Innate and Adaptive Immunity Flashcards
What are 4 physical barriers to infection?
Skin
Mucous
Respiratory cilia
Commensal organisms
What are 4 biochemical barriers to infection?
Sebaceous secretions in skin
Lysosome in tears
Spermine in sperm
Gastric acidity
How do most infectious agents enter the body?
Via the mucosal surfaces of: Nasopharynx Respiratory tract Alimentary tract Genito-urinary tract
What’s the definition of an antigen?
A substance capable of inducing an immune response
What are the basic differences between innate and adaptive immunity?
Innate immunity is the primary line of defence, immediate response, recognises certain threats, no antigen presentation and no immunological memory
Adaptive immunity is the secondary line of defence, delayed response, recognises all threats and it has antigen presentation, clonal selection, immunological memory
What do T and B lymphocytes do?
T lymphocytes: cytotoxic, memory, helper, suppressor
B lymphocytes: plasma cells, memory cells
What are Eosinophils, Basophils and Mast cells involved in?
Eosinophils: parasitic infections and allergic responses
Basophils & Mast cells: inflammatory and hypersensitivity reactions
What are the blood cells of the immune system?
Neutrophils Eosinophils Basophils Lymphocytes Monocytes Platelets Erythrocytes
What are some tissues/organs of the immune system?
MALT mucosa associated lymphoid tissue
Thymus where T cells mature
BALT bronchus associated lymphoid tissue
Lymph nodes = small peripheral collections of lymphoid tissue
Spleen = large collection of lymphoid tissue
Kupfer cells in liver = macrophages
Bone marrow is site of haematopoiesis and maturation of B lymphocytes
What type of protein are antibodies and what type of immunity are they involved in?
gamma globulin proteins
Adaptive humoral immunity
What are the 4 humoral components of the immune system?
Acute phase proteins (a, B, y globulins)
Complement (B globulins)
Antibodies (y globulins)
Cytokines (IL, TNF)
What’s phagocytosis?
Recognition and engulfing of microbes, which are then killed by the release of toxic chemicals into the enclosed vacuole
What are the 2 cell types involved in phagocytosis? How are their roles different?
Polymorphonuclear leukocytes (neutrophils) involved in INNATE immunity
Mononuclear phagocyte system (monocytes and macrophages) involved in ADAPTIVE immunity
Outline phagocytosis in innate cell-mediated immunity
- Chemotaxis and adherence of microbe to phagocyte
- Ingestion of microbe by phagocyte
- Formation of a phagosome
- Fusion of phagosome with lysosome to form a phagolysosome
- Digestion of ingested microbe by enzymes
- Formation of a residual body containing indigestible material
- Discharged of waste materials
Outline natural killer cells role in innate cell-mediated immunity
All human cells express MHC Class I molecules on their surface - these are lost in infected/neoplastic cells
NK cells detect the change by lack of stimulation and become activated
Cytotoxicity comes from pore-forming molecules that are inserted into the target cell and cytotoxic molecules are pumped in