Immunoglobulin Y

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Immunoglobulin Y , abbreviated as IgY , is a class of immunoglobulin molecules that are found in the serum of chickens and, in high concentrations, in the yolks of hen's eggs in particular . As with the other immunoglobulins, IgY are proteins that are formed by the immune system in response to certain foreign structures and specifically recognize them.

properties

Immunoglobulin Y is the functional equivalent of IgG in chickens and, like IgG , is made up of two light and two heavy chains. Structurally, the two immunoglobulin classes differ mainly in the heavy chains, which in IgY have a molecular mass of around 65.1 kilodaltons and are therefore larger than in IgG. The light chains of IgY are slightly smaller compared to IgG with a molar mass of around 18.7 kilodaltons. The molar mass of IgY is about 167 kilodaltons. The steric flexibility of the IgY molecule is less than that of IgG.

Functionally, IgY is partially comparable to both IgE and IgG. However, in contrast to IgG, IgY does not bind to protein A or protein G , nor to cellular Fc receptors . In addition, IgY does not activate the complement system . The name immunoglobulin Y was proposed by GA Leslie and LW Clem in 1969 after showing differences between the immunoglobulins and immunoglobulin G found in chicken eggs. Other synonymous names are Chicken IgG , Egg Yolk IgG or 7S-IgG .

Bioanalytical Applications

For the targeted acquisition of antibodies and their use in bioanalysis , IgY offers various advantages over the use of mammalian antibodies. Since the antibodies are obtained from the yolk of laid eggs, it is a non-invasive method of antibody production. So no blood has to be taken from the animals to obtain blood serum. Repeatedly laying eggs from the same chicken significantly increases the available amount of a particular antibody. The cross-reactivity with proteins from mammals is also significantly lower than that of IgG. In addition, the immune response to certain antigens is more pronounced in chickens than in rabbits or other mammals. Since only IgY of the immunoglobulins formed during the immune response is found in chicken eggs, no IgA or IgM contamination is contained in the corresponding preparations . The yield of IgY from a chicken egg is comparable to that of IgG from rabbit serum.

A disadvantage of IgY compared to mammalian antibodies is that it is more difficult to purify from egg yolk than IgG from blood serum. In large part, this is due to the fact that Protein A and Protein G can not bind IgY . This means that it cannot be separated from other components of the sample, for example other proteins, with the help of these two substances. In addition, the abundant lipids and lipoproteins in the egg yolk must be removed before use. Blood sera containing antibodies, on the other hand, can in part be used directly in bioanalytics, i.e. without complicated purification steps.

Application in food

IgY is used as a component of food in Asian countries such as Japan in particular . For example, yoghurt products containing specific IgY are sold there. This will prevent the attachment of bacteria of the kind Helicobacter pylori in the stomach . The IgY used for this is obtained from the eggs of immunized chickens. Antibodies are thus also produced against salmonella and other bacteria, but also against viruses and used as part of food to protect against these pathogens .

literature

  • Rüdiger Schade, Irene Behn, Michael Erhard: Chicken Egg Yolk Antibodies, Production and Application. Springer-Verlag, Berlin 2001, ISBN 3-540-66679-6 .
  • GA Leslie, LW Clem: Phylogeny of immunoglobulin structure and function. 3. Immunoglobulins of the chicken. In: Journal of Experimental Medicine . 130 (6) / 1969. Rockefeller University Press, pp. 1337-1352, ISSN  0022-1007 .
  • A. Polson, MB von Wechmar, MH van Regenmortel: Isolation of viral IgY antibodies from yolks of immunized hens. In: Immunological Communications. 9 (5 )/1980. Dekker, New York, pp. 475-493, ISSN  0090-0877 .
  • A. Polson, MB von Wechmar, G. Fazakerley: Antibodies to proteins from yolk of immunized hens. In: Immunological Communications. 9 (5 )/1980. Dekker New York, pp. 495-514, ISSN  0090-0877 .

Individual evidence

  1. ↑ Elvira Schecklies: Polyclonal Antibodies . First edition. VCH Verlagsgesellschaft, Weinheim 1996, ISBN 3-527-30078-3 .
  2. ↑ H. Suzuki, S. Nomura, T. Masaoka et al.: Effect of dietary anti-Helicobacter pylori-urease immunoglobulin Y on Helicobacter pylori infection . In: Alimentary Pharmacology and Therapeutics . 20 Suppl 1, July 2004, p. 185-192 , doi : 10.1111 / j.1365-2036.2004.02027.x , PMID 15298626 .
  3. ↑ K. Horie, N. Horie, AM Abdou et al .: Suppressive effect of functional drinking yogurt containing specific egg yolk immunoglobulin on Helicobacter pylori in humans . In: J. Dairy Sci . tape 87 , no. December 12 , 2004, pp. 4073-4079 , PMID 15545368 .