Children’s Brain Tumour Cells Produce RNA Particles with Incomplete Retrovirus Characteristics

Abstract

Short-term cultures of cells from human brain tumours have been reported to synthesise RNA particles of density in the range characteristic of C type RNA retroviruses, with associated DNA polymerase activity. Fresh tumour cells obtained from 6 children with astrocytoma and 7 children with medulloblastoma, together with one sample of normal brain tissue and normal leukocytes from brain tumour patients were assayed by several characteristics for the presence of primate retrovirus. 1 of 6 (17%) astrocytomas and 4 of 7 (57%) medulloblastomas released RNA particles which banded in sucrose gradients at a density of 1.16–1.18 g/cm³ together with a short segment of DNA, which was eliminated by prior ribonuclease treatment and two proteins of 28k and 16k daltons. These findings were compatible with the presence of a primate retrovirus. Immune coprecipitation of ¹²⁵I-labelled proteins from the 1.16–1.18 g/cm³ gradient region failed to show any reactivity with antisera to p28 core antigens or the p70 reverse transcriptase antigens of simian sarcoma virus, baboon endogenous virus or Mason Pfizer virus. Assays for DNA polymerase activity in culture supernatant fluid showed only a low amount of activity with template preferences not characteristic of the retroviral reverse transcriptase enzyme.

Pathogenesis of Multiple Sclerosis: Implications Based on Its Multifactorial Etiology

“…It also is not clear [58,59] how T-cell subsets change before or after exacerbation of disease, i.e., whether decreases in Ts function occur because of active disease, or vice versa. [62,63], coronaviruses [64], and other viruses or virus-like agents [65][66][67] can be isolated from various tissues of MS patients. However, our experience [68][69][70], and those of other investigators, in dicates that such viruses (and other agents) often are latent in the tissues of immunologically debilitated patients.…”