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Explain what immunity is and how cells have it?

2 Answers

  • 8 years ago
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    Immunity is a biological term that describes a state of having sufficient biological defenses to avoid infection, disease, or other unwanted biological invasion.


    Cell-mediated immunity is an immune response that does not involve antibodies but rather involves the activation of macrophages, natural killer cells (NK), antigen-specific cytotoxic T-lymphocytes, and the release of various cytokines in response to an antigen. Historically, the immune system was separated into two branches: humoral immunity, for which the protective function of immunization could be found in the humor (cell-free bodily fluid or serum) and cellular immunity, for which the protective function of immunization was associated with cells. CD4 cells or helper T cells provide protection against different pathogens. Cytotoxic T cells cause death by apoptosis without using cytokines, therefore in cell mediated immunity cytokines are not always present.

    Cellular immunity protects the body by:

    activating antigen-specific cytotoxic T-lymphocytes that are able to induce apoptosis in body cells displaying epitopes of foreign antigen on their surface, such as virus-infected cells, cells with intracellular bacteria, and cancer cells displaying tumor antigens;

    activating macrophages and natural killer cells, enabling them to destroy pathogens; and

    stimulating cells to secrete a variety of cytokines that influence the function of other cells involved in adaptive immune responses and innate immune responses.

    Cell-mediated immunity is directed primarily at microbes that survive in phagocytes and microbes that infect non-phagocytic cells. It is most effective in removing virus-infected cells, but also participates in defending against fungi, protozoans, cancers, and intracellular bacteria. It also plays a major role in transplant rejection.


    Source(s): BIOLOGY BOOK
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  • Anonymous
    8 years ago

    Immunity is the resistance in the body to illness. Fortunately, it can also be enhanced or damaged by how we take care of ourselves and family. Antioxidants are the key to a strong immunity. Mainly found in fruits and vegetables at best but a healthy lifestyle in general build strong immunity. Some of the best foods for immunity (I'm sure others will find things I miss here) are Brocolli, Carrots, Cauliflour, Spinach and many more. Study up on it.

    Source(s): Education/Reading
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