THE PROCESS OF SCIENCE BIC biologists believe that the immune system\'s defense
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THE PROCESS OF SCIENCE BIC biologists believe that the immune system's defense against 1. Most ctions largely rests on its ability to distinguish self molecules from 13. Org nd to If molecules. This concept seems central to our understanding une function. However, like all scientific ideas, it is not beyond Several immunologists have developed an alternative hypothesis: tne the immune system's effectiveness rests mostly on its ability to recognize damage to body tissues caused by the invaders, not on its ability to recognize nonself. If you were going to test the "damage" hypothesis, what might you look for? Which type of cell would you expect to be directly affected by damaged tissues? Why? Some proponents argue that the "damage" hypothesis makes more sense from an evolutionary perspective, claiming that it is more advantageous for an organism's defense system to respond to tissue damage than to the mere presence of a foreign microbe. Do you agree? Why or why not? 0Explanation / Answer
The immune system works to defend our body against foreign invaders (like viruses, bacteria) as well as abnormal cells (cancer cells). An important function of our immune system is to recognize self from non-self-cells. All the organisms possess recognition system that allows them to discriminate between self and non-self.
The alternative hypothesis suggests the ability of immune system to recognize damaged tissue is more effective than the ability to recognize non-self. This concept (‘damage’ hypothesis) is referred to as danger model. According to this, when cells or tissues are damaged by injury, they start to secrete danger signals or express on their surface which are recognized by the immune system and thus acts accordingly. Hence, it does not distinguish between self and non-self, but rather between that might cause damage and things that will not.
In order to test the damage hypothesis, we need to look for specific damaged tissue and the causative agent. The invaders that has the capacity to damage a tissue in a short time can proliferate and expand swiftly. The immune system should have the specific ability to recognize the damage causing cells.
Epithelial cells which line the surfaces of the organs throughout the body is likely to get affected directly by the damaged tissues, since they are the ones that are in direct contact with the damaged tissues.
Defense of an organism occurs in order to reject the harmful, protect the useful, and ignore the harmless. Hence, when something triggers a tissue damage, body responding to that damage makes more sense than a foreign microbe as such entering the body and creating an immune response. In order to defend the body against a foreign harmful agent, the body itself produces inflammation which happens due to cell damage. Hence, it can be concluded that, the ability to recognize tissue damage is more effective than the ability to recognize a microbe. It is thus more advantageous and makes more sense than self/non-self concept.
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