View
444
Download
13
Category
Preview:
Citation preview
SISTEM IMUN
Kekebalan/imunitas : resistensi suatu organisme
terhadap infeksi mikroba patogen tertentu
Sistem imun : mekanisme pertahanan diri suatu
organisme (sel inang) terhadap infeksi
Dasar imunitas : kemampuan sistem imun untuk
mengenali substansi asing/antigen (sel hewan, virus,
bakteri, toksin, toksoid, vaksin, dll) dari sel/
substansi sel inang
ANTIGEN
Antigen : suatu bahan asing yang dapatmenimbulkan respon imun.
Semakin asing komposisi atau struktur kimia suatuantigen, semakin menginduksi respon imun.
Antigen umumnya bahan dengan BM tinggi. Ada 2 senyawa alami antigenik :
1. Protein lebih efektif
2. Polisakarida, terutama polisakarida
kompleks berukuran besar, contoh : kapsul
bakteri
ANTIGEN
Antigen dapat berupa :
1. Bahan yang larut dalam air: toksin bakteri, toksoid
atau protein serum
2. Partikulat : sel hewan, virus, atau bakteri lebih
efektif
Antigen-
binding
sitesAntibody A
Antigen
Antibody BAntibody C
Epitopes
(antigenic
determinants)
Determinan antigen/epitop :
situs reaktif pada
permukaan atau bagian
dalam antigen yang
berikatan dengan antibodi
menentukan kespesifikan
respon imun
ANTIGEN
Jumlah epitop per antigen : sekitar 2-3, ada yg sampai
200
Bentuk epitop antigen biasanya spesifik untuk spesies
tertentu
Antigen heterogenetik/heterofil : kelompok antigen
yang terdapat pada spesies-spesies yang berbeda
Contoh : antigen Forssman pada sel darah merah
marmot, kuda, sapi, kucing, ayam dan beberapa bakteri
menginduksi antibodi yang sama/mirip
HAPTEN
Hapten : bahan-bahan yang tidak bersifat
antigenik, tetapi bila bergabung dengan molekul
antigen seperti protein, dapat berfungsi sebagai
epitop antigen
Contoh : oligosakarida, lemak dan asam nukleat
AJUVAN
Ajuvan : bahan yang ditambahkan pada antigen untuk
merangsang pembentukan antibodi,
Contoh :
- Alum dan garam-garam alumunium lainnya
- Natrium alginat
- Endotoksin bakteri
- Suspensi air-minyak dengan/tanpa mikroba
patogen yang telah dilemahkan/dimatikan, contoh :
ajuvan Freund yang berisi minyak mineral, zat
pengemulsi dan suspensi M. tuberculosis
SUMBER ANTIGEN
Antigen alami :
Antigen jaringan manusia : antigen pada sel
darah dan jaringan
Antigen bakteri dan virus
Antigen hewan dan tumbuhan
Antigen buatan :
Vaksin
Toksoid
ANTIGEN PADA SEL DARAH
Antigen pada sel darah manusia : antigen A, B, Rh, MN, Ss, P,
dll.
Antigen A dan B digunakan untuk penggolongan darah
berdasarkan reaksi isoantibodi
ANTIGEN PADA SEL DARAH
Transfusion with incompatible blood :leads to
destruction of the transfused cells can be fatal
Another red blood cell antigen, the Rh factor
Creates difficulties when an Rh-negative
mother carries successive Rh-positive fetuses
erytroblastosis fetalis
ANTIGEN PADA JARINGAN
The immune system’s ability to distinguish self from
nonself tissue transplantation
Transplanted tissues are usually destroyed by the
recipient’s immune system
MHC (major histocompatibility complex) molecules
are responsible for stimulating the rejection of tissue
grafts and organ transplants
The chances of successful transplantation are
increased :
If the donor and recipient MHC tissue types are
well matched
If the recipient is given immunosuppressive drugs
ANTIGEN PADA BAKTERI
Antigen bakteri terdiri dari komponen struktural sel, eksotoksin dan enzim
Komponen struktural sel :
1.1. Kapsul : kapsul pada pneumokokus, antigen kapsular
2. K atau Vi pada Salmonella typhi
3.2. Flagel : antigen H pada Salmonella typhi
4.3. Endotoksin : kompleks polisakarida-fosflipid-protein,
5. seperti antigen O pada Salmonella typhi.
6.
Struktur antigen digunakan sebagai dasar klasifikasi suatubakteri
ANTIGEN ALAMI LAINNYA
Antigen pada struktur terluar virus yang terdiri
dari protein, lipoprotein atau glikoprotein
Antigen hewan dan tumbuhan dapat berbahaya
bagi kesehatan.
Contoh : antigen regweed (sejenis rumput-
rumputan) yang menyebabkan hay fever
ANTIGEN BUATAN
Vaksin :
- suspensi mikroba hidup yang dilemahkan (contoh :
vaksin poliomielitis Sabin) atau
- mikroba mati (contoh : vaksin demam tifoid,
vaksin poliomielitis Salk) atau
- produk-produknya (contoh : toksin bakteri)
- bagian dari selnya (contoh : fragmen struktur terluar
virus hepatitis B vaksin hepatitis B)
yang dapat menimbulkan kekebalan sel inang terhadap
infeksi mikroba tersebut
Toksoid : toksin yang telah dirusak, tanpa mengubah
antigenisitasnya menghasilkan antibodi antitoksin
TIPE SISTEM IMUN
Imunitas non spesifik/alamiah (innate immunity)
Is present before any exposure to pathogens
and is effective from the time of birth
Involves nonspecific responses to pathogens
Imunitas spesifik/dapatan (acquired/adaptive
immunity)
Develops only after exposure to inducing agents
such as microbes, toxins, or other foreign
substances
Involves a very specific response to pathogens
Innate and acquired immunity
INNATE IMMUNITY
Rapid responses to a
broad range of microbes
ACQUIRED IMMUNITY
Slower responses to
specific microbes
External defenses Internal defenses
Skin
Mucous membranes
Secretions
Phagocytic cells
Antimicrobial proteins
Inflammatory response
Natural killer cells
Humoral response
(antibodies)
Cell-mediated response
(cytotoxic
lymphocytes)
Invading
microbes
(pathogens)
Innate immunity
Innate immunity provides broad defenses against
infection : external and internal defenses
External defenses
Intact skin and mucous membranes
Form physical barriers that bar the entry of
microorganisms and viruses
Certain cells of the mucous membranes produce
mucus
A viscous fluid that traps microbes and other
particles
Innate immunity
In the trachea, ciliated epithelial cells
Sweep mucus and any entrapped microbes upward,
preventing the microbes from entering the lungs
Secretions from the skin
Give the skin a pH between 3 and 5, which is acidic
enough to prevent colonization of many microbes
Also include proteins such as lysozyme, an enzyme
that digests the cell walls of many bacteria
Internal Defenses
Internal defenses :
1. Phagocytic cells
2. Antimicrobial proteins
3. Inflammantory respons
4. Natural killer cells
Leukosit
Granulosit :
Neutrofil : pertahanan tubuh terhadap infeksi bakteri serta
proses peradangan kecil melalui fagositosis. Aktivitas dan
matinya neutrofil dalam jumlah besar menyebabkan nanah.
Eosinofil : pertahanan tubuh terhadap infeksi parasit.
Basofil dan mast cell bertanggung jawab terhadap reaksi
alergi dengan mengeluarkan histamin yang menyebabkan
peradangan.
Monosit membagi fungsi fagositosis dengan neutrofil.
Monosit dikenal sebagai makrofag, setelah meninggalkan
aliran darah serta masuk ke dalam jaringan.
Sel natural killer: sel yang dapat membunuh sel tubuh yang
telah terinfeksi virus atau telah berubah sel kanker.
Leukosit
Agranulosit :
Sel B: membuat antibodi yang akan berikatan dengan
antigen utuh, lalu menghancurkannya. Sel B
menghasilkan sel memori
Sel T: terdiri dari dari sel T helper dan sel T sitotoksik.
Kedua sel T mengkoordinasi sistem imun dan
menghancurkan antigen/bakteri yang telah
menginfeksi sel.
Adenoid
Tonsil
Lymph
nodes
Spleen
Peyer’s patches
(small intestine)
Appendix
Lymphatic
vesselsMasses of
lymphocytes and
macrophages
Tissue
cells
Lymphatic
vessel
Blood
capillary
Lymphatic
capillaryInterstitial
fluid
Lymph
node
The lymphatic system
Macrophages, can be found migrating through the body and in various
organs of the lymphatic systemInterstitial fluid bathing the
tissues, along with the white
blood cells in it, continually
enters lymphatic capillaries.
1
Fluid inside the
lymphatic capillaries,
called lymph, flows
through lymphatic
vessels throughout
the body.
2
Within lymph nodes,
microbes and foreign
particles present in
the circulating lymph
encounter macro-
phages, dendritic cells,
and lymphocytes,
which carry out
various defensive
actions.
3
Lymphatic vessels
return lymph to the
blood via two large
ducts that drain into
veins near the
shoulders.
4
1. Phagocytic Cells
Phagocytes attach to
their prey via surface
receptors
And engulf them,
forming a vacuole
that fuses with a
lysosome
Pseudopodia
surround
microbes.
1
Microbes
are engulfed
into cell.
2
Vacuole
containing
microbes
forms.
3
Vacuole
and lysosome
fuse.
4
Toxic
compounds
and lysosomal
enzymes
destroy microbes.
5
Microbial
debris is
released by
exocytosis.
6
Microbes
MACROPHAGE
Vacuole Lysosome
containing
enzymes
2. Antimicrobial Proteins
Numerous proteins function in innate defense
By attacking microbes directly of by impeding
their reproduction
About 30 proteins make up the complement
system
Which can cause lysis of invading cells and help
trigger inflammation
Interferons
Provide innate defense against viruses and help
activate macrophages
3. Inflammatory Response
In local inflammation, histamine and other chemicals
released from injured cells promote changes in blood
vessels that allow more fluid, more phagocytes, and
antimicrobial proteins to enter the tissuesPathogen Pin
Macrophage
Chemical signals
CapillaryPhagocytic cells
Red blood cell
Blood
clotting
elements
Blood clot
Phagocytosis
Fluid, antimicrobial proteins,
and clotting elements move
from the blood to the site.
Clotting begins.
2Chemical signals released
by activated macrophages
and mast cells at the injury
site cause nearby capillaries
to widen and become more
permeable.
1 Chemokines released by various
kinds of cells attract more
phagocytic cells from the blood
to the injury site.
3 Neutrophils and macrophages
phagocytose pathogens and
cell debris at the site, and the
tissue heals.
4
4. Natural Killer Cells
Natural killer (NK) cells
Patrol the body and attack virus-infected body
cells and cancer cells
Trigger apoptosis in the cells they attack
Acquired immunity
In acquired immunity, lymphocytes provide
specific defenses against infection
Lymphocytes
Arise from stem cells in the bone marrow
The vertebrate body is populated by two main
types of lymphocytes
B lymphocytes/B cells
T lymphocytes/T cells
Newly formed
lymphocytes are all alike
But they later develop
into B cells or T cells,
depending on where
they continue their
maturation
Lymphocyte Development
As B and T cells are
maturing in the bone and
thymus
Bone marrow
Lymphoid
stem cell
B cell
Blood, lymph, and lymphoid tissues
(lymph nodes, spleen, and others)
T cell
Thymus
Acquired immunity
Acquired immunity includes two branches
The humoral immune response involves the
activation and clonal selection of B cells,
resulting in the production of secreted
antibodies
The cell-mediated immune response involves the
activation and clonal selection of T cells
Clonal selection : binding of antigen to a mature
lymphocyte induces the lymphocyte’s
proliferation and differentiation
The humoral immune response
Generates a clone of short-lived activated effector
cells and a clone of long-lived memory cells
Antigen molecules
Antigen
receptor
B cells that
differ in
antigen
specificity
Antibody
molecules
Clone of memory cellsClone of plasma cells
Antigen molecules
bind to the antigen
receptors of only one
of the three B cells
shown.
The selected B cell
proliferates, forming
a clone of identical
cells bearing
receptors for the
selecting antigen.
Some proliferating
cells develop into
short-lived plasma
cells that secrete
antibodies specific
for the antigen.
Some proliferating cells
develop into long-lived
memory cells that can
respond rapidly upon
subsequent exposure
to the same antigen.
In the secondary immune response
Memory cells facilitate a faster, more efficient
responseA
ntib
ody c
on
ce
ntr
ation
(arb
itra
ry u
nits)
104
103
102
101
100
0 7 14 21 28 35 42 49 56
Time (days)
Antibodies
to AAntibodies
to B
Primary
response to
antigen A
produces anti-
bodies to A
2Day 1: First
exposure to
antigen A
1 Day 28:
Second exposure
to antigen A; first
exposure to
antigen B
3 Secondary response to anti-
gen A produces antibodies
to A; primary response to anti-
gen B produces antibodies to B
4
B Cell Receptors for Antigens
B cell receptors
Bind to specific, intact antigens
Are often called membrane antibodies or
membrane immunoglobulin (Ig)
Antibodi : substansi khusus yang dibentuk sel B
sebagai respon terhadap antigen
ANTIBODI
Antigen-
binding
site
Antigen-
binding siteDisulfide
bridge
Light
chain
Heavy chains
Cytoplasm of B cell
A B cell receptor consists of two identical heavy
chains and two identical light chains linked by
several disulfide bridges.
(a)
Variable
regions
Constant
regions
Transmembrane
region
Plasma
membrane
B cell
C C
Struktur imunoglobulin terdiri dari unit monomer yang terdiri
dari 2 rantai polipeptida ringan (sekitar 25.000 dalton) dan 2
rantai polipeptida berat (sekitar 50.000 dalton)yang
dihubungkan dengan ikatan sulfida
DNA of
undifferentiated
B cell
DNA of differentiated
B cell
pre-mRNA
mRNA Cap
B cell
B cell receptorLight-chain polypeptide
Intron
Intron
Intron
Variable
regionConstant
region
V1 V2 V3
V4–V39
V40 J1 J2 J3 J4 J5
V1 V2 V3 J5
V3 J5
V3 J5
V C
C
C
C
C
Poly (A)
Deletion of DNA between a V segment
and J segment and joining of the segments1
Immunoglobulin gene rearrangement
Transcription of resulting permanently rearranged,
functional gene2
RNA processing (removal of intron; addition of cap
and poly (A) tail)3
4 Translation
JENIS ANTIBODI
Berdasarkan urutan asam amino
dalam rantai beratnya, antibodi
terbagi menjadi :
1. Imunoglobulin G (IgG)
tipe (gamma)
2. Imunoglobulin M (IgM)
tipe (mui)
3. Imunoglobulin A (IgA)
tipe (alfa)
4. Imunoglobulin D (IgD)
tipe (delta)
5. Imunoglobulin E (IgE)
First Ig class produced after initial exposure to
antigen; then its concentration in the blood declines
Most abundant Ig class in blood; also present in
tissue fluids
Only Ig class that crosses placenta, thus conferring
passive immunity on fetus
Promotes opsonization, neutralization, and agglutination
of antigens; less effective in complement activation than
IgM (see Figure 43.19)
Present in secretions such as tears, saliva, mucus,
and breast milk
Triggers release from mast cells and basophils of
histamine and other chemicals that cause allergic
reactions (see Figure 43.20)
Present primarily on surface of naive B cells that have
not been exposed to antigens
IgM
(pentamer)
IgG
(monomer)
IgA
(dimer)
IgE
(monomer)
J chain
Secretory
component
J chain
Transmembrane
region
IgD
(monomer)
Promotes neutralization and agglutination of
antigens; very effective in complement activation
(see Figure 43.19)
Provides localized defense of mucous membranes by
agglutination and neutralization of antigens (see
Figure 43.19)
Presence in breast milk confers passive immunity on
nursing infant
Acts as antigen receptor in antigen-stimulated
proliferation and differentiation of B cells (clonal
selection)
IgG
- 70-80 % dari Ig total
- IgG terbagi menjadi 4 sub kelas IgG1
(59%), IgG2 (30%), IgG3 (8%) dan IgG4
(3%), semuanya berbentuk monomer.
- IgG diwariskan ibu ke janin melalui
plasenta dan kolostrum .
- Fungsi IgG : pertahanan diri utama
pada bbrp minggu pertama setelah
kelahiran, pertahanan diri setelah IgM
IgM
- 6 % dari Ig total
- Makroglobulin berukuran 5 kali lebih besar
dari IgG, karena terdiri dari 5 unit
monomer dengan suatu peptida tambahan
(rantai J berfungsi menstabilkan
struktur IgM.
- Adanya 5 monomer membuat ikatan IgM-
antigen lebih dari 1 situs, sehingga
efektif thd bakteri/virus.
- Situs IgM : sebagian besar pada aliran
darah
- Fungsi IgM: merupakan antigen pertama
yang muncul setelah stimulasi antigen.
IgA
- 10% dari Ig total
- Struktur dasar : 2 rantai berat dan 2 rantai ringan
dalam bentuk polimer (sebagian besar dimer,
sebagian kecil trimer) melalui ikatan disulfida.
- Situs IgA : serum, sekresi tubuh eksternal (air mata,
air liur, air mani, air seni dan kolostrum, dan sekresi
di selaput lendir paru-paru dan usus
- Fungsi IgA : perlindungan utama pada
bayi yang baru lahir, melindungi mukosa
dan permukaan luar tubuh
IgD Function not fully
understood
Found on B-cell surface
during different stages of
maturation
Possible involvement in
cell differentiation
IgE
Most IgE bound to IgE
receptor on mast cells
Antigen binding to IgE
releases inflammatory
substances
Histamine
Pathogenesis of hay fever,
allergic asthma
The allergic response
IgE antibodies produced in response to initial exposure to an allergen bind to receptors or mast cells.
1 On subsequent exposure to the same allergen, IgE molecules attached to a mast cell recog-nize and bind the allergen.
2 Degranulation of the cell,triggered by cross-linking of adjacent IgE molecules, releases histamine and other chemicals, leading to allergysymptoms.
3
1
2
3
Allergen
IgE
Histamine
Granule
Mast cell
NAMA FUNGSIONAL ANTIBODI
Pemberian nama antibodi menggambarkan reaksi in vitro/in vivo antibodi dengan antigen, yaitu :
1. Antitoksin : menetralkan toksin
2. Opsonin : membuat mikroba lebih peka
terhadap fagositosis
3. Aglutinin : menggumpalkan antigen
4. Presipitin : pengendapan/flokulasi antigen
5. Antibodi pengikat komplemen : penambatan
/fiksasi komplemen (protein antimikrobal)
6. Lisin : lisis/penguraian antigen
Jika multifungsi, antibodi dapat diberi beberapanama
Antibody-mediated mechanisms of
antigen disposalBinding of antibodies to antigens
inactivates antigens by
Viral neutralization
(blocks binding to host)
and opsonization (increases
phagocytosis)
Agglutination of
antigen-bearing particles,
such as microbes
Precipitation of
soluble antigens
Activation of complement system
and pore formation
Bacterium
Virus Bacteria
Soluble
antigens Foreign cell
Complement
proteinsMAC
Pore
Enhances
Phagocytosis
Leads to
Cell lysis
Macrophage
Acquired immunity
Acquired immunity includes two branches
The humoral immune response involves the
activation and clonal selection of B cells,
resulting in the production of secreted
antibodies
The cell-mediated immune response involves the
activation and clonal selection of T cells
Clonal selection : binding of antigen to a mature
lymphocyte induces the lymphocyte’s
proliferation and differentiation
Antigen-
Binding site
chain
Disulfide bridge
chain
T cell
A T cell receptor consists of one
chain and one chain linked by
a disulfide bridge.
(b)
Variable
regions
Constant
regions
Transmembrane
region
Plasma
membrane
Cytoplasm of T cell
T Cell Receptors for Antigens
Each T cell receptor
Consists of two different
polypeptide chains
T cells bind to small
fragments of antigens
That are bound to normal
cell-surface proteins
called MHC (major
histocompatibility
complex) molecules
V
C
MHC molecules
Infected cells produce MHC molecules
Which bind to antigen fragments and then are
transported to the cell surface in a process
called antigen presentation
A nearby T cell
Can then detect the antigen fragment
displayed on the cell’s surface
Depending on their source
Peptide antigens are handled by different
classes of MHC molecules
Class I MHC molecules
Infected cell
Antigen
fragment
Class I MHC
molecule
T cell
receptor
(a) Cytotoxic T cell
A fragment of
foreign protein
(antigen) inside the
cell associates with
an MHC molecule
and is transported
to the cell surface.
1
The combination of
MHC molecule and
antigen is recognized
by a T cell, alerting it
to the infection.
2
1
2
Found on almost all nucleated cells of the body
Display peptide
antigens to
cytotoxic T cells
Cytotoxic T cell
Perforin
Granzymes
CD8TCR
Class I MHC
molecule
Target
cell Peptide
antigen
Pore
Released
cytotoxic
T cell
Apoptotic
target cell
Cancer
cell
Cytotoxic
T cell
A specific cytotoxic T cell binds to a
class I MHC–antigen complex on a
target cell via its TCR with the aid of
CD8. This interaction, along with
cytokines from helper T cells, leads to
the activation of the cytotoxic cell.
1 The activated T cell releases perforin
molecules, which form pores in the
target cell membrane, and proteolytic
enzymes (granzymes), which enter the
target cell by endocytosis.
2 The granzymes initiate apoptosis within the
target cells, leading to fragmentation of the
nucleus, release of small apoptotic bodies,
and eventual cell death. The released
cytotoxic T cell can attack other target cells.
3
1
2
3
The activated cytotoxic T cell
Secretes proteins that destroy the infected target
cell
Class II MHC molecules
Located mainly on dendritic cells,
macrophages, and B cells
Display antigens
to helper T cells
1
2
Microbe Antigen-
presenting
cell
Antigen
fragment
Class II MHC
molecule
T cell
receptor
Helper T cell
A fragment of
foreign protein
(antigen) inside the
cell associates with
an MHC molecule
and is transported
to the cell surface.
1
The combination of
MHC molecule and
antigen is recognized
by a helper T cell, alerting it
to the infection.
2
(b)
The role of helper T cells
in acquired immunity
After a dendritic cell engulfs and degrades a bacterium, it displays
bacterial antigen fragments (peptides) complexed with a class II
MHC molecule on the cell surface. A specific helper T cell binds
to the displayed complex via its TCR with the aid of CD4. This
interaction promotes secretion of cytokines by the dendritic cell.
Proliferation of the T cell, stimulated
by cytokines from both the dendritic
cell and the T cell itself, gives rise to
a clone of activated helper T cells
(not shown), all with receptors for the
same MHC–antigen complex.
The cells in this clone
secrete other cytokines
that help activate B cells
and cytotoxic T cells.
Cell-mediated
immunity
(attack on
infected cells)
Humoral
immunity
(secretion of
antibodies by
plasma cells)
Dendritic
cell
Dendritic
cell
Bacterium
Peptide antigen
Class II MHC
molecule
TCR
CD4
Helper T cell
Cytokines
Cytotoxic T cell
B cell
1
2 3
1
2 3
B Cells: A Response to Extracellular
Pathogens
2
13
B cell
Bacterium
Peptide
antigen
Class II
MHC
molecule
TCR
Helper T cell
CD4
Activated
helper T cell Clone of memory
B cells
Cytokines
Clone of plasma cellsSecreted antibody
molecules
Endoplasmic
reticulum of
plasma cell
Macrophage
After a macrophage engulfs and degrades
a bacterium, it displays a peptide antigen
complexed with a class II MHC molecule.
A helper T cell that recognizes the displayed
complex is activated with the aid of cytokines
secreted from the macrophage, forming a
clone of activated helper T cells (not shown).
1 A B cell that has taken up and degraded the
same bacterium displays class II MHC–peptide
antigen complexes. An activated helper T cell
bearing receptors specific for the displayed
antigen binds to the B cell. This interaction,
with the aid of cytokines from the T cell,
activates the B cell.
2 The activated B cell proliferates
and differentiates into memory
B cells and antibody-secreting
plasma cells. The secreted
antibodies are specific for the
same bacterial antigen that
initiated the response.
3
The roles of the major participants in the
acquired immune response
Humoral immune response Cell-mediated immune response
First exposure to antigen
Intact antigensAntigens engulfed and
displayed by dendritic cells
Antigens displayed
by infected cells
Activate Activate Activate
Gives rise to Gives rise to Gives rise to
B cellHelper
T cellCytotoxic
T cell
Plasma
cells
Memory
B cells
Active and
memory
helper
T cells
Memory
cytotoxic
T cells
Active
cytotoxic
T cells
Secrete antibodies that defend against
pathogens and toxins in extracellular fluid
Defend against infected cells, cancer
cells, and transplanted tissues
Secreted
cytokines
activate
Autoimmune Diseases
In individuals with autoimmune diseases
The immune system loses tolerance for self and turns
against certain molecules of the body
Rheumatoid arthritis
Is an autoimmune disease that leads
to damage and painful inflammation
of the cartilage and bone of joints
• Other examples of autoimmune diseases include
- Systemic lupus erythematosus
- Multiple sclerosis
- Insulin-dependent diabetes
Immunodeficiency Diseases
An inborn or primary immunodeficiency
Results from hereditary or congenital defects that
prevent proper functioning of innate, humoral, and/or
cell-mediated defenses
In severe combined immunodeficiency (SCID)
Both the humoral and cell-mediated branches of
acquired immunity fail to function
An acquired or secondary immunodeficiency
Results from exposure to various chemical and
biological agents
Range from temporary states to chronic diseases
That physical and emotional stress can harm immunity
Acquired Immunodeficiency
Syndrome (AIDS)People with AIDS
Are highly susceptible to opportunistic infections
and cancers that take advantage of an immune
system in collapse
Because AIDS arises from the loss of helper T cells
Both humoral and cell-mediated
immune responses are impaired
The loss of helper T cells
Results from infection by the
human immunodeficiency virus (HIV)1µm
Recommended