Lecture 4 Flashcards
Examples of Immune Over-reaction
Autoimmune problems (Lupus, Type 1 diabetes) and Allergic reaction (Food sensitivities, eczema)
Examples of Immune Under-reaction
Cancer and Infection (Bacteria, Mold/fungus)
What the 2 forms of Immunity?
Innate and adaptive immunity
Traits of Innate Immunity
Fast, general, no diversity or specificity, no memory, first line of defence
Traits of Adaptive Immunity
Slower, specific and specialized, diverse, memory, offers selective and precise protection
Microbiology behind innate immunity
Phagocytes, dendritic cells, complement, and NK cells
Microbiology behind adaptive immunity
B lymphocytes which form antibodies, T lymphocytes and Effector T cells
Types of Innate Barriers
Anatomic and Physiologic barriers
Anatomic barriers
Skin and Mucous membranes
Physiologic barriers
Temperature, Gastric pH, Enzymes, Normal flora (good bacteria)
Innate cells
Neutrophils, Macrophages, Natural Killer cells
Neutrophils
Neutrophils are a type of white blood cell that help heals damaged tissues and resolves infections
Marcrophages
Recognize pathogens via Fc and complement receptors;
Phagocytose pathogens
Natural Killer Cells
Seek out abnormal cells (cancer or infected with virus) and kill them
Phagocytes
Cells that have the ability to ingest, and possibly digest, foreign particles, such as bacteria, carbon, dust, or dye
Innate Proteins
Acute phase reactants and complement
Acute phase reactants
Serum concentrations increase or decrease by at least 25% during inflammatory states (examples, ESR, CRP, Ferritin)
Complement
Produced by a predecessor protein or in response to the presence of foreign material in the body and that triggers or participates in a complement reaction (enhances the ability of antibodies)
Adaptive Immunity cells
Antigen presenting cells, lymphocytes including B-cells and T-cells
Types of T-cells
CD4 and CD8
Types of adaptive immunity reactions
Humoral and cell mediated reactions
Humoral reactions produce…
Antibodies (b-cells); extracellular protection
Cell mediated reactions produce…
CD8 T-Lymphocytes
Antibodies
My cells; produced by B-cells in response to foreign antigens (diverse and specific to the antigen they are fighting)
Antigen
Not my cells; A substance recognized as foreign matter and will be bound by antibodies or T-cell receptors
B-cells
Each B-cell produces one Ab specific against one antigen before exposure to the antigen
What surface Ig were found on the B-cells?
IgD and IgM
How many memory B-cells are produced?
One
True or false: Each T-cell produces a T-cell receptor that recognizes one specific antigen after exposure to the antigen
False; The T-cell receptor is produced before exposure
CD8 T-cells
Cytotoxic T-cells which kill cells containing foreign antigens (all or nothing; a very aggressive reaction)
CD4 T-cells
T-helper cells; Promote the various responses of the adaptive immune system
MHC class 1 molecule
Cell surface recognition elements are expressed on virtually all somatic cells (binds with CD8 cells for cell death of the target cell)
Professional Ag-presenting cells present antigens to…
Macrophages, Dendritic cells, B-cells, MHC Class 2, and CD4 T-cells
CD4 Th1 cell
Promotes cell mediated immunity
CD4 Th2 cell
Promotes humoral immunity
How are Immune responses initiated?
Lymphocytes’ recognition of antigens
How is the immune response regulated?
Once the immune system is on it must be turned off. This done with many negative feedback loops and T-regulatory cells
Major Histocompatibility complex (MHC)
Most Polymorphic genes in the human genome. One set of alleles from each parent encodes both alpha and beta chains. These create 4 MHC from each locus
Thymus
Where CD4 and CD8 T-cells mature (negative and positive selection occur); We have a full Thymus when we are born (constantly making these cells) and deteriorates as we age (weaker immunity)
Positive Selection
Targeting the desired cell population with an antibody specific to a cell surface marker (MHC)
Negative Selection
Select against self antigens
Toll-Like Receptors
Expressed in endosomes/surface based on
where they will encounter targets (expose any danger to the cell)
Where is the genetic coding region for Class 1 and Class 2 MHC molecules
Chromosome 6
Another name for MHC genes
Human Leukocyte Antigen (HLA genes)
Cytokines
Small proteins secreted by many cells (within or outside of the immune system) that mediate many of the functions of other cells
Types of cytokines
Autocrine, paracrine, endocrine
One cytokine having multiple effects makes it…
Pleotropic
Different cytokines having the same effect make it…
Redundant
Cells in the circulating system
Cells in the peripheral blood and lymph (2% of cells)
Cells in the Organ System
Central lymphoid organs and Peripheral lymphoid organs (98% of cells)
What central lymphoid organ is a site for B-cell maturation
Bone marrow
What peripheral lymphoid organ is a site for filtering antigens?
Lymph nodes
What peripheral lymphoid organ white pulp is a site for filtering antigens in the blood?
Spleen
What peripheral lymphoid organ is a site for surveillance of antigens in the gut?
Mucosal associated lymphoid tissue
