Background: Glioblastoma is the most common and aggressive type of primary brain tumor in adults. A key problem is the capacity of glioma cells to inactivate the body's immune response. The complement system acts as a functional bridge between the innate and adaptive immune response. Still, the role of the complement system has almost been forgotten in glioma research. In our present study, we hypothesize that C1 inactivator (C1-IA) is upregulated in astrocytoma grade IV, and that its inhibition of the complement system has beneficial effects upon survival.
Methods and results: We have explored this hypothesis both on gene and protein levels and found an upregulation of C1-IA in human glioblastoma cells using data from a publicly available database and our own mRNA material from glioblastoma patients. Furthermore, we demonstrated the presence of C1-IA by using immunohistochemistry on glioma cells from both humans and rats in vitro. Finally, we could demonstrate a significantly increased survival in vivo in animals inoculated intracerebrally with glioma cells pre-coated with C1-IA antibodies as compared to control animals.
Conclusions: Our findings indicate that overexpression of C1-IA is present in glioblastomas. This could be demonstrated both at the gene level from patients with glioblastoma, on mRNA level and with immunohistochemistry. Treatment with antibodies against C1-IA had beneficial effects on survival when tested in vivo.