cells Flashcards
what cells are involved in the innate immune response
- mast cells
- NK cells
- phagocytes
- complement
repsonsible for acute inflammation and killing of pathogen
what cells are involved in the adaptive immune response
T and B lymphocytes
what cells are phagocytes
- neutrophils
- monocytes
- macrophages
- dendritic cells
what cells are lymphocytes
- T cells
- B cells
- NK cells
what are eosinophils, mast cells and basophils
- granular cells
- release chemicals for acute inflammation
what are mast cells
- They serve as a first line of defence against antigens entering the body due to their location in the skin and mucosa. Mast cells are especially important in the homeostasis of the commensal bacteria of the gut
- degranulate and release histamine and tryptase - released because of an immune response
what are basophils and eosinophils
- circulate in blood
- recruited to sites of infection
- basophils is thought to be the release of cytokines, leukotrienes and histamine to aid immunity to pathogens
- eosionophils - movement to inflamed areas, trapping substances, killing cells, anti-parasitic and bactericidal activity, participating in immediate allergic reactions, and modulating inflammatory responses.
what are neutrophils
- circulate freely in blood
- rapidly recruited to inflamed and infected tissue
- short lived profesional killer
- 3 ways they attack pathogens = pagocytosis, release of antimicrobial peptides and degradive proteases, generate extracellular traps
- active neutrophils produce TNF
- dead and dying neutrophils and tissue cells and microbial debris = pus
what are monocytes and macrophages
- monocytes are precursers of macrophages
- limit inflammation
- involved in tissue repair and wound healing
what is the function of macrophages
- Reside in tissues
- Ingest and kill extracellular pathogens
- Clear debris from dead tissue cells
- Inflammation
- Tissue repair and wound healing
- Antigen presentation
what are dendritic cells
- Immature cells in peripheral tissues
- When in contact with pathogen, mature and migrate to secondary lymphoid tissues
- Stimulate adaptive immune responses (antigen presentation)
what are natural killer cells
- Large granular lymphocytes
- Specifically kill tumour and virally infected cells
- Can also kill antibody-bound cells
what are B cells
- Mature cells constantly circulate through blood, lymph and secondary lymphoid tissues
- produce antibodies
what are T cells
- Mature cells constantly circulate through blood, lymph and secondary lymphoid tissues
- defence against pathogens
what are helper T cells
- regulators of immune system
- activate other immune cells
- CD4+
what are cytotoxic T cells
- kill virally infected body cells
- CD8+
what is the primary lymphoid tissue
site of luekocyte development (red bone marrow and thymus)
what is the secondary lymphoid tissue
sites where adaptive immune repsonses initiated (lymph node, tonsils, spleen)
what are the mechanisms of communication in the immune system
Direct contact
- receptor-ligand interactions
Indirect contact
- production and secretion of cytokines
what are cytokines
- Produced in response to infection, inflammation, tissue damage
- Co-ordinate the immune system by modulating cell behaviour
Examples
- Interferons =Anti-viral functions
- TNF (tumour necrosis factor)=Pro-inflammatory
- Chemokines = Control and direct cell migration
- Interleukins
Various functions
IL2 (T cell proliferation)
IL10 (Anti-inflammatory)
explain briefly the innate immune response
- recognition phase for PRRs and PAMPs
- activation phase
- effector phase
what immune response do antigens cause
adaptive immune response by activating B and T cells
B and T cells recognise pathogen by
- T cell antigen receptor = membrane bound protein heterdimer (alpha and beta chain)
- B cell antigen receptor = membrane bound antibody (IgM or IgD) with a light and heavy chain and disulphide bridges
how are antigens activated
- MHC/HLA proteins display peptide antigens to T cell
- class 1 - expressed on all nucleated cells - present peptide antigens to cytotoxic T cells
- class 2 - expressed only on dendritic cells, macrophages, B cells - present peptide antigen cells
what are IgG immunoglobulins (antibodies)
most abundant, actively transported across placenta
what are IgM
surface bound monomer, 1st Ig type produced during an immune response
what are IgD
extremely low levels in blood, surface bound
what are IgE
extremely low levels normally, produced in allergic response
what are IgA
2nd most abundant type, monomeric form in blood, dimeric form in breast milk, saliva, tears, mucosal secretions
what can B cells differentiate into
- plasma cells (effector B cells) which produce antibodies
- memory B cells - immunologiclal response
