Diagnosis of natural rubber latex allergy

The accurate diagnosis of a latex-allergic individual begins with a comprehensive clinical history. Atopy, food allergies, hand dermatitis, and temporal relationships between allergic symptoms and natural rubber product exposure are risk factors that increase the suspicion of latex allergy. If symptoms are temporally delayed (hours-days) and confined to skin-latex product contact areas, Type IV hypersensitivity should be suspected and patch testing may be performed to identify activated T cells that are specific for selected rubber chemical additives. If ocular, upper and lower airway, and/or systemic allergic symptoms are observed with rapid onset (minutes) following a definable latex exposure, Type I hypersensitivity should be suspected. One or several confirmatory tests for latex-specific IgE antibody in the skin or blood may next be performed to verify a sensitized (IgE antibody positive) state. If the clinical history remains discordant with a skin test or blood test result, in vivo provocation tests may be cautiously considered for adjudication. Diagnostic methods for latex-specific IgE antibody detection in skin and blood are overviewed, with a focus on their performance, advantages, and limitations.     

Allergenic proteins of natural rubber latex

As the living cytoplasm of laticiferous cells, Hevea brasiliensis latex is a rich blend of organic substances that include a mélange of proteins. A small number of these proteins have given rise to the problem of latex allergy. The salient characteristics of H. brasiliensis latex allergens that are recognized by the International Union of Immunological Societies (IUIS) are reviewed. These are the proteins associated with the rubber particles, the cytosolic C-serum proteins and the B-serum proteins that originate mainly from the lutoids. Procedures for the isolation and purification of latex allergens are discussed, from latex collection in the field to various preparative approaches adopted in the laboratory. As interest in recombinant latex allergens increases, there is a need to validate recombinant proteins to ascertain equivalence with their native counterparts when used in immunological studies, diagnostics, and immunotherapy.     

Natural rubber latex allergy in the occupational setting

Over the last decade, the prevalence of natural rubber latex (NRL) allergy has reached epidemic proportions among workers who use or who are exposed to powdered latex products. NRL-associated occupational asthma is confined largely to those exposed to powdered latex glove use or other latex aerosols. The most frequent presenting symptom of NRL allergy is contact urticaria; inhalation may cause symptoms of allergic rhinitis and asthma. Skin prick testing is the most accurate tool for diagnosis of NRL allergy. The cornerstone of management is cessation of exposure; substitution with non-NRL or nonpowdered NRL gloves results in predictable rapid disappearance of latex aeroallergen.     

Regulatory initiatives for natural latex allergy: US perspectives

The US Food and Drug Administration (FDA) has regulatory authority over foods, human drugs, cosmetics, medical devices, radiological products, biologics, and veterinary products. Among these products, FDA believes that the use of medical devices, including medical gloves, condoms, catheters, and breathing bags, represents the greatest source of natural latex proteins to exposed individuals. A medical device is defined in the Federal Food Drug and Cosmetic Act (FFDCA) as an instrument, apparatus, implement, machine, etc., that is intended for use in the diagnosis or treatment of disease or is intended to affect the structure or any function of the body of a human or other animal, and that does not achieve any of its principal intended purposes through chemical action in the body. This article provides some brief, general background about FDA's medical device regulatory process and then addresses the issue of natural latex allergy. Finally we discuss the steps the Agency has taken to evaluate the magnitude and nature of the problem, and FDA's efforts to assist manufacturers, health professionals, and others in minimizing exposure and sensitization to natural latex proteins in medical devices.     

Micromorphological characterization and label-free quantitation of small rubber particle protein in natural rubber latex

Commercial natural rubber is traditionally supplied by Hevea brasiliensis, but now there is a big energy problem because of the limited resource and increasing demand. Intensive study of key rubber-related substances is urgently needed for further research of in vitro biosynthesis of natural rubber. Natural rubber is biosynthesized on the surface of rubber particles. A membrane protein called small rubber particle protein (SRPP) is a key protein associated closely with rubber biosynthesis; however, SRPP in different plants has been only qualitatively studied, and there are no quantitative reports so far. In this work, H. brasiliensis was chosen as a model plant. The microscopic distribution of SRPP on the rubber particles during the washing process was investigated by transmission electron microscopy–immunogold labeling. A label-free surface plasmon resonance (SPR) immunosensor was developed to quantify SRPP in H. brasiliensis for the first time. The immunosensor was then used to rapidly detect and analyze SRPP in dandelions and prickly lettuce latex samples. The label-free SPR immunosensor can be a desirable tool for rapid quantitation of the membrane protein SRPP, with excellent assay efficiency, high sensitivity, and high specificity. The method lays the foundation for further study of the functional relationship between SRPP and natural rubber content.     

Extraction and characterization of a natural rubber from Euphorbia characias latex

A natural rubber was identified and characterized for the first time in the latex of the perennial Mediterranean shrub Euphorbia characias. Four different methods, i.e., acetone, acetic acid, trichloroacetic acid, and Triton® X‐100, followed by successive treatments with cyclohexane/ethanol, were employed to extract the natural rubber. The rubber content was shown to be 14% (w/v) of the E. characias latex, a low content compared with that of Hevea brasiliensis (30–35%) but a similar content to other rubber producing plants. E. characias rubber showed a molecular weight of 93,000 with a M_w/M_n of 2.9. ¹H NMR, ¹³C NMR, and FTIR analysis revealed the characteristic of the cis‐1,4‐polyisoprene typical of natural rubber. These results provided novel insight into latex components and will ultimately benefit the broader understanding of E. characias latex composition. © 2012 Wiley Periodicals, Inc. Biopolymers 97: 589–594, 2012.     

Biological coagulation of skim latex using Acinetobacter sp. isolated from natural rubber latex centrifugation effluent

An Acinetobacter sp, isolated from latex centrifugation effluent, effectively coagulated skim rubber from skim latex. After coagulation for 48 h without the addition of any nutrients, at an optimum dilution of 1:10(v/v) and with an inoculum concentration of 6.4 mg dry cell /ml, the yield of the skim rubber was 8 % (w/v) and the COD of the residual solution was only 0.4 g/l. chemical coagulation at the same dilution resulted in 7 % (w/v) yield of dry rubber content and 2.2 g COD /l.     

Degradation of latex and of natural rubber by Streptomyces strain La 7

Streptomyces strain La 7 was isolated from the banquete of a city high way in Karlsruhe. According to partial 16S rRNA gene sequencing it was identical with Streptomyces albogriseolus and Streptomyces viridodiastaticus. DNA-DNA-similarity studies revealed 80.3-82.4% similarity between each of two of the three strains. Although phylogenetically closely related, Streptomyces strain La 7 differed from the two reference strains by morphological as well as physiological features and might represent a new species aside of S. albogriseolus and S. viridodiastaticus. The new Streptomyces strain La 7 was grown in a medium containing a latex emulsion or squares of natural rubber gloves as the only carbon source. On agar plates with a latex overlay agar, translucent halo formation around the colonies was observed. The unvulcanized latex was metabolized and the carbon from the isoprene units was apparently used for cell growth. In shake cultures with unlimited oxygen supply, during 60 days of incubation, 140 mg of the 175 mg totally emulgated latex were degraded exponentially. In sterile control flasks about 3% of the initial amount of latex could not be recovered after incubation on a shaker, presumably due to photochemical transformation. During static incubation of sterile medium, the latex formed a sticky layer at the surface of the medium and on the glass walls and recovery of the material was more difficult. Estimation of the protein content of cells from total nitrogen resulted in about 50% of the degraded latex being incorporated into cells, if a standard cell composition was assumed. Direct protein analysis according to Bradford (1976) gave much lower estimates, presumably due to a low content of aromatic amino acids. Stripes of natural rubber were degraded by Streptomyces strain La 7 during 70 days to an extent of about 30%. Scanning electron microscopy demonstrated, that hyphes of Streptomyces strain La 7 colonized and penetrated the latex surface with a concomitant deterioration of the latex material.     

A rubber particle protein specific for Hevea latex lectin binding involved in latex coagulation

In the first of this three paper series, an in vitro latex coagulation was shown to arise from aggregation of rubber particles (RP) and lutoid membranes. RP aggregation was shown to be induced by a specific Hevea latex lectin-like protein (HLL) present on the lutoid membrane. In this second paper, a binding protein (BP) ligand counterpart for HLL was identified. This RP-HLLBP, having a specific interaction, with HLL was isolated from RP and characterized. The protein was extracted from the small RP in the presence of a surfactant (0.2% Triton-X-100) and further purified to homogeneity. Purification steps included acetone precipitation, heat-treatment, and column chromatography. The presence of RP-HLLBP was monitored by its ability to compete with erythrocytes in the hemagglutination inhibition (HI) assay. The purified RP-HLLBP had an HI titre of 1.37 microgml(-1), a pI value of 5.4, optimum activity at pH 5-8 and was thermostable up to 60 degrees C. On SDS-PAGE a single glycoprotein with M(r) of 24 kDa was detected while on native PAGE the major Mr was about 120 kDa. The purified RP-HLLBP was shown to inhibit latex coagulation. Chitinase, but no other glycosidase tested, abolished its HI action and inhibited HLL-induced RP aggregation in a competitive dose dependent manner. This indicated the presence of, and role for, N-acetylglucosamine residues in the binding recognition. The Hevea latex lectin-like protein can thus be referred to as a Hevea latex lectin. Based on protein identification by peptide mass fingerprinting, the RP-HLLBP was confirmed to be the small rubber particle protein (SRPP). This work has unambiguously determined the role of an intrinsic RP glycoprotein (RP-HLLBP or SRPP) as a key component in formation of the rubber latex coagulum.     

Structural analysis of the glycoprotein allergen Hev b 4 from natural rubber latex by mass spectrometry

The lecithinase homolog (Hev b 4) from Hevea brasiliensis (Q6T4P0_HEVBR) is an important natural rubber latex allergen. Hev b 4 is a highly glycosylated protein and its carbohydrate moiety has been implicated in the binding of IgE from natural rubber latex allergic patients. The cDNA for Hev b 4 has recently been cloned and sequenced. Here, we have analyzed the post-translational modifications of natural Hev b 4 by liquid chromatography/electrospray ionization-mass spectrometry of tryptic peptides. Seven of the eight potential glycosylation sites were found to be occupied. One site, however, was only partially glycosylated. Asn224 was substituted by complex type N-glycans with fucose and xylose, whereas all other sites carried either oligomannose glycans or a mixture of oligomannose and complex N-glycans. Glycosylation site Asn308, the most C-terminal one of the eight sites, was only found in the non-glycosylated form. The complex type N-glycans apparently form the molecular basis for the immune reaction with patients' sera. A large fraction of Hev b 4 molecules contains two or more complex N-glycans and thus a physiological reaction against these polyvalent allergens on the basis of the carbohydrate is in theory possible. Aside from allowing glycosylation analysis, the mass spectrometric data defined the N-terminal cleavage site of Hev b 4. This study once more demonstrates the outstanding analytical potential of electrospray ionization-mass spectrometry coupled with liquid chromatographic separation.     

Murine models for acquired immune deficiency syndrome

The mouse has been suggested as a host for comparative studies of several aspects of Human Acquired Immune Deficiency Syndrome (AIDS). Models include studies where part or all of the genome of Human Immunodeficiency Virus (HIV) has been incorporated into murine DNA in living mice. However, the most promising opportunities for study of immunological changes, vaccine development, cofactor involvement in disease, and anti-retroviral and immunostimulatory drug testing involve infection with murine retroviruses which cause many functional changes similar to AIDS. The viruses' effects on immune systems are reviewed with special emphasis. LP-BM5 murine leukemia virus which infects T and B cells, and macrophages. LP-BM5 infection suppresses cell functions while causing polyclonal lymphocyte activation. Murine immunological characterization, availability of inbred mouse strains, economy of using mice versus primates or humans models, and similarity of immune change caused by murine retroviruses compared to those seen in AIDS caused by HIV encourage rapid development of the LP-BM5 murine leukemia model.     

A role for a Hevea latex lectin-like protein in mediating rubber particle aggregation and latex coagulation

An in vitro aggregation of washed lutoid membrane and rubber particles, respectively, prepared from the bottom (lutoid) fraction and rubber layer of centrifuged fresh latex, leading to the formation of rubber coagulum necessary for a latex coagulation was demonstrated. A Triton X-100 extract of washed lutoid membrane proteins, isolated and prepared from the bottom fraction of centrifuged fresh latex was examined for its role in the latex coagulation process. It induced agglutination of rabbit erythrocytes, indicating the presence of a lectin-like protein. Hevea latex lectin-like protein (HLL) was purified to homogeneity by active chitin binding separation, followed by DEAE-Sepharose chromatography. Its M(r) analyzed by SDS-PAGE was 17 kDa, whereas that determined by gel filtration was 267 kDa. The HLL had a pI value of 7.2. Several glycoproteins were shown to inhibit the HLL-induced hemagglutination. The hemagglutinin activity of HLL was enhanced by Ca(2+). Of most interest was the finding that HLL strongly induced aggregation of the Hevea latex rubber particles (RP). This strong RP aggregation leads to latex coagulation, indicating the possibility that it is involved in the formation of the coagulum that plugs the latex vessel ends and stops the flow of latex upon tapping. In addition, the purified HLL also induced aggregation of RP taken from several other non-Hevea latex producing plants. This might indicate either a common or universal role of this lectin-like protein in RP aggregation and hence latex coagulation. This paper, for the first time, provides clear and unequivocal evidence for either a key biological role or physiological function of an endogenous latex lectin-like protein in the sequential process of latex coagulation.     

Murine tumor suppressor models

Tumor suppressor genes have been shown to be necessary for proper maintenance of cell growth control. Inactivation of these genes in the germline of humans is linked to inherited cancer predisposition. Moreover, sporadically arising human tumors often have somatic mutations in tumor suppressor genes. During the past few years, advances in molecular and cellular biology have led to the creation of animal models that have germline mutations of various tumor suppressor genes. Such mice potentially represent important animal models for familial cancer predisposition syndromes, and the study of the tumorigenesis process has been greatly assisted by their development. Such models have also demonstrated the importance of tumor suppressor function in embryonic development. In this review, we describe mice with inactivated germline tumor suppressor genes that are genetically analogous to 10 different inherited cancer syndromes in humans. We describe the variable usefulness of the mutant mice as models for human disease.     

Approaches to prevention and treatment of latex allergy

Data on sensitization to latex as well as measures aimed at prevention and treatment of latex allergy, are presented. The intensity of the symptoms manifestation of latex allergy was shown to depend on the duration of contact with latex. To prevent the development of latex allergy, the following preparations were used: the antihistaminic preparation Claritine, the immunocorrecting preparations Ruzam and polycomponent vaccine VP-4. The use of Claritine was shown to lead to the alleviation of the symptoms of latex allergy, but after treatment with Claritine was stopped the symptoms of latex allergy reappeared. The clinical effect lasted for as long as 2 months after treatment with Ruzam, while in case of polycomponent vaccine VP-4 use remission was registered even 3 months later. The data presented thus confirm topicality of the latex allergy problem and practical importance of using the immunocorrecting preparations Ruzam and polycomponent vaccine VP-4 for its prevention and treatment.     

Sequence analysis of a gene product synthesized by Xanthomonas sp. during growth on natural rubber latex

Xanthomonas sp. secretes an extracellular protein (Mr approximately 70+/-5 kDa) during growth on purified natural rubber [poly(1,4-cis-isoprene)] but not during growth on water-soluble carbon sources such as glucose or gluconate. A 1.3 kbp DNA fragment coding for an internal part of the structural gene of the 70 kDa protein was amplified by nested polymerase chain reaction (PCR) using amino acid sequence information obtained after Edman degradation of selected trypsin-generated peptides of the purified 70 kDa protein. The PCR product was used as a DNA probe to clone the complete structural gene from genomic DNA of Xanthomonas sp. The sequenced DNA contained a 2037 bp open reading frame which coded for a polypeptide of 678 amino acids (Mr 74.6 kDa) and which included the features of the N-terminal signal peptidase cleavage site (Mr approximately 72.9 kDa for the mature protein). Analysis of the amino acid sequence revealed the presence of two heme binding motifs (CXXCH) and a approximately 20 amino acids long sequence that is conserved in the Paracoccus denitrificans and Pseudomonas aeruginosa diheme cytochrome c peroxidases (CCPs). This region includes a histidine residue (H519 in Xanthomonas sp. and H265 and H271 in the Pseudomonas strains, respectively) that is essential for activity in CCPs and that is also conserved in other bacterial oxidases. Blast analysis confirmed the relatedness of the 70 kDa protein to heme-containing oxidases and suggested that it is a member of a new family of relatively large (approximately 500 to approximately 1000 amino acids) extracellular proteins with so far unknown function being only far related in amino acid sequence to P. denitrificans and P. aeruginosa CCPs.     

Micro‐organisms in latex and natural rubber coagula of Hevea brasiliensis and their impact on rubber composition,structure and properties

Natural rubber, produced by coagulation of the latex from the tree Hevea brasiliensis, is an important biopolymer used in many applications for its outstanding properties. Besides polyisoprene, latex is rich in many nonisoprene components such as carbohydrates, proteins and lipids and thereby constitutes a favourable medium for the development of micro‐organisms. The fresh rubber coagula obtained by latex coagulation are not immediately processed, allowing the development of various microbial communities. The time period between tree tapping and coagula processing is called maturation, during which an evolution of the properties of the corresponding dry natural rubber occurs. This evolution is partly related to the activity of micro‐organisms and to the modification of the biochemical composition. This review synthesizes the current knowledge on microbial populations in latex and natural rubber coagula of H. brasiliensis and the changes they induce on the biochemistry and technical properties of natural rubber during maturation.