Chapter 11: Innate and Adaptive Immunity Flashcards
First line of defense
skin and mucous membranes
Second line of defense
inflammation
Third line of defense
immune response
Innate (Natural) Immunity
normally in place before an encounter with an infectious agent and provides rapid protection against infection
involves first and second lines of defense
rapid response - nonspecific
does not create memory - does not involve antibodies
Neutrophils
most abundant phagocytic WBC
“first responder” - arrives first but does not stay long
Eosinophils
active in parasitic infection and allergic reaction
Basophils
produce histamine and proteolytic enzymes
Monocytes/Macrophages
Largest WBCs
Arrive later but are more efficient and have longer life span than neutrophils
Natural Killer (NK) Cells
lymphocytes that can cause spontaneous cytotoxicity against infected cells on first exposure (rupture pathogen membranes)
produce cytokines
Adaptive (Acquired) Immunity
immunity that is acquired through previous exposure to infectious or other foreign agents
recognize and destroy specific foreign agents
slower to respond (more efficient w/ each exposure)
creates memory and antibodies
Humoral Immunity
mediated by B lymphocytes
principle defense against extracellular microbes and their toxins (bacteria)
create circulating antibody-secreting plasma cells
Cell-mediated Immunity
mediated by cytotoxic T lymphocytes
functions in the elimination of intracellular pathogens (viruses)
develop receptors that recognize and signal for destruction of infected cells
B Lymphocytes
principle defense against extracellular microbes/toxins (bacteria) in humoral immunity
Plasma B cells - produce antibodies
Memory B cells - remain in body for a longer time to recognize antigen if it returns
T lymphocytes
principle defense against intracellular pathogens (viruses) and cancer
develops specificity to fight a specific antigen
Helper T cells
assist in antigen recognition and binding to help B cells produce antibodies
CD4 helper T cells = master regulators for the immune system
Release cytokines to activate B cells, CD8 T cells, NK cells, macrophages
Regulatory T cells
function to control immune system responses
Cytotoxic T cells (CD8)
monitor the activity of all the cells in the body and destroy any that threaten the integrity of the body
Dendritic Cells
serve as the communication link or bridge between innate and adaptive immune responses
Antigen-Presenting Cells (APCs)
responsible for processing and presentation of antigens to lymphocytes
includes macrophages, dendritic cells, and B lymphocytes
must be able to express both classes of MHC
Antigens
foreign organisms (microbial or nonmicrobial) that trigger antibody response by B cells
Epitopes
immunologically active sites called antigenic determinants that has a distinct molecular shape that can be recognized and bound by immunoglobulins and antibodies
Fab
antigen-binding fragments on the Y ends of IG molecules
Fc
tail end of the Ig molecule that determines the function of the class of Ig
IgG
gamma globulin
most prevalent
antibacterial, antitoxin, antiviral
only Ig that crosses the placenta
IgA
predominant Ig in secretions (saliva, nasal & respiratory, and breast milk)
protects mucous membranes
IgM
first antibodies to be produced by a developing fetus
forms natural antibodies (i.e. ABO antigens)
instrumental in ultimate lysis of microorganisms
IgD
found in cell membranes of B cells
functions as receptor for antigens
poorly understood
IgE
binds to Fc receptors on basophils and mast cells
involved in parasitic, allergic, and hypersensitivity reactions
Interleukin-1 (IL-1)
activates endothelium in inflammation
induces fever and acute-phase response
stimulates neutrophil production
Interleukin-2 (IL-2)
growth factor for activated T cells
activates cytotoxic T cells (CD8) and NK cells
Interleukin-4 (IL-4)
promotes growth and survival of T, B, and mast cells
induces T2 helper cells
activate B cells and eosinophils
induces IgE type responses (allergic or parasitic response)
Interleukin-5 (IL-5)
induces eosinophil growth and development
Interleukin-6 (IL-6)
stimulates liver to produce mediators for acute-phase inflammatory response (CRP)
proliferation of antibody-producing cells (plasma B cells)
Interleukin-10 (IL-10)
inhibitor of activated macrophages and dendritic cells
inhibits T1 helper cells
Interleukin-12 (IL-12)
enhances NK cells cytotoxicity in innate immunity
induces T1 helper cells in adaptive immunity
Tumor Necrosis Factor-α (TNF-α)
induces inflammation, fever, and acute-phase inflammatory response
activate neutrophils and endothelial cells
kills cells through apoptosis
Type I Interferons (IFN-α and IFN-β)
inhibit (interfere with) viral replication
activate NK cells
Active Immunity
requires the host’s own immune system to develop an immunological response including the development of memory
long-lasting but requires days to weeks to develop full response
Naturally-acquired Active Immunity
exposed to a pathogen
Artificially-acquired Active Immunity
administration of a vaccine (immunization)
Passive Immunity
immunity transferred from another source
short term protection that lasts days to weeks
Naturally-acquired Passive Immunity
passed from mother to fetus via placenta or breast milk
Artificially-acquired Passive Immunity
administration of Igs from humans or animals
Tolerance
ability of the immune system to react to foreign antigen but remain nonreactive to self-antigens (prevent autoimmune responses)
