Group A Strep present in M protein throat infection; expresses arge amounts of M protein >Rheumatic fever is a classic Large amounts of IgG produced example of se against M protein on Strep molecular mImicry Antibodies against M protein can bind to molecules on cardiac cells that are very similar to M protein Antibody-induced injury to heart valves and sarcolemma
16 ➢Rheumatic fever is a classic example of molecular mimicry
3. Inappropriate expression of class II MHC Wrong"cells induced to express MHC Class antigen(and act as APCS)-IDDM Hashimoto's Additional signals, such as IFN-gamma >IL-1 and TNF
17 ➢ “Wrong” cells induced to express MHC Class II antigen (and act as APCs) – IDDM, Hashimoto’s ➢ Additional signals, such as IFN-gamma →IL-1 and TNF 3. Inappropriate expression of class II MHC
4.Epitope spreading >Definition Initial response to one self determinant (one peptide) could expand to involve additional determinants on the same molecule as well as additional self-proteins 18
18 4.Epitope spreading ➢Definition: Initial response to one self determinant (one peptide) could expand to involve additional determinants on the same molecule as well as additional self-proteins
H1-specific helper T cell activates histone H1 Activated b cell specific B cells that process nucleosomes differentiates into containing H1 and present H1 peptides anti-H antbody Determinant nucleosome H1-specific T cell CD40L DNA 8 spreading CD40 It explains how a B cell response to one H1-specific helper T cell activates DNA- Activated B cell specific B cells that process nucleosomes differentiates into cryptic epitope and present H1 peptides plasma cells secreting can mature into a full-blown 》° autoimmune response
19 It explains how a response to one cryptic epitope can mature into a full-blown autoimmune response
5. Polyclonal B cell activation by CMV, EBV, and some g-negative bacteria T-cell-independent Large amounts of IgM produced
20 5. Polyclonal B cell activation by CMV, EBV, and some G-negative bacteria - T-cell-independent - Large amounts of IgM produced