Immunogenicity antigen metabolism

It is reasonable to presume that the immunogenic and adjuvant activity of lipospheres may be the result of a combination of factors. These factors may include a focused and enhanced delivery of the antigen to an antigen-presenting cell (macrophage) and protection of the antigen from metabolic destruction at other sites in the body that do no participate in the immune response. 

Naisbitt, D.J., Fraser Gordon, S., Pirmohamed, M., Burkhart, C., Cribb, A.E., Pichler, W.J., and Kevin Park, B., Antigenicity and immunogenicity of sulphamethoxazole demonstration of metabolism-dependent haptenation and T-cell proliferation in vivo, Br. J. Pharmacol., 133, 295, 2001. 

Three forms of calcitonin are available, salmon, porcine and human calcitonin. Long-term use of porcine calcitonin, being the most antigenic product, can lead to the production of neutralizing antibodies. Synthetic salmon preparations are therefore preferable. Human calcitonin is less immunogenic but it is also less active. Human calcitonin monomer has a half-life of about 10 minutes while the half-life of salmon calcitonin is considerably longer. However these half-lives are not directly related to the duration of action which varies from 30 min to 12 hours after intravenous administration and from 8 hours to 24 hours when administered subcutaneously or intramuscularly. Calcitonin is metabolized in the blood and in tissues like for example the kidneys. 

The resulting epitope density may depend on the number of lysine groups in the particular protein, and this will in turn affect the immunogenicity of the antigen. Trifluoroacyl adducts have been detected on the outer surface of hepatocytes, presumably as a result of the hapten-complex processing and delivery by MHC I, which is described above. The fact that the production of the trifluoroacetyl chloride is part of the major metabolic pathway and that the majority of patients produce trifluoroacylated proteins suggests that it is differences in the immune surveillance system or immune responsiveness, which determine which patients will succumb to the immunotoxic effect. 

Toxins. Metabolic products from microorganisms, plants, or animals with a poisonous effect on mammals, especially, humans. T. are mostly immunogenic, i.e., they can induce the formation of specific antibodies (antitoxins) as a result of their antigen character. They belong to widely differing classes of compounds such as proteins, lipopolysaccharides, alkaloids, terpenoids, steroids, aliphatic acids, biogenic amines, and guanine derivatives. 

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