Intro to immunology Flashcards
What are the major physical barriers to infection?
Saliva
Mucocilliary Escalator
Gastric Acid
Natural Flora
Flushing & urine pH
What cell types are involved in innate immunity?
In blood:
- NK cells
- Basophils
- Eosinophils
- Monocytes
In Tissue
- Mast Cells
- Macrophages
- Dendritic Cells
By what mechanisms does the innate immune system function?
1) Inflammation
2) Recruiting immune cells
3) Complement Activation
4) Opsonisation
5) Phagocytosis
6) NK cytotoxicity
What are cytokines?
Molecules that regulate the nature, duration & intensity of immune responses by binding to specific receptors
E.g. Interleukins, TNF-alpha, chemokines & TGF-beta
Where are cytokines made?
Th cells & Macrophages
Which cytokines are pro and anti-inflammatory?
Pro-inflammatory = TNF-alpha, IL-1, IL-6 & chemokines
Anti-inflammatory = IL-10 & TGF-beta
Describe what happens during inflammation?
Pattern Recognition Receptors (PRR) detect a breach in defence/foreign body and trigger:
- Vasodilation
- Vascular permeability
- Cell Adhesion Molecules
- Chemotaxis
- Sensitivity to Pain
How is complement activated?
C3 is activated first. By any of the 3 pathways, Classical/Lectin/Alternative
What are the functions of complement?
Chemotaxis of phagocytes
Opsonisation
Lysis of micro-organisms
Maintain solubility of Ab/Ag complexes
What is Opsonisation?
Tagging cells for phagocytosis
Done by complement C3b/C4b, antibodies & plasma cells
What do NK cells do in innate immunity?
Perforin-induced Apoptosis
Define an antigen vs antibody?
Antigen is any molecule that induces an immune response. An antibody is a glycoprotein made by b cells that binds antigens
What are the 2 types of adaptive immunity?
Humoral - B cells & Abs
Cell-mediated - T Lymphocytes
How do adaptive immune cells recognise antigens?
B cells/Abs detect BCR directly
T cells detect MHC on antigen presenting cells
Immune Tolerance is a process of ensuring our Lymphocytes are tolerant towards our own tissues. Where does this occur?
Central Tolerance:
T = Thymus
B = Marrow
Peripheral Tolerance:
- 2nd lymphoid organs & circ