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Which..of..the..following..are..considered..the.."first..responders"..of..the..innate..im
mune..system?..-..Correct..Answer-
Neutrophils;..they..appear..first..in..any..immune..response
Hives..(urticaria)..are..an..example..of..a:..
a...Type..1..Hypersensitivity..reaction
b...Type..2..Hypersensitivity..reaction
c...Type..3..Hypersensitivity..reaction
d...Type..4..Hypersensitivity..reaction..-..Correct..Answer-
A...Type..1..hypersensitivity..reaction;..hives..(urticarial)..are..an..example..of..a..Typ
e..1..hypersensitivity..reaction..mediated..by..the..antibody,..IgE..and..mast..cells
Anaphylaxis..is..a..________..hypersensitivity..reaction
a...Type..1
b...Type..2
c...Type..3
d...Type..4..-..Correct..Answer-
A...Type..1;..they..are..mediated..by..IgE..and..mast..cells...An..individual..who..is..hig
hly..sensitized..to..the..antigen..may..experience..anaphylaxis
,Allergic..contact..dermatitis..is..an..example..of..________..hypersensitivity..reactio
n.
a...Type..1
b...Type..2
c...Type..3
d...Type..4..-..Correct..Answer-
D...Allergic..contact..dermatitis..is..an..example..of..Type..4..hypersensitivity..reactio
n..mediated..by..T-
cells...When..the..individual..comes..in..contact..with..the..allergen..(ex...poison..ivy),.
.an..antigen..complex..is..formed...On..subsequent..exposure..to..the..antigen,..sensit
ized..T-
cells..activate..the..inflammatory..process..that..causes..the..allergic..contact..dermat
itis..to..appear
Type..2..(Cytotoxic)..Hypersensitivity..reactions..are..mediated..by:..
a...IgA..or..IgE
b...IgM..or..IgA
c...IgG..or..IgM
d...IgE..or..IgG..-..Correct..Answer-
C...Type..2..hypersensitivity..reaction..is..mediated..by..IgG..or..IgM
Type..1:..Allergic..Reaction..-..Correct..Answer-
On..initial..encounter..with..an..allergen,..the..individual..will..first..produce..IgE..ant
ibodies...After..the..allergen..is..cleared,..the..remaining..IgE..molecules..will..be..bo
und..by..mast..cells,..basophils,..and..eosinophils..that..contain..receptors..for..the..Ig
E..molecules...This..process..is..referred..to..as..sensitization...On..subsequent..expo
sure..to..the..allergen,..the..IgE..molecules..located..on..the..sensitized..cells..induces.
,.their..immediate..degranulation...This..causes..the..release..of..inflammatory..medi
ators..such..as..histamine,..leukotrienes,..and..prostaglandins..that..results..in..vasod
ilation,..bronchial..smooth..muscle..contraction,..and..mucus..production...Type..I..
hypersensitivity..reactions..can..be..local..or..systemic...Systemic..reactions..can..res
ult..in..anaphylaxis,..a..potentially..life-
threatening..condition...Allergic..asthma..is..an..example..of..a..Type..I..hypersensiti
vity..reaction...On..exposure..to..certain..allergens..(typically..inhaled),..individuals..
with..allergic..asthma..experience..inflammation..of..the..airways,..characterized..by
..tissue..swelling..and..excessive..mucus..production...This..narrowing..of..the..airwa
ys..makes..it..difficult..to..breathe.
Type..2:..Tissue-Specific..-..Correct..Answer-
A..Type..II..hypersensitivity..reaction..is..tissue-
specific..and..usually..occurs..as..a..result..of..haptens..that..cause..an..IgG..antibody..
or..IgM..antibody..mediated..response...The..antibodies..are..specifically..directed..t
o..the..antigen..located..on..the..cell..membrane...A..hapten..is..a..small..molecule..tha
t..can..cause..an..immune..response..when..it..attaches..to..a..protein...Macrophages..
are..the..primary..effector..cells..of..Type..II..responses...Typical..examples..of..Type..
II..reactions..are..drug..allergies,..as..well..as..allergies..against..infectious..agents...T
he..Type..II..response..begins..with..the..antibody..binding..to..the..antigen..and..may
..cause..the..following:
1...The..cell..to..be..destroyed..by..the..antibody
2...Cell..destruction..through..phagocytosis..by..macrophages
3...Damage..to..the..cell..by..neutrophils..triggering..phagocytosis
4...Natural..killer..cells..to..release..toxic..substances..that..destroy..the..target..cell
5...Malfunction..of..the..cell..without..destruction
Examples..of..type..II..reactions..include..drug..allergies,..hemolytic..anemia,..blood
..transfusion..mismatch..with..resulting..transfusion..reaction..and..Rh..hemolytic..d
isease.
, Type..3:..Immune-Complex..Reaction..-..Correct..Answer-
The..Type..III..hypersensitivity..reaction..is..also..an..antigen-
antibody..response...The..major..difference..between..Type..II..and..Type..III..respo
nses..is..that..in..a..Type..II..response,..the..antibody..binds..to..the..antigen..on..the..ce
ll..surface,..but..in..Type..III..responses,..the..antibody..binds..to..the..antigen..in..the..
blood..or..body..fluids..and..then..circulates..to..the..tissue...Type..III..reactions..are..n
ot..organ..specific..and..use..neutrophils..as..the..primary..effector..cell...In..type..III..
hypersensitivity..reactions..immune-
complex..deposition..(ICD)..causes..autoimmune..diseases,..which..is..often..a..com
plication...As..the..disease..progresses..a..more..accumulation..of..immune-
complexes..occurs,..and..when..the..body..becomes..overloaded..the..complexes..are
..deposited..in..the..tissues..and..cause..inflammation..as..the..mononuclear..phagoc
ytes,..erythrocytes,..and..complement..system..fail..to..remove..immune..complexes..
from..the..blood...One..of..the..classic..Type..III..reactions..is..serum..sickness.
Type..4:..Cell-Mediated/Delayed..Reaction..-..Correct..Answer-
The..type..IV..hypersensitivity..reactions..are..known..as..cell-
mediated..responses..and..use..lymphocytes..and..macrophages..as..primary..media
tors...Unlike..the..first..three..types..of..responses,..which..are..humoral..immune..fun
ctions,..a..Type..IV..response..is..mediated..by..T-
lymphocytes..and..does..not..use..antibodies...A..typical..reaction..from..a..Type..IV..c
ell-
mediated..response..would..be..a..localized..contact..dermatitis...When..the..individ
ual..comes..in..contact..with..the..antigen,..T-
cells..are..activated..and..move..to..the..area..of..the..antigen...The..antigen..is..taken..u
p,..processed,..and..presented..to..macrophages,..leading..to..epidermal..reactions..c
haracterized..by..erythema,..cellular..infiltration..and..vesicles...This..process..is..illu
strated..in..contact..dermatitis.
Type..1..Hypersensitivity..Summary..-..Correct..Answer-
Mechanism:..IgE..action..on..mast..cells