In this lecture, we'll focus on the
Principles of Cytokine-Receptor Interactions and Signal Transduction.
The word cytokines in Greek is cyto means cells,
and kinos means movement.
Cytokines are small proteins released by cells of the immune system for
intercellular communication in the generation of an immune response.
Traditional hormones are secreted by glands into
the bloodstream to act on distant cells in the so-called endocrine fashion.
Cytokines differ from classical hormones in that they are produced by
a number of tissues or cell types rather than by specialized glands.
They generally act locally in paracrine acting on
nearby cells or autocrine manner acting on cells that secrete them.
Since cytokines play fundamental roles in the immune response,
I'll first briefly introduce our immune system.
There are two arms to our human immune system.
Innate immunity is what we're born with.
It is highly conserved.
It is our first-line host defense against
an infection through pattern recognition of conserved
the molecules associated with microorganisms,
the microbial non-self by our pattern recognition receptors.
Innate immunity is linked to adaptive immunity
through the activation of professional antigen-presenting cells.
Adaptive immunity elicits specific immune responses against
the specific antigens through the activation of T and B lymphocytes.
It is critical to note that adaptive immunity also feeds
back to innate immunity through both humoral and cellular responses.
Numerous studies have now indicated that this dysregulation of
either innate or adaptive immunity can lead to
autoimmune inflammatory diseases and also contribute to tumorigenesis.