The preparation of pyrogen-free foetal calf serum for use in cell and tissue cultured.

A method is described for the preparation of foetal calf serum from blood drawn by heart puncture from calf foetuses obtained from a local municipal abattoir. This method differs from that previously described in that the Seitz Supra EK filter pads used in preliminary purification steps have been abandoned. These pads contain significant amounts of pyrogenic bacterial lipopolysaccharides and attempts to depyrogenate them with sodium hypochlorite, hydrogen peroxide and 1% foetal calf serum were unsuccessful. The modified method uses pyrogen-free glass fibre and cellulose fibre filters and provides an entirely satisfactory serum as proved by negative Limulus amoebocyte lysate tests and the excellent growth of cells.