Differential proliferative response of human and mouse astrocytes to gamma-interferon

We have previously shown that gamma-interferon promoted the proliferation of adult human astrocytes isolated from brain biopsy specimens. In contrast, in the present study, astrocytes derived from neonatal mouse brains and treated with recombinant murine gamma-interferon responded by a decrease (average of 50% at 100 U/ml) in proliferation. The basal rate of proliferation as assessed by bromodeoxyuridine incorporation was markedly increased in neonatal mouse astrocytes when compared to the adult human cells, suggesting that age, and the corresponding metabolic activity of cells, could be important determinants in the mitogenic response of astrocytes to cytokines. However, subsequent examinations of fetal human and adult mouse astrocytes, with comparable basal rate of proliferation to neonatal mouse and adult human cells respectively, showed gamma-interferon to promote DNA synthesis in fetal human astrocytes while inhibiting that of adult mouse astrocytes. The results suggest species differences in the proliferative response of human and mouse astrocytes to the cytokine gamma-interferon.