35] Interferon induction with microbial products

Abstract

This chapter describes two approaches to obtain extracorporeal photopheresis (ECP) by either aqueous or phenol extraction of heat-killed bacterial cells. These preparations have been shown to induce interferon and provide antiviral resistance in animals. The phenol extraction, provides a phenol-soluble protein (PSP) for which the starting material is an envelope suspension composed of the 10,000g pellet referred to above suspended in saline to 0.5 g/ml. The PSP may be concentrated while still in the dialysis bag by removing water through contact with polyethylene glycol flakes (20,000 MW polymer, Carbowax) and made isotonic by further dialysis, then diluted to the desired volume (usually equal to that of the 0.5 g per milliliter of envelope suspension) with saline and sterilized by filtration. After intravenous injection of 0.2 ml of ECP or PSP into the tail vein of adult female mice, samples of blood are taken from the retroorbital venous sinus in CO 2 -narcotized mice, usually 2 hour after injection, the time of maximum titer (about 1000 units/ml).