4 Classes of Pathogens The Immune System Protects Us Against?
Bacteria
Viruses
Fungi
Parasites (protozoa + worms)
What are the Two Branches of The Immune System
Innate = first line of defence Adaptive = comes into play when innate defences are breached
Compare Recognition Mechanism of Innate + Adaptive Immunity
Innate = fast (within hours), fixed, limited number of specificities, constant during response
Adaptive = slow (within days), variable, numerous highly selective specificities, improve during the response.
What do Phagocytes do?
Reduce the invaders genes from active polymers to inactive monomers - both innate or adaptive can elicit phagocytic cells
Adhesion, Ingestion, Digestion
Adaptive Immune Response: Specificity
Specific for distinct Antigens
Adaptive Immune Response: Antigenic Determinant/Epitope
The portion of the antigen that is recognized
Adaptive Immune Response: Diversity
Can recognize 10*16 distinct antigens –> using antibodies/T cell receptors
Adaptive Immune Response: Memory
Exposure to Ag increases is ability to respond to the same or closely related Ag again.
Second Response =
faster, larger, qualitatively different.
Adaptive Immune Response: Self Limited
These responses are transient and tightly regulated + controlled
Adaptive Immune Response: Self/Non-Self Discrimination
ability to tell self from non-self
Tolerance
Immunological unresponsiveness to self is termed
What are the 4 Postulates of the Clonal Selection Hypothesis?
- Each lymphocyte bears a single type of receptor with a unique specificity.
- Binding of a foreagn molecule to the receptor site of a lymphocyte, if affinity is high enough, leads to activation of lymphocyte.
- The differentiated effector cells derived from the activated lymphocyte will have receptors identical to those of the parent cell from which that lymphocyte was derived.
- Lymphocytes bearing receptors for self molecules are deleted at an early stage in lymphoid cell development and are absent from the repertoire of mature lymphocytes.
Humoral Immune Response
Mediated by antibodies (Ab)
Produced by bone marrow derived or B lymphocytes
Cell Mediated Immune Rsponse
Mediated by thymus-derived or T lymph
Pluripotent Stem Cells
Myeloid progenitor
monocytes (macrophages, dendritic cells)
granulocytes (PMN’s)
mast cells
Common lymphoid progenitor
B Lymphocytes
T Lymphocytes
NK cells
What type of WBC is most abundant + what type of immune response is it important for?
Neutrophils - 45-75%; innate immunity: one of 2 phagocytic cells in the body
What WBC is very important to Adaptive Immunity?
Lymphocytes
Define: Macrophage, what role do they play?
Myeloid Progenitor
Macrophage is the mature form of a monocyte. INNATE IMMUNITY
The monocyte migrates out of the blood and into the tissue where is becomes the resident immune molecule.
A Mcrophage in brain, lung and liver will look slightly different bc they receive slightly different signals from the tissue itself.
Second type of Phagocytic Cell in the body.
They also activate T cells and an adaptive immune response if they cannot control the pathogen.
Liver – Kupfer cells (macrophages)
Kidney – Mesengial macrophages
Lung – Alveolar Macrophages
Brain – Microglia.