Lecture 4 Flashcards
What are antigen presenting cells?
degrade pathogens and produce peptides to attach to the Major HistoCompatibility receptors and then the MHC + antigen fragments are displayed on APC membrane
What cells are the link between humeral immunity and cell-mediated immunity?
T cells
What do helper T cells do?
- display the surface antigens TCR & CD4
- secrete cytokines
- associate with MHC class II
What do cytotoxic T cells do?
- display TCR and CD8
- destroy pathogens
- associate MHC class I
What are TCRs composed of?
two trans membrane antigen recognizing and binding peptides connected by a disulphide bond
What is the function of TH1?
activates Tc and phagocytes against intracellular bacteria and protozoa
What is the function of TH2?
activates humeral response: most active against helminthic infections
What is the function of TH17?
defence against chronic muscosal infections
What are the function of TH0 cells?
can differentiate into other helper T cells
What is the function of regulatory T cells?
restore homeostasis after infection, lack of T(reg) cells is associated with chronic inflammation
How is humoral immunity triggered?
antigen triggers the differentiation of a B-cell into a plasma cell
How is cell-mediated immunity triggered?
antigens on MHC I and II are presented to T cells
What are super antigens?
directly link TCR on T cell with MHC on APC without undergoing processing and presentation of epitope
What is a cytokine storm?
when super antigens activate a large number of T-cells causing a massive release of cytokines
What is clonal selection?
when an invading antigen selects which B-cell clone will proliferate to large numbers
