Molecular Mimicry

Molecular mimicry is defined as the theoretical possibility that sequence similarities between foreign and self-peptides are sufficient to result in the cross-activation of autoreactive T or B cells by pathogen-derived peptides. Despite the promiscuity of several peptide sequences which can be both foreign and self in nature, a single antibody or TCR (T cell receptor) can be activated by even a few crucial residues which stresses the importance of structural homology in the theory of molecular mimicry. Upon the activation of B or T cells, it is believed that these "peptide mimic" specific T or B cells can cross-react with self-epitopes, thus leading to tissue pathology (autoimmunity). Molecular mimicry is a phenomenon that has been just recently discovered as one of several ways in which autoimmunity can be evoked. A molecular mimicking event is, however, more than an epiphenomenon despite its low statistical probability of occurring and these events have serious implications in the onset of many human autoimmune disorders.

In the past decade the study of autoimmunity, the failure to recognize self antigens as "self," has grown immensely. Autoimmunity is a result of a loss of immunological tolerance, the ability for an individual to discriminate between self and non-self. Growth in the field of autoimmunity has resulted in more and more frequent diagnosis of autoimmune diseases. Consequently, recent data show that autoimmune diseases affect approximately 1 in 31 people within the general population. Growth has also led to a greater characterization of what autoimmunity is and how it can be studied and treated. With an increased amount of research, there has been tremendous growth in the study of the several different ways in which autoimmunity can occur, one of which is molecular mimicry. The mechanism by which pathogens have evolved, or obtained by chance, similar amino acid sequences or the homologous three-dimensional crystal structure of immunodominant epitopes remains a mystery.

Read more about Molecular Mimicry:  Immunological Tolerance, Autoimmunity, Probability of Mimicry Events, Structural Mimicry, Epitope Spreading, Control of Molecular Mimicry, Conclusion

Other articles related to "molecular mimicry":

Pathophysiology - Rheumatic Heart Disease
... and not fully understood, but it is known to involve molecular mimicry and genetic predisposition that lead to autoimmune reactions ... Molecular mimicry occurs when epitopes are shared between host antigens and GAS antigens ... In RHD, molecular mimicry results in incorrect T cell activation, and these T lymphocytes can go on to activate B cells, which will begin to produce self-antigen-specific antibodies ...
Molecular Mimicry - Conclusion
... The concept of molecular mimicry is a useful tool in understanding the etiology, pathogenesis, treatment, and prevention of autoimmune disorders ... Molecular mimicry is, however, only one mechanism by which an autoimmune disease can occur in association with a pathogen ... Understanding the mechanisms of molecular mimicry may allow future research to be directed toward uncovering the initiating infectious agent as well as recognizing the self determinant ...
Human Herpesvirus 6 - Clinical Significance - Multiple Sclerosis
... A few of the suggested mechanisms involve molecular mimicry, phosphorylation pathways, and cytokines ... Multiple sclerosis – molecular mimicry The first study to specifically investigate HHV-6-related demyelination appeared in the literature during 1996, when a previously healthy 19-month old child developed ... The molecular mimicry hypothesis, in which T cells are essentially confusing HHV-6 with myelin basic protein, first appeared around this time ...

Famous quotes containing the word mimicry:

    The character of the crowds is made up of mimicry and hostility.
    Franz Grillparzer (1791–1872)