Calf Serum Factor Research Articles

A Universal Virus Inactivant for Decontaminating Blood and Biopharmaceutical Products

Removal of virus infectivity from blood and biopharmaceutical products prepared from blood is an issue of considerable importance. For biopharmaceutical products, removal can usually be achieved by a series of fractionation steps or by inactivation with a suitable reagent. Irrespective of the methods that are chosen it is vital that the biological activity of the product is not impaired. For blood and unfractionated plasma or serum, the problem is even more challenging.Selective inactivation of the genome is the key step in the preparation of killed virus vaccines. Viruses belonging to all the recognised families can be inactivated by imines. In this paper it is shown that the biological properties of several proteins, including the cell growth-promoting factors in calf serum, are not impaired using conditions which ensure the inactivation of >1015infectious units of poliovirus and foot-and-mouth disease virus (FMDV). Also shown is that both viruses can be inactivated by imines at 4°C, thus providing a method for removing infectivity from protein preparations which are unstable at higher temperatures. The RNA extracted from FMDV inactivated at 4°C was not degraded and contained no hidden breaks but nevertheless was non-infectious. However, it could be amplified by PCR using primers corresponding to the gene coding for a portion of the viral RNA polymerase, but not from that coding for VP1, one of the structural proteins, showing that alteration of a base or bases had occurred in that region. Surprisingly, it could be translated in the rabbit reticulocyte system although some of the products were different from those obtained with unmodified RNA.

Recombinant γ-interferon stimulates iodide uptake and cyclic AMP production by the FTRL 5 thyroid cell line

The effect of recombinant rat γ-interferon (γ-IFN) on iodide uptake and cAMP production by rat thyroid cells in vitro was studied using the continuously growing, functional FRTL 5 cell line. Both functions were stimulated by γ-IFN at concentrations of 1–10 U/ml. Iodide uptake was dependent on protein synthesis, since it was blocked by cycloheximide treatment, but was not dependent on growth factors in calf serum routinely used for FRTL 5 cell culture. These results show that γ-IFN can stimulate thyroid cell function as well as aberrant Ia expression in vitro.

Stimulation of in-vitro growth of rat liver cells with calf serum drawn following partial hepatectomy

The study described indicates that there is a factor or factors in calf serum drawn following partial hepatectomy which accelerates the in vitro growth of liver cells of another species, in this case, the rat. This factor appears to be stimulatory specifically to liver cells, as opposed to kidney cells or HESM cells. The effect may be noted with serum drawn from the calf for 1 to 3 weeks following partial hepatectomy, and not with serum drawn from the same calf prior to the liver extirpation or more than 3 weeks following the extirpation. It appears that development of this stimulatory effect in the serum of the donor animal is related to the excision of liver tissue, and not to the excision of kidney or a segment of the intestinal tract, or to the removal of whole blood.