1. Principles of Immunology Cytokines

2. Cytokines (Greek cyto-, cell; and -kinos, movement) are small cell-signaling protein molecules that are secreted by the cells of the nervous system and by numerous cells of the immune system and are a category of signaling molecules used extensively in intercellular communication. Cytokines can be classified as proteins, peptides, or glycoproteins; the term "cytokine" encompasses a large and diverse family of regulators produced throughout the body by cells of diverse embryological origin.

3. Word List Autocrine Endocrine Immunoglobulin superfamily Interleukin
Paracrine
Pleiotropy
Stem cell factor

4. Chemical Structure Low molecular weight proteins, <30kD
High affinity for receptors
Active in picomole amounts

5. Chain of Cytokine Action
Stimulus>Cytokine-producing cell>
Cytokine>Receptor>Target cell>
Biological effect(s)

7. Names of Cytokines Source Function Intercellular action
e.g.,Lymphokines(secreted by lymphocyte)
Function
e.g.,Chemokines(low molecular weight)
Intercellular action
e.g., Interleukins(secreted by leukocyte)

8. Action of Cytokines Autocrine Paracrine Endocrine
Affects the generating cell (self)
Paracrine
Affects cells in the immediate vicinity
Endocrine
Affects cells remote from the secreting cell

10. Action of Cytokines Pleiotropy Redundancy Synergy Antagonism Cascading
Affects multiple cell types
Redundancy
Multiple cytokines affects cells of the same type
Synergy
Cytokines acting in concert on the same cell
Antagonism
Competing actions
Cascading
Cytokines acting sequentially

12. Redundancy

13. Cytokine-generating Cells
Innate immunity
Macrophages
Endothelial cells
Fibroblasts
Adaptive immunity
T lymphocytes
NK cells

15. Cytokine Receptors Ig super family Class I- hematopoietin
Class II-interferon
TNF
Chemokine

20. Cytokine Receptors Multimeric receptors
Common signal-transducing subunits
Unique high affinity subunits
High affinity subunits associated with activation of target cell

21. Signal Transduction Initiated by cytokine binding
Phosphorylation of tyrosine
Binding of STAT(Signal transducers and activators of transcription)
Translocation of STAT to cell’s DNA
Transcription of specific target genes

23. Role of Cytokines in Hematopoiesis
SCF (Stem cell factor)
GM-CSF (Granulocyte-macrophage colony-stimulating factor)
IL-3 (Interleukin 3)
IL-5 (Interleukin 5)
IL-7 (Interleukin 7)
IL-11(Interleukin 11)

25. Cytokines in the Immune Response
Innate immune response
IL 1-(Macrophage)-fever, capillary effects
IL 6-(Macrophage)-adaptive immunity via B cells
IL 12(Macrophage)-adaptive immunity via T helper cells
TNF (Macrophage)-capillary effects, activates neutrophils
IFN alpha (Macrophage)-multiple effects
IFN beta (Fibroblasts)-multiple effects

26. Cytokines in the Immune Response
Adaptive immune response
IL 2-(T cells)-multiple effects)
IL 4-(T cells & mast cells)-T cell differentiation, IgE production
TGF beta –(T cells, macrophages)-inhibits adaptive immune response
IFN gamma-(T cells, NK cells)-Macrophage activation

28. Subsets of T helper Cells
IgG production/Complement fixation
Macrophage activation
DTH
CTL production
T helper 2
IgE production
Eosinophils

30. Cytokine antagonism and viral diseases
Using cytokines therapeutically