>>We have two complementary immune systems: innate and acquired. - TopicsExpress



          

>>We have two complementary immune systems: innate and acquired. Innate immunity is the body’s natural, knee-jerk reaction to an unknown infection. Innate immunity is fast, broad, and incredibly nonspecific. When it gets activated, you know the feeling all too well—fever, cough, runny nose, and body aches. In short: inflammation. You can already see why you might not want to “boost” this part of the immune system. Like it or not, as soon as a virus enters your body, innate immunity kicks in. And when it does, the symptoms are pretty similar, regardless of which of the several hundred typical cold viruses it happens to be. Before your body has determined the precise identity of the new invader, your innate immunity mounts a fever to try to cook the microbes and produces cough and phlegm to try to flush those critters out. These haphazard responses are mildly helpful, supremely annoying, but—and this is crucial—are not what actually defeats an infection. Treatments for symptomatic cold viruses suppress, not boost, our crude and clunky innate immune responses. The real work of neutralizing an infection is the purview of acquired immunity, the targeted branch of your immunologic military that is built up over your lifetime. The acquired immune system contains B and T cells that produce and interact with proteins called antibodies that can attack an unbelievable number of specific infections. While a small percentage of antibodies are passed from mother to child, the majority are produced when a person first encounters a particular infection. The resulting antibodies are analogous to weapon caches our bodies keep in storage for decades in the event of a future invasion: It’s the ultimate Cold War. If the body has been previously exposed to an infectious pathogen (or vaccinated against it), the acquired immune system “remembers” it and is able to quickly recognize it in the event of future reinfection. Once reactivated, the acquired immune system synthesizes only the correct antibodies, with astonishing precision and efficiency. Most common and mild viruses are cleared quite trivially in this way, usually within days. It is evolution at its finest. New viruses are dealt with in a similar way. The only difference is that the immune system has no memory of novel viruses, so it takes longer to produce just the right antibodies. Meanwhile, the innate immune system rages on for much longer than necessary. While the acquired immune system’s antibodies have already fought and won the real battle, the innate branch just doesn’t get the communiqué, so it fights on unwittingly. As we all know, coughs and runny noses can linger for weeks, even after the mildest of viral infections.
Posted on: Sun, 21 Dec 2014 17:53:07 +0000

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