both antibody and T Cell immunity would be best.
“Many researchers assume protection will largely come from neutralizing antibodies, which primarily prevent viruses from entering cells. Yet Joseph Kim, CEO of Inovio Pharmaceuticals, which is making a DNA COVID-19 vaccine, says a response by T cells — which clear infected cells — proved a better correlate of immunity in monkey studies of the company’s MERS vaccine, which is now in phase II trials. “I think having a balance of antibody and T cell responses probably is the best approach.”
