Basic immunology 21-26

1. Basic Immunology
Lecture21 - 26th

2. Basic Immunology
Lecture21 - 22th
Hypersensitivity
Immunoglobulin and cytokin mediated
hypersensitive reactions.
Allergy. DTH.

3. • Pathologic overreactions of the effector
phase of immune response with sever
tissue damage (necrosis).
• Different mechanisms can be detected in
the background. Gell and Coombs (1963)
proposed differentiating four types of
hypersensitivity.
• The term of immunoglobulin or cytokine
mediated hypersensitivity is used recently.
Hypersensitivity

4. Hypersensitive reactions
Immunoglobulin mediated hypersensitivities
Type I. immediate form (allergies)
Type II. cytotoxic form (serum sickness)
Type III. immunocomplex disease
Cell mediated hypersensitivities
Type IV. Delayed Type Hypersensitivity

9. Type I hypersensitivity

10. IgE binding receptors

13. Pharmacologic Mediators of Immediate Hypersensitivity
Preformed mediators in granules
histamine
bronchoconstriction, mucus secretion,
vasodilatation, vascular permeability
tryptase proteolysis
kininogenase
kinins and vasodilatation, vascular permeability,
edema
ECF-A
(tetrapeptides)
attract eosinophil and neutrophils
Newly formed mediators
leukotriene B4 basophil attractant
leukotriene C4, D4 same as histamine but 1000x more potent
prostaglandins D2 edema and pain
PAF
platelet aggregation and heparin release:
microthrombi

15. Clinical forms of allergic reactions
• Acute allergy – anaphylaxis
• Subacute and chronic allergies initiated
by aeroallergens and food allergens
• Secondary organ failures caused by
chronic allergies

16. Anaphylaxis is a serious
acute allergic reaction
that is rapid in onset and
may lethal.

18. Food allergy skintest

22. Therapeutic relevances
1. Acute intervention
(adrenalin, corticosteroid)
2. Prevention
• Allergen free environment
• Desensibilization
3. Treatments
• Antihistamins
• Non-specific immunosuppression

23. Hypersensitivity Type II
ADCC

24. Hypersensitivity Type II

27. Hypersensitivity Type III.

28. Hypersensitivity Type III.

29. Macrophage activation phases
Resting Activated Hyperactivated
--------------------->IFNgamma---------------------->LPS, Immuncomplex
double stranded RNA
Phagocytosis Antigen presentation
Tumor cell and
parasite killing
Chemotaxis Tumor cell binding
Proliferation decreased prolif. No proliferation.
No cytotoxicity No APC
MHC II -, MHC II+, O2 high MHCII -, O2high
O2 low TNF,cytotoxic
Protease secretion

30. Phases of DTH
• Sensitization phase: 1-2 weeks following primary
contact with the antigen. APC (Langerhans cells
vascular endothelial cells or macrophages) derived
IL-12 induce Th cells
• Activation phase: Th1 activation, proliferation,
sometimes CD8+ CTL activation.
• Effector phase: the secondary antigen contact
causes Th cell activation, cytokine secretion (24h),
recruitment and activation of macrophages and
nonspecific inflammatory cells (peaks 48-72 hours).
Only 5% of the infiltrating cells are T cells, 95% is
nonspecific.

31. Phases of Delayed-Type Hpersensitivity
(DTH)
I. Sensitization:

32. II. Effector phase

34. Tuberculin skintest

35. Phases of DTH
• Granulomatosus reaction: if the pathogen is
not easily cleared, survives in the cells, release
their antigens into the cytoplasm: CD8+ CTL
activation and – prolonged DTH response –
continuous macrophage activation, they adhere
closely to one another: epitheloid shape, giant
cell formation: tissue damage, necrosis, fibrosis.

36. Sarcoidosis (Type IV Hypersensitivity)

37. Hypersensitivity Type IV.

38. Contact dermatitis caused by
„metal allergy”
DTH

39. Comparison of Different Types of hypersensitivity
type-I
(anaphylactic)
type-II
(cytotoxic)
type-III
(immune
complex)
type-IV
(delayed type)
antibody IgE IgG, IgM IgG, IgM None
antigen Exogenous cell surface soluble tissues & organs
response time 15-30 minutes minutes-hours 3-8 hours 48-72 hours
appearance weal & flare
lysis and
necrosis
erythema and
edema, necrosis
erythema and
induration
histology
basophils and
eosinophil
antibody and
complement
complement and
neutrophils
monocytes and
lymphocytes
transferred
with
antibody antibody antibody T-cells
examples
allergic asthma,
hay fever
erythroblastosis
fetalis,
Goodpasture's
nephritis
SLE, farmer's
lung disease
tuberculin test,
poison ivy,
granuloma

40. Basic Immunology
Lecture 23-24th
Immunological tolerance
Physiological and pathological
autoimmunity

41. Tolerated skin grafts on MHC (H2) identical mice

42. TOLERANCE & AUTOIMMUNITY
• Upon encountering an antigen, the immune system
can either develop an immune response or enter a
state of unresponsiveness called tolerance.
• Immunological tolerance is thus the lack of ability to
mount an immune response to epitopes to which an
individual has the potential to respond.
• Targeting type and tolerating type immune
responses composed by the same cellular and
molecular components, the differences are in
the effector phase only.
• Targeting type immune response or tolerance
needs to be carefully regulated since an
inappropriate response – whether it be autoimmune
reaction to self-antigens or tolerance to a potential
pathogen – can have serious and possibly life-
threatening consequences.

43. AUTOREACTIVITY
Autoimmune diseases
TOLERANCE
Immunodefficiencies

44. Immune tolerance can result from a number
of causes including:
• No direct contact with the antigen;
• Prior contact with the same antigen in fetal life or in
the newborn period when the immune system is not
yet mature;
• Prior contact with the antigen in extremely high or
low doses;
• Exposure to radiation, chemotherapy drugs, or other
agents that impair the immune system;
• Heritable diseases of the immune system;
• Acquired diseases of the immune system such as
HIV/AIDS.

45. TOLERANCE
- PASSIVE
- ACTIVE
AUTOIMMUNITY
- PHYSIOLOGIC REGULATION
- AUTOIMMUNE DISEASES

46. Passive tolerance
Unresponsiveness: no MHC recognition or
inhibited cellular differentiation.
• Tolerance induced by the nature
of the antigen
• Tolerance induced by the body

47. Passive tolerance induced by the
nature of the antigen
• chemical nature
• dose of the antigen
- low dose tolerance (T cell mediated,
long ranging)
- high dose tolerance (B cell mediated,
short ranging)
• mode of the administration

48. Tolerance induced by the body
• sequestered antigens
no MHC recognition
no antigen presentation
no systemic response
• heredited or acquired immunodeficiency
• clonal anergies

49. T-cell tolerance
– Central Tolerance: selection in the Thymus
– Peripheral Tolerance
• Failure to Encounter Self Antigens
• Receipt of Death Signal
• Lack of Co-stimulation
• Blocking type adhesion molecules
• Control by Regulatory T cells

50. Failed co-stimulation results low dose
tolerance

51. Anergy
Deletion
Anergy
No response
T cell
tolerance

52. B-cell Tolerance
- Central tolerance
- Peripheral tolerance

53. Immunological Yin-Yang
The cytokines IL-12 and TGF beta 1 are predominant influences in "peripheral"
and "mucosal" lymphatic tissues. Thus vectorial expression of these cytokines
affect T cells and B cells in such a way that proliferating B cells become
committed to secrete "peripheral" IgG or "mucosal" IgA, respectively.

54. ACTIVE TOLERANCE
Anti-idiotype network
• Anti-idiotype antibodies against T cell and B cell
receptors and immunoglobulins
• Antigen-specific inhibition and induction of
memory
Natural immune system
(“Immunological homunculus”)
• Low affinity IgM natural autoantibodies produced
by CD5+ B cells
• γ/δ T cells

55. Anti-idiotype network (N. K. Jerne)
idiotípus
paratop
anti-idiotípus 2
(idiotop-specifikus)
anti-idiotípus 1
(paratop-specifikus)
anti-anti-idiotípus 1 anti-anti-idiotípus 2 anti-anti-idiotípus 1 anti-anti-idiotípus 2
idiotopantigén
• T- & B-cell suppression
• Memory formation;
• Biological mimicri (insulin
– anti-insulin – anti-anti-
insulin ~ insulin)

56. Naturally occurring (auto)antibodies
Autoantibodies of the IgM (mostly), or IgG and IgA classes,
reactive with a variety of serum proteins, cell surface
structures and intracellular structures, are ‘naturally’
found in all normal individuals. Present in human cord
blood and in ‘antigen-free’ mice, their variable-region
repertoire is selected by antigenic structures in the body and
remains conserved throughout life. Encoded by germline
genes with no, or few, mutations, natural autoantibodies are
characteristically ‘multireactive’ and do not undergo
affinity maturation in normal individuals. Natural
autoantibodies may participate in a variety of physiological
activities, from immune regulation, homeostasis and
repertoire selection, to resistance to infections, transport and
functional modulation of biologically active molecules.

57. Antigens recognized by natural
autoantibodies
Heatshock
proteins
hsp65, hsp70, hsp90, ubiquitin
Enzymes aldolase, citockrom c, SOD,
NAPDH, citrate synthase,
topoisomarase I.
Cell membrane
components
2-microglobulin, spectrin,
acetylcholin receptor
Cytoplasmic
components
actin, myosin, tubulin, myoglobin,
myelin basic protein
Nuclear
components
DNS, histones
Plasma proteins albumin, IgG, transferrin
Cytokines,
hormones
IL-1, TNF, IFN, insulin,
thyreoglobin

59. Autoimmune diseases affect 5-7% of the population !

60. AUTOIMMUNITY
• Physiological autoimmunity: part of
the normal immunological regulation
• Pathological autoimmunity: diseases
caused by self reacting immune
responses with permanent tissue/organ
injury

61. • Inflammation and tissue necrosis
- Cellular components:
(T cells CD8 and Th1, NK, Mf, DC, Ne, Eo, Ba, Mc)
- Humoral components:
(Ig+complement, ADCC, cytokines, chemokines,
tissue hormones and mediators)
Pathomechanism of autoimmunity

62. Pathomechanism of autoimmunity
• Multifactor mechanism
(general catastrophe of bio-regulation caused
by external and internal factors)
- Autoimmune “steady state” (failure
of dynamic balance on self tolerance and
autoimmunity)
- Role of infections (molecular mimicry
or inefficient natural antibody network)

63. Autoimmune steady state
Self
reacting
immune
response
with
tissues
damages
Active
tolerance
and
tissue
repair

64. Pathogens and human
antigens
Peptid
residues
Overlaping
sequences
Human cytomegalovirus
IE2
HLA-DR molecule
79
60
PDPLGRPDED
VTELGRPDAE
Poliovirus VP2
Acetylcholine receptor
70
176
STTKESRGTT
TVIKESRGTK
Papilloma virus E2
Insulin receptor
76
66
SLHLESLKDS
VYGLESLKDL
Klebsiella pneumoniae
nitrogenase enzym
HLA-B27 molecule
186
70
SRQTDREDE
KAQTDREDL
Adenovirus 12 E1B
Alfa-gliadin
384
206
LRRGMFRPSQCN
LGQGSFRPSQQN
HIV p24
Human IgG
160
466
GVETTTPS
GVETTTPS
Measles virus P3
Myelin basic protein
31
61
EISDNLGQE
EISFKLGQE

66. Pathomechanisms of autoimmune
diseases
- Autoimmunity by the antigen
- Failed differentiation and selection
of lymphocytes
- Genetic background

67. Autoimmunity by the antigen
Tissue injury or inflammation, leading to:
- Release of sequestered self antigens
- Structural alterations of self antigens
- Increased costimulation on tissue
APCs

68. • Abnormal selection of lymphocyte
repertoire
• Polyclonal activation of anergic self-
reactive lymphocytes
• Stimulation by foreign antigens that
cross-react with self
Autoimmunity by the failure of
self tolerance

71. Thyroid gland
Graves’ disease
Hashimoto thyreoiditis
DR3
DR5
3.7
3.2
TSH receptor ↑
Thyroid mikrosome
peroxidase, thyroglobulin ↓
Pancreas
IDDM
DR4/D
R3
DQB
0302
20
100
Β-inslet cellss ↓
GAD, HSP60, junB, insulin,
pre/pro insulin
Neural system
Sclerosis multiplex
Myasthenia gravis
DR2
DR3
4.8
2.5
Brain white matter, MBP,
PLP, MOG, MAG
Peripheral neurons and
striated muscle
Acetycholin receptor
Heart: rheumatic fever
Blood: AHA,
thrombocytopenia
DR3,D
R4
S. Β-haemolyticus/Myosin
Vvs gP
Thrombocyte gP

72. SLE DR3/
DR2
5.8
Kidney, serous layers
ds/ssDNS, Sm-IC, SSA,
SSB
Sjögren syndrome Exocrine glands, salivary
glands, liver, kidney, brain,
thyreoid gland, heart, lung,
gut
Rheumatoid
arthritis (RA)
DR4
DR1
4.2 Joint connective tissues,
collagen Type II, IgG RF
Spondyloarthritis
(SPA)
Reiter disease
Salmonella/Shigella arthritis
B27
B27
B27
90
33
20.7
Vertebra
Clamydia, Yersinia

75. Basic Immunology
Lecture 25- 26th
Autoimmune diseases.
Immunity against cancer.

79. In Graves' Disease a patient
produces autoantibodies that
bind to the receptors for thyroid-
stimulating hormone (TSH).
TSH is produced by the pituitary
gland and the receptors for TSH
are present on thyroid cells.
Binding of these autoantibodies
mimics the normal action of
TSH which is to stimulate the
production of two thyroid
hormones, thyroxine and
triiodothyronine. However, the
autoantibodies are not under a
negative feedback control
system and therefore lead to
overproduction of the thyroid
hormones. For this reason
these autoantibodies have been
termed long-acting thyroid-
stimulating (LATS)
antibodies. Overproduction of
thyroid hormones leads to many
metabolic problems.
Grave’s disease

80. A patient with this disease produces autoantibodies to the acetylcholine
receptors on the motor end-plates of muscles. Binding of acetylcholine in
therefore blocked and muscle activation is inhibited. The autoantibodies also
induce complement-mediated degradation of the acetylcholine receptors,
resulting in progressive weakening of the skeletal muscles.
Myasthenia gravis

81. Autoimmune hemolytic anemia

82. Goodpasture syndrom

83. Systemic Lupus Erythematosus (SLE) is characterized by fever, weakness,
arthritis, skin rashes, pleurisy, and kidney dysfunction. Affected individuals may
produce autoantibodies to a range of tissue antigens such as DNA, histones,
RBCs, platelets, leukocytes, and clotting factors. SLE typically appears in
women between 20 and 40 years of age with a female:male ratio of 10:1. An
example of complications arising from SLE is when immune complexes are
deposited along the walls of small blood vessels. This deposition activates
complement system, resulting in glomerulonephritis and damage to the blood-
vessel wall (vasculitis) causing widespread tissue damage.
Characteristic "butterfly" rash
over the cheeks of a young
girl with SLE.

85. Kaposi M. Arch Dermat u Syph 1869; 1: 18-41.
SLE

86. Paul Kee rajza saját kezéről
Systemic sclerosis
(Scleroderma)

87. Diffuse cutaneous SSc (dcSSc): skin manifestation both on the extremities and on
the trunk, severe internal organ involvement, poor prognosis
Limited cutaneous SSc (lcSSc): skin involvement only on the face and distal part of
extremities, no internal organ involvement, good prognosis
The major autoantibody in SSc targets DNA topoisomerase I (Topo I or Scl-70)
Anti-Topo I autoantibodies are detected mainly, but not exclusively in dcSSc

88. Periarteritis nodosa
The medium sized arteries in the fat tissue appear magenta
red because their wall is impregnated with fibrin (fibrinoid
necrosis). There is also marked inflammation in the wall of
these blood vessels extending into the perivascular
connective tissue (arteritis and periarteritis).

89. Periarteritis nodosa

92. Raynaud's Syndrome

93. anti-Phopholipid syndrome
Livedo reticularis
Antiphospholipid Syndrome (APS, APLS,
Hughes Syndrome, or Sticky Blood):
abnormal antibodies linked to abnormal blood
clots within veins and arteries.

95. Hashimoto’s disease

96. Inflammatory reaction of synovial membrane in the of joint capsule initiates
fluid accumulation in the joint cavity and fibrotic connective tissue
development (pannus) fulfilling the joint cavity and causing sever and
permanent movement restrictions. Sever bone and cartilage destruction
occurs at the same time. Following tissue damages caused by inflammatory
reaction develop in the serous membrane of the lung and heart, in the pleura,
eyes and skin.

98. Demyelinisation in multiple
sclerosis

99. Sjögren syndrome

100. Inflammatory Bowel Diseases

101. Crohn’s disease

102. Ulcerative colitis

103. Immunity against malignant tumors.

105. Tumor Specific Antigen
TSA – mutations of somatic cells induced by
spontaneous mutations, integration of viral genes,
chemical carcinogenesis or x-rays.
Each carcinogenic factor induces a unique and
specific class of antigens.
TSA is the result of somatic mutations which is
recognized (according to the individual MHC
haplotype) by the immune system.
NO general TSA specific in all tumors!

106. Tumor Assotiated Antigen
Products (e.g. hormones, growth factors, cell
surface receptors, differentiation molecules
etc.) of both normal and altered cells during
their differentiation.
Production of TAAs is not related with
tumorous transformation exclusively, but
expression profile of TAAs could be
characteristic in some tumours, and useful
as „tumor markers” in differential diagnosis
or in the monitoring of therapeutic efficiency.

108. Most frequent tumor markers
Tumor marker Abbr. Oncological application
Alpha-foetoprotein AFP Liver and germline tumors
Cancer antigen 125 CA 125 ovarial cancers
Cancer antigen 15,3 CA 15,3 Breast cancer
Cancer antigen 72,4 CA 72,4 Gastric cancer
Cancer antigen 19,9 CA 19,9 Pancreatic cancer
Carcinoembrionic antigen CEA Gastrointestinal cancers
Neuronspecific enolase NSE Small cell pulmonary cancer
Prostate specific antigen PSA Prostate cancer
Squamous cell carcinoma antigen SCC Planocellular cancers
Tissue polipeptid antigen TPA Urinary bladder and
pulmonary cancers
Tissue polipeptid-specific antigen TPS Metastatic breast cancers

110. Immune reactions against
tumor cells
• Components of the innate and natural
immunity (iNKT, MAIT, iγδT cells)
• T cell mediated (CD8+, CD4+Th1, NK)
• macrophage mediated
• immunoglobulin mediated (ADCC)
• network of cytotoxic cytokines

112. „Tumor escape”
• Downregulation or owerexpression of MHC class I.
• Owerexpression of FcRs.
• Failed cytokine receptors.
• Masking and blocking glykoproteines.
• Production of tumor associated cytokines.
• Blocking cytokines produced by macrophages or
dendritic cells.
• Activation of Treg cells.
• Expression of blocking adhesion molecules.

114. Tumor-associated cytokines inhibit anti-tumor immunity.
IL10, TGFß, and vascular endothelial growth factor (VEGF),
can inhibit the maturation and activation of antigen-
presenting dendritic cells (DC) as well as regulate the
generation of effector and/or regulatory T cells.

115. Tumor assotiated macrophages
„Double edged sword”

116. Possible immuntherapies
• immunotargeting against TAA
• Immune checkpoint inhibitors
• Immunomodulation
• Tumor vaccines
• Oncolytic viruses

117. Immunotoxin therapy

118. Immunotoxin therapy of Hairy Cell Leukemia
with BL22

119. HER-2/neu

120. Immune checkpoint inhibitors

121. Mistletoe lectin
Two chains of the Viscum
Album Agglutinin-I (VAA-I):
• „A chain” (29 kD) strong ribosoma
inactivator by the N-glikosidase
activity.
• Sugar binding „B cahian” (34 kD) is
responsible for the imunomodulant
activity.

122. Oncolytic viruses
• An oncolytic virus is a virus that preferentially
infects and lyses cancer cells; these have obvious
functions for cancer therapy, both by direct
destruction of the tumor cells, and, if modified,
as vectors enabling genes expressing anticancer
proteins to be delivered specifically to the tumor
site.
• Most current oncolytic viruses are engineered for
tumour selectivity, though there are a few
naturally occurring ones such as the Seneca
Valley virus .