Chapter 43

infectious agents that cause disease; bacteria, viruses, protists and fungi

animal's most basic defense against a pathogen

found in all animals; active immediately upon infection and are the same whether or not the pathogen has been previously encountered; ex: barrier defenses

second defense system found only in vertebrates; activated after innate immune defenses take effect; develops more slowly and works better the second time around

viscous fluid that enhances defenses by trapping microbes and other particles

recognize fragments of molecules characteristic of a set of pathogens

engulf and destroy microbes intracellularly by enzymes (phagocytic); attracted by signals from infected tissues; most abundant phagocytic cells in mammalian body, found in blood, extracellular fluid and peripheral lymphoid tissues

also engulf and destroy microbes intracellularly by enzymes (phagocytic); also found in blood, extracellular fluid and peripheral lymphoid tissues

type of phagocyte but has low phagocytic activity; defends against parasitic worms (multicellular invaders) by discharging enzymes that destroy the invader and consume antibody-antigen complexes

found in tissues in direct contact with environment; stimulate development of acquired immunity (a monocyte that has left the blood?)

proteins secreted by body cells infected by a virus; provide innate defense against infections because they induce nearby uninfected cells to produce substances that INHIBIT viral reproduction

basophils; mast cells

important signaling molecule that causes inflammation; released by both mast cells and basophils; release causes blood vessels to dilate and become more permeable so antimicrobial proteins can be delivered to infection site

connective tissue cells that store chemicals in granules for secretion

recognize and eliminate diseased cells (those that fail to exhibit class I MHC protein, cancerous) by secreting proteins that lead to cell death

lymphocyte (WBC) that originates from stem cells in bone marrow but migrate to thymus; component of the ACQUIRED immune response

lymphocyte (WBC) that originates from stem cells in bone marrow and stays there to mature; part of the ACQUIRED immune response

proteins secreted by phagocytic cells (macrophages/dendritic cells, aka part of the innate immune response) that help recruit and activate lymphocytes

any foreign molecule that is specifically recognized by lymphocytes and elicits a response from them; most are large proteins or polysaccharides; some can be secreted into extracellular fluid (like bacterial toxins) while others may protrude from surface of pathogens/foreign cells

receptors [are about 1,000] in B & T cells plasma membrane; B cells sometimes give rise to plasma cells (aka cells that secrete a soluble form of antigen receptor); SECRETED protein is called an antibody/immunoglobin (think body is what comes from the body)

the small portion of the antigen that's recognized by B & T cells' antigen receptors

subgroup of T cells that recognize class I MHC molecules that display bound antigen fragments; they use toxic gene products to kill infected cells

molecules that bind to antigen fragments that have already been digested through phagocytosis or endocytosis [internalized antigens]; only produced by antigen-presenting cells (aka dendritic cells, macrophages & B cells)

group of T cells that assist both B cells and cytotoxic T cells; antigen-presenting cells show helper T cells as well as cytotoxic T cells antigens to help aid in the process of destruction

created from the cloning of activated B or T cells; are short lived and attack the antigen or any pathogen producing said antigen

created from the cloning of activated B or T cells; long-lived (but less numerous) cells that bear receptors for specific antigens

the proliferation of a lymphocyte into a clone of cells in response to binding an antigen

the production of effector cells from a clone of lymphocytes during the first exposure to an antigen; peaks about 10-17 days after initial exposure

a faster, longer lasting, and larger response that occurs after an individual has been exposed to the same antigen; shown in the larger amount of antibodies present in a shorter amount of time for this response than for a primary response

involves the activation and clonal selection of effector B cells which secrete antibodies (proteins) that circulate in the blood and lymph (body fluids); defends mostly against germs outside cells (extracellular germs)

predominant; involves the activation of clonal selection of cytoxic T cells which identify and destroy the target cells; antibodies aren't secreted, cells are just told what to do; response defends mostly against intracellular pathogens, transplanted tissues, cancerous cells; helper T cells aid in both types of responses

dilation of peripheral blood vessels cause a precipitous drop in blood pressure; epi pen = epinephrine, which counteracts this allergic response