PROM1 and malignant glioma: The IgY anti-CD133 obtained recognized specifically the CD133 protein; cytotoxicity tests confirmed that the avian immunoglobulin was nontoxic to various cell lines from human and rat malignant glioma, suggesting that the binding of anti-CD133 IgY antibody without the cytotoxic protein to these cells does not activate cell death pathways.