top of page

Immune System

image.png

Acquired Immunity

  • —Immunity obtained from the development of antibodies in response to exposure to an antigen

    • Vaccination, infectious disease, or from the transmission of antibodies from mother to fetus, breast feeding

  • —Adaptive response to a substance the body sees as “non-self”

  • —Involves memory for “that” invader (immune system remembers having seen that organism before)

  • —Basis for vaccination

  • —Development of memory lymphocytes (WBC)

    • Get a better response after a subsequent invasion

Cells of the Immune System

image.png

study question:

  • describe the roles of cells of the immune system

  • Polymorphonuclear leukocytes

    • neutrophils​

      • phagocytic​

      • engulf invading bacteria

      • initial wave of attack (response to inflammation)

    • eosinophils

      • secrete enzymes that destroy antigens​

    • basophils

      • secrete histamine​

      • keep inflammatory response going

      • involved in allergic reactions

  • lymphocytes

    • T-cells​

      • Helper T cells (T4)​

        • different receptors on cell surfaces (CD4)​

        • major modulator of immune response

      • Cytotoxic T cells (T8)

        • ​different receptors on cell surfaces (CD8)

        • kills cells directly

    • B-cells (humoral immunity)

      • circulate in plasma​

      • produce antibodies

      • have memory

    • NK cells (innate immunity)

      • non specific​

      • can kill tumors and viruses

  • monocytes (blood) and macrophages (tissue)

    • phagocytosis​

    • APCs

      • process antigens (invader) for lymphocytes to finish job​

    • trigger T cells

study questions:

  • describe the differences between helper T cells and cytotoxic T cells

  • what does B-cells "having memory" mean?

image.png

Cytokines

  • Cells of the immune system communicate via cytokines

    • hormone like polypeptides​

    • produced and secreted by one cell type, binds to a receptor on another cell type

  • classified based on cell that produces them

    • lymphokines - produced by lymphocytes​

    • monokines - produced by monocytes

    • adipokines - produced by adipocytes

  • common cytokines

    • interleukins​

      • regulate inflammatory response​

      • activate WBC

      • differentiation of WBC

      • induce synthesis of more cytokines

      • stimulates production of antibodies

      • stimulates liver to produce positive acute phase proteins

    • TNFs

      • cytotoxin to tumor cells​

      • stimulates production of more cytokines

      • activates macrophages

      • may cause insulin resistance

    • INFs

      • anti viral​

      • activates NK and macrophages

      • promote cell mediated immunity

  • cytokines can act locally or systematically

  • specific cytokines are associated with specific diseases

Immune Responses

Cellular Immunity

  • T cells

  • monocytes

  • macrophages

  • PMN

T-cells

  • memory T cells

  • helper T cells

    • produce cytokines that activate other cells in immune system​

    • stimulate B cells to produce antibodies

  • suppressor T cells

    • inhibit activity of other immune cells​

    • they stop immune response when not needed anymore

  • cytotoxic T cells

    • scavenge any abnormal cells and destroy them​

Humoral Immunity

  • B cells

  • plasma cells

  • antibodies

  • complement

B cells

  • made in bone marrow

  • B cells become plasma cells which produces antibodies when a foreign antigen trigger immune response

  • antibodies are specialized proteins that recognize and bind to a foreign substance or antigen

    • they specifically recognize that antigen​

  • antibody + antigen forms a complex

    • signals other immune cells to destroy the foreign substance​

Antibodies

  • made up of 2 heavy and 2 light chains that form a Y shape

  • tips of the Y are unique and match the antigen

  • stem of the Y interacts with other immune cells

image.png
image.png
image.png

SECRETIONS​

1. cytokines

2. antibodies: produced by B cells in response to antigen

  • includes immunoglobulins

    • IgM - initially produced​

    • IgG - most prevalent, produced on initial exposure to antigen

    • IgE - causes acute allergic reactions

3. complement system

  • a group of proteins

  • assists antibodies

  • acts in a cascade

  • can destroy invaders alone of with other immune cells

©2023 by Syracuse University Dr.Margaret Voss

bottom of page