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chapter 21
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2 different main types of immune defense
innate (nonspecific) and adaptive
innate definition
to be born with an ability
2 innate (nonspecific) defense categories
(general defensive measures), surface and internal
surface defenses
first line of innate defense (skin and mucous membranes)
how does acidity relate to immune function?
higher acidity kills bacteria, pathogens, and other immune threats
internal defenses
second line of innate defense (phagocytes, natural killer [NK] cells, and inflammation)
phagocytes of internal defenses
neutrophils, monocytes, and macrophages (some have ability to lyse things)
natural killer (NK) cells
kill virus-infected and cancerous cells
what do NK cells induce
apoptosis (programmed cell death)
apoptosis real-world association example
tadpoles losing their tails as they develop
what are NK cells similar to from the adaptive defenses
cytotoxic T-cells
how does inflammation play a part in internal defenses?
isolates infection to prevent spread and alerts immune system
vasodilation role in inflammation
allows delivery of cells to injury to aid recovery via widening of blood vessels
inflammatory chemicals
histamine, kinins, prostagladins, complement, and cytokines
phagocyte mobilization ***must know
delivery of neutrophils and macrophages
4 key steps of phagocyte mobilization
1.leukocytosis (4-5x increase in neutrophil count after injury)
2.margination (neutrophils cling to cap walls)
3.diapedesis (neutrophils flatten and move thru cracks)
4.positive chemotaxis (phagocytes sniff out chemical signal)
antimicrobial proteins prod during inflammation
interferons (IFNs) and complement (molecule group)
functions of antimicrobial proteins
directly attack or inhibit microbe prod
interferons (IFNs)
released by virus-infected cells, protect nearby cells
complement
20+ plasma proteins that lyse microbes and amplify response
what causes a fever
pyrogens which are released by leukocytes and macrophages
effects of a fever
interferes with microbe reprod, increases metabolic rate, and hoarding zinc and iron (nutrients) from the microbes
adaptive (specific) defenses
act against recognizable invaders
two types of adaptive defenses
humoral and cell-mediated immunity
unique ability of adaptive defenses
memory of invaders
humoral (antibody-mediated) immunity
targets foreign bodies
cell-mediated immunity
targets infected cells affected by viruses, bacteria, parasites, and cancer
virus
infectious agent that multiplies by inhabiting a living host’s cells
antigens ***TQ
molecules that trigger immune response and thus stimulating antibody production
antibodies ***TQ
defensive proteins (immunoglobulins) produced in response to antigen
complete antigens
immunogenic (causes immune response) and reactive
immunogenic antigen
only causes immune response
reactive antigen
able to react/bind to antibodies
incomplete antigens
an antigen that is powerless alone, but can combine with other self-made molecules to generate response
antigenic determinants
immunogenic part of an antigen
immunogenic definition
ability to cause an immune response
self-antigens
2 main classes of major histocompatibility complex (MHX) proteins found on own cells
class I MHCs
found on most body cell surfaces (except rbcs)
class II MHCs
only found on specialized immune system cells
origin site of rbc and thymus
red bone marrow
where do b cells mature
red bone marrow
where do t cells mature
thymus
life cycle of B and T lymphocytes
born in bone marrow, b cell stays to mature, t cell moves to thymus to mature, naive cells travel to secondary lymphoid organs (nodes, spleen) and might eventually encounter foreign antigens that activate them, clonal selection leads to proliferation (creation of more lymphocytes)
***review positive/negative selection in life cycle of B and T lymphocytes
***
immunocompetence
lymphocyte ability to recognize and bind to an antigen
self-tolerance
lymphocyte ability to ignore self-made antigens
antigen-presenting cells (APCs)
phagocytize antigens and present fragments to T cells
**review apcs slide
humoral immunity
B cells and antibodies fight specific invaders
steps in humoral immunity
naive B cells bind to antigen, become active and antigen specific, clonal selection duplicates those active B cells, most become plasma cells, some become memory cells
plasma cells
effector cells that produce antibody
effector cell
a cell that responds to stimuli and brings about change
memory cells
long living cells that provide immunological memory
2 immunological memory phases
primary response and secondary response
**review primary/secondary response
active immunity
B cells make own antibody and memory cells from pathogen or vaccine exposure
how do vaccines grant active immunity
they have antigenic determinants, mRNA, toxoids, etc.
passive immunity
antibody received from an outside source
different sources of passive immunity
placenta, mother’s milk, or injection (ex. antivenin/antivenom or tetanus antibody)
antibodies
proteins of the immune system (immunoglobulins)
5 classes of antibodies
IgM, IgA, IgD, IgG, IgE
IgM
1st class released during primary response (complement fixation/activation, agglutination)
**agglutination
particles clumping together in the presence of antibody or complement
IgA
common in body secretions (sweat, intestinal juice, milk)
IgD
common on B cell surfaces as antigen receptor
IgG
most abundant antibody in plasma, complement fixation/activation
main antibody of primary and secondary responses
IgG
IgE
triggers histamine release, inflammatory response, allergies
**antibody funtions
neutralization, agglutination, precipitation (converting state of matter to make it easier to phagocytize), complement activation
what effect do antibody functions lead to/enhance?
phagocytosis, inflammation, and cell lysis
monoclonal antibodies
single type of antibody grown in lab from descendants of a single cell, specific to one antigenic determinant
what can monoclonal antibodies be used for?
treating cancer, autoimmune diseases, and other diseases (not useful for treating rapidly evolving viruses)
cell-mediated immunity
involves different kinds of T cells attacking defective cells
what do CD4 cells become?
most become helper T cells, some become regulatory T cells
what do CD8 cells become?
cytoxic t cells
**class I MHC proteins
found on all cells except RBCs
**class II MHC proteins
found only on antigen-presenting cells (APCs)
boy in a bubble disease
severe combined immunodeficiency syndromes (SCIDS)