Immunology Flashcards
Variolation definition?
Exposure of an individual to the contents of dried small pox pustules from an infected patient
Causes for the emergence of new infectious diseases?
Global Village-increased mobility
Population growth- proximity, sanitation
Changes in human behaviour
Changes in dynamics of other infections- increased TB prevalance has lead to more TB cases
Loss of natural habitat- from rainforests
Interactions of pathogens with humans- resistance
3 barriers to infection?
Skin
Mucous
Commensal bacteria
How is skin a barrier to infection?
Physical barrier
Physiological factors (low pH)
Sebaceous glands secrete hydrophobic oils
Lysozomes
How is mucous a barrier to infection?
Secretory IgA
Enzymes
Cilia trap pathogens and remove mucous
How is commensal bacteria a barrier to infection?
Compete with pathogens for scarce resources
- Produce anti-microbial short chain fatty acids
- Compete for essential nutrients
- Reduction in pH of bowel
- Synthesis of vits K
Briefly describe the innate immune response in its response time and type of response?
Rapid response (0-4 hours) General response
What cells does the innate response involve?
Mast cells
NK cells
Phagocytes
Complement
What are the cells in the immune response responsible for?
Acute inflammation
Killing of pathogens
What molecules does the innate immune system rely on?
PAMPs:PRRs
PRRs detect PAMPs
What is a PAMP?
Pathogen associated molecular pattern
Detected by PRRs
What is a PRR?
Pattern recognition receptors
Which immune response are PAMPs:PRRs involved in?
Innate
Briefly describe the adaptive immune system in its response time and type of response?
Slow response (4-96 hours) Unique response
Which two molecules are involved mainly in the adaptive immune response?
Antigens are received by antigen receptors
Cells of the adaptive immune system?
Phagocytes
Lymphocytes
Eosinophils, mast cells & basophils
Which types of phagocytes are involved in the adaptive immune system?
Neutrophils
Monocytes
Macrophages
Dendritic cells
What is the role of phagocytes?
Ingest and kill bacteria
Important source of cytokines
Types of lymphocytes in the adaptive immune response?
T cells
B cells
NK cells
What is the role of eosinophils, basophils and mast cells in adaptive immune response? What type of cells are they?
Release chemicals for acute inflammation
Granular cells
Soluble/humoral factors of the adaptive immune system?
Antibodies
Complement proteins
Antibodies in the blood are also referred to as?
Immunoglobins
When are antibodies produced in the adaptive immune response?
In response to an antigen
What is the role of complement proteins?
Critical role in inflammation and defence
Components of the adaptive immune system?
Cells + Soluble factors
Cells= phagocytes, lymphocytes, eosinophils/basophils/mast cells
Soluble factors= AB’s & Complement proteins
Where are mast cells found and what is their role?
Reside in tissues
Protect mucosal surfaces
What happens when mast cells degranulate?
Release histamine and tryptase
Then gene expression causes production of new pro-inflammatory substances eg chemokines, TNF, leukotrienes
Role of baso/eosinophils?
Circulate in blood and are recruited to sites of infection
Where are neutrophils in the body?
Circulate in blood
Role of neutrophils?
Short-lived professional killer cells
Rapidly recruited to inflamed and infected tissues
PAMP recognition and activation
3 mechanisms how neutrophils attack pathogens?
- Phagocytosis
- Release of antimicrobial peptides and degradative proteases
- Generate extracellular traps
What do active neutrophils produce?
TNF
What makes up pus?
Dead/dying neutrophils
Tissue cells
Microbial debris
What are monocytes?
Precursors of macrophages
What do monocytes do?
Limit inflammation
Involved in tissue repair and wound healing
Where do macrophages reside?
In tissues
What do macrophages do?
Ingest and kill EXTRAcellular pathogens Clear debris from dead tissue cells Tissue repair and wound healing Antigen presentation Inflammation
What are dendritic cells?
Immature cells in peripheral tissues
When do dendritic cells mature?
When in contact with a pathogen, they mature to secondary lymphoid tissues and stimulate adaptive response