Transcript Cells and tissues of the immune system

Cells and tissues of the immune system
Lisbeth N. Fink
Nutritional Immunology Group – CBS - DTU
Protecting borders to the outside world
Challenges
1) Discrimination between self and non-self
–
–
–
–
–
bacteria
fungi
vira
parasites
(transplants)
2) Evolution
3) Dealing with non-pathogenic factors
First lines of defense
Anatomical Physiological
Skin
Mucosae
Ciliae
Temperature
pH
Lysozyme
Lymphoid organs and lymphatics
Second line of defense: Humoral factors
Humor = liquid
(From greek, 4 humors controlling health and mood: blood, phlegm, yellow and black bile)
Antibodies – specific
pathogen recognition
Complement system
– non-specific recognition
Reactive oxygen species
(ROS) – bactericidal activity
Inflammation – recruitment of cells
Third line of defense: Immune cells
Haematopoieisis
Red blood cells
Leukocytes/
White blood cells
Lymphocytes
Adaptive/Specific Innate/Non-specific
Characteristics of the two parts
Adaptive/Specific
Innate/Non-specific
T cells
B cells
Antibodies
Memory
MHC - HLA
Diversity
Somatic hypermutation
Polymorphism
Granulocytes
Monocytes
Macrophages
Dendritic cells
NK cells
NK T cells
Complement
Pattern recognition
Characteristics of the two parts
Adaptive/Specific
Innate/Non-specific
T cells
B cells APC
Antibodies
Memory
MHC - HLA
Diversity
Somatic hypermutation
Polymorphism
Granulocytes APC
Monocytes APC
Macrophages APC
Dendritic cells APC
NK cells
NK T cells
Complement
Pattern recognition
Antigen uptake - phagocytosis
Phagocytic cells:
Granulocytes
Monocytes
Macrophages
Dendritic cells
Antigen uptake
Preference for ”opsonized” bacteria
MHC I and II
Tc
TH
T cells
Recognizes MHC I
on all cells
Recognizes MHC II
on APC
Kills:
Infected cells
Tumour cells
Helps:
B-cells
T cells
Macrophages
T cell receptor
Antigen presentation
3. Signal
Cytokines ↔ Cytokine receptors
Activation + Proliferation + Help or Killing
B cells – plasma cells
T cell help for B cell activation
B cells – memory cells
Meeting places (B – T – APC)
What about ’endogenous’ challenges?
Cancer cells – tumor antigens
Immune reactions within self-tissues: autoimmunity
Discontinuation of immune responses
…and reactions to harmless environmental factors:
allergy (to food, pollen, fur etc.)
Immunity vs. Tolerance