Human glioblastoma is one of the most deadly forms of cancer, leaving most patients 3-6 months to live following tumor detection. Current glioma treatments include resection of the main tumor mass, which is not entirely effective. Resection leaves tumor cells that have metastisized into the surrounding brain tissue where they can form new sites of tumor. We have found that NSCs that have been therapeutically engineered to secrete an enzyme activated pro-drug have novel clinical potential for tracking invasive high grade glioma cells. We propose to use a therapeutically engineered NSC line (HB1.F3; characterized vmyc-immortalized fetal NSCs, karyotype- normal human XX, HLA experssion- class I positive, class II negative) to target high grade gliomas in patient trials. The aim of this study is to determine the immunogenicity of HB1.F3 NSCs in an immune competent (C57 Black) mouse brain. Results will aid in determining the feasibility and safety of potential future glioma patient trials by analyzing the risk of an immune reaction that could result in the rejection of these therapeutic drug-delivery vehicles, or cause the patient to become ill. The immunogenecity of these cells will be measured via immunohistochemical staining of brain and spleen tissue, and FACS sorting of fresh spleen cells.