Seminar on above topics

1. Cell Cannibalism, Apoptosis and
Autoimmunity
Presenter : Dr Manjunatha T M

2.  The word cannibalism is derived from cannibals
which is the Spanish name for the Carib people
formerly well known for practicing cannibalism –
practice of humans eating the flesh or internal
organs of other human beings.
 Cellular cannibalism is defined as the ability of a
cell to engulf another living cell leading
eventually to the death of the internalized cell.

3.  It is an important morphologic feature to
distinguish benign from malignant lesions and an
emerging indicator of both the anaplastic grade
and invasiveness.
 Cannibalism has been related to the metastatic
capabilities of malignant cells.
 It is considered as a sort of “feeding” activity
aimed at sustaining survival and progression of
malignant tumor cells in an unfavorable

4. micro environment .
The phenomenon of cell cannibalism has been
observed in several tumors such as lung
carcinoma, renal carcinoma, bladder carcinoma,
breast carcinoma, endometrial stromal sarcoma,
gastric adenocarcinomas, malignant melanoma,
and lymphomas.
Selected tumor cells behave as lower
microorganisms, such as amoebae and bacillus

5. subtilis, which use their eating to feed,
Professional phagocytes in multicellular animals
use their eating to forage the body from necrotic
material and debris and to initiate the immune
response.

6. Cellular cannibalism —morphology and appearance
 CC in cytological or histological preparation is
manifested as a cell that is contained within another
bigger cell with a crescent shaped nucleus.
This particular appearance is attributed to the fact
that ingested cell is contained in a big vacuole that
pushes the nucleus of cannibalistic cell to the
periphery .

7.  Owing to such appearance it was described
by Leyden in 1904 as “birdeye cells”

8. Schematic representation of the main successive steps of CC

10. Pathogenesis of Cell cannibalism
Lack of Nutrition and acidic environment
Activation of specific lytic enzymes, caveolin formation ,release of
Cathepsin B and Ezrin
Weakening of Intercellular Membrane junctions
Release of cells in Intercellular matrix
Interaction with cannibalistic host cells
Imbalance in adhesion forces between the cannibalistic host
cell
and the weakened cell
Engulfment and entrapment of the weakened cell by the Cannibalistic

11. Mechanism
A elements of cytoskeleton regulation and cell cell
junctions such as actin, myosin II, cadherins and Rho
signaling have been noted.
Numerous studies have revealed that cannibalistic
cells use caveolin1, ezrin and actin to consume the
cells in contact with its outer membrane.

12.  The internalized cells are taken up into a vacuole
which is surrounded by host plasma membrane
 It is so large that it squishes the host's nucleus
into a crescent shape along the cell membrane.
 A cannibalistic vacuole forms which most likely
fuses with lysosomes to form caveosomes rich in
cathepsinB

13.  Numerous studies have revealed that
cannibalistic cells use caveolin1, ezrin and actin
to consume the cells in contact with its outer
membrane

14.  COMPLEX CANNIBALISM : A malignant cell which
has engulfed another malignant cell might, in turn,
get engulfed by a third malignant cell. The process
is referred to as complex cannibalism

15. Type of cells
affected
Feeds on live cells Feeds on dead cells
and toxic materials
Mechanism of
action
In this phenomenon, free cell
lay down on the membrane
of cannibal cells and then
suddenly get into the tumor
cells and gradually
degenerate and dies off
In this process,
macrophage,
embrace, surround
and engulf external
body through
formation of huge and
long pseudopod
Type of
activity
Associated with feeding and
is increased in condition of
low nutrient supply. Aimed
at surviving in unfavorable
condition. Usually seen in
Associated with
scavenging activity
triggered by starvation
in normal cells
Characteristics CC Phagocytosis
Comparison of CC and phagocytosis as two distinct modes of cell in cell invasion

16. Role of pH Cannibalistic cells
are resistant to
low pH.
Acidic conditions
increases CC
Macrophages
usually dies at low
pH
Role of caveolin1 Caveolae mediated
endocytosis has a
key role
Not involved
Role of cathepsin B Overexpression of
cathepsin B noted
Not involved
Role of ligand
receptor
interaction
No specific ligand
receptor
interaction seen
Protein protein
interaction noted

17.  Factors regulating cellular cannibalism :
Following factors are known to control
phenomenon of cannibalism:
(I) Hunger of the tumor cells/low nutrient supply
(II) Tumor microenvironment, i.e., acidity and
hypoxia. Carcinogenesis (malignant tumors)
results in acidic micro environment

18. (III) Dynamic link between caveolin1,
actin cytoskeleton and ezrin.
This network has a key role in formation of
cannibalistic vacuole and caveosome and is
driving force for cannibalism.
(IV) Overexpression of cathepsin B and acidic
milieu of lysosomal like vesicles typify
cannibalistic cells .

19.  Cellular cannibalism: assessment parameters :
Cannibalism can be assessed by following
para meters
(I) cellularity of cannibalism — it is semi
quantitatively assessed as: (1+) < 5 cells, (2+) 5–
20 cells and (3+) > 20 cells in each preparation.
(II) Jose et al. graded cellularity of cannibalism as
Grade I (< 5 cells), Grade II (6–15 cells) and Grade
III (> 16 cells)

20. (II) diameter of cannibalism — analyzed using
an image analysis system;
(III) chromatin pattern — evaluated as
heterochromatin pattern or euchromatin
pattern
(IV) background — assessed as necrosis isomorphic
erythrocytes and dysmorphic erythrocytes;
(V) vimentin reactivity.

21. CELLULAR CANNIBALISM: HOW IT DIFFERS FROM
OTHER CELL IN CELL PHENOMENON?
Entosis. Entosis is a homogeneous cell in cell
invasion while cannibalism can be either
homogeneous or heterogeneous.
In entosis, live epithelial cells or tumour cells detach
from extracellular matrix and then invade their
neighbour cells.

22.  Entosis rely on conjugations or adherens
junctions and needs Rho and ROCK activities for
internalization, suggesting that entosis is an
active process and requires actin polymerization.
 Emperipolesis. Emperipolesis is a heterogenous
cell in cell invasion in which engulfed cells are
hematopoietic. The cells are only temporarily
internalized and are not destroyed .

23.  The hallmark of Rosai-Dorfman disease is
emperipolesis, in which lymphocytes and other
inflammatory cells reside undisturbed within
the cytoplasm of the histiocytes .

24. Physiological and pathological conditions exhibiting
Emperipolesis
Physiological Phenomenon Pathological Phenomenon
Emperipolesis of
erythroblasts by
megakaryocyte in fetal liver
Rosai Dorfman disease ,
Autoimmune hemolytic
anemia ,
Myeloproliferative disorders
Emperipolesis of
lymphocytes by human
glial cells in brain
Leukemia, Malignant
lymphoma ,
ITP , Neuroblastoma , Breast
Carcinoma

25. Efferocytosis. The recognition and elimination of
apoptotic cells by tissue macrophages and non
professional phagocytes such as epithelial cells,
endothelial cells, fibroblast and neutrophils.
Efferocytosis is critical for development, tissue
homeostasis and resolution of inflammation. It is
different from other types of cell in cell
phenomena both cytologically and biologically .

26. Entosis

27. Emperipolesis

28. Emperipolesis of RBCs

29. APOPTOSIS

30. Introduction
• Apoptosis is the process of programmed cell
death.
• Biochemical events lead to characteristic cell
changes (morphology) and death. These changes
include blebbing, cell shrinkage, nuclear
fragmentation, chromatin condensation, and
chromosomal DNA fragmentation.

31. • Between 50 and 70 billion cells die each day
due to apoptosis in the average human adult.
• For an average child between the ages of 8
and 14, approximately 20 billion to 30 billion
cells die a day

32. History
• German scientist Carl Vogt was first to describe
the principle of apoptosis in 1842.
• In 1972 Kerr first introduced the term apoptosis
in a publication which in Greek means
“ Falling off “
• Kerr received the Paul Ehrlich and Ludwig
Darmstaedter Prize on March 14, 2000, for his
description of apoptosis.

33. • The 2002 Nobel Prize in Medicine was awarded
to Sydney Brenner, Horvitz and John E. Sulston
for their work identifying genes that control
apoptosis

35. APOPTOSIS IN BIOLOGIC PROCESSES Apoptosis is
responsible for mediating cell death in a several
physiologic and pathologic processes
Physiologic Processes:
1. Organised cell destruction in sculpting of tissues
during development of embryo.
2. Physiologic involution of cells in hormone-
dependent tissues e.g. endometrial shedding,
regression of lactating breast .

36. after withdrawal of breast-feeding.
3. Normal cell destruction followed by replacement
proliferation such as in intestinal epithelium.
4. Involution of the thymus in early age
Pathologic Processes:
1.Cell death in tumours exposed to chemo
therapeutic agents.

37. 2. Cell death by cytotoxic T cells in immune
mechanisms such as in graft-versus-host disease
and rejection reactions.
3. Progressive depletion of CD4+T cells in
the pathogenesis of AIDS.
4. Cell death in viral infections e.g. formation of
Councilman bodies in viral hepatitis.

38. 5. Pathologic atrophy of organs and tissues on
withdrawal of stimuli e.g. prostatic atrophy after
orchiectomy, atrophy of kidney or salivary gland .
6. Cell death in response to low dose of injurious
agents
e.g. radiation, hypoxia and mild thermal injury.

39. 7. In degenerative diseases of CNS e.g.
in Alzheimer’s disease, Parkinson’s
disease, and chronic infective dementias.
8. Heart diseases e.g. in acute myocardial
infarction (20% necrosis and 80apoptosis).

40. APOPTOSIS: important in embryogenesis
Morphogenesis (eliminates excess cells):
Selection (eliminates non-functional cells):

41. APOPTOSIS: important in embryogenesis
Immunity (eliminates dangerous cells):
Self antigen
recognizing cell
Organ size (eliminates excess cells):

42. BIOCHEMICAL CHANGES :
Biochemical processes underlying
the morphologic changes are as under:
1. Proteolysis of cytoskeletal proteins.
2. Protein-protein cross linkages.
3. After initial pyknosis of nucleus, there
is fragmentation of chromatin by activation
of nuclease.
4. Appearance of phosphatidyl serine on the

43. surface of cell membrane
5. In some forms of apoptosis, appearance
of an adhesive glycoprotein thrombospondin
on the outer surface of apoptotic bodies.
6. Appearance of phosphatidylserine
and thrombospondin on the outer surface
of apoptotic cell facilitates early recognition
by macrophages for phagocytosis prior

45. Mechanism of apoptosis

46. Intrinsic (Mitochondrial) Pathway of Apoptosis

47. Loss of survival signals ,DNA damage ,Irradiation
Activation of sensors ( BH3 only proteins )
Antagonism of BCL2 ( Anti apoptotic proteins)
Activation of BAX and BAK channels(Pro –apoptotic proteins)
Leakage of cytochrome C , other proteins
Binds to protein APAF-1 (apoptosis-activating factor-1)

48. Forms Apoptosome
Apoptosome + Caspase 9
Cleaves adjacent caspase 9 (autoamplification process)

49. Fas , a death receptor
FasL on T cells
FADD (death domain of
adaptor protein)
Procaspase 8
Active caspase 8
Executioner caspases
,caspase 3 and 6
Intrinsic (Mitochondrial) Pathway of Apoptosis

51. MORPHOLOGIC FEATURES : The characteristic
morphologic changes in apoptosis by light microscopy and
electron microscopy are as under:
 Involvement of single cells or small clusters of cells in
the background of viable cells.
 Apoptotic cells are round to oval shrunken masses of
intensely eosinophilic cytoplasm (mummified cell)
containing shrunken or almost-normal organelles .
 The cell membrane may show blebs or projections on

52.  There may be formation of membrane-bound
near spherical bodies containing condensed
organelles around the cell called apoptotic
bodies.
 Characteristically, unlike necrosis, there is no
acute inflammatory reaction around apoptosis.

53. •The most well characterized ligands of these
death receptors to date are FasL, TNalpha,
Apo3L, and Apo2L. Corresponding receptors
are FasR, TNFR1, DR3, and DR4/DR5,
respectively

54. Members of the Bcl-2 family of proteins may be
pro- or anti-apoptotic.
•The anti-apoptotic proteins are Bcl-2, Bcl-x, Bcl-xL,
Bcl-XS, Bcl-w, and BAG.
•Pro-apoptotic proteins include Bcl-10, Bax, Bak,
Bid, Bad, Bim, Bik, and Blk.

56. CASPASES
• Caspases or cysteine-aspartic proteases or
cysteine-dependent aspartate-directed
proteases are a family of cysteine proteases that
(cleave proteins after aspartic residues)
• They play essential roles in apoptosis
(programmed cell death), necrosis, and
inflammation.
• Single chain of pro-enzymes.

57. Apoptotic stimulus Activation Substrate
Cleavage Enzyme.

58. 3 TYPES OF CASPASES
• Inflammatory Caspases: 1, 4, and 5
• Initiator Caspases: 2, 8, 9, and 10
–Long N-terminal domain
–Interact with effector caspases
• Effector Caspases: 3, 6, and 7
–Little to no N-terminal domain

59. FEATURE APOPTOSIS NECROSIS
Definition Programmed and
coordinated cell death
Cell death along with
degradation of tissue by
hydrolytic enzymes
Causative
agents
Physiologic and pathologic
processes
Hypoxia, toxins
Morphology 1.No inflammatory reaction
2.Death of single cells
3.Cell shrinkage
4.Cytoplasmic blebs on
membrane
5.Apoptotic bodies
6.Chromatin condensation
7.Phagocytosis of apoptotic
1.Inflammatory reaction
always present
2.Death of many adjacent
cells
3.Cell swelling initially
4.Membrane disruption
5.Damaged organelles
6.Nuclear disruption
7.Phagocytosis of cell
Contrasting features of apoptosis and necrosis

60. Molecular
changes
1.Lysosomes and other
organelles intact
2.Initiation of apoptosis by
loss of signals of normal
cell survival and by action
of agents injurious to the
cell
3.Triggered by intrinsic
(mitochondrial) pathway
(pro- and anti-apoptotic
members of Bcl-2 family),
extrinsic (cell death
receptor initiated) pathway
(TNF-R1, Fas, FasL) and
finally by activated capases
1.Lysosomal breakdown
with liberation of
hydrolytic enzymes
2.Initiated by various
etiologies (ischaemia
hypoxia, chemicals,
physical
agents,microbes etc).
3.Cell death by ATP
depletion, membrane
damage, free radical
injury

61. Necroptosis and Pyroptosis
■ Necroptosis resembles necrosis morphologically and
apoptosis mechanistically as a form of programmed cell
death.
■ Necroptosis is triggered by ligation of TNFR1, and viral
proteins of RNA and DNA viruses.
■ Necroptosis is caspase-independent but dependent on
signaling by the RIP1 and RIP3 complex.
■ RIP1-RIP3 signaling reduces mitochondrial ATP generation,
causes production of ROS, and permeabilizes lysosomal
membranes, thereby causing cellular swelling and

62. membrane damage as occurs in necrosis.
■ Release of cellular contents evokes an
inflammatory reaction as in necrosis.
For example,
1.necroptosis occurs during the formation of the
mammalian bone growth plate;
2.Cell death in steatohepatitis, acute pancreatitis,
reperfusion injury, and neurodegenerative diseases such as
Parkinson disease.

63. ■ Pyroptosis occurs in cells infected by microbes.It
involves activation of caspase-1 which cleaves the
precursor form of IL-1 to generate biologically active IL-1.
Caspase-1 along with closely related caspase-11 also
cause death of the infected cell.

64. Autoimmunity
 Immune reactions against self antigens.
 autoimmunity is the opposite of immune tolerance

65. Conditions to be met for diagnosis of an
autoimmune disease
• The presence of an immune reaction specific for
some self antigen or self tissue
• Evidence that such a reaction is not secondary to
tissue damage but is of primary pathogenic
significance
• The absence of another well-defied cause of the
disease.

66. Mechanisms of Immunologic Tolerance

67.  Central Tolerance: In this process, immature
self-reactive T and B lymphocyte clones that
recognize self antigens during their maturation in
the central (or generative) lymphoid organs (the
thymus for T cells and the bone marrow for B
cells) are killed or rendered harmless.
 Mechanism :When immature lymphocytes
encounter the antigens in the thymus, many of
the cells die by apoptosis.

68. This process, called negative selection or deletion, is
responsible for eliminating self-reactive
lymphocytes from the T-cell pool.
• When developing, B cells strongly recognize self
antigens in the bone marrow, many of the cells
reactivate the machinery of antigen receptor gene
rearrangement and then
•Begin to express new antigen receptors, not specific
for self antigens.This process is called receptor editing .

69. PERIPHERAL TOLERANCE
• T-cells that escape intrathymic negative selection
can cause tissue injury unless they are deleted or
muzzled in the peripheral tissues.
• 3 “back up” mechanisms that silence such
potentially auto reactive T-cells are:-
1.Clonal deletion by apoptosis
2.Clonal anergy
3.Peripheral suppression by T-cells(regulatory T cell

70. Mechanisms related to autoimmunity
• Defective tolerance or regulation
• Abnormal display of self antigens.
• Inflammation or an initial innate immune response.
• Antigen Mimicry
• Alteration of Normal Proteins
• Release of Sequestered antigens
• Epitope spreading
• Failure of Regulatory T Cells

71. Pathogenesis of Autoimmunity

73. Classification of Autoimmune Diseases

74. Important Autoimmune Diseases
Antibodies to Receptors
Autoimmune Disease Target of the Immune
Response
Myasthenia Gravis Acetyl Choline Receptor
Grave’s Disease TSH1 Receptor
Insulin Resistance
Diabetes
Insulin Receptor

75. Important Autoimmune Diseases
Antibodies to Cell Components other than Receptors
Autoimmune Disease Target of the Immune
Response
Systemic Lupus
Erythematosis
dsDNA, Histones,
Rheumatoid Arthritis IgG in joints
Rheumatic Fever Heart and joint Tissue
Hemolytic Anaemia RBC membrane
ITP Platelet membrane
Good Pastture’s Syndrome Basement Membrane

76. Important Autoimmune Diseases Cell Mediated
Autoimmune Disease Target of the Immune
Response
Multiple Sclerosis Myelin
Celiac Disease Enterocytes

77. Role of Susceptibility Genes :
Most autoimmune diseases are complex multigenic
disorders.
It has been known for decades that autoimmunity
has a genetic component. Association of HLA Alleles
with Disease. Among the genes known to be
associated with autoimmunity, the greatest
contribution is that of HLA genes .

78. Genetic Factors Related to Autoimmunity
HLA Gene

79. Association of Non-MHC Genes with Autoimmune Diseases
•Polymorphisms in a gene called PTPN22, which encodes
a protein tyrosine phosphatase, are associated with
rheumatoid arthritis, type 1 diabetes, and several other
autoimmune diseases.
•Polymorphisms in the gene for NOD2 are associtaed
with Crohn disease, a form of inflammatory bowel disease .
•Polymorphisms in the genes encoding the IL-2 receptor
(CD25) and IL-7 receptor α chains are associated with multipl
sclerosis and other autoimmune diseases.

80. General Features of Autoimmune Disease
• Autoimmune diseases tend to be chronic,
sometimes with relapses and remissions,
and the damage is often progressive.
• The clinical and pathologic manifestations
of an autoimmune disease are determined
by the nature of the underlying immune
response.

81. Role of infections in autoimmunity

82. Two mechanisms :
Infections may upregulate the expression of costimulators
on APCs. If these cells are presenting self antigens, the result
may be a breakdown of anergy and activation of T
cells specific for the self antigens.
Some microbes may express antigens that have the same
amino acid sequences as self antigens. Immune responses
against the microbial antigens may result in the activation of
self reactive lymphocytes. This phenomenon is called
molecular mimicry.

83.  Example of such mimicry is rheumatic heart disease, in
which antibodies against streptococcal proteins cross-
react with myocardial proteins and cause myocarditis

84. Sytemic Lupus Erythematosus
• Women 20 to 40 years
• F:M Ratio 10:1
• Prevalent in African-American and Hispanic women
• Auto-Abs against RBCs & Platelets- Complement
mediated lysis- hemolytic anemia and
thrombocytopenia
• Auto-Abs against nuclear antigens- complement
system activation- damage to blood vessels-

85. vasculitis and glomerulonephritis
•Neutropenia: Expression of a type 3 complement
receptor (CR3) on neutrophils.
Sytemic Lupus Erythematosus :
SLE is an autoimmune disease involving multiple
autoantibodies, particularly antinuclear antibodies
(ANAs),
Injury is caused mainly by
deposition of immune complexes and binding of

86. SLE Antinuclear Antibodies
• These are directed against nuclear antigens
and can be grouped into four categories:
–Antibodies to DNA
–Antibodies to histones
–Antibodies to nonhistone proteins bound to RNA
–Antibodies to nucleolar antigens.

87. SLE Summary
1. Systemic autoimmune disease caused by auto
antibodies produced against numerous self
antigens and the formation of immune complexes.
2. The major auto antibodies, and the ones
responsible for the formation of circulating
immune complexes, are directed against nuclear
antigens. Other autoantibodies react with
erythrocytes, platelets, and various complexes of.

88. phospholipids with proteins
3.Disease manifestations include nephritis, skin
lesions and arthritis (caused by the deposition of
immune complexes), and hematologic and
neurologic abnormalities.
4. The underlying cause of the breakdown in
self-tolerance in SLE is unknown; it may
include excess or persistence of

89. multiple inherited susceptibility genes, and
environmental triggers (e.g., UV irradiation, which
results in cellular apoptosis and release of nuclear
proteins).

92. Autoimmune Anemia
• Pernicious Anemia
–Auto-Abs against intestinal protein on
parietal cells- hampers uptake of vit B12.
• Autoimmune Hemolytic Anemia
–Auto-Ab against RBC Antigens
–Complement Lysis- Phagocytosis of RBC.

93. Hashimoto’s Thyroiditis
•Middle Aged Women.
•Sensitized TH-1 for Thyroid
Antigens.
•Thyroid Gland infiltration by
Lymphocytes, Macrophages and
Plasma Cells.
•Abs against thyroglobulin and
thyroid peroxidase.
•Hypothyroidism

94. Goodpasture’s Syndrome
Lungs of a patient
with Goodpasture’s
•Auto-Abs against basement
membrane Ags.
•Glomeruli and Alveoli affected.
•Kidney Faliure and Pulmonary
Hemorrhage.
•IgG and C3b deposit on the basement
membrane.

95. Diabetes
CTL Infiltration
Macrophage
Activation
Cytokines Released
+ Lytic Enzymes
Auto-Abs also
Present
IDDM

96. Grave’s Disease
•TSH (from pituitary gland)
binds to receptors on
thyroid cells
•Hormones Thyroxine and
Triiodothyroxine.
•Auto-Abs agonists.
Overstimulation
of Gland.

97. Myasthenia Gravis
• Progressive weakening of skeletal muscles.
• Auto-Abs bind to acetylcholine receptors on
the motor end of the muscle cells.
• AcTh cannot bind.
• Antibodies ultimately
destroy the muscle cells.
• Antibodies act as Antagonists.

99. Multiple Sclerosis
T Lymphocytes enter cerebrospinal fluid. Certain
viruses pre-dispose a person for developing MS.

100. • Chronic Inflammation of Joints.
• Auto-Abs or Rheumatoid Factors react with
determinants in the Fc region of IgG.
• Classsic Rheumatoid Factor: IgG Antibody.
• IgM-IgG complexes deposit into the joints.
• Triggers Type-III Hypersensitivity
Reaction.
Rheumatoid Arthritis

101. Sjogren Syndrome
 Sjogren Syndrome is a chronic disease
characterized by dry eyes (keratoconjunctivitis
sicca) and dry mouth (xerostomia) resulting from
immunologically mediated destruction of the
lacrimal and salivary glands .
 Sjögren Syndrome Types
• Primary
–Isolated, Also called sicca syndrome
• Secondary
–Related to other autoimmune diseas

102. References
• Kumar V ,Abbas A K, Aster J C. Cellular
Responses to Stress and Toxic Insults, 9th
ed.Guragon:2014 p.52-60
• Sharma D, Koshy G, Grover S, et al. Cellular
cannibalism: an insight. Chrismed J Health Res
2015; 2: 14–8.
• Stuart AE. Phagocytic engulfment and cell
adhesiveness as cellular surface phenomena. J
Clin Pathol 1977;30:592.

103. • Fais S. Cannibalism: A way to feed on
metastatic tumors. Cancer Lett
2007;258:15564.
• Bauchwitz MA. The bird's eye cell:
Cannibalism or abnormal division of tumor
cells. Acta Cytol 1981;25:92.
• Kumar V ,Abbas A K, Aster J C. Autoimmune
diseases, 9th
ed.Guragon:2014 p.211-227