Introduction to the Immune System Flashcards
What are the main functions of the immune system?
- Recognize/destroy pathogens
- Recognize/clear effete/damaged self components
- Initiate tissue/wound healing processes
- Exhibit “tolerance” to innocuous material including self
What can the CBC, serum markers, and serum antibodies tell us about immunity?
The presence of a current or previous infection
What are some ways that the immune system can be harnessed to help patients?
- Vaccines –> Prevent infection
- Cancer Immunotherapies –> Treat cancer
What are some clinical issues that the immune system can cause in response to certain treatments?
- Reactions due to blood transfusions
- Graft vs Host or Host vs Graft diseases
Immunodeficiency
Immune defects which result in susceptibility to recurrent infection
Can be congenital or acquired
Examples of causes: Malnutrition, chemotherapy, and HIV-AIDS
Immune hypersensitivity
Excessive immune reaction that leads to tissue damage
Examples: Allergies, chronic infections, contact sensitivities
Autoimmunity
Loss of tolerance leads to reaction against healthy self
Examples: Type 1 diabetes and rheumatoid arthritis
Immune Malignancy
Cancers of the immune system
Examples: leukemias and lymphomas
Innate Immunity (Basics)
- Provides immediate protection from infection
- Does not change in response to reinfection
- Initiates processes that lead to activation of adaptive immunity
Adaptive/Acquired Immunity (Basics)
- Adapts to a variety of non-self components
- Responses upon reinfection are faster, better, and stronger
- Generates proteins and cells that enhance innate immune function
Main components of blood
55% is plasma (93% of which is water and 7% are proteins by weight)
45% consists of cells, of which 1.6% are leukocytes
Neutrophils
- Innate immune cells
- Makes up ~50% of circulating WBCs
- Migratory and phagocytic
Which cells are granulocytes?
Basophils
Eosinophils
Neutrophil
Mast Cellls
- Innate immune cells
- Resident in connective tissue (includes epithelial linings of the lung and GI tract)
- Upon activation –> Release inflammatory mediators from their intracellular granules
Are lymphocytes part of the innate or adaptive immunity?
Cells of the adaptive immunity are known as lymphocytes, and include B-cells and T-Cells
What are effector cells?
Activated lymphocytes (T-Cells and B-Cells)
What are do activated B-Cells do?
Produce soluble anti-bodies
What cells are a part of the adaptive immunity?
B-Cells and T-Cells
What cells are part of the innate immunity?
Basophils
Eosinophils
Neutrophils
Macrophages
Natural killer cells
Mast cells
Dendritic cells
Which WBCs are fully differentiated before leaving the bone marrow?
Basophils
Eosinophils
Neutrophils
Naive B Cells
Which WBCs differentiate from blood precursors after they enter tissue?
Mast cells
Macrophages
Dendritic cells
Where do immature T cells complete maturation?
In the thymus where they then become fully differentiated naive T cells before reentering the blood
Are naive B and T cells activated?
No. While they are differentiated, they need to be activated before B-Cells –> Plasma Cells and T-Cells –> Effector T-Cells
What do hematopoetic stem cells (HSC) first differentiate into?
HSC are pleuripotent and self-renewing cells that can differentiate into:
- Common lymphoid progenitor
- Myeloid progenitor
- Erythroid progenitor
What can erythroid progenitor cells differentiate into?
Erythroblasts which ultimately become erythrocytes
or
Megakaryocytes which produce platelets
What can myeloid progenitor cells differentiate into?
The granulocytes (Basophils, Eosinophils, or Neutrophils)
or
The tissue resident cells (Macrophages, mast cells, or dendritic cells)
What do monocytes differentiate into?
Macrophages
What line of cells do monocytes come from?
They come from the myeloid line and come from myeloid progenitor cells
What can common lymphoid progenitor cells differentiate into?
B-Cells
T-Cells
NK-Cells
How long does the adaptive immunity take to activate?
Days to weeks
Antibody
- Extremely high binding specificity
- Can target anything (protein, carbohydrate, nucleic acid, small molecules, drugs, etc.)
Antigen
Any molecule that a antibody (or T-cell receptor) binds to
Epitope
The part of an antigen molecule to which an antibody attaches itself
Plasma cell
Activated Naive B Cells that produce antibodies
Memory B Cells
Some activated B Cells become long lived memory B cells that circulate in the body which upon re exposure to the same infection produce a much faster and more robust response
Primary response
Adaptive immunity is activated for the first time
Secondary response
Adaptive immunity has memory B cells for that infection and can thus respond more quickly and with a stronger response
Memory T cell
A small portion of long-lived T cells (called memory T cells) remains for rapid response upon pathogen re-exposure
Helper T cell
- Type of activated T cell
- Interact with macrophages that have eaten a particular pathogen
- Induce killing activities of these macrophages
Cytotoxic T cell
- Type of activated T cell
- When engaging with the surface antigen of a viral infected cell –> kills infected cell
Cell mediated immunity
Activities of effector T cells
Humoral immunity
Activities of antibodies made by Plasma cells
Tolerance
Adaptive immunity avoiding reacting to self cells
