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Interferon's

Global Water & Biology, Conservation Research Institute and Access BioMedical offers human, mouse, rabbit and rat interferon for biochemical research in cell cultures and animal models. Accompanying these are negative control (mock interferon) preparations, antisera as well as purified immunoglobulin G fractions neutralizing the human, mouse and rat interferons (match pre-immune control sera are available), and antisera neutralizing the common viral interferon inducers (newcastle disease and parainfluenza 1 viruses) and assay challenge viruses  (encephalomyocarditis and vesicular stomatitis viruses). [A complete listing of antiviral sera and immunoglobulin's will be found on p. 71 and 76, respectively.]

Our laboratory is dedicated to excellence in interferon research. It is the original, and remains the sole source worldwide for most of these products. Many of the products have been in commerce since 1977 and have established a reputation for consistency, stability and utility in a wide range of studies in vitro and in vivo.

All interferon and anti-interferon products are supplied insterile, lyophilized form stable to ship at ambient temperature. For long-term storage, refrigeration is recommended. Stability of the rehydrated reagents is further discussed on page 5 and in application notes with accompany the products.

All buffers used in lyophilization are suitable for parenteral use by intravenous, intramuscular, intraperitoneal and subcutaneous routes without dilution and are compatible  in vitro at dilutions of about 1/25  (glycine buffer) or about 1/10 (other buffers). The buffers are interchangeable in virtually all applications. Samples of sterile, lyophilized buffer controls are available (page 20).  Buffer formulations are given on page 5.

CYTIMMUNE interferon activities established by repetitive comparative assays with interferon reference reagents  provided by the Antiviral Substance Program, National Institute of Allergy and Infectious Disease, National Institute of  Health (Table 1), using a modification of the vital dye uptake assay [1,2]. Access BioMedical participated in the 1985 collaborative titration of new human and mouse interferon reference reagents distributed by NIAID and the World Health Organization beginning in 1988 , and provided three if the mouse interferon preparations which have been adopted as reference reagents by these organization.

Protein concentrations are established by the coomassie blue-binding assay [3] using electrophoretically purified bovine serum albumin as standard.

Preparation of Interferons

With the exception of recombinant human alpha/1 and alpha/2 interferons (p. 8) all of the interferons offered by Access Biomedical are produced from nonrecombinant animal cell cultures using proprietary methods for cell growth, induction, accumulation, purification and lyophilization of the materials. The interferons are induced by exposing high- density cell cultures to the Manhattan (Kansas) strain of Newcastle disease virus, most of which is removed at the conclusion of induction. Interferons are accumulated in medium which contains no exogenous protein. During the accumulation phase, a gross protein concentration of 30 to 100 g/mL appears in the extracellular medium, consisting primarily of noninterferon proteins secreted by the cultures during accumulation of interferon as well as trace amounts of bovine serum proteins remnant from the growth phase and chick chorioallantoic fluid and Newcastle disease virus proteins arising from the induction phase. The titers of the crude interferons as removed from induced cell cultures are generally of the order of (approx.)10^5 IU per mL (human, rabbit and rat) to >10^6 IU/mL (mouse), and therefore the specific activities of the crude materials are usually in the range 10^6 to 5 x 10^7 IU/mg.

Designations of Interferons

The mouse and human interferon activities are designated as alpha or beta based upon: (1) distinct properties in a variety of chromatographic systems including controlled- pore glass, blue sepharose, hydroxylapatite, gel filtration and immunoaffinity columns; (2) distinct electrophoretic mobilities in discontinuous SDS- PAGE which confirm published reports; (3) distinct patterns of inactivation, stabilization or renaturation of activity by a variety of detergents, mercaptoethanol and heat; (4) distinct patterns of cross- reactivity when assayed with heterospecific cell cultures; and (5) results of neutralization by specific antisera or immunoglobulins in checkerboard titrations. More information is given on p. 22. The designations of mouse and human interferons as alpha or beta have been verified extensively in other laboratories. In particular, the mouse alpha, beta and alpha + beta interferon reference reagents distributed beginning in 1988 by the NIH (U.S.) and NIBSC (U.K.) have been prepared from interferons provided by Access Biomedical  which are identical to lots listed herein, and whose designations as alpha, beta or the unfractionated mixture have been verified rigorously in other laboratories in connection with their adoption as international reference reagents (see p. 23).

Acid- labile human alpha interferons have been prepared from time to time and are available on special order.

Access Biomedical currently does not offer gamma interferons of any animal species. However, a highly purified monoclonal rat immunoglobulin G1 which neutralizes mouse gamma interferon is available (please see p. 18). 

In Vivo Studies

Cytimmune interferons have been examined repeatedly since 1977 for acceptability in pharmacodynamic and pharmacologic studies in mice, rats and rabbits with excellent results. In no case has toxicity been associated with these materials. All buffers are suitable for parenteral use. Buffer control samples are available, at no charge, to the unconvinced. Any of the products at 10^6 IU/mg or higher is acceptable even in long- term dosage regimens (weeks to months). Nonetheless, to have the greatest margin of safety in long- term studies against the effects of small amounts of serum and other non- interferon proteins present in the materials, products at 10^7 IU per mg or higher are recommended.

Extensive experience has shown that Cytimmune interferon products are not toxic in vitro or in vivo. Consequently, we do not routinely test each lot for endotoxin or LPS activity. However, occasional checks of particular lots including mock, crude (10^5 IU/mg) and purified (10^7 - 10^8 IU/mg) interferons have invariably given undetectable results (less than 1 to 3 ng per mL) using the Limulus assay.

Access Biomedical has provided large quantities in single lots of rather highly purified mouse interferons (particularly purified beta or the unfractionated mixture of alpha + beta interferons) in support of two types of application requiring large amounts of material:

* for further purification to 1 to 2 x 10^9 IU/mg, generally by immunoaffinity chromatography. Such material is generally provided in frozen, aseptic form (rather than sterile and lyophilized) and at significant discount as compared with the sterile lyophilized form.

* for immediate parenteral use (upon rehydration of sterile, lyophilized material) in studies of antitumor or anti- viral activity, transplantation immunity and other types of studies in mice.

Specifications are generally in the range of 10 to 100 x 10^6 IU/mL and 3 to 20 x 10^7 IU/mg. Package sizes for nonsterile (aseptic), frozen material of about 50 to 100 x 10^6 IU, and package sizes in the range 10 to 20 x 10^6 IU for lyophilized, sterile materials, are generally available from stock. Orders for virtually any quantity are filled with material of a single lot so as to preclude uncertainty arising from the changing of lots during the course of study.

In order to facilitate studies in vivo, we recognize that interferon costs cannot remain prohibitively high. Researchers should not use catalogue list prices when inferring prices for large quantities of interferons. Discounts for catalogue items begin at ten or more vials of a single lot number and increase proportionately for larger quantities of catalogue items. Moreover, the price per 10^6 IU for quantities larger than about 50 to 200 x 10^6 IU (depending upon item and specifications) drops even more quickly so that investigators are assured satisfactory supply at prices which are reasonable. Access Biomedical  is pleased to provide written quotations, including complete product specifications, for large quantities of any of the Cytimmune INTERFERONS listed herein or for comparable items prepared according to your specifications when required.

Large quantities of murine interferons alpha, beta and alpha + beta have been provided by Access Biomedical  to many laboratories for parenteral use in antitumor, antiviral and transplantation studies in mice. Comparable if not identical lots of the same three murine interferon preparations have also been incorporated by Dr. S. Grossberg into reference reagents for mouse alpha, beta and alpha + beta interferons which are presently distributed by NIAID and WHO. This means that in vivo studies employing large quantities of our interferon products can now be standardized with reference reagents which are exact standards in the qualitative as well as quantitative sense [21].