immune recognition

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Created by
ashley parker

Cards (30)

  • the FAB is connected to the FC by disulphide bonds
  • a native antigen can be linear or continuous
  • the BCR recognises antigen in association with Iga and igb, forming the BCR complex
  • what is the B cell co-receptor complex made up of
    CD19, 21, 81
  • CD19
    adaptor for activation
  • CD21
    complement coated pathogen activates this protein
  • CD81
    enhances signalling
  • IgM
    primary and secondary, involved in complement fixation and agglutination
  • IgG
    primary and secondary, complement fixation, can cross placenta
  • IgA
    protects mucosal surfaces, monomeric in serum, dimeric in mucosal sites
  • IgE
    inflammation, parasitic infection, allergy
  • TCRs recognise antigen in the form of a complex of a foregin peptide bound to an MHC molecule
  • 2 classes of TCR
    ab: conventional, yg: non conventional (abundant in gut mucosa)
  • the TCR is assisted by 2 sets of CD3 molecules and zeta chains, both of these are attached to ITAMS, that mediate the downstream signalling
  • cd8 binds to the alpha 3 domain of MHC class 1
  • cd4 binds the beta 2 domain of the MHC class 2
  • MHC molecules allow T lymphocytes to detect cells that have ingested or have been infected with microorganisms, the T lymphocytes recognise the foreign peptide fragment attached to the MCH and bind to it
  • in healthy cells, the MCH presents self peptides, and the T cells dont react
  • MHC class 1 binds short peptides of 8-10 amino acids
  • MHC class 2 binds peptides of more than 15 amino acids
  • MHC genes are found on human chromosome 6
  • MHC 1 are expressed on cell surfaces of all nucleated cells
  • MHC 2 are expressed on the surfaces of professional antigen presenting cells
  • co dominant expression
    both parental alleles of each MHC are expressed, this increases the number of different MHC molecules that can present peptides to T cells
  • CD8 can kill any type of virus infected cell
  • CD4 helper T lymphocytes interact with dendritic cells, macrophages, and B lymphocytes
  • MHC restriction
    T lymphocytes (via TCRs) recognise antigens only when they are presented in association with self MHC molecules
  • self MCH and viral peptide
    recognition of foreign peptide on target cells and lysis
  • self MHC with no viral peptide
    recognition of self peptide, no lysis
  • foreign MHC and viral peptide
    no recognition, no lysis