Overview of the Immune System The bottom line: You are one bad monkey!
A closer look at general (Innate) Immune Response Skin Mucous Membranes Mucus, Fluids Cillia, hairs Inflammation Fever! Serum Proteins: Complement System. Infection - cell lysis Interferons Natural Killer Cells (NK) Cells: Apoptosis, general fighters against Cancer and Viruses
Phagocytosis: A major player in Immunity (General and Specific) Phagocytes…
Meet the Leukocytes Neutrophils Monocytes/ Macrophages Eosinophils Basophils
Where can we find these cells and proteins?
Where else can we find these cells?
Inflammation: a General Immune Response Chemokines Vasodilation pre/vascoconstriction post Histamine (from mast cells in connective tissue) increase capillary permiability Chemokines attact WBC (Neutrophils then Monocytes) = phagocytosis When antigens are “mopped up” and clot has stopped bleeding, inflamation dies down. Fever often associated with inflammation:
An overview of Specific Immunity: Four Characteristics/Attributes of Immunity Specificity Diversity Memory (Effective Response) Capacity to distinguish self from non-self Two types of immunity Humoral: Cellular:
Specific Immune Response: Mediated by Lymphocytes
Lymphocyte development
Four Characteristics/Attributes of Immunity Specificity: Each Lymphocyte is specific for a specific antigen Diversity Memory Capacity to distinguish self from non-self
An Example of Specificity: A bacteria has multiple antigens (epitopes)
A VIRUS HAS MUTLIPLE EPITOPES AS WELL!
Lymphocyte Receptor Diversity 1 million 10 million
Four Characteristics/Attributes of Immunity Specificity Diversity: Your immune system can respond to millions of antigens Memory (Effective Response) Capacity to distinguish self from non-self
Lymphocytes are Diverse Why: receptors (B & T Cell) are polymorphic proteins based on a similar structure which are translated from polymorphic, recombined genes. This occurs during lymphocyte development. These receptors hook up with other diverse, specific proteins found in other cells called MHC molecules These other proteins arise from Multi Histonecompatibility Complex (MHC) genes (these genes are in your cells, and produce proteins as needed)
How does this specificity arise? Lymphocytes (T cells) become activated for an antigen when they interact with infected cells or with macrophages or dedritic cells. This specificity is made possible by: Class I MHC Class II MHC
T-cell + MHC = Specificity
A closer look at T-cells
Lymphocytes: T cells and B cells Antibodies Macrophages Killer T-cells Activate B-cells to make antibodies Activate and recruit other immune cells during infection CD4 Helper T-cells Images by The Museum of Science and Industry, Chicago and The Chedd-Angier Production Company, Watertown, MA.
Four Characteristics/Attributes of Immunity Specificity Diversity Memory (Effective Response) Capacity to distinguish self from non-self
Clonal Selection: Antigen-driven cloning of lymphocytes DPL Short life (effective) Long life (memory)
In other words… Each antigen, by binding to specific receptors, selectively activates a tiny fraction of cells from the body’s diverse pool of lymphocytes: this relatively small number of selected cells gives rise to clones of 1000s of cells, all specific for -- and dedicated to -- eliminating that antigen.
One more look at Immune Memory Exposure 2 Exposure 1 …This is the principle behind vaccinations
Four Characteristics/Attributes of Immunity Specificity Diversity Memory (Effective Response) Capacity to distinguish self from non-self
Acquired Immunity: An Overview
Acquired Immunity: An Overview
Acquired Immunity: An Overview
Helper T-Cells: A closer look
Killer T-cells: A closer Look
Humoral Immunity 1: Activation of Helper T cells APC
Humoral Immunity 2: T cells activate B cells
Humoral Immunity 3: Clonal Selection, and Secretion of Antibodies 2000 Ab/second!
Immunoglobins: Globular Proteins secreted by Plasma B-cells Neutralization, agglutination Help with MAC Confers immunity to fetus, Promotes Neutralization, agglutination General defense, found in mucous membranes Promotes histamine release, Allergic response May help with B cell differentiation and clonal selection
How do Antibodies Work? Membrane Attack Complex
Blood Groups: An application of Humoral Immunity
Allergic Response