Chicken Antibodies

Abstract

The chicken immune system has been studied for many years and these studies have contributed substantially to our understanding of the fimdamental concepts of immunology and the development of different immunoglobulin classes It is thus surprising that only a small fraction of the antibodies presently used in laboratories are of avian origin A laying hen produces more yolk antibodies than a rabbit can produce during the same time period, and the animal care costs are lower for the chicken compared to the rabbit Chicken antibodies offer many advantages to the traditional mammalian antibodies when used for the detection of mammalian antigen Due to the evolutionary difference chicken IgY will react with more epitopes on a mammalian antigen, which will give an amplification of the signal Chicken antibodies can also be used to avoid interference in immunological assays caused by the human complement system, rheumatoid factors, human anti-mouse IgG antibodies (HAMA) or human and bacterial Fc-receptors The antibodies can be purified in large amounts from egg yolk, making laying hens highly efficient producers of polyclonal antibodies IgY is an ancestor to mammalian IgG and IgE and also to IgA. ANTIBODY DIVERSITYThe antibody diversity in chicken differ from mammals and is mainly due to somatic hyperconversion. Rearrangement apparently contributes little to the diversity as both the heavy and the light chain loci consist of only one functional V gene (38,44). There seems to be a deficiency in the mechanism for selecting higher-affinity somatic mutants.Chicken antibody has the valency of 2.0 and sometimes higher which might be due to large antigen-binding sites (43). Most chicken IgY bind antigen strongly but display precipitation properties only at raised salt concentrations (16). The poor precipitation properties might be due to steric hindrance of the Fab arms to crosslink epitopes of two large antigens. The conditions permitting precipitation (salt -1.5 M) might loosen the restricted movement of the Fab arms and give functional independence to the binding sites. I80 ADVANTAGES OF CHICKEN ANTIBODIESAs the difference between the antigen and the immunized animal increases, the immune response usually increases. There is a vast phylogenetic difference between avian and mammalian species compared to the difference between two mammalian species. This evolutionary spread means that there is no immunological cross-reactivity between chicken IgY and mammalian IgG (18). Thus, chicken should be a better choice than e.g. rabbits for the production of antibodies against mammalian proteins. Due to evolutionary differences chicken antibodies will bind to more epitopes on a mammalian protein than the corresponding mammalian antibody. It has been shown that 3-5 times more chicken antibody than swine antibody will bind to rabbit IgG (1 7), which will amplify the signal (35). Chicken antibodies also recognize other epitopes than mammalian antibodies (41).This gives access to a different antibody repertoire than the traditional m...

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“…IgY antibodies can be isolated in large quantities from egg yolk using simple separation methods; the non-invasive production method also brings the great benefit concerning the welfare of the immunized animals [42]. IgY antibodies can also be used to avoid interference in immunological assays caused by the human complement system, rheumatoid factors, human anti-mouse IgG antibodies (HAMA) or human and bacterial Fc-receptors [43]. Similarly, for clinical use as antibody-based therapeutics, they neither activate mammalian complement nor interact with mammalian Fc receptors that could mediate inflammatory responses [44].…”

Dengue virus specific IgY provides protection following lethal dengue virus challenge and is neutralizing in the absence of inducing antibody dependent enhancement

“…Another key advantage of IgY is its inability to bind mammalian FcγR; therefore, it is possible that anti-DENV IgY will be able to neutralize a viral infection without inducing ADE [18]. Furthermore, IgY does not interact with other Fc-binding receptors, which limits its ability to elicit an inflammatory reaction in humans [19–24]. Although IgY is able to activate complement in the avian system, its unique structure prevents it from being able to activate human complement [23].…”

Prophylactic and Therapeutic Efficacy of Avian Antibodies Against Influenza Virus H5N1 and H1N1 in Mice

“…Chickens produce a unique immunoglobulin molecule called IgY that is functionally equivalent to mammalian IgG [8]. IgY are found in the sera of chickens and are passed from hens to the embryo via the egg yolk, imparting a high concentration of chicken IgY to the developing embryo [9]. Egg IgY have been used to prevent bacterial and viral infections [see review [10]] of the gastrointestinal tract and recently for protection against Pseudomonas aeruginosa infection of the respiratory tract of patients with cystic fibrosis (CF) [11].…”