diseases & immunity

8/16/2019 Diseases & Immunity

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Disease Causing Organisms

Bacteria

Viruses Protozoans

Helminths



Diseases of the Immune system

MHC haplotypes and susceptibility to

diseasesuto immune disorder

Immunodeficiency disease



Immune !esponse to Bacteria

"eutralization of Bacterial to#ins or enzymes

by antibodiesDirect $illing of bacteria by antibody%

complement or by lysozymes

Opsonization and phagocytosis by neutrophils

and macrophage

Destruction of intracellular bacteria



Immune !esponse to Bacteria



Opsonization of Bacteria



Bacterial 'asion of Immune !esponse

(ecretion of Proteases that clea'e Ig

#) "eisseria gonorrhoeae* ") meningitidis*Haemophilus influenzae

!epeated change of surface antigens

#) ") gonorrhoeae (urface molecules that inhibit phagocytosis

#) (treptococcus pneumoniae



1enetic susceptibility to Bacterial Infection

Complements C. 2 C3 deficiency and

Properdin deficiency predisposes the person to Nisseria infection

Mutation in I/045% I/05- and I6"γ receptor is

$no7n to increase the susceptibility to

Mycobacterium tuberculosis infection I/04! associated $inase +I!8, deficiency

predisposes the person to Staphylococcus

penumoniae infection



Immune !esponse /eading to Bacterial

Pathogenesis

1ranuloma formation



CD: 9 Cell Immune !esponse to Viruses



CD: 9 Cell mediated $illing of Virus

Infected cell



"8 Cell Mediated 8illing of Virus Infected

cell



Viral e'asion of host Immune response

By bloc$ing I6"0 and I6"0 production

path7ay +Protein $inase,0hepatitis C 'irus Inhibition of 9P molecule by ICP;< protein

of H(V04 and 5) Class I loading of antigen is

pre'ented

Cytomegalo'irus do7n regulated Class I MHC

e#pression



Cytosolic Path7ay of ntigen Processing

and Presentation by Class I MHC



Viral e'asion of host Immune response

Inhibition of C;b complement by the protein of

Vaccinia 'irus

Inhibition of C-b complement by the glycoprotein

component of H(V

By constantly changing the antigenic domains on the

surface +HIV and H4"4,

By immunosuppression of the host +HIV and BV,

"8p-= binding to human Cytomegaol'irus coat



Virally induced autoimmune disorders

Polio 'irus capsid protein VP5 cross reacts

7ith the acetylcholine receptor in motor endplates in muscles and may be associated 7ith

de'elopment of autoimmune myasthenia

gra'is)

type I diabetes in children is associated 7ithinfections by co#sac$ie'irus



Virally induced autoimmune disorders

pstein 2Barr 'irus +BV, D" polymerase

resembles myelin basic protein henceantibodies produced against BV D"

polymerase cross reacts 7ith myelin basic

proteins resulting in autoimmune multiple

sclerosis



Immune !esponse to Protozoan parasites

Plasmodium +Malaria,

9rypanosoma +(leeping sic$ness,/eishmania +/eishmaniasis,

9o#oplasma +9o#oplasmosis,

#ist as intracellular and e#tracellular life cycle

stages in host

Cell mediated and Humoral immune response isseen



'asion of host Immune response by

protozoans

Very short e#tracellular life cycle

Very high rate of multiplication duringintracellular stage and emergence

!epeated change of antigenic domains

(hedding off surface coat



Protozoan induced autoimmune disorders

Chagas> disease caused by Trypanosoma

cruzi

antibody cross reacts 7ith cardiacmuscles and neurons



Immune !esponse to Helminth parasites

scaris +!ound 7orm,

9aenia +9ape 7orm, 6ilaria +/ymph 7orm,

9richinella +(piral round 7orm,

(chistosoma +Blood flu$e,



Immune !esponse to Helminth parasites



H/ haplotypes and diseases

n$ylosing spondylitis 0H/0B5< Molecularmimicry 7ith Klebsiella pneumoniae antigen

H/0D!5 also ma$es a person more prone to Mycobacterium tuberculosis infection)

H/0D!B404-=5 increases the susceptibility to

hepatitis BH/0B5< & B.< sho7 slo7 progression of

ID(



H/ haplotypes and diseases

H/0B-. accelerated progression of ID(

H/0B5< & B.< are associated 7ith ?uic$clearance of Hepatitis C 'irus

Class II MHC0 +H/0D!B4 4- & D@B4 =A,

$no7n to suppress ID( progression



H/ haplotypes and utoimmune diseases

Psoriasis is lin$ed to H/0B4-% B4A% and B4<

H/ D!; is associated 7ith u'enilerheumatoid arthritis

H/0D!- and D!; are associated 7ith type 4

diabetes

H/0D!.- ha'e tenfold increased

susceptibility rheumatoid arthritis




H/0D!- and D!; are 5= times more li$ely to

de'elop u'enile diabetes mellitusH/04% B: and D!- is associated 7ith

increased ris$ of de'eloping diabetes%

myasthenia gra'is and systemic lupus

erythymatosus +(/,H/0D!5 is associated 7ith . times more

susceptibility to multiple sclerosis +M(,




H/0B:0D!- haplotype increases the

susceptibility to 1ra'es disease or autoimmunethyroiditis

H/0D!B4 alleles =4=4% =;=4% =;=; and 4;=5

is associated 7ith rheumatoid arthritis



Immunodeficiency disorder

. Bare lymphocyte syndrome +B/(,

9ype I B/( is associated 7ith defecti'e class IMHC e#pression

9ype II B/( is associated 7ith defecti'e class

II MHC e#pression

9ype III B/( is associated 7ith defecti'e

e#pression of class I and II MHC




Phagocytic deficiencies

!eduction in "eutrophil countsDefecti'e phagocytic function

dherence defects

Chemotactic defects

8illing defects




Humoral deficiencies

0lin$ed gammaglobulinemia +/,0lin$ed hyper IgM syndrome

Common 'ariable hypogammaglobulinemia

(electi'e immunoglobulin deficiencies




Cell0mediated deficiencies

Di1eorge syndromeCombined immunodeficiencies

!eticular dysgenesis

(e'ere combined immunodeficiency +(CID,

is$ott0ldrich syndrome

c?uired Immunodeficiency (yndrome

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