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Unformatted text preview: Chapter 9 I. General Concepts 1. TH Cells have many identical receptors on their surface that recognize the peptides from the APC MHC class II molecule 2. Tcell Ag receptors (TCRs) are heterodimeric protein complexes closely associated with either CD4 T H cells or Tc Cells 3. Two types of TCR Alpha/Beta and Gamma/Delta - each with 2 different peptide chains. Each TCR is bound to cell membrane so Ag binding site faces out. 4. For a Tcell response to occur, helper Tcells must recognize a foreign Ag bound to MHC class II Ag in the presence of a costimulator and in association with a second signal mediated through CD28. 5. Two types of TH Cells TH1 and TH2 that secrete different mixes of interleukins and stimulate different types of responses 6. TH1 secretes interleukin-2 and interferon-gamma. These act in cell-mediated immune responses6....
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- Spring '08