lecture 11) the adaptive immune response Flashcards
give 3 characteristics of adaptive immunity
immunological memory
specific to antigen
not immediate
what are the humoral cells involved in adaptive immunity?
antibodies
cytokines
what are the cellular cells involved in adaptive immunity?
T and B cells
how can phagocytes link innate and adaptive immunity?
phagocytes can act as antigen presenting cells
what do T cells recognise?
major histocompatibility complex (MHC)
what is a major histocompatibility complex?
a peptide of the antigen on an antigen presenting cell
what sort of complex is MHC?
trimolecular complex
approximately, what is the amino acid length of the MHC?
8-11 amino acids
what other sort of antigen other than a peptide can MHC present to T cells?
carbohydrate
what is a CD?
cluster of differentiation
what exact T cells do MHC I present to?
CD8+T cells
what exact T cells do MHC II present to?
CD4+T cells
what are CD1 molecules?
similar to MHC structure
forms groves that the peptide sits in
presents glycolipid
what do macrophages do to the bacteria to present it to the T cell?
engulfs
lyses
chops
presents
not all bacteria stay in the endosome or phagosome. what breaks down the bacteria should this be the case?
proteasome chops the bacteria up
what type of cells are CD8+T cells?
cytotoxic T lymphocytes
where do the CD8+T cells recognise the antigen peptide from?
cytosol
what protein in MHC I molecules are essential to initiate an immune response?
beta 2M protein
how come MHC can be presented before degradation of bacteria?
MHC I and II present
what do T cells also set down when killing the bacteria?
memory T cells
what is the importance of memory T cells?
when the same antigen is presented again, memory cells release perforins and granzymes
name the 2 major pathways of cytotoxic T cells
perforin
CD95 pathway
describe the perforin pathway of cytotoxic T cells
perforin deliver from cytoplasmic granules to infected cells to kill them
granules fuse to membrane forming pores allowing entrance
describe the CD95 pathway of cytotoxic T cells
FasL expression increases CTL
CTL binds to Fas on APC
causes apoptosis
what do both the perforin and CD95 pathways of cytotoxic T cells lead to?
cell apoptosis rather than lysis
what dye is used to bind to RNA or DNA only when cells are dead?
propioiodide
what type of T cells are CD4+ T cells?
helper T cells (Th0, Th1, Th2)
what protein do CD4+T cell lack in comparison to other CD4 cells?
globulin
how many polypeptides are CD4+T cells comprised of?
2
which has a longer amino acid sequence chain; MHC I or MHC II?
MHC II
what type of cytokines do CD4+T cells produce?
each T helper cell produces different cytokines
what T helper cell aids the formation of B cells?
Th2
what sort of infection of TB would you have if you had adequate adaptive immunity?
latent infection
what is the only contagious form of infection of TB?
TB disease that occurs only when there is inadequate innate immunity
what is the latent infection contained in?
granuloma
what is the clinical name for the latent TB infection?
milary TB
how come TB can recruit more immune cells?
innate cells that have taken up bacteria have produced cytokines that will recruit more T cells to the site of infection
if TB were to recruit more immune cells, what does this mean for the granuloma?
granuloma is immune
what cells are recruited to make fibrotic encapsulation and what/how is the granuloma formed?
fibrotic cells
firbrotic encapsulation enhances the cell wall forming a chronic granuloma
what enhances macrophage migration to granulomas?
ESAT6 (mycobacterial protein) secreted through ESX-1
what do B cells normally produce in the granuloma?
antibodies
what are B cells also a source of to recruit more lymphocytes and macrophages
cytokines
how does TB spread (granuloma)?
feed on granuloma
spreads due to liquefaction (liquefied caseous granuloma)
where did the name caseous granuloma come from?
cattles lung smelled of cheese when riddled with bacteria
what 3 approaches (singly or in combinations) establish the efficacy or antibody-mediated immunity against a microbe?
1) passive administration of a microbe specific antibody modifies the course of infection to the benefit of the host
2) inverse relationship between the presence of microbe specific antibody in host and susceptibility to infection
3) establish increased susceptibility to disease in host with deficits in hummoral immunity
how are TB cell wall molecules recognised by phagocytes?
through PRRs
what does TB initially cause?
alveolar macrophages to produce chemokines and cytokines
what is TNF-alpha?
tumour nercrosis factor alpha
prototype proinflammatory cytokine produced by phagocytic cells activated by mycobacteria or mycobacterial components
what do phagocytic cells produce upon phagocytisis of mTb?
IL-12
what do IL-12 cells recruit to site of infection of TB?
NK cells
what role might post-translocational modifications of mycobacterial proteins play in host immunity?
CD8 cytotoxic
CD4 helper (chemo and cyto) to modulate immune response
peptide could have lipid or carbohydrate component to hijack immune signalling
