Immunogenicity

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The immunogenicity , and immunogenicity called, is the property of a substance in the animal or human body as an immune response described reaction of the immune system trigger. Substances with an immunogenicity are called immunogens . The immunogenicity is not a fixed parameter, but depends on the immune system of the organism in which the substance in question is located. It is therefore both individually different and also dependent on the degree of phylogenetic relationship between the animal species from which the antigen originates and the animal species in which it acts as an immunogen.

Factors

A substance that is recognized by the organism as an antigen can trigger an immune response via various mechanisms and therefore have an immunogenic potential. Protein or peptide components play a central role in the immunogenicity of a substance mediated by the adaptive immune system. Only these are presented after enzymatic cleavage in the lysosomes on the cell surface of antigen-recognizing cells, such as B-lymphocytes , macrophages or dendritic cells , and recognized by T-lymphocytes . The immunogenicity of lipopolysaccharides , bacterial DNA and double-stranded viral RNA is due to the involvement of the innate immune system and mostly an activation of toll-like receptors .

The degree of immunogenicity of a substance depends on several factors. These include, in particular, foreign bodies, molecular size and chemical structure. Other factors, such as the type of immunogen uptake, can also influence the degree of immunogenicity. Antigens administered subcutaneously or intracutaneously trigger the strongest immune response, while potential immunogens administered intravenously are largely tolerated.

Alienness

An important prerequisite for immunity is foreignness. The reason for this is the self-tolerance of the immune system, with which the body's own antigens are recognized and an immune reaction is suppressed.

Molecular size

Another relationship exists between the size of the molecule and the immunogenicity of a substance. Substances with a molecular mass of less than about 5000 Dalton are usually not immunogenic.

Chemical structure

Another influencing factor are the chemical properties of the molecule, whose secondary and tertiary structure must have certain characteristics for an immunogenic effect. The molecule segments in question that are relevant for an immune response are also referred to as epitopes . The number and density of such epitopes on a molecule thus determine the extent of immunogenicity. Particulate or aggregated proteins are highly immunogenic because they are particularly easily taken up by the antigen-presenting cells .

Individual evidence

  1. ↑ Wolfgang Jelkmann: Immunogenicity of recombinant therapeutics . In: Irene Krämer, Wolfgang Jelkmann (Hrsg.): Recombinant drug-medical progress through biotechnology . Springer, 2008, ISBN 3540879730 , pp. 63-74.
  2. ↑ Medzhitov R, Janeway Jr. CA: Decoding the Patterns of Self and Nonself . In: Science . 296, 2002, pp. 297-300.

literature

  • Immunologists' Toolbox: Immunization. In: Charles Janeway , Paul Travers, Mark Walport, Mark Shlomchik: Immunobiology. The Immune System in Health and Disease. 6th edition. Garland Science, New York 2004, ISBN 0-8153-4101-6 , pp. 683-684
  • Wolfgang Jelkmann: Immunogenicity of recombinant therapeutics . In: Irene Krämer, Wolfgang Jelkmann (Hrsg.): Recombinant drug-medical progress through biotechnology . Springer, 2008, ISBN 3540879730 , pp. 63-74.