Immune System 112 Final Wilson Flashcards
innate immunity
- We are born with innate immunity
- it is non-specific, (i.e., all foreign matter is attacked equally)
- forms the first and second line of defense and
- includes the skin, antimicrobial substances, and the body’s ability to provoke fever or inflammation
adaptive immunity,
- body’s ability to recognize and respond to specific foreign substances
- involves lymphocytes known as B-cells and T-cells.
- Adaptive immunity not only responds to specific substances, but also remembers them so that it can respond more efficiently should they be encountered again
pathogens,
harmful or disease causing micro organisms
mechanical barriers,
- Skin
* mucosae
internal defenses
Cells and chemicals
• Phagocytes
• Natural killer (NK) cells
• Inflammatory response (macrophages, mast cells, WBCs, and inflammatory chemicals)
• Antimicrobial proteins (interferons and complement proteins)
• Fever
humoral immunity,
antibody mediated
cellular immunity
cell mediated
lysozyme,
An enzyme that destroys micro organisms
antimicrobial proteins (interferons, transferrins, complements),
discourage microbial growth
• Interferons: Small proteins that protect uninfected cells in an area where a virus is present; inhibit protein synthesis and degrade viral RNA
• Complements: plasma proteins that destroy foreign substances by amplifying inflammation to help lyse and kill bacteria
• Transferrins: mucosal protein that binds to Fe and keeps it from bacteria that need it for proliferation
opsonization,
phagocyte adheres to pathogens or debris (“handles”)
1st/2nd line of defense,
- 1st line: External body membranes (skin and mucosae)
* 2nd line: antimicrobial proteins, phagocytes, and other cells
phagocytosis,
cell eating (destruction of pathogens)
margination,
leukocytes cling to capillary walls (cell adhesion molecules; CAMS)
diapedesis,
leukocytes pass through capillary walls
chemotaxis,
attract neutrophils, monocytes, and lymphocytes to area
antibody,
A protein molecule that is released by a plasma cell & that binds specifically to an antigen; an immunoglobulin.
antigen,
A protein molecule that is released by a plasma cell & that binds specifically to an antigen; an immunoglobulin.
reactivity,
the ability to react with the activated lymphocytes and the antibodies released by immunogenic reactions.
immunogenicity,
the ability to stimulate specific lymphocytes to proliferate
epitope,
antibody attachment point on an antigen
hapten,
partial antigen: an antigen that can only stimulate antibody production when combined with a specific protein
self antigen (determined by MHC genes),
not foreign or antigenic to you , but they are strongly antigenic to other individuals.
somatic recombination,
gene segments are shuffled and combined in different ways
immunocompetency,
able to recognize and bind to a specific antigen
clonal selection,
when an antigen binds to the particular lymphocyte that has a receptor for it, the antigen selects that lymphocyte for their development
vaccines,
dead or attenuated pathogens (active humoral immunity; artificially acquired)
neutralization,
simplest defensive mechanism; occurs when antibodies block specific sites on viruses or bacterial exotoxins
agglutination,
clumping that occurs when cell-bound antigens are cross-linked
co-stimulation,
when a T cell binds one or more co-stimulatory signals
cytokines
released by TLR (toll-like receptors) found on epithelial cells and macrophages; chemical “alarm”
abscess
accumulation of pus in a confined space not open to the outside
ulcer,
an open sore
pus,
dead neutrophils, damaged tissue cells, & fluid
fever
abnormally high body temperature that occurs because the hypothalamic thermostat is reset
autoimmune disease,
immune system loses the ability to distinguish self from foreign
hypersensitivities,
result when the immune system damages tissue as it fights off a perceived threat that would otherwise be harmless to the body.
graft rejection
caused by self antigens
What are the cells of the immune system?
- Phagocytes
- Natural Killer (NK) cells
- B cells
- Plasma Cells
- Memory B cells
- Helper T Cells
- cytotoxic T cells
- regulatory T cells
Role of phagocytes (monocytes like macrophages, dendritic cells, and antigen presenting cells(APCs)*; also neutrophils),
Innate: Find and eat bacteria, viruses, and dead or injured body cells
Role of natural killer cells
Innate: kill a variety of viruses & tumor cells
Role of B cells
Adaptive: recognize and bind a specific antigen
Role of plasma cells
Adaptive: the antibody-secreting effector cells of the humoral response
Role of memory B cells
Adaptive: mount an almost immediate humoral response if they encounter the same antigen again in the future
Role of helper T cells
Adaptive: help activate B cells, other T cells, and macrophages, and direct the adaptive immune response.
Role of Memory T cells,
Adaptive: respond quickly after any subsequent encounter with the same antigen
Role of cytotoxic T cells,
attack infected and cancerous cells
Role of regulatory T cells,
prevents immune cells from attacking your own cells
Steps in phagocytosis,
- Phagocyte adheres to pathogens or debris
- Phagocyte pulls it inside, enclosing it within a membrane-lined vesicle
- Lysosome fuses with phagocytic vesicle forming a phagolysosome
- Lysosomal enzymes digest the particles
- Exocytosis of the vesicle removes indigestible & residual material
role and steps of inflammation
a. Redness
b. Heat
c. Swelling
d. Pain
(And sometimes 5. Impairment of function)
3 aspects of adaptive immunity,
- It’s specific: it recognizes and targets particular pathogens or foreign substances that initiate the immune response
- It’s systemic: immunity is not restricted to the initial infection site.
- It has “memory”: after an initial exposure, it recognizes and mounts even stronger attacks on previously encountered pathogens
where do B cells and T cells mature in body?
- B cells mature in bone marrow
* T cells mature in Thymus
how does the adaptive immune system become active (what cells signal to the B and T cells that an intruder is present?),
- to become active, must meet or be primed by an initial exposure to a specific antigen.
- Helper T cells help activate the B & T cells
how does immunological memory work?
Memory B cells are primed to respond to the same antigen; more rapid response
Active vs. passive humoral immunity (which type is a vaccine?),
Active immunity: provokes immune system
• Naturally acquired
o Infection (contact with pathogen)
• Artificially acquired
o Vaccine (dead or attenuated pathogens)
Passive immunity:
• Naturally acquired
o Antibodies pass from mother to fetus via placenta
o To infant in her mother’s milk
• Artificially acquired
o Injection of immune serum (gamma globulin)
what are the functions of antibodies?
- Neutralization: binding Ig to virus, toxins, bacteria to block activity or infectivity
- Agglutination: clumping of cells by Ig binding, aids in phagocytosis
- Opsinization: coating cell with Ig, enhances binding of macrophage by binding to the tail region of Ig (Fc region)
- Precipitation: clumping of soluble molecules by Ig binding, aids in phagocytosis
- Complement activation: Ig bound to cell surfaces activates complement cascade to attack targeted cell
What are the self-antigens on T4 vs. T8 cells?
- Self-antigen on T4 cell: Class II MHC protein
* Self-antigen on T8 cell: Class I MHC protein
What activates a B cell?
Helper T cell
What activates a T cell?
By APC presentation of antigen
