CH:11 - Immunity Flashcards
Immune System
The body’s internal defence system.
Antigen
A substance that is foreign to the body and stimulates an immune response (e.g. any large molecule such as a protein)
Self
Refers to substances produced by the body that the immune system does not recognise as foreign, so they do not stimulate an immune response.
Non-self
Refers to any substance or cell that is recognised by the immune system as being foreign and will stimulate an immune response.
Antibody
A glycoprotein (immunoglobulin) made by specialised lymphocytes in response to the presence of a specific antigen; each type of antibody molecule has a shape that is complementary to its specific antigen.
Immune Response
The complex series of responses of the body to the entry of a foreign antigen; it involves the activity of lymphocytes and phagocytes.
Clonal Selection
Individual lymphocytes have cell surface receptors specific to one antigen; this specificity is determined as lymphocytes mature and before any antigens enter the body (during an immune response the only lymphocytes to respond are those with receptors specific to antigens on the surface of the invading pathogen).
Clonal Expansion
The increase in number of specific clones of lymphocytes by mitosis during an immune response.
Plasma Cell
Short-lived, activated B-lymphocyte produced during clonal expansion; plasma cells produce and release antibody molecules.
Memory B-Cell
Long-lived, activated B-lymphocyte that is specific to one antigen; memory cells are activated to differentiate (develop) into plasma cells during secondary immune responses to the specific antigen.
Primary Immune Response
The first immune response to a specific antigen.
Secondary Immune Respnse
The second and any subsequent immune responses to a specific antigen.
Immunological Memory
The ability of the immune system to mount a larger and more rapid response to an antigen that has already been encountered before.
Variable Region
Region of an antibody molecule composed of parts of the light and heavy polypeptide chains that form the antigen-binding site; the amino acid sequences of the variable site form a specific shape that is complementary to a particular antigen.
Antigen Presentation
The process of preparing antigens and exposing them on the surface of host cells (e.g. macrophages) for recognition by T-lymphocytes.
T-helper Cells
Type of T-lymphocyte that secretes cytokines to coordinate activity during immune responses.
T-killer Cells
Type of T-lymphocyte that attaches to cells, releasing toxic substances to kill infected cells and cancer cells.
Cytokine
Any signalling molecule released by cells to influence the growth and/or differentiation of the same or another cell.
Active Immunity
Immunity gained when an antigen enters the body, an immune response occurs and antibodies are produced by plasma cells.
Natural Active Immunity
Immunity gained by being infected by a pathogen.
Vaccine
A preparation containing antigens to stimulate active immunity against one or several diseases.
Artificial Active Immunity
Immunity gained by putting antigens into the body, either by injection or by mouth.
Vaccination
Giving a vaccine containing antigens for a disease, either by injection or by mouth; vaccination confers artificial active immunity without the development of symptoms of the disease.
Passive Immunity
The temporary immunity gained without there being an immune response.
