The abbreviation ADAM means „A Disintegrin And Metalloproteinase” and describes a group of glycoproteins, which are together with the SVMP’s (Snake Venom Metalloproteases) part of the reprolysin family of metalloproteases. ADAM12 is a part of the ADAM family. The two existing splice forms ADAM12-S and ADAM12-L are composed of a typical domain structure, which is a “signal peptide”, a “prodomain”, a “metalloproteinase domain”, a “disintegrin domain”, a “cysteine-rich domain” and in case of ADAM12-L a additional “transmembrane domain” and a “cytoplasmic tail”. ADAM12 mainly functions as a mediator of cell to cell contact, such as cell adhaesion, cell cell fusion and cell invasion. ADAM12 is a catalytically active protease and has a proven role during myoblast fusion and in the formation of osteoclasts. ADAM12 has also been found in syncytiotrophoblasts of placenta, even though its function during fusion of syncytiotrophoblasts has not been proven yet. The proven overexpression of ADAM12 in human cancer tissues, such breast and bladder cancer, leads to the presumption, that ADAM12 is connected to tumor cell invasion. Here the ADAM12 concentration also correlates with the tumor progression and the tumor grading. ADAM12 has also been detected in serum of pregnant women, which leads to the presumption, that ADAM12 has an important role for fetal growth, growth of the placenta and the preservation of pregnancy. It has been shown, that a low ADAM12 concentration in the serum of pregnant women in the first trimester correlates with the development of Trisomie 18 and 21 in the children and preaclampsia in the pregnant women. It has also been shown, that the overexpression of ADAM12 mediates shedding of the Oxytocinase (P-LAP). A low Oxytocinase level in pregnancy is an indication for a disfunctional placenta. Finally ADAM12 is responsible for the activation of growth factors such as EGF (epidermal growth factor), IGF I and II (insulin like growth factor). The overexpression of ADAM12 in cardiomyocytes leads to the activation of EGF resulting in the development of HOCM (hypertrophic obstructive cardiomyopathia). IGF I and II are of main importance during embryonal and fetal development. The aim of this work is to produce a specific polyclonal antibody against the different domains of ADAM12. The production of this antibody requires to be cheap and easy on the one hand and on the other hand the amount of produced antibody is supposed to be big. Also the antibody needs to be reproducible. Therefore hens as well as rabbits have been immunized with the same immunogen against ADAM12. The resulting IgY and IgG antibodies were tested in western blot immunoreactions and immunohistochemical staining on placenta of the first and the third trimester. In the end the results have been compared. As well the IgY antibodies out of egg yolk as the IgG antibodies out of rabbit sera proved their specificy for ADAM12 in the western blot immunoreaction. They were able to show the typical ADAM12 lines at 92, 68 and 40 kDa. The immunohistochemical staining of slices of first trimester and term placenta showed, that IgG antibodies out of rabbit sera served very well for the detection of ADAM12 in the syncytiotrophoblasts of placenta villous. Instead the IgY antibodies out of egg yolk are only able to prove the existence of ADAM12 in the syncytiotrophoblast villous of first trimester placenta. In the future ADAM12 will be of high clinical significance and can serve as a possible marker for diagnostic and progress of certain diseases. For the development of a standardized test for the detection of ADAM12 we need a cheap production of high amounts of ADAM12 specific and reproducible antibodies. The IgY antibodies out of egg yolk offer a few advantages towards the IgG antibodies out of rabbit sera. The IgY antibodies are much cheaper in their production and their extraction is unbloody and non invasive. Furthermore the amount of antibody out of one hen during a whole year is about thirty times higher than the amount of antibody out of the whole serum of one rabbit. It is a matter of fact that hens are distant from mammals in their origin, which results in a stronger immunoreaction. Also the IgY antibodies don’t show any cross reactivity towards human rheumatic factors. That leads to less wrong positive results in serum testings. The disadvantage of commercially purchased IgG antibodies out of rabbit sera is that at some point of time their charge is not available anymore and the new clones will be of a modified antibody specificy. In conclusion the development and production of IgY antibodies out of egg yolk is a cheap and realistic alternative.