TOPIC 12 - immunology Flashcards
what does the immune system provide protection against?
- microbial pathogens including bacteria, viruses, parasites, fungi
- tumor cells
what is innate immunty
- First line of defence- deal with pathogen before adaptive immunity kicks in
- Non-specific response
- all animals have it
what is adaptive immunity
- Second line of defence
- Highly specific with memory= faster and greater response in future infection
what is active immunity
-Antigens enter body and trigger
Innate and adaptive immune systems
-Provides long term protection
what is passive immunty
-Antibodies pass from mother to
Foetus across the placenta
-Infant in breast milk
-Provides short term protection
what is the common stem cell which immune cells originate from?
common pluripotent hematopoietic stem cell
in bone marrow
what are the linages of pluripotent hematopoietic stem cell
Myeloid lineage generates
Lymphoid lineage
what cells are in the myeloid lineage
Polymorphonuclear leukocytes (neutrophil, eosinophil, basophil) Monocyte/macrophages, dendritic cells, mast cells
what cells are in the lymphoid lineage
- B- and T-
- natural killer (NK)
- lymphocytes
what are Polymorphonuclear leukocytes or granulocytes
characterised by multilobed (2 to 5) nuclei and cytoplasmic granules
what are neutrophils
- Principal phagocytic cell of innate immunity
- Rapidly migrate to sites of infection
- ingest microbes by phagocytosis
- release oxygen free radicals
- degranulate releasing proteins with microbicidal properties e.g. lysozyme
what are eosinophils
Important defender against multicellular parasites and have a role in allergy and asthma
what are basophils
Involved in inflammatory allergic reactions. Releases the potent vasodilator, histamine.
what are monocytes
-Circulate in blood, bean shaped nuclei, precursors of
tissue macrophages.
- Effectors of the inflammatory response to microbes.
- Kills pathogens via phagocytosis, free radical production, myeloperoxidase and inflammatory cytokines.
what are macrophages
- Derived from blood monocytes
- Participate in innate and adaptive immunity
- Phagocytosis, microbicidal mechanisms, antigen presentation to other cells
what are dendritic cells
Process and present antigens (antigen presenting cell {APC}) on their cell surface to T-lymphocytes to initiate specific immune responses.
what are mast cells
Similarities with basophils, release histamine, close association with allergy and inflammation
what kind of immunity are small lymphocytes involved in immunity
specific immunity
what do b lymphocytes do?
B-cell
- produce antibodies
- present antigens to other cells (APC)
- can produce long lived memory cells- rapid and faster production of antibody on second exposure/ subsequent viral infection
what do t lymphocytes do?
T cell
- plays critical role in development and regulation of cell mediated immunity
- Influences the activities of other cells (e.g. B-cells)
- able to kill virally infected and tumour cells
- generate long lived memory cells
what is a natural killer cell/NK cell and what do they do?
Large granular lymphocyte
- generally considered part of the innate immune response.
- Release perforins and granzymes
- trigger apoptosis in target cell.
- Kill infected cells which do not express foreign surface antigen, respond rapidly, involved in tumour immunosurveillance
what are the 2 key immunological sites in the body
primary lymphoid tissue
secondary lympoid tissue
what is 1’ lymphoid tissue
Development and maturation of lymphocytes: bone marrow (B lymphocytes) and thymus gland (T lymphocytes)
what is 2’ lymphoid tissue
Mature lymphocytes encounter antigens/pathogens:
Includes: lymph nodes, spleen and lymphoid tissue at other sites e.g. tonsils, appendix, adenoids, Peyer’s patches (in ileum),bronchial associated lymphoid tissue (BALT).