Animal Science with Biology

1. IMMUNOLOGY BASICS
Lactation Biology
Animal Science 337

2. MEANS OF AQUIRING IMMUNITY
1. ACTIVE: make own antibody
chance encounter w/Ag
a) natural
pregnancy
vaccination
b) artificial
introduce Ag via trt.

3. MEANS OF AQUIRING IMMUNITY
2. PASSIVE: transfer preformed antibody
a) natural : mother to fetus
(6 mo protection)
placental vs. colostral
b) artificial: immune therapy

4. Type of immune response
• Innate
• defense we are
born with
–phagocytic
cells
–complement
proteins
– anatomical *
– physiological *
• Adaptive/acquired
• defense that
develops with
exposure/time
–serum
antibodies
–T cells (CMI)
* 1st line of defense!!!

5. Mechanisms of immunity:
• Cellular
–cells responsible
for protection
–lymphocytes
–phagocytes
• Humoral
–antibodies (in
serum) are
responsible for
protection

6. Two Arms of The Immune System
Neutrophils Macrophages B lymphocytes
T lymphocytes
Innate Immunity Adaptive Immunity
Phagocytes Lymphocytes
Antigen
presentation
TH1 or TH2 Cytokines
TH1 Cytokines
chemokines
Antigen
presentation
TH1 Cytokines
Antibodies
pathogens pathogens
Cytotoxicity
© Jeanne L. Burton, Michigan State University

7. Cells of the Immune System
Helper T cell (TH)
TH
Tissue macrophage
M
PMN
Circulating neutrophil
Myeloid-lineage cells of the innate immune system
Lymphoid-lineage cells of the adaptive immune system
B cell
B
Cytotoxic T cell (TC )
TC
© Jeanne L. Burton, Michigan State University

8. • large cell (10-25 um dia)
• main purpose: phagocytosis / kill
• act non specifically
• “chemotactic” capability
• potent phagocytosis when activated
by T lymphocytes (lymphokines)
• Express Ag on surface to T / B cells

9. • multilobulated nucleus
• lysosomal granules
• phagocytosis and kill
• 1st white blood cell to infection site
• die and release contents
• irritate surrounding tissue / recruit cells
• Phago. improved by opsonization with Ig

10. Circulating
neutrophil
Inflammatory
neutrophil
Extracellular bacteria
M
PMN
PMN
Tissue
macrophage
IL-1, IL-6,
IL-8,TNF-a
IFN-g
TNF-a
Infected
Gland
Blood
Macrophages and neutrophils are needed to kill extracellular bacteria,
such as those the infect the mammary glands of dairy cows
No memory
M or
PMN cells
develop
© Jeanne L. Burton, Michigan State University

11. Inflammation: part of innate immunity

12. • poor at phagocytosis
• granules contain histamine / serotonin
• vasodilators / permeability factors
• requires binding of 2 IgE for release

14. lymphocytes
• small (5 – 15 um)
• No lysosomes : all “brain” until activated
• distinguish self from non self
• specific : recognize specific antigens
• MEMORY**
• need presentation of Ag by macrophage

15. cytokines
• interactions
- antigen
- macrophage
- T cell (Th)
- B cell
- cytokines
• interactions
- antigen
- macrophage
- T cell (Th)
- cytokines
T helper (Th)
T suppressor
T killer
others

16. Bob Luebke
ITB/ETD/NHEERL
Role of the Immune System
in Homeostasis
• Bidirectional interaction with other systems
– Reproduction
• “Self control” to prevent rejection of the fetus
• Stimulation of placental growth
• Linked to breeding success (rodents!)
– Endocrine
• Immune (autoimmune) diseases
– CNS
• Repair
• Neurogenesis
• Neurotransmitter/cytokine production and

17. Bob Luebke
ITB/ETD/NHEERL
Basics of Immunology
The Immune Response
Innate Immunity Adaptive (Acquired) Immunity
-Phylogenetically ancient
-Limited recognition
-Rapid (minutes – hours)
- No cell proliferation required
-Limited memory (? mammals)
-First appeared in jawed fishes
- Infinite array of specificities
- Slow (days)
-Requires proliferation and differentiation
-Long-lasting memory

18. Bob Luebke
ITB/ETD/NHEERL
Basics of Immunology
• The adaptive immune
response to antigen
– Recognition as foreign
• First encounter: usually initiated
by innate immune system cells
• Receptor-mediated
– Antigen processing and
presentation
• B cells, macrophages, dendritic
cells
– Gene transcription, mediator
release, cellular proliferation

19. Bob Luebke
ITB/ETD/NHEERL
Organs of the Immune System
Bone Marrow: source of immune
system cells

20. Bob Luebke
ITB/ETD/NHEERL
Immune System Anatomy

21. Bob Luebke
ITB/ETD/NHEERL
Organs of the Immune System
Thymus: source of naive T cells

22. Bob Luebke
ITB/ETD/NHEERL
Fate of T Cells in the Thymus
Positive selection: optimal binding to self Ag prevents apoptosis
Negative selection: superoptimal binding to self Ag induces apoptosis

23. Bob Luebke
ITB/ETD/NHEERL
B cells: Tolerance to “Self”
Anergy: low expression of
IgM on surface; can’t bind Ag
Clonal ignorance: too few
copies of Ag in the periphery

24. Bob Luebke
ITB/ETD/NHEERL
Thymus size and architecture:
May be very sensitive to xenobiotics
Also sensitive to acute toxicity
Figure from IPCS: ENVIRONMENTAL HEALTH CRITERIA 180 Principles and
Methods for Assessing Direct Immunotoxicity Associated with Exposure to Chemicals

25. Bob Luebke
ITB/ETD/NHEERL
Organs of the Immune System
Spleen: Antigen trapping and presentation,
clonal expansion, cellular export

26. Bob Luebke
ITB/ETD/NHEERL
Organs of the Immune System
Lymph nodes: Antigen trapping and presentation,
clonal expansion, cellular export

27. Bob Luebke
ITB/ETD/NHEERL
Cells of the Immune System
Innate Immune System: Granulocytes
Neutrophil (“PMN”)
First responders
Phagocytosis and killing
of bacteria
Inflammation
Eosinophil
Allergy
Killing parasite larvae
Basophil
Circulating mast cells
Allergy/anaphylaxis

28. Bob Luebke
ITB/ETD/NHEERL
Cells of the Immune System
Innate Immune System: Granulocytes
Neutrophil (“PMN”)
First responders
Phagocytosis and killing
of bacteria
Inflammation

29. Bob Luebke
ITB/ETD/NHEERL
Cells of the Immune System
Innate Immune System: Monocytes
Monocyte/macrophage
Macrophage with ingested
asbestos fiber (encarta.msn.com)
Phagocytosis and killing of bacteria
Antigen processing
Inflammation
©Dennis Kunkel Microscopy,
Inc.

30. Bob Luebke
ITB/ETD/NHEERL
Cells of the Immune System
Adaptive Immune System: Lymphocytes
Activated B cell
Peripheral blood Activated T cell (SEM)
B cells: Mature into plasma cells, secrete antibody (IgM, IgG, IgA, IgE, IgD)
T cells: T helper - produce stimulatory and regulatory cytokines
T cells: T cytotoxic/suppressor – contact-dependent cytotoxicity,
regulation of immune response
NK cells: direct killing of cells (innate arm of IS)

31. Cell Mediated Immunity

32. T Lymphocytes
• Recognize Ag only with MHC proteins
• Produce Lymphokines (not antibodies)
• Cell Mediated Immunity

33. T-Cell Subpopulation
CD-4 CD-8
Help B-Cells produce Antibody Cytotoxicity Reactions
T-Cell

34. Cell-mediated immunity
• T cells can only recognize and
respond to processed fragments
of protein.
• T cells are suited for cell to cell
interaction and target body cells
infected by virus, bacteria and
abnormal or cancerous body cells

35. Cytotoxic T cells

36. Cell-mediated immunity: T-cells
• Activation of T cells—T cell receptors bind to
antigen presented by the antigen-MHC
complex.
• CD4 and CD8 proteins interact with antigen
and help maintain MHC-antigen coupling.
• Types of T-cells
– Helper T cells (CD4)
– Cytotoxic T cells (CD8)
– Memory T-cells

37. 05 Dec. 2007 Immunity.ppt 37

38. Antigen-presenting cells

39. Antigen-presenting cells

43. T-Cell Activation
“ Activation and clonal expansion of CD4 and CD8 Cells”
Goal:

44. T cell activation
T cells must accomplish a double recognition.
• They must recognize nonself (antigen) and self
(MHC protein of a body cell) (Antigen recognition) .
• Co-stimulation by binding to other proteins on
APC
• Cytokines (IL 1 and 2) are released by APC or
T cell following co-stimulation

45. Antigen recognition and co-
stimulation lead to activation.
Antigen binding without co-
stimulation leads to anergy in T and
B cells.

46. Class II MHC
Peptide
TCR
CD4
Specific Antigen Recognition

47. APC
B7
MHC II
CD24
CD28
TCR TCR
T-Cell

48. Activated T cell
• Activation leads to enlargement,
differentiation and proliferation of T
cells.
• T cells that are reproduced are clones
of originally activated T cell.
• Activation, differentiation and
proliferation occurs in secondary lymph
organs and tissue.
• Activation leads to release of

49. T-Cell Activation
Lymphocyte activation
(periarteriolar sheats) paracortical area

50. T Cell-mediated Immunity
Principal function-Response to
intracellular pathogens and cells
expressing foreign antigens
Recirculation-Naïve T cells circulate
between the blood stream and the
lymphatic system

51. Priming of T Cells
• Three types of effector T cells
– CD8 (TC)
– CD4 (TH1)
– CD4 (TH2)
• Each type
– Responds to different types of Ags
– Activated by different Ag presentation
– Has different effector function

52. T Cell Effector Types
• CD8
– Viruses and intracellular bacteria
– MHC I
– Cytotoxic effector cells
• CD4 TH1
– Bacteria and parasites in APCs
– MHC II
– Effectors activate macrophages, CTLs and induce B cells to
produce opsonins
• CD4 TH2
– Extracellular bacteria and toxin producers
– MHC II
– Activate B cells to produce multiple antibody classes

53. T- Helper Subsets
Different types of T- Helper
subsets
Th-1
• Hypersensityvity Reactions
• Produce IL2 and Gamma IFN
• Cell mediated cytotoxicity (virucidal activity)
Th-2
• Principal role in B-cell activation
• Produce IL-4 and IL-5 (no IL-2 or Gamma
IFN)
• Antibody mediated activity (bactericidal
activity)

54. APCs
• Dendritic cells
• Macrophages
• B cells
”
‫ثم‬ ‫الدنيا‬ ‫الحياة‬ ‫متاع‬ ‫متعناه‬ ‫كمن‬ ‫القيه‬ ‫فهو‬ ‫حسنا‬ ‫وعدا‬ ‫وعدناه‬ ‫أفمن‬
61 ‫القصص‬ “‫المحضرين‬ ‫من‬ ‫القيامة‬ ‫يوم‬ ‫هو‬

56. Dendritic Cells
• Antigen presentation is sole function
• Antigenic uptake is followed by migration
to lymph nodes
• Expression of MHC I, MHC II and B7
• Loses phagocytic property
• Secretes chemokines

57. Macrophages
• Involved in both innate and adaptive
immunity
• May destroy pathogens or present Ag to T
cells
• Expression of MHC I, MHC II and B7

58. B Cells
• Binds soluble antigens
• Constitutively expresses MHC II
• Induced to express B7

59. NK Cells
• 5% of lymphocytes
• Nonspecific cytotoxicity
• No TCR/CD3
• Not MHC restricted
• No memory

61. Immunity.ppt 61

62. Cell-mediated immunity
• T cells can only recognize and respond to
processed fragments of protein.
• T cells are suited for cell to cell interaction and
target body cells infected by virus, bacteria and
abnormal or cancerous body cells or cells that
are transplanted or infused.
• Antibodies can only inactivate an antigen and
NOT destroy it.
• Antibodies prepare an organism for destruction

63. T-Cell Activation
• Lymphokines produced by lymphocytes
• Cytokines produced by other cells
Autocrine Paracrine

64. HUMORAL IMMUNITY (Ab or AMI)
• Antigen + Macrophage + T cell + B cell
• Antibodies or Immunoglobulins
• SPECIFICITY!
• MEMORY
• (immunity: short, long, or no term)
cytokines

65. Antibodies are produced by antigen-activated B
lymphocytes and, in cattle, come in six isotypes
Fab = antigen binding = Fab
Fc = biological
function
IgM (m)
IgG1 (g1)
IgG2 (g2)
IgG3 (g3)
IgA (a)
IgE (e)
variable region
constant region
H H
L
L
(Fc-m)
© Jeanne L. Burton, Michigan State University
L = light chain
H + heavy chain

66. Antibodies

67. Functions
• Variable region (Fab) bind
specifically-neutralize, ppt
or agglutinate
**** antigen binding region
• Constant region (Fc) –
- activate effector cells or
complement
- opsonin end

68. Immunoglobulin classes
• IgD is attached to B-cell
plasma membrane
• IgM is released during
primary response
• IgG functions in late
primary and secondary
response
• IgA found in body
secretions
• IgE causes release of
histamine

69. Antibody Isotypes-5

70. Antibody defense: PLANe
• Precipitation
• Lysis: Complement fixation and activation
• Agglutination
• Neutralization
• Enhancing phagocytosis

71. Opsonization
• Free IgG binds Fc
receptors with low
affinity
• IgG bound to Ag,
binds to Fc receptors
with high affinity
• Cross-linking
receptors sends
signal

72. IgG:
IgG1 IgG2
• Principle Ab in serum
• 14 – 18 mg / ml
• IgG1: 11 mg/ml
• IgG2: 7 mg/ml
• fixes complement
• late response to Ag
IgG1 IgG2
• selective transfer (colostrum) 10 opsonin
• fetal / neonatal defense for
• toxin inactivation phagocytosis
• principal milk / colostrum Ig
(farm species)

73. IgM
IgE
• largest Ig
• pentamer
• serum (1-3 mg/ml)
• fixes complement
• 1st Ig produced
to Ag challenge!
• Binds to mast cells
basophils
• ACTIVATION
• RELEASE OF
- histamine - serotonin

74. The various Fc portions of antibody molecules have very different
biological functions, including pathogen blocking, complement
fixation, toxin neutralization, and opsonization of bacteria for
enhanced phagocytosis by neutrophils and macrophages
IgG1 = endotoxin
neutralization &
complement fixation
IgG2 = opsonization
& neutrophil
phagocytosis
IgM = blocking &
complement
fixation
serum
complement
© Jeanne L. Burton, Michigan State University

75. IgA
• 3 different forms in serum
• different form in secretion ( secretory piece)
• serum: 1-3 mg/ ml
• activates complement: serum (yes) milk (no)
Secretory piece
• local immunity and secretions
• prevents bacterial adherence
• maternal milk: very important
• primary Ig in colostrum (humans)!

77. Type Number of
ag binding
sites
Site of action Functions
IgG 2 •Blood
•Tissue fluid
•CAN CROSS
PLACENTA
•Increase
macrophage activity
•Antitoxins
•Agglutination
IgM 10 •Blood
•Tissue fluid
Agglutination
IgA 2 or 4 •Secretions (saliva,
tears, small intestine,
vaginal, prostate,
nasal, breast milk)
•Stop bacteria
adhering to host
cells
•Prevents bacteria
forming colonies on
mucous membranes
IgE 2 Tissues •Activate mast cells
 HISTAMINE
•Worm response

78. CYTOKINES / LYMPHOKINES
• Small polypeptide messengers
• very powerful in low doses
• multiple uses
• hormones
1. Interleukins
2. Interferon: viral
3. Colony Stimulating factors: GCFS
4. Tumor Necrosis Factor (TNF)
inflammation / cell movement / traffic

79. OTHER IMMUNE FACTORS
• Complement: 9 specific serum proteins
- interaction of components provide
numerous biological events
• Lactoferrin: Iron binding protein
*** competes with bacteria for iron
• Lactoperoxidase ( LP/ SCN- / H2o2 syst.)
** antioxidant / oxygen radicals

82. Cell Adhesion Molecules
• Selectins
• Mucins
• Integrins
• Immunoglobulin superfamily

83. Torloni MD
Adhesion Molecules
LFA1
LFA3
APC
T-Cell
Endothelial Cell

84. B7
CD28
CD4
TCR
IL1
T-Cell
IL2
IL2
Clonal Expansion
IL2
IL2

85. Macrophage
CD4 Cell
IL1
CD4
CD4
MHC II
IL2
receptors
IL2
IL2
B-Cell
IL2
IL4
IL5
IL6 Prolifereation
Plasma Cell Memory B Cell
1- CD4 Cells are stimulated by contact with
antigen
2- T-Cell finds B-Cell with that specific
Antigen
2- T-Cell causes that specific B-Cell to
expand

86. Triggering of IL1
B7
CD28
CD4
TCR
IL1
IL2
IL2

87. Stimulation of B-Cells
B-Cell
T-Cell
LFA1
LFA3
No antigen specificity
1- Binding
2- Release

88. T-Cell
LFA1
LFA3
1- Binding
B-Cell
2- Antigen specificity
B-Cell
Prolifereation
Plasma Cell
Memory Cell
3- B-Cell Proliferation

89. First exposure Re-exposure
Time

90. Activation of Cytotoxic T-Cells
• Recognize Ag in conjunction with MHC-1
• All host cells express class I antigens
• Serve as 1st line of defense against changed “self” antigens
- Virus infected cells
- Tumor cells

91. TNF-
T-Cells with same specificity

92. IgG, IgM, IgA, IgE, IgD
B Cell
T Cell
TdTH
NK Cell
Mast Cell
T8 (cytotoxic)
T8 (suppressor)
MIF ,MAF
CF
IL-1
IL-1
BCDF,
BCGF
IL-1
IL-2
IL-2
Cytokines
Effect

93. 1) TNF- produced
2) TNF- binds to
receptor
3) Recptor and TNF-

are internalized

94. 4) TNF-  + receptor
are degraded
5) Endonuclease is activated
outside cell
cytoplasm

95. 6)Endonuclease cuts DNA
7) Fragmented DNA appears in cytoplasm
8) Cell function is disrupted
Activation of lysosymes &
production of free radicals
also occurs.

98. Role of Cytokines : Interleukin-1
Macrophage
Monocyte
LPS
Toxins
Foreign material
IL-2 production
IL2 receptor production
B-Cell Proliferation
NK Cell Activity
Acute phase reactants
Fever
PMN demargination
PMN degranulation
Prostaglandin release (fibroblasts & monocytes)
Muscle wasting
Depression
Sleep disturbance
Loss of appetite
Chronic Effects:
Acute Effects:

99. Role of Cytokines : Interleukin-2
• Detected 2 - 6 hrs after after antigen stimulation
• Short half life
• Amplifies Cellular Immune response locally
• Stimulates B-Cell proliferation
• Induces IgG2 production
• activity of NK cells
• Induces LAK cell activity*
*Kills cells resistant to NK cell - independent of MHC

100. Role of Cytokines : Interleukin-3
• “ Hemopoiteic growth factor”
- Myeloids
- Megakariocytic
- Erythrocytic
- T- Cell
- B- Cell
Stimulates Proliferation of Hematopoietic Precursors:
Half Life = Less than 30 minutes
permeability
phagocytosis

101. SEM Picture of a Mast Cell
TEM of a Mast Cell

102. A
Antigens from plasma
bind to pre-formed IgE
attached to mast cells
B
Antigen binding causes
activation of histamine
release mechanism from
mast cells.
C
Histamine is released
from mast cells and
causes increase in
vascular permeability

103. Pluripotential Stem Cell
Committed Stem Cells
CFU-Meg
Lymphocytes
B T
CFU-Ba CFU-Eo CFU-E CFU-B CFU-T
BFU-E
CFU-Ms
CFU-GM
CFU-G CFU-M
IL3
IL3

104. Role of Cytokines : Interleukin-4
• Produced by T-Helper cells
• Activation / Proliferation of B cells previously stimulated by antigen
• Enhances expression of MHC II molecules
• Induces production of CD-23 on B Cells surface
• Induces IgG 1 synthesis
• Essential in IgE formation
• Role in converting other cytokines
• Similar to IL-13
“ promotes resting B-Cell expansion”
IL-4

105. B-Cell
Prolifereation
Plasma Cell
Memory Cell
IL-5
Th-Cell
Role of Cytokines : Interleukin- 5
IL5 induces production of IGM and class
switching to IGA
IL-6