Infection and Immunity Flashcards
What is immunity?
Resistance to disease
What is the importance of immunity?
Developing control strategies
What is immunopathology?
The causes of diseases
What are all immune cells derived from?
Pluripotent hematopoietic stem cells
What do pluripotent hematopoietic stem cells divide into?
Common lymphoid progenitor and common myeloid progenitor
What do common lymphoid progenitor cells divide into?
B cells
T cells
Killer cells
Where do all common lymphoid progenitor cells reside?
In the lymph nodes
Where do B cells mature?
In bone marrow
Where do T cells mature?
In the thyroid
What do common myeloid progenitor cells divide into?
Neutrophils
Eosinophils
Basophils
Is innate immunity antigen dependent?
No
Does innate immunity have a time lag?
No
Is innate immunity specific?
Relatively non-specific
Does innate immunity have immunological memory?
No
What are the three main innate immunity barriers?
Skin
Gut villi
Lung cilia
What are innate immunity soluble factors?
Protein and non-protein secretions
What cells are part of innate immunity?
Phagocytes
Mast cells
Basophils
Natural killer cells
Is adaptive immunity antigen dependent?
Yes
Does adaptive immunity have a time lag?
Yes
Is adaptive immunity antigen specific?
Yes
How does adaptive immunity develop?
From memory of previous infection
Are there any adaptive immunity barriers?
No
What are adaptive immunity soluble factors?
Immunoglobulins = antibodies
What are adaptive immunity cells?
B and T lymphocytes
What is an antigen?
Foreign marcomolecules that induce specific immunity
Name four types of molecules that act as antigens.
Peptides
Carbohydrates
Lipids
Nucleic acids
When do phagocytes develop into macrophages?
When they enter tissue
When do phagocytes develop into neutrophils?
When they are in the blood
What do the receptors on phagocytes recognise?
Specific components of microorganisms
- Lipopolysaccharides
- Mannose and other sugar residues
- Teichoic acids
- N-formyl peptides
- Bacteria heat shock proteins
What microorganisms have lipopolysaccharides on their outer membrane?
Gram negative bacteria
What microorganisms have teichoic acids on their outer membrane?
Gram positive bacteria
What are phagocytes directed to the site of infection by?
Chemical messengers released by macrophages present in the infected tissue
What type of bacteria do phagocytes kill?
Oxygen independent microorganisms
How do phagocytes kill oxygen independent microorganisms?
- Phagosome containing the bacteria fuses with a lysosome containing hydrolytic enzymes
- The phagocytes oxygen uptake is increased and causes respiratory burst
What do enzymes in macrophages produce?
Reactive oxygen species
What does activation of the phagocyte lead to?
Induction of nitric oxide synthase which produces high levels of nitric oxide
Where are mast cells found?
In tissues
Where are basophils found?
In the blood
What do mast cells and basophils contain that stimulates inflammation?
Cytoplasmic granules
What is degranulation induced by?
Traume
Toxins
Proteases and cationic proteins released from other immune cells
Antibodies
What does degranulation release?
Histamines
Anticoagulants
Leukotrienes
Cytokines
What do natural killer cells contain?
Toxin chemicals contained in granules
What do natural killer cells do?
Kill infected and malignant cells
Contact infected cells
What do natural killer cells release?
Granules which punch holes in infected cell membranes
High levels of cytokines
What B cells produce?
Antibodies and immunoglobulins
What is humoral immunity?
Antibodies released by B cells bind to microorganisms or toxins and neutralise them directly or tag them for other parts of the immune system to destroy
What are the two main types of T cells?
T helper cells
Cytotoxic T cells
What are the two main forms of T helper cells?
T helper 1
T helper 2
What do cytotoxic T cells express?
CD8
How do cytotoxic T cells interact with target cells?
- Recognise antigen on target cell
- Lethal hit is delivered by T cells using agents
- T cell detaches from the target cell
- The target cell dies by apoptosis
What agents are used by cytotoxic T cells to give target cells a lethal hit?
Perforin
Granzyme B
T cells are the _________ of the immune response
Coordinators
What do T cells secrete?
Cytokines
What are cytokines?
Signalling molecules which aid cell to cell communication and stimulate inflammation
What type of immune cell recognises antigens?
T cells
What do histamines do?
Increase permeability of capillaries to white blood cells
What do anticoagulants do?
Reduce the risk of blood clots
What are leukotrienes?
Inflammatory chemicals
- Tighten airway muscles
- Produce excess mucus
