Answer the following questions Suppose a person suffers from the loss of the act
ID: 51862 • Letter: A
Question
Answer the following questions
Suppose a person suffers from the loss of the activity of the cell-mediated immune response. Can you think of what problems might result? Explain your thoughts and ideas fully.
What are the advantages of having both an innate and an adaptive immune system of defense?
Individuals with an ineffective adaptive immune system cannot react to non-self antigens. Describe some of the problems these individuals are likely to encounter.
Name a situation in which it might be beneficial to an individual to suppress normal immune function. What are the risks of doing this?
Explanation / Answer
The immune system provides the body with resistance to disease. Innate immunity is furnished by relatively nonspecific mechanisms, such as the rapid inflammation experienced shortly after injury or infection. In contrast to innate mechanisms that hinder the entrance and initial spread of disease, adaptive immunity is more selective in its activity, and upon repeated exposures to pathogens can often prevent disease. There are two kinds of adaptive immune responses.Humoral immune responses are effective against agents that act outside of cells, such as bacteria and toxins. During humoral immune responses, proteins called antibodies, which can bind to and destroy pathogens, are secreted into the blood and other body fluids. In contrast, cell-mediatedimmune responses are important in resisting diseases caused by pathogens that live within cells, such as viruses. During cell-mediated responses, immune cells that can destroy infected host cells become active. Furthermore, cell-mediated immunity may also destroy cells making aberrant forms or amounts of normal molecules, as in some cancers.
Numerous aspects of adaptive immunity differ substantially in aged individuals from what is seen in young adults. For example, aged individuals often have attenuated or otherwise impaired immune responses to various bacterial and viral pathogens. Indeed, this general trend forms the basis for recommended immunizations against infectious agents that younger individuals resist easily. Aged individuals often respond differently to vaccination, however, sometimes resulting in a lack of protective immunity. In addition, unto-ward immune phenomena, such as certain forms of autoimmunity, as well as cancers involving cells of the immune system, show increased incidence in aged individuals. A complete understanding of these age-associated changes in immune status and function remains elusive, requiring knowledge of the mechanisms underlying maintenance, activation, and control of the immune system.
Cell interactions in immune responses. Although antigen binding is necessary to activate a B or T cell, that alone is insufficient to induce an immune response. Instead, both humoral and cell-mediated responses require interactions between three cell types: antigen-presenting cells (APCs), Th cells, and either a B cell or Tc cell. Generally, the interaction between the APC and Th cells involves not only the binding of the TcR by the antigenic peptides in association with the MHC, but a series of second signals. These requisite second signals are afforded by the interactions of both membrane-bound ligand receptor pairs, known collectively as costimulators,as well as a variety of soluble growth and differentiation factors secreted by the antigen-presenting cells.