Protecting molecules in biologically derived compositions...

Details Protecting molecules in biologically derived compositions... Protecting molecules in biologically derived compositions...

2000-02-11

2001-11-06

Naff, David M. (Department: 1651)

Chemistry: molecular biology and microbiology

Treatment of micro-organisms or enzymes with electrical or...

C435S002000, C435S262500, C435S195000, C435S196000

Reexamination Certificate

active

06312931

ABSTRACT:

BACKGROUND OF THE INVENTION
The use of biologically derived compositions in scientific research and in the manufacture of pharmaceutical/therapeutic substances is ubiquitous. Various human and animal sera are routinely used as a source of protein agents for treatment of various diseases and disorders; for example, to provide desired biomolecules effective as therapeutic agents and for the recovery of antigens that are useful in preparation of vaccines. Tissue culture methods are now commonly employed in the production of numerous pharmaceutical/therapeutic agents and related compositions, such as recombinant DNA and/or recombinant protein (from genetically engineered cell lines), virus vectors, amino acids, peptones, insulin and monoclonal antibodies; the products of such bioreactors require further processing.
Because these compositions are derived from living organisms, including humans, animals, plants and bacteria, they can be contaminated with one or more viruses, bacteria or other pathogens or with chemical toxins generally as result of some processing step. Persons having severely compromised immune systems, such as those with Acquired Immune Deficiency Syndrome (AIDS), are at particular risk for infection from exposure to contaminating pathogens or to chemical toxins in biologically derived compositions. In addition to posing a risk of infection to an individual or an animal receiving such a biologically derived composition, the effectiveness of the composition itself may be compromised by the presence of viral, bacterial and other pathogenic or chemically toxic contaminants.
Recombinant DNA and proteins, monoclonal antibodies, viral vectors and related compositions are also examples of biologically derived compositions used in both research and manufacturing processes that may be contaminated by viruses, bacteria and/or other pathogens. Therefore, in developing pharmaceutical manufacturing processes, steps are usually included to remove or inactivate viruses and other pathogens or toxins that might be present in such biologically derived compositions. Numerous methods of decontaminating or sterilizing biologically derived compositions are presently available, including physical methods, chemical methods, heat methods, irradiation methods and combinations thereof.
Certain well known methods of removing or inactivating viruses, bacteria and/or other pathogens contaminating biologically derived compositions are described, for example, in U.S. Pat. No. 4,540,573 (Neurath, et al.), U.S. Pat. No. 4,946,648 (Dichtelmüller, et al.), U.S. Pat. No. 5,418,130 (Platz, et al.), U.S. Pat. No. 5,527,704 (Wolf, Jr., et al.), U.S. Pat. No. 5,663,043 (Zepp, et al.) and U.S. Pat. No. 5,866,316 (Kempf, et al.). These patents describe combination treatments of biologically derived compositions to inactivate viral and/or bacterial contaminants therein, but include the use of at least one chemical agent to either directly degrade the contaminating organism or to sensitize it for degradation by another chemical agent or heat or radiation. In contrast, the use of light having particular characteristics has more recently been found to be particularly effective and efficient to treat such compositions. For example, U.S. Pat. Nos. 4,726,949, 4,866,282 and 4952,812, Miripol, et al. describe the irradiation of a thin layer of white blood cells with continuous ultraviolet radiation predominately of a wavelength of 280 nm to 320 nm, for about 0.25 to 15 minutes, in order to cause the white blood cells to substantially lose their capability to set off an immune reaction in an alloimmunized patient.
Broad-spectrum pulsed light (BSPL) provides an approach for deactivation of microorganisms and toxins using high-intensity, short-duration pulses of incoherent, polychromatic light in a broad-spectrum. BSPL can also be used to achieve desired rearrangement of biomolecules that are photosensitive to render them more biologically active. BSPL is different from continuous, non-pulsed UV light in a number of ways. The spectrum of BSPL contains UV light, but also includes a broader light spectrum, in particular between about 170 nm and about 2600 nm. The spectrum of BSPL is similar to that of sunlight at sea level, although it is 90,000 times more intense, and includes UV wavelengths between 200 and 300 nm which are normally filtered by the earth's atmosphere. BSPL is applied in short duration pulses of relatively high power, compared to the longer exposure times and lower power of non-pulsed UV light. See for example U.S. Pat. No. 5,034,235 (Dunn et al.), U.S. Pat. No. 5,489,442 (Dunn et al.), U.S. Pat. No. 5,768,853 (Bushnell et al.) and U.S. Pat. No. 5,786,598 (Clark et al.).
BSPL provides biological effects which are different from non-pulsed UV light. For example, pigmented bacteria, such as
Aspergillus niger,
are known to be more resistant to UV radiation than are bacillus spores. In studies using BSPL, however,
Aspergillus niger
was more sensitive, on dry surfaces, to BSPL than were three different bacillus spores:
Bacillus stearothermophilus, Bacillus subtilis
and
Bacillus pumilus.
Further, conventional UV treatment injures DNA by mechanisms that may be reversed under certain experimental conditions classified as either “dark enzymatic repair” or “light enzymatic repair” (Block, S.,
Disinfection, Sterilization and Preservation,
4
th
ed., Williams and Wilkins, U.S.A. (1991)). This photoreactivation by either dark or light enzymes does not occur when BSPL is used to treat microorganisms such as,
Bacillus subtilis, Bacillus pumilus, Aspergillus niger, Clostridium sporogenes, Candida albicans, Staphylococcus aureus, Escherichia coli, Salmonella choleraesuis
and
Pseudomonas aeruginosa.
The presence of wavelengths in the visible range differentiates BSPL from UV light as does the means for generating the two different lights. UV light is usually generated using mercury lamps, which pose some safety hazards; whereas BSPL is commonly generated by lamps using an inert gas, e.g. xenon.
BSPL has been found to be particularly effective in inactivating viruses which are often of greatest concern when manufacturing and using biologically derived compositions. Viruses are frequently grouped based upon their genome, i.e., DNA or RNA viruses, and/or according to the physical characteristic of being enveloped or non-enveloped. Further, individual viruses are generally categorized into a family of viruses with which they share certain evolutionary characteristics. Thus, for example, viruses in the herpes virus family (Herpesviridae) are enveloped DNA viruses, and viruses in the Adenoviridae family are non-enveloped DNA viruses. Examples of enveloped and non-enveloped RNA virus families are, respectively, the Flaviviridae family (which includes Yellow Fever virus, Hepatitis C virus and Bovine Diarrhea virus) and the Picornaviridae family (which includes Poliovirus, Rhinovirus and Hepatitis A virus). Viruses that are most virulent to humans include, for example, Parvovirus, Simian Vacuolating Virus (SV40), Human Immunodeficiency Virus (HIV), Hepatitis Viruses and Bovine Viral Diarrhea Virus (BVDV). BSPL is effective against all of the above.
BSPL has been used to decontaminate and/or sterilize various target objects, such as food products, packages, water and other fluid, semifluid and solid objects. Such is primarily accomplished by placing the target object into, or passing target object through, a BSPL sterilization chamber, and exposing the object to an appropriate number of flashes of BSPL at an appropriate energy level, as described in detail in the above four patents and U.S. Pat. No. 5,900,211 (Dunn, et al.). Its applications are also discussed in detail in the publication “Pure Bright® Sterilization System”, W. H. Cover of PurePulse Technologies of San Diego, Calif. (June 1999). While BSPL has been demonstrated to be useful in deactivating various microorganisms, it may also undesirably degrade certain biomolecules of interest, rendering them less biologically active and thus greatly reducing i

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