Polynucleotide aggregates enhance the transport of protein at the surface of cultured mammalian cells

It was known that polycationic polymers enhance the entry of macromolecules into cells. We now show that polynucleotides may have similar effects, when used as large aggregates. Poly(1-vinylcytosine):polyinosinic acid, an inducer of interferon production in human cells, can cause at 40 μg/ml a 75-fold enhancement of albumin uptake by sarcoma cells in culture. Most of this activity (85%) is related to the presence of aggregates retained by 0.65 μ millipore membranes. The prior finding that enhancers of albumin transport have increasing effects with increasing molecular sizes may thus extend to complexes of supramolecular sizes.