Lecture 21 - cell mediated immunity Flashcards Preview

BII > Lecture 21 - cell mediated immunity > Flashcards

Flashcards in Lecture 21 - cell mediated immunity Deck (14):

complement cascade

-do more on this!



-largest molecule
-mostly blood and lymphatics
-First in primary antibody response
-very effective agglutinator
-good activated of compliment pathway
-important defence against blood borne spread of infections such as bacteria



-main antibody in pool
-diffuses into extravascular spaces
-potent antitoxin antibody
-effective barrier against viral infections
-actively transported across placenta
-good complement activaor
-strongly bound to pahgocytic cells to enhance pahgocytosis



main role is protection of external body surfaces
surface protection of gut, resp and genitourinary tracts



-very small amounts in blood and body fluids
-found on surface of antigen sensitive naive B cells
-Receptor for antigen binding to activate naive B cells



-generally not much in blood
-bind strongly to mast cells - this causes the symptoms , granules released
-people that make more of this have allergic reactions and asthma
-important in parastiic infections and allergins



immunise an animal with an antigen and purify serum from animal and then get antibodies specific from things
-mainly made in large animals and can make lots of antibodies to fight against antigens
-however these were mainly polyclonal antibodies - making a range of different antibodies and not alot of one specific type
-want monoclonal antibody


Lymphadenopathy (enlarged lymph nodes) and splenomealy


-what can be done for treatment involved with monoclonal antibodies

-can use chemotherapy which contains a monoclonal antibody directed against B cell surface antigens - pure antibody prepared in lab
-able to be injected and can bind to these and kill them

lymphocytosis - increase in no. of lymphocytes in the blood


Skin graft rejection

-what happens with primary graft vs secondary graft

First graph - taken from a different person, has been sewn into place
-if it is not compatable with recepipietn then will look like big blood dot thats dead- dies due to immune response due to T cell mediated recognising the antigen and responding
-Second graft - from same donor to same recipient where graft doesnt vascularise very wel, and is rejected quickly - will be more immediate as memory cells will be there and will be mostly antibody mediated


Cytotoxic T cell action

-3 ways of action

All of these use recognition of target and CD8
-recognition causes the release of granules

1. Perforin and enzymes, these are similar to late components of complement cascade to go onto punch holes in membranes
2.Hydrolytic enzymes (granzymes) - get throguh the holes and start to digest the cell they are attatched to
3. Cytokines released that induce apoptosis in some of the target cells


Lymphocyte ontogeny (how lymphocytes are made)

-where do b and t cells originate, mature, and migrate to

Bone marrow and thymus - primary lymphoid organs - make B and T cells

T cells differentiate in thymus, then travel to secondary lymphoid organs

B cells leave bone marrow mature, and also go to secondary lymphoid organs


B cell ontogeny

stem cells - triggered by various molecules, go to B cell lineage

-pre b cells
-immature b cell - surface IgM
-mature b cell - surfaec igM and igD


immunoglobulin genes

-have 2 sets of genes that code for antibodies
-one for heavy chain, 2 for light chains
-V, D, J exons, C exons
-get veriable region of heavy chain - in bone marrow - there is random reassortment of heavey chain (of V, D, J)
-get many different combination of V,D,J that code for the variable region of the heavy chain
-then these become transcribed and translated
-heavey and light chain together become the surface ig on B cells
-cna regonise loads of different antigens


Class switching

-any antibody can switch from IGM, to make IGG but have same variable regions
-heavy chain is variable, and the light chain is not variable but can change
-could transcribe all the rna for the Cu to Ca region
-or could chop out some of the exons and end without some of the regions
-the T cells control the switching
-but have same antigen binding site

V region stays constant, C region changes