Chapter 3 Flashcards
types of T lymphocytes
Helper T cells, cytotoxic T cells, suppressor T cells
how many binding sites does the T cell receptor have
1
antigen presentation
required for T cells
APC
antigen presenting cells
types of APC
macrophages
dendritic cells
B cells
what is the best type of APC
dendritic cell
major histocompatibility proteins (MHC)
present antigen to responding cells of immune system (T cells)
MHC Class I
present on all cells w/nucleus
CD8+
what are MHC I not present on
red blood cells
MHC Class II
only on APCs
CD4+
sequence of humoral immunity (B lymphocyte)
- B cell sees virus (must interact w/helper T cell)
- B cell becomes plasma cell
- Memory B cells are formed
sequence of cellular immunity (T lymphocyte)
- Cytotoxic T cells kill epithelial cells attacked by virus (helper T cells assist)
- Memory cells are left over
types of immune response
primary and secondary
primary immune response
first exposure
naive cells
secondary immune response
follows initial encounter’s formation of memory cells
AKA activating memory cells
basis of vaccines
what immunoglobulin is made first
IgM
hypersensitivity
too much of a response to the wrong antigen
immunodeficiency
too little of a response to antigen
autoimmune disease
inappropriate response to antigen
malignancy
cancer of immune tissues
types of hypersensitivity reactions
type 1, 2, 3, 4
what types of hypersensitivity reactions are mediated by B cells and antibodies
types 1, 2, 3
what type of hypersensitivity reaction is mediated by T cells
type 4
time frame of Type 1 hypersensitivity
immediate/instantly
what kind of antibodies are involved in hypersensitivity
preformed antibodies (already encountered antigen)
IgE antibody is made after first exposure
what does the IgE antibody do in Type 1 hypersensitivity
becomes embedded in mast cell, binds, degranulates
what cells are involved in Type 1
mast cells and basophils
mast cells in Type 1
affect smooth muscle because they are full of granules, also mediated by prostaglandins (derivatives of arachidonic acid)
effect of granules in mast cells (Type 1)
degranulation (histamine and serotonin)
vasodilation, increased capillary permeability, edema accumulation BLOOD VESSELS
is Type 1 hypersensitivity systemic or local?
both
systemic Type 1 hypersensitivity effects
enters blood, activating massive amounts of mast cells, leading to constriction, decreasing BP
local Type 1 hypersensitivity effects
nose, sinuses, GI tract
phase of IgE-mediated allergic reaction (Type 1)
immediate (wheel & flare)
late (eosinophil chemotaxis)
what is the main ‘disease’ of Type 1 hypersensitivity
allergic
hypersensitivity to environmental substance
atopy
genetic sensitivity
what is the most common allergen?
dust mites
examples of Type 1 hypersensitivity
hay fever, hives, atopic dermatitis (eczema), systemic anaphylaxis, asthma
why are mast cells important for parasitic infections
IgE ejects parasites
helminth
parasitic
hygiene hypothesis
westernized countries have allergic disorders vs. developing countries do not
treatment for Type 1 hypersensitivity
avoidance, drugs
anti-histamines, corticosteroids, anti-IgE therapy, beta adrenergics, desenstitization
anti-histamine
blocks vasoactive histamine receptors
corticosteroids
decreases immune system by decreasing cortisol levels
anti-IgE therapy
IgE to IgG antibodies
beta adrenergics
albuterol, opens airways by SNS
what is Type 2 hypersensitivity
cytotoxic (attacks host cell)
tissue specific antibody attaches directly to antigen in target tissue
what cells mediate Type 2
B cells
what antibodies are included in Type 2
IgG or IgM
types of interaction in Type 2
death of target cells
antibodies block receptor function (myasthenia gravis)
examples of Type 2 hypersensitivity
transfusion reactions, hemolytic disease of newborn (Rh factor), autoimmune reaction (myasthenia gravis)
what is Type 3 hypersensitivity
normal immune complex
what is Type 3 mediated by
antibody and antigen (forms immune complex)
what is Type 3 cleared by
red blood cells
main point of Type 3
failure to clear complexes
- deposition induced inflammatory response in blood vessels, kidneys, joints
is Type 3 deposition local or systemic?
can be distant (systemic)
circulates via blood to different site from formation
can also be local
remains at site (farmer’s lung)
what is Type 3 influenced by
size of complex (smaller complexes circulate longer, increasing immune response)
vascular permeability
what is a good word to describe Type 4 hypersensitivity
delayed
does Type 4 depend on antibodies?
no
what mediates Type 4
T lymphocytes
steps of Type 4 hypersensitivity
- initial sensitization via antigen uptake, hapten, presentation by APC
- APCs present to Helper T cells
- memory T cells migrate to site
- second exposure releases mediators, attracting other cells
hapten
part of antigen binding to normal protein
examples of Type 4 hypersensitivity
poison ivy, metallic injury, tuberculosis test
what is an autoimmune disease
attacks self, self becomes foreign
examples of autoimmune diseases
SLE, RA, myasthenia gravis, Type I Diabetes, MS
why does the body turn on itself?
imperfect B/T cell programming
inaccessible self-antigens
altered antigen
molecular mimicry
infection and inflammation (viral)
decrease suppressor T cell function
genetic susceptibility (MHC proteins)
molecular mimicry
Type 2 hypersensitivity
foreign antigen resembles pathogen and host antigen, immune response initiated by microbe becoming directed at self cells
what is the most common autoimmune disease
type 1 diabetes
examples of molecular mimicry
rheumatic fever
Systemic Lupus Erythematosus (SLE)
Lupus
systemic autoimmune disease