Antigen generation

Mezey, E., Chandross, K.J., Harta, G., Maki, R.A., McKercher, S.R. (2000). Turning blood into brain cells bearing neuronal antigens generated in vivo from bone marrow. 

In the last years, the number of publications related to QD-FRET-based systems has increased continuously. In 2008, a FRET-based nanosensor was developed for the rapid detection of human cardiac troponin I, which is a key factor for the early detection of myocardial infarction.96 In this system, a donor(QD)-labeled protein A is bound to an acceptor-labeled capture antibody and the presence of troponin I antigen generates a conformational change within the structure of the antibody. This results in a change of the distance between the donor and acceptor and, therefore, a shift in energy transfer is observed. A limit of detection of 55 nM of troponin in human plasma and a very short time of analysis (1 minute) were reported using this biosensor. 

Addition of GIcNAc in a pi-6 linkage to Tn antigen generates the putative core 6 structure (Fig. 2g). Core 6 structures have been reported to occur in human ovarian tissue, but an enzyme responsible for core 6 formation has not been identified (19). 

Willis RA, Bowers WJ, Turner MJ, Fisher TL, Abdul-Ahm CS, Howard DF, Federoff HJ, Lord EM, Erehnger JG (2001) Dendritic cells transduced with HSV-1 amphcons expressing prostate- specific antigen generate antitumor immunity in mice. Hum Gene Ther 12 1867-1879. 

Melhotra I, Ouma J, Wamachi A, et al In utero exposure to helminth and microbial antigens generates cytokine responses similar to that observed in adults.. 1 Clin Invest 1997 99 1759-1766. 

Eva Mezey, Karen J. Chandross, Gyongyi Harta, Richard A. Maki, Scott R. McKercher, Turning Blood into Brain Cells Bearing Neuronal Antigens Generated in Vivo from Bone Marrow, Science, 290 (2000), 1779-1782. 

Schwartz, H. R., Nerurkar, L. S., Spies, J. R., Scanlon, R. T., and Bellanti, J. A., 1980, Milk hypersensitivity RAST studies using new antigens generated by pepsin hydrolysis of beta-lactoglobulin, Ann. Allergy 45 242. 

An allergen is usually an inert substance (e.g. pollen, house dust mite faeces) that in some individuals can trigger the generation of an (inappropriate) antigenic response. Mediated by TH2 lymphocytes, it causes B-Lymphocytes to produce lgE. Subsequent exposure of a sensitized individual to the allergen is therefore able to cross-link IgE antibodies on the surface of mast cells and trigger an immune response and histamine release. 

In this type of reaction an antigen elicits the generation of cytotoxic T-lymphocytes ( immune defense). Cytotoxic T-lymphocytes (Tc) destroy antigen bearing cells by inducing apoptosis. This reaction can be viewed as the cellular counterpart to the humoral Type II reactions. They play an important physiological role in the defense of viruses, and can become allergic reactions under the same conditions as described for Type II reactions. 

It is clear that generated by such a random process the initial repertoire of antigen specifity in all individuals of human beings should be quite similar. This implies that initially in each individal there develop lymphocytes which recognize antigens of this very individual, i.e. autoantigens. 

Autoimmune Disease. Figure 2 Generation of autoreactivity. APC, antigen presenting cell IFN, interferon LPS, lipopolysaccharide MHC, major histocompatibility complex T, T-lymphocyte TCR, Tcell (antigen) receptor TLR, toll like receptors. For details see text. 

Cellular therapies in transplantation and cancer are based on specific cells separated or sorted from human blood, bone marrow, or cord blood by means of their specific cell surface markers or cell differentiation antigens, e.g., CD3, CD4, CD8, CD 14, CD 19, and CD34. For example, the CD34+ stem cells, especially those derived from human embryos, have the capacity to differentiate in culture to generate different somatic cells, e.g., liver cells, heart cells, neurons, etc. This exploding field of research is now termed regenerative medicine. 

Monoclonal antibodies (mAh) are molecules that recognize and bind a specific foreign substance called an antigen. They are produced from a single clone of B lymphocytes. Conventionally, mouse mAh have been generated for experimental and diagnostic use. Techniques have been developed to humanize mouse mAh to facilitate their therapeutic use in humans. It is also now possible to make mAh which are fully human. 

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