Self antigens are antigens derived from cells of an organism the immune system , such as macrophages , lymphocytes , B cells and NK cells , as the body's own presents be. The self-antigens are important for immunological tolerance, in which the immune system recognizes the body's own substances as such and does not fight them ( self-tolerance ).
Self antigens and their function
T lymphocytes that recognize a self antigen during thymocyte development in the thymus - that is, are autoreactive - are selected out by apoptosis ( negative selection ).
The self-antigens presented are not complete proteins , but peptide fragments . The fragments arise from protein degradation in the proteasome (→ see main article Antigen presentation ). In the thymus, the T cells become more tolerant
- Components of the serum,
- general proteins of cell metabolism and
- Cell surface antigens
"Trained". Negative selection also takes place outside the thymus, in the periphery, when T cells come into contact with the self antigen. If this selection does not take place, for example because the thymus epithelia do not express enough self-antigens , this can lead to autoimmune diseases . In these cases , the self-antigens are autoantigens to which autoantibodies can bind.
B cells that recognize soluble, i.e. not cell-bound, self-antigens are anergic to these "antigens" .
With self-antigens coupled to strong adjuvants , it is possible to obtain autoreactive T cells, i.e. T cells that are directed against one's own body, through immunization.
- ↑ JW Kappler et al .: T cell tolerance by clonal elimination in the thymus. In: Cell 49, 1987, pp. 273-280. PMID 3494522
- ↑ HP Blüthmann et al .: T-cell-specific deletion of T-cell receptor transgenes allows functional rearrangement of endogenous alpha- and beta-genes. In: Nature 334, 1988, pp. 156-159. PMID 3260351
- ↑ U. Steinhoff et al: Prevention of autoimmune lysis by T cells with specificity for a heat shock protein by anti-sense oligonucleotide treatment. In: PNAS 91, 1994, pp. 5085-5088. PMID 7910966
- ↑ UJ Steinhoff: From tolerance to autoimmunity. In vivo analyzes on the function and importance of autoreactive CD4 + and CD8 + T cells. Habilitation, Humboldt University Berlin, 2000 DNB 965789241/34
- ^ WO Weigle: Analysis of autoimmunity through experimental models of thyroiditis and allergic encephalomyelitis. In: Adv Immunol 30, 1980, pp. 159-273. PMID 6160739 (Review)
- M. Blackman et al .: The role of the T cell receptor in positive and negative selection of developing T cells. In: Science 248, 1990, pp. 1335-1341. PMID 1972592
- AC Allison and AM Denman: Self-tolerance and autoimmunity. In: Br Med Bull 32, 1976, pp. 124-129. PMID 782632
- M. Kleinewietfeld: Characterization of CD25 + regulatory T cells. Dissertation, FU Berlin, 2006
- Tolerance and Autoimmunity (University of Vienna; PDF file; 2.67 MB)
- Autoimmunity II (Kiel University; PDF file; 399 kB)