Detection of neuronal tissue from brain grafts with anti-Thy-1.1 antibody.

Grafting of neural tissue has been used to investigate the ability of central nervous system (CNS) axons to elongate into peripheral nerve grafts; to investigate the growth characteristics of material transplanted within the CNS; and to determine if grafts producing amines or peptides can replace a natural or experimentally induced depletion of these biogenic molecules. In such experiments donor tissue has been distinguished from host by injection into graft cells of horseradish peroxidase or radioactive leucine or by detecting biogenic molecules in the grafted tissue with antibodies. All these methods have limitations and a technique which allows identification of the total neuronal cell output from transplanted tissue would be a powerful tool in delineating host-graft interactions. Polymorphic cell-surface antigens have not previously been exploited as markers. The Thy-1 antigen is an abundant glycoprotein of neurones and in the mouse exists in two allotypic forms called Thy-1.1 and Thy-1.2. We now show that tissue from Thy-1.1-positive animals grafted into Thy-1.1-negative brains can be clearly identified in cryostat sections using an anti-Thy-1.1 monoclonal antibody conjugated with peroxidase. We have used the method to study grafts from normal fetal mice which correct a developmental deficiency when transplanted into hpg mutant mice.