Intro to Immunity Flashcards
Name the main phagocytes involved in phagocytosis
Although most cells are capable, neutrophils, macrophages, dendritic
cells excel in phagocytosis
These cells can contain, kill and process microorganisms for antigen presentation which is vital in innate immunity as this initiates adaptive immunity
What occurs at lymph nodes?
Lymph enters via afferent lymphatic vessels which filters through multiple layers of antigen presenting cells (APCs), T and B cells
Lymph exits via the efferent lymphatic vessel
Where are immune cells found normally in the body?
Immune cells are normally distributed throughout the body
How does the immune system detect pathogens?
Immune system detects ‘danger’through a series of pathogen associated molecular patterns (PAMPs) or Damage associated molecular pattern
(DAMPs) molecules
Work with both positive and negative signals derived from tissues
What are antigens?
Usually proteins or carbohydrates attached / secreted by microbes and infected cells
Where in the lymphatic system are lymph nodes found?
At regular intervals along the lymph vessels, there are lymph nodes
What are antibodies?
Glycoproteins formed by B cells and plasma cells that bind specifically with high affinity ‘non-self’ antigens
What is the benefit of lymph nodes to the immune system?
Dense concentration of immune cells provides the ideal environment for immune responses. Nodes are common sites for interactions of infections and immune systems
What are the functions of the innate immune system?
- Prevention, control and elimination of infection
- Removal of damaged cells and initiation of tissue repair
- Activating adaptive immune response
- Influence type of adaptive response that develops
What is phagocytosis?
Process by which cells internalise solid matter including microbial
pathogens
Describe the structure of PAMPs
small molecular motifs consevred within a class of microbes which can include: - glycans - lipopolysaccharides - bacterial flagellin - lipoteichoic acid - peptidoglycan - nucleic acid variants e.g. dsRNA
What biological molecules are involved in innate immunity?
Epithelial barriers
- prevent microbe entry
(e. g. skin, GI tract, respiratory tract)
Mucosal secretions
- flushing action and antimicrobial properties
Cells
- Resident in tissues (e.g. mast cells)
- circulating in body (neutrophils)
Proteins - circulating in blood (e.g. complements)
Cytokines
- locally produced by infected cells (interferons)
What are the main events during inflammation?
- increased blood supply to affected area
- increased permeability to vascalature
- migration of WBCs out of capillaries into affected
tissues
How do antibodies produce an immune response?
They can neutralise targets or recruit other components to kill tragets by Fc mediated effector functions
We have the potential to make antibodies against any foreign targets
Describe DAMPs structure
Molecules released by stressed cells undergoing necrosis
They vary depending on cell type and injured tissue
Some endogenous danger signals are proteins
- (heat shock proteins or cytokines)
Non protein DAMPs include:
- ATP
- heparin
- DNA