microbiology burton's chapter 16

8/17/2019 Microbiology Burton's Chapter 16

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SPECIFIC HOST DEFENS

MECHANISMS: AN INTRODUC

TO IMMUNOL16



LEARNING OBJECTIVESAFTER STUDYING THIS CHAPTER, YOU SHOULD BE ABLE TO:

• Defne the oo!"n# te$%&: "%%'noo#(, "%%'n"t(, )nt"* #en"+ ete$%"n)nt,"%%'no#o-'"n&, .$"%)$( $e&.on&e, &e+on)$( $e&.on&e, )#)%%)#o-'"ne%"),h(.o#)%%)* #o-'"ne%"), T +e, B +e, .)&%) +e, )n "%%'no&'.* .$e&&"on

• D"/e$ent")te -et!een h'%o$) )n +e*%e")te "%%'* n"t( 0C1I2• D"&t"n#'"&h -et!een )+t"3e )+4'"$e "%%'n"t( )n .)&* &"3e )+4'"$e "%%'n"t(• D"&t"n#'"&h -et!een n)t'$) )+t"3e )+4'"$e "%%'n"t( )n )$t"f+") )+t"3e )+4'""%%'n"t( )n +"te )n e5)%.e o e)+h• D"&t"n#'"&h -et!een n)t'$) .)&&"3e )+4'"$e "%%'n"t( )n )$t"f+") .)&&"3e )+4"%%'n"t( )n +"te )n e5* )%.e o e)+h• O't"ne the &te.& "n3o3e "n the .$o+e&&"n# o T*"ne.enent )nt"#en& )n T*e)nt"#en&

• Ient"( the t!o .$"%)$( 'n+t"on& o the "%%'ne &(&te%• Con&t$'+t ) ")#$)% o ) %ono%e$"+ )nt"-o( %oe+'e• Ient"( )n e&+$"-e the f3e "%%'no#o-'"n +)&&e& 0"&ot(.e&2• L"&t the t(.e& o +e& th)t )$e 6"e -( n)t'$) 6"e$ 0N72 +e& • N)%e the o'$ t(.e& o h(.e$&en&"t"3"t( $e)+t"on&• O't"ne the &te.& "n3o3e "n )e$#"+ $e)+t"on&, &t)$t"n# !"th the "n"t") &en&"t"8)t)e$#en )n en"n# !"th the t(."+) &(%.to%& o )n )e$#"+ $e)+t"on• C"te &"5 e5)%.e& o )e$#en&

• L"&t f3e .o&&"-e e5.)n)t"on& o$ ) .o&"t"3e t'-e$+'o&"& 0TB2 &6"n te&t



IntroductionThe immune systconsidered to be a sp

host deense

mechanism and th

third !ine o deen



Ed#ard $e



%ouis Pas



Emi! &ehrin' and (itasato Shiba



E!ie Metchni



• Anti'ens are mo!ecu!es that stimthe immune system to produce antib

• Antibodies are proteins producthe immune system in response to a

THE (E* TO +NDE,STANDIN-

IMM+NO%O-*



P,IMA,* F+NCTIONS OF

THE IMM+NE S*STEM

. dierentiate bet#een /se!0 and /non

1somethin' orei'n23 and destroy that #hnonse!"



MA$O, A,MS OF THE IMM+NE S*S

Antibodies p!ay a ma4or ro!e in

immunity3 but p!ay on!y a minor ro!e3 i a

CMI 1ce!!.mediated immunity2"



Cell-Mediated Immuni

In5o!5es many dierent ce!

types3 inc!udin' macropha'e

he!per ce!!s3 cytoto6ic T ce!!

de!ayed hypersensiti5ity T c

natura! )i!!er ce!!s3 )i!!er ce!

'ranu!ocytes" A!thou'h antib

may p!ay a ro!e in some type

ce!!.mediated immune react

they do not p!ay a ma4or ro!e

Humoral Immunity

A!#ays in5o!5es the

production o antibodies"

Antibodies p!ay a ma4or

ro!e in humora! immunity"

Immune y!tem



IMM+NIT*A si'niicant resu!t o

immune responses i

ma)e a person resist

certain inectious di

7hen one is resista certain disease3 on

to be immune"



Immunity that resu!ts rom the acti5e

production or receipt o protecti5e antib

durin' one8s !ietime is ca!!ed ac9uireimmunity"



Ac9uired Immunity

passi5e ac9uiredacti5e ac9uired immunity

natura!acti5e

ac9uired

immunity

artiicia!acti5e

ac9uired

immunity

natura! passi5e

ac9uired

immunity

a

p

a

im



ACTIE AC;+I,ED IMM+NIT

Natura! acti5e ac9uired immunityImmunity that is ac9uired in response to the

a !i5e patho'en into the body 1i"e"3 in respons

actua! inection2

Artiicia! acti5e ac9uired immunityImmunity that is ac9uired in response to 5acc



PASSIE AC;+I,ED IMM+NIT*

Natura! passi5e ac9uired immunityImmunity that is ac9uired by a etus #hen it recei5

materna! antibodies in utero or by an inant #hen it

recei5es materna! antibodies contained in co!ostrum

Artiicia! passi5e ac9uired immunityImmunity that is ac9uired #hen a person recei5es

antibodies contained in antisera or 'amma '!obu!in



Antibodies that protect us rom

inection or reinection are ca!!

protecti5e antibodies"



accination de!iberate!y e6poses a per

harm!ess 5ersion o a patho'en 1or to6in23

stimu!ate that person8s immune system to p

protecti5e antibodies and memory ce!!s"



Some 5accines contain #ea)ened1attenuated2 patho'ens3 #hereas o

contain dead 1inacti5ated2 path



• He.)t"t"& B 0He. B2 3)++"ne



• Rot)3"$'& 3)++"ne



• D".hthe$") to5o"*tet)n'& to5o"*)+e')$.e$t'&&"& 0DT)P2 3)++"ne



• H)e%o.h"'& "n9'en8)e t(.e - 0H"-2 +on'#)te3)++"ne



• In)+t"3)te .o"o3"$'& 3)++"ne



• 11R 3)++"ne



• V)$"+e) 0+h"+6en.o52 3)++"ne



• In9'en8) 3)++"ne



• Pne'%o+o++) 3)++"ne 0$e+o%%ene o$+h"$en "n +e$t)"n h"#h*$"&6 #$o'.&2



• 1en"n#o+o++) 3)++"ne 0$e+o%%ene o$+h"$en "n +e$t)"n h"#h*$"&6 #$o'.&2



In passi5e ac9uired immunity3 a precei5es antibodies3 rather than

producin' them" This can occur

natura!!y or in an artiicia! manne



A etus recei5in' materna! antibodies

utero and an inant recei5in' materna!

antibodies in co!ostrum are e6amp!es

natura! passi5e ac9uired immunity"

Natura! passi5e ac9uired immunity



Artiicia! passi5e ac9uired immunity

,ecei5in' a shot o 'amma '!obu!in is a

e6amp!e o artiicia! passi5e ac9uired

immunity"



CE%%S OF THE IMM+NE S*STEM

The ma4or ce!! types that participate iimmune responses are:

< T !ymphocytes 1T ce!!s2

< & !ymphocytes 1& ce!!s2< N( ce!!s 1a cate'ory o !ymphocytes

Macropha'es



The t#o ma4or types o T ce!!she!per T ce!!s and cytoto6ic T

ce!!s"



7HE,E DO IMM+NE ,ESPONSES OC

Immune responses occur at many body s

inc!udin' the sp!een3 !ymph nodes3

tonsi!s3 and adenoids"

H+MO,A% IMM+NIT*



H+MO,A% IMM+NIT*

In humora! immunity3 specia! '!ycoproteincu!es composed o carbohydrate and protein2 ca

antibodies are produced by & ce!!s in response

'ens" In many cases3 these antibodies are capab

reco'ni>in'3 bindin' to3 and inacti5atin' or

destroyin' speciic patho'ens"



A C!oser %oo) at Anti'ens

Anti'ens stimu!ate the imm

system to produce antibodie



A bacteria! ce!! has many mo!ecu!es osurace capab!e o stimu!atin' the pro

o antibodies? these indi5idua! mo!ecu

anti'enic sites are )no#n as anti'enideterminants 1or epitopes2



Indi5idua! mo!ecu!es that stimthe production o antibodies a

reerred to as anti'enicdeterminants or epitopes"



Some sma!! mo!ecu!es ca!!ed "a#may act as anti'ens on!y i they

coup!ed #ith a !ar'e carrier mo!ecsuch as a protein"



Then the antibodies ormed a'ainstanti. 'enic determinant1s2 o the hapte

may combine #ith the hapten mo!ecu

#hen they are not coup!ed #ith the ca protein"



Hapten @ Protien Anti'en

Hapten @ Hapten Antibod



Processin' o Anti'ens in the &od

For antibodies to be produced #ithin the

a comp!e6 series o e5ents must occur3 so

#hich are not comp!ete!y understood" It i

)no#n that macropha'es3 T ce!!s3 and & c

oten are in5o!5ed in a cooperati5e eort"

T d d t ti



T.dependent anti'ens"

The processin' o T.dependent anti'

re9uires the participation o he!per T

ce!!s3 as #e!! as macropha'es and &

T independent anti'ens



T.independent anti'ens

He!per T ce!!s are NOT in5o!5e

processin' o T.independent anti

ON%* & ce!!s are re9uired"



The ce!!s that secrete

antibodies are ca!!ed

p!asma ce!!s? they are

deri5ed rom & ce!!s"



The initia! response to an anti'en is ca!!e primary response3 #hereas a subse9uent

to the same anti'en is reerred to as the

secondary3 anamnestic3 or memory respo



A C!oser %oo) at Antibodies

Antibodies are usua!!y 5ery speci

bindin' on!y #ith the anti'enic

determinant that stimu!ated their production"



An antibody is an immuno'!obu!

ha5in' particu!ar speciicity or a

anti'en"



A monomer resem

the !etter *" It co

o t#o hea5y cha

t#o !i'ht chains3

anti'en.bindin' s

and an FC re'ion

Antibody Structure



The i5e immuno'!obu!in c!asses aI'A3 I'D3 I'E3 I'-3 and I'M"



The combination o an antibody and

anti'en is ca!!ed an anti'enBantibod

comp!e63 A'BAb comp!e63 or immu

comp!e6"



Amon' other u

antibodies canneutra!i>e to6in

pre5ent attachm

patho'ens to hoand promote

pha'ocytosis"



1ono+on) Ant"-o"e&

1ono+on) )nt"-o"e& )$e .$o'+e -( on#* "3e

+e& +)e h(-$"o%)&;

CELL*1EDIATED I11UNITY



Ce*%e")te "%%'ne $e&.on&e& "n3o3e %)n(t(.e& o +e& )n +(to6"ne&< )nt"-o"e& )$e $)$e(," e3e$, "n3o3e;

A typica! ce!!.mediated cytoto6ic response #ou!d in5o!5e the o!!o#in'



Step " A macropha'e en'u!s and partia!!y di'ests a patho'en" Fra'ments

determinants2 o the patho'en are then disp!ayed on the surace o the macro

the macropha'e acts as an anti'en. presentin' ce!!2"

Step " A TH ce!! binds to one o the anti'enic determinants bein' disp!aye

macropha'e surace" The TH ce!! produces cyto)ines3 #hich reach an eecto

immune system 1e"'"3 a TC ce!! or N( ce!!2"

Step " The eector ce!! binds to a tar'et ce!! 1i"e"3 a patho'en.inected hos

disp!ayin' the same anti. 'enic determinant on its surace2"

Step " esicu!ar contents o the eector ce!! are dis. char'ed" These inc!ud

and other proteins and en>ymes3 #hich !itera!!y punch ho!es in the tar'et ce!!

Other cyto)ines re!eased by eector ce!!s are tumor necrosis actor 1TNF2 an

to6ic actor"

Step G" To6ins produced by the eector ce!!s enter the tar'et ce!!3 causin'

DNA and or'ane!!es The tar'et ce!! dies

N)t'$) 7"e$ Ce&



C(toto5"+ T +e& )n N7 +e& 6" o$e"#n +e&, ho&t+e& "ne+te !"th 3"$'&e& o$ -)+te$"), )n t'%o$+e&;

HYPERSENSITIVITY AND HYPERSENSITIVITY REACTIONS



H(.e$&en&"t"3"t( +)n -e tho'#ht o )& )n o3e$(&en&"t"3e "%%'ne &(&te%;



I%%e")te*t(.e h(.e$&en&"t"3"t( $e)+t"on& o++'$!"th"n => ho'$& o e5.o&'$e to )n )nt"#en, !he$e)&e)(e*t(.e h(.e$&en&"t"3"t( $e)+t"on& t)6e on#e$th)n => ho'$& to %)n"e&t the%&e3e&;



Type I Hypersensiti5ity ,eactions



C!assic a!!er'ic responses !i)e hay e5and ood a!!er'ies are e6amp!es o typ

hypersensiti5ity reactions3 #hich are

immediate.type hypersensiti5ity react

The Ae$#"+ Re&.on&e



The Ae$#"+ Re&.on&e

Peo.e !ho )$e .$one to )e$#"e&)$e e&+$"-e )& -e"n# )to."+;

The( .$o'+e I#E )nt"-o"e& !hen

the( )$e e5.o&e to )e$#en&0)nt"#en& th)t +)'&e )e$#"+$e)+t"on&2;

Foo!"n# the"$ .$o'+t"on, I#E)nt"-o"e& -"n to the &'$)+e o-)&o.h"& )n %)&t +e&;De#$)n')t"on o the -)&o.h"&)n %)&t +e& o++'$& !hen)e$#en -"n& to the&e I#E)nt"-o"e&;



Lo+)"8e An).h()5"&

Type I hypersensiti5ity reactions 1anaphy!actic reac

either be !oca!i>ed or systemic" Systemic reactions

th ! !i d ti

Systemic Anaphy!a6is



Systemic anaphy!acticreactions can !ead to

anaphy!actic shoc)3

#hich3 i not treated

9uic)!y and proper!y3can !ead to death"

%ate6 A!!er'y



Irritant contact dermatitis

%ate6 a!!er'y

A!!er'ic contact dermatitis



Many hea!thcare #or)ers de5e!op !ate6 a!necessitatin' measures to a5oid contact #

containin' products"

A!!er'y S)in Testin' and A!!er'y Shots

microbiology burton's chapter 16

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