IL2-like material is present in human placenta and amnion.

Human term placenta was shown to react with different polyclonal and monoclonal anti-interleukin 2 (IL2) antibodies by using indirect immunofluorescence on frozen sections. Labelling was localized on syncytiotrophoblast membrane, amniotic epithelium and cytotrophoblast of the reactivity [corrected]. The reproducibility of the observations with different basal plate. These features were observed with two different rabbit anti-IL2 polyclonal antibodies, a sheep IL2 antiserum and 15.2, an anti-IL2 monoclonal antibody. However, DMS-1, a second anti-IL2 monoclonal antibody, did not react. Pre-incubation of anti-IL2 sera with IL2 resulted in the disappearance of syncytiotrophoblast reactivity. The reproducibility of the observations with different reagents strongly suggests that the recognized molecule shares several epitopes with IL2. However, it has not been possible to demonstrate the presence of a conventional IL2 receptor by using two monoclonal antibodies directed to the 55 kDa chain of IL2 receptor.