Chemistry: natural resins or derivatives; peptides or proteins; – Proteins – i.e. – more than 100 amino acid residues – Plant proteins – e.g. – derived from legumes – algae or...
Reexamination Certificate
1995-09-15
2004-07-06
Nolan, Patrick J. (Department: 1644)
Chemistry: natural resins or derivatives; peptides or proteins;
Proteins, i.e., more than 100 amino acid residues
Plant proteins, e.g., derived from legumes, algae or...
C530S868000
Reexamination Certificate
active
06759517
ABSTRACT:
This invention relates to allergenic proteins of natural rubber latex in substantially purified form, their production and their use, together with monoclonal antibodies developed against those allergenic proteins, in assays for the qualitative and quantitative determination of the levels of the allergenic proteins in natural rubber latex or in products made from latex. Assays for identifying and/or quantitating antibodies in blood or blood products that mediate the occurrence of an allergic reaction induced by natural rubber latex are also provided, together with in vivo and in vitro diagnostic tests for detecting hypersensitivity to natural rubber latex and which involve use of the aforesaid allergenic proteins. The invention also provides for the use of the aforesaid allergens as de-sensitising agents in the treatment of latex protein allergy. There is still further provided a method for removing allergenic proteins from latex products.
There now follows a glossary defining certain of the terms used hereinafter:
Total protein: All protein and fragments thereof present in a sample.
Antigenic proteins: A group within total proteins. These proteins elicit antibody production in the animal and human body. The antibodies elicited might include those of the IgE class which are able to induce an allergic reaction and also those that do not induce allergy. “Antigenic proteins” can also refer to proteins that are recognised by (react with) antibodies.
Allergenic proteins: A group within antigenic proteins (and hence a sub-group within total proteins). These proteins elicit production of the IgE class of antibodies in the animal or human body. They can induce an allergic reaction where IgE specific to them are present. “Allergenic proteins” can also refer to proteins that are recognised by (react with) IgE.
Allergens: Substances (proteins or otherwise) that elicit production of the IgE class of antibodies in the animal or human body. They can induce an allergic reaction where IgE specific to them are present. “Allergens” can also refer to substances that are recognised by (react with) IgE.
With regard to latex protein allergy, the only known allergens are proteinaceous in nature. Hence, in this context, the terms latex allergens, allergens, allergenic proteins and protein allergens are synonymous.
Antibodies: Immunoglobulins present in the serum of an animal and synthesised by plasma cells in response to an antigen.
IgE: A group within antibodies. IgE specific for an allergen is elicited in the animal or human body by its exposure to the allergen. Subsequent exposure to the allergen may induce an allergic reaction.
Polyclonal antibodies: A collection of antibodies against a particular antigen. Since most antigens have a large number of epitopes, there can be many different antibodies against a given antigen.
Monoclonal antibody: An immunoglobulin (antibody) produced by a single clone of lymphocytes. A monoclonal antibody recognizes only a single epitope on an antigen.
Epitope: An antigenic determinant in a molecule which is specifically recognised by an antibody combining site or by the antigen receptor of a T-cell.
Hybridoma: A cell line obtained by the fusion of a myeloma cell line, which is able to grow indefinitely in culture, with a normal antibody secreting B-cell. The resulting cell line has the properties of both partners, and continues to secrete the antibody product of the normal B-cell. By selecting a myeloma that has ceased to make its own immunoglobulin product, but has retained the machinery for doing so, the hybridoma secretes only the normal B-cell antibody. Since the cell line is cloned, the antibody is monoclonal.
Allergenic proteins (allergens) can induce an allergic reaction in sensitised persons which, in severe cases, can lead to an anaphylactic shock that is potentially lethal. Proteins present in latex products, such as latex gloves, can induce a form of allergy known as “Type I hypersensitivity” in a small proportion of people who use such products. The use of rubber products, especially dipped latex products, is therefore being viewed with some caution and concern from the healthcare viewpoint.
Natural rubber from the commercial rubber tree,
Hevea brasiliensis
, is an important commodity in the economies of many Asian and African countries. Natural rubber is marketed in the form of bales, sheets and as latex concentrate. A major demand for natural rubber latex concentrate is in the manufacture of “dipped-latex” products such as gloves for examination, surgical and domestic use. In 1993, Malaysia alone exported latex dipped goods valued at a total of US$880 million. The global demand for latex examination gloves in particular has increased significantly in recent years with the rise in the incidence of the Acquired Immuno-deficiency Syndrome (AIDS) due to HIV infection.
There have been recent reports that gloves and other surgical aids manufactured from natural rubber latex can cause contact urticaria which, in a few cases, has led to anaphylactic reactions in persons previously sensitised (Nutter, 1979; Turjanmaa et al., 1984; Axelsson et al., 1987; Leynadier et al., 1989). Anaphylaxis can be life-threatening and is therefore far more serious than the generally mild skin sensitivities caused by the various chemical compounds used in glove manufacture. While contact dermatitis arising from chemicals has been recognized for many years, the allergic response to proteins in latex products such as gloves and catheters poses a potentially serious threat to their users. Those most at risk are health care workers, who may wear latex gloves more or less continuously throughout their working day, and their patients. Ultimately, the product manufacturers and the latex industry as a whole will feel the repercussions from the perceived threat, even though the proportion of people that are actually at risk is very small. Regulatory agencies such as the US Food and Drug Administration (FDA) have already indicated that they will require all natural latex goods to be identified as such in the near future. The US FDA may also soon be setting standards for acceptable levels of total protein in latex products. If this problem is not addressed with the urgency it deserves and means established to distinguish between “safe” and “unsafe” products, it is even possible that future legislation could impose a blanket ban on the use of all latex products in medical care.
Latex protein allergy has therefore been regarded with increasing concern in recent years, especially by the manufacturers of latex products and by those involved in healthcare. Evidence has pointed to water-extractable proteins in latex as the cause of the latex-induced anaphylactic reaction which is mediated through an interaction between allergenic latex proteins and a class of antibodies (IgE), in the sensitised person. IgE specific immunoassays of protein fractions have suggested that more than one specific protein may be involved (Turjanmaa et al. 1988; Slater, 1991).
In view of the importance of the latex protein allergy problem, both from the healthcare perspective and from the viewpoint of latex product manufacturers, active research in this connection is being undertaken in various laboratories worldwide. The main objectives of the investigations are:
(a) To produce a latex concentrate containing lower levels of allergens. Latex concentrate suppliers are seeking to reduce allergens in the source material used for the manufacture of latex products.
(b) To manufacture a low allergen latex product. Latex product manufacturers are seeking to reduce allergens in their finished products.
(c) To develop an assay for the quantitation of allergens present in latex concentrate or in products. Both the latex suppliers as well as latex product manufacturers require an assay for the purpose of standardisation and quality control to complement (a) and (b).
In the conventional preparation of latex concentrate, field latex is stabilised with ammonia (to prevent flocculation or coagulation of the rubber) and then concentrat
Cardosa Mary Jane
Samsidar Hamzah
Samuel-Verghese Shirley
Sharifah Hamid
Sunderasan Elumalai
Nolan Patrick J.
Universiti Sains Malaysia
Wenderoth Lind & Ponack LLP
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