Autoreactive antibodies

Autoimmunity is essential in each individual - and normally it does exist. Natural autoreactive antibodies ensure immunological homoeostasis. The immune system is well-equipped to fulfil its tasks of distinguishing between endogenous and exogenous structures. 

B cells likely cross previously damaged sections of the blood-brain barrier to arrive in the CNS, an area normally free of B cells. Autoreactive T cells cause B cells to form autoantibodies to myelin. B-cell antibodies also initiate the complement cascade which causes myelin degradation.7... 

Mietzner, B., M. Tsuiji, J. Scheid, K. Velinzon, T. Tiller, K. Abraham, J. B. Gonzalez, V. Pascual, D. Stichweh, H. Wardemann, and M. C. Nussenzweig. 2008. Autoreactive IgG memory antibodies in patients with systemic lupus erythematosus arise from nonreactive and polyreactive precursors. Proceedings of the National Academy of Sciences of the United States of America 105 9727-9732. 

Figure 3. Effects of heavy metals (Hg andAu) on Immune cells. Hg was described as able to interact with the nuclear antigen fibrillarin which was assumed to cause a T-cell response against this modified autoantigen. True autoreactive T-ceiis specific for the native antigen were detected in a second time. Hg was shown to induce the expression of a normally cryptic epitope of RNAse A leading to the activation of specific T-cells. However the relevance of this mechanism in terms of induction of autoimmunity has not been demonstrated. Hg orAu have also been shown to poiyctonaity activate T-cells mimicking the effects of stimulation with anti-TCR antibodies. This results in an increase in intracellular Ca concentration, MAP kinase activation and cytokine expression.

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