An important defense against disease in vertebrate animals i

An important defense against disease in vertebrate animals is the ability to eliminate, inactivate, or destroy foreign substances and organisms. Explain how the immune system achieves THREE of the following: provides an immediate nonspecific immune response activates T and B cells in response to an infection responds to a later exposure to the same infectious agent distinguishes self from non-self

Solution

1. Provides an immediate non-specific immune response: First of all, the physical barriers are present that helps in preventing the pathogens entering inside the body. The physical barriers inculdes skin and mucous membrane. Also, certain chemical barriers like antimicrobial proteins are also secreted by the body to provide immunity against pathogens. Inflammatory system and complement system also aids in providing non-specific immune response. Inflammatory response leads to an increase in the white blood cell at the site of infection while complement system aids in recruiting the white blood cells to the site of infection in the body.

2. Responds to a later exposure to the same infectious agent: This action is mediated by the memory cells. B cells synthesize the antibodies against the antigens in the body. If an antigen encounter occurs in the body, the memory cells store information regarding this encounter and provide a heightened immune response to a subsequent encounter of the same antigen. Memory cell receptors has a great affinity for the antigens. So, they bind with the antigens and provide a faster immune response.

3. Distinguishes self from non-self: A number of mechanism exists to distinguish self from non-self. All the cells have a unique tags such as markers, glycoproteins etc. which helps in distinguishing them from one other. Also, MCH (Major histocompatibility factor) helps in distinguishing self from non-self. It heps in recognising the tissue grafts. MCH are of two types: MCH1 and MCH 2.