the adaptive immune response Flashcards
the adaptive immune response (3)
specific to antigen, time lag and immunological memory
professional phagocytes are
monocytes, macrophages, neutrophils, tissue dendritic cells and mast cells
following ingestion of pathogen, what happens?
as well as ingesting, phagocytes especially macrophages can act as antigen presenting cells (APCs)
process of antigen presentation
phagocyte ingests a bacteria. Part of the bacteria (antigen) goes to the surface of the phagocyte, The phagocyte presents the antigens to T helper cells. this activates the helper t cell
Antigen presenting cells are
a link to the adaptive immune system
endoplasmic reticulum is associated
with degradation of microbe
transporters are associated
with antigen processing
cytolytic T I lymphocytes (CD8+) recognise
antigens presented by MHC I molecules
MHC I molecules
comprised of two polypeptides and present antigens originating from the cytosol
two major killing mechanisms of MHC I molecule
perforin and CD95 pathway
perforin killing mechanism of MHC I molecule
perforin delivered from cytoplasmic granules that fuse with the membrane of the APC forming pores to allow granzymes to enter the infected cell
CD95 pathway mechanism of MHC I molecule
FasL expression increases on CT and binds to Fas on the APC , leading to apoptosis
both perforin and CD95 pathways lead to
apoptosis rather than cell lysis, triggering the dead cells tone taken up by nearby macrophages
recognition of MHC II molecules by CD4+ T cells
recognise antigens presented on MHC II
MHC II molecule
two polypeptide- present antigens originating from the phagosome, peptides slightly longer than those presented by MHC I
difference in peptides presented by MHC II
MHC II present slightly longer peptides than those presented by MHC I
for recognition by CD4+ T ce;;s
costimulation needed- co-recepter in addition to MHC/ peptides/ TCR complex
costimulation
co-recepter in addition to MHC/ peptides/ TCR complex
CD8+ T cell and
MHC I
CD4+ T cell
MHC II
different Th produce diff
cytokines