3: L14 Flashcards
what is inflammation characterised by
o Swelling (tumor) o Redness (rubor) o Heat (calor) o Pain (dolor)
What organs are immune privileged and what does that mean
o Developed own strategies to control
o Susceptable to tissue damage // cannot repair
o Immune response may actually damage structures resulting in loss of function
2 Types of immune suvrailence
Humoral + cellar
what are the two divisions of cellular immuntiy
innate + adoptive
Neutrophil Granulocytes & Macrophages function
take foreign particles and destroy them in lysosomes
Difference between neutrophil and macrophage
N= mobile, die after phagocytosis, 24hr life
M= months life, can engulf many pathogens, act as antigen presenting cells to T cells
Eosinophilic & Basophilic Granulocytes Mast cells , NK-cells function
deliver substances
kill parasites/tumur cells
induce or support inflammatory responses
function of M cells
• Transport antigens from lumen to lamina propria AG not normally allowed to cross lining
function of dendritic cells
• DCs Take up antigens from their environment
- Activate phagocytic cells
- Present antigens on MHC surface molecules to T-lymphocytes
follicular dendritic cells function
present antigen to B-lymphocytes
what are b lymphocytes also called
plasma cells
how are early b cells activated and their function
activated according to surface receptor (specific to AG) – = cells then “primed”
o Recognised with help of T cells and FDC they mature into plasma cells
plasma cell function
• Plasma cells: antibody production in lymphatic or migrate to other tissues
o Some ABs expressed on surface (eg IgA important in gut etc)
• Plasma cells make IgM / IgG
what do memory b cells do
react faster to same AG, mature cells, FDC not required activate
• Function of Antibodies
o Bind to antigenic (AG) molecules , Neutralize toxins
o Help phagocytosis, virus neutralisation
o Vaccines work by specific AB produced over long time
where is IgA, G and M distributed to
- IgA - Added to secretion of glands , Tears , Nasal cavity , Bronchial surface , Gastrointestinal surface
- IgG & IgM - Delivered to blood and extracellular liquid
- Light chains + heavy chains (small/large connected by bonds)
the production of antibodies is the main function of what system
humeral
describe the ‘constant region;
Bottom of Y connects to cell surface (if antibody expressed on cell surface, this is what membrane binds tw), morphology more common to other antigens)
o Top arms of the Y= binds to antigen itself (each antigen= specific antigen site)
what’s a light/heavy chain
on antibody- light chain is singular piece, heavy chain connect bottom of y to top
Describe the primary AB response- first encounter antigen
- B cells differentiate and activate- produces IgM (penta structure), + small amount of IgA (bc of 5 binding sites // mop up more antigen (despite being weaker immune response than IgG)
Describe the secondary AB response- second encounter antigen
larger IgG response as stronger immune response
describe why the antibody class switch from primary (M) to secondary (G)
o Within B cell germline, different parts of chromosome responsibly for particular parts
o V region (AB binding site)= V, D, J cites = splicing
• Different antibody combine DVJ in different sequences= permeablity + almost endless variation
what are the two types of lymphocytes
Cytotoxic T-cells (CD8+)
Helper T-cells (CD4+)
what do Cytotoxic T-cells (CD8+) do
- Recognise foreign bodies – activated CTL
- Kill virus infected cells
- Kill tumour cells
what do Helper T-cells (CD4+) do
- Produce cytokines = hormone-like soluble factors
- Regulate immune response through cell surface molecule interaction (cell:cell)
- Regulate and Support B-cell differentiation (recognise same AG)
- Recognise different parts of same AG (epitopes)
- Support cytotoxic T-cell function (CD8+ must be activated (c.f. NK cells))
describe the steps of Cytotoxic T-cells (CD8+)
- Infected cell= presentation of antigen molecule with CD8 marker + class 1 MHC (t cell recognises not normal cell + extra markers)
- Responds to these = production of active cytotoxic t cells
- = Produce lymphotoxin etc =designed to puncture and degrgade cell
• Main driver= t cell receptor and CD8 molecule= complex created
describe the steps of Helper T-cells (CD4+)
- Other cell degrade infected cell and presents antigens to T helper cells (presents Class II MHC co-localised with CD4)
- = activated + cell division > release cytosine
- Targets cell to destroy
- And memory cells primed and activated
describe MHC protein role in ummuno
cell phagocytise pathogen/abnormal peptides and bind MHC to the unusual product (MHC Class II on the antigen presenting cell, and Class I on the peptides)
abnormal fragments displayed on membrane by MHC
What does class 1 MHC activate
abnormal cell= CD8 T cells
Class II= presence of pathogen // CD4
What are cytokines
Chemical messengers released by tissue cells:
• to coordinate local activities
• to act as hormones to affect whole body
Stimulate T cell divisions:
difference between Th1 and 2 cytokines
TH1= Pro inflamm Th2= antinflamm
what do alpha, beta and gamma interferons do
- Released by activated lymphocytes and macrophages (usually by virus)
- Alpha interferons: produced by leukocytes stimulate NK cells
- Beta interferons: secreted by fibroblasts slow inflammation
- Gamma interferons: secreted by T cells and NK cells, stimulate macrophage activity
