Question

8. Compare and contrast the mechanisms by which the innate and adaptive immune response recognize pathogens. Make sure you are specific in your response.

Answer 1

Pathogens are responsible for many diseases in organisms. The organism's immune system responds to these pathogens and defends them. The immune response is classified as an innate or non-specific immune response and active or acquired or specific immune response.

The innate immune response is an antigen-independent response that immediately prevents the action of pathogens by cellular and biochemical defense mechanisms. It is present in our body from birth. The cells responsible for the defense mechanism are phagocytic cells like macrophages, neutrophils, natural killer cells, basophils, eosinophils, dendritic cells, mast cells, etc. The immune system cells and physical barriers (skin, chemicals in the blood) are the defense mechanisms in innate response. Here, cells use specialized receptors such as pattern recognition receptors (PRR) to recognize different pathogens like bacteria, viruses, etc. The defense mechanisms such as phagocytosis of bacteria by macrophages and neutrophils, or the release of antiviral interferons are activated by the binding of pathogens to these receptors.

The adaptive immune response is an antigen-dependent or antigen-specific response which is more complex than the innate response. It is developed after birth and expands over time. The cells included in the defense mechanisms are T and B lymphocytes. When the antigen from the pathogen is recognized by the adaptive immune system, it produces millions of clones of immune cells (T or B lymphocyte) which have the same antigen receptor as the original immune cells and defends the same pathogen by producing antibodies that can bind to and neutralize pathogens and their toxins. The adaptive immune response is highly specific, long-lasting, stores information about past infections and is sustained long-term by memory T cells so that it can respond quickly to future pathogens that it has encountered before.