Towards immunotherapy for peanut allergy

PURPOSE OF REVIEW: Food allergy is a major cause of life-threatening hypersensitivity reactions. Peanut allergy is the most serious of the hypersensitivity reactions to foods due to its persistence and high risk of severe anaphylaxis. Currently, strict avoidance of the allergenic food and ready access to self-injectable epinephrine is the 'standard of care' for food allergy. Based on extensive characterization of food allergens and a better understanding of the immunological mechanisms underlying allergic disease, promising therapeutic modalities for food allergy treatment and prevention are being developed. RECENT FINDINGS: Immunotherapeutic strategies include peptide immunotherapy, mutated protein immunotherapy and DNA immunization, which all strive to decrease the deleterious Th2 response. Another approach already in clinical trials for peanut allergy is the anti-IgE therapy which prevents circulating IgE from binding to effector cells, consequently decreasing clinical symptoms after peanut ingestion. In order to be applicable, these strategies must be well tolerated, inexpensive and easily administered. Realistic treatment options would likely involve a combination of different approaches. SUMMARY: Food allergy affects approximately 4-6% of children and 3-4% of adults. Peanut allergy can be devastating as reactions range from urticaria to severe anaphylactic shock and death. The only preventive measure for peanut allergy is strict avoidance of the incriminating food. It is likely immunotherapy will be available in the near future as a well tolerated and effective therapy for treating peanut allergy. The use of the anti-IgE therapy in conjunction with other immunotherapy would possibly be the best treatment option in the future.     

Cloning and Sequencing of a Candida albicans Catalase Gene and Effects of Disruption of This Gene

Catalase plays a key role as an antioxidant, protecting aerobic organisms from the toxic effects of hydrogen peroxide, and in some cases has been postulated to be a virulence factor. To help elucidate the function of catalase in Candida albicans, a single C. albicans-derived catalase gene, designated CAT1, was isolated and cloned. Degenerate PCR primers based on highly conserved areas of other fungal catalase genes were used to amplify a 411-bp product from genomic DNA of C. albicans ATCC 10261. By using this product as a probe, catalase clones were isolated from genomic libraries of C. albicans. Nucleotide sequence analysis revealed an open reading frame encoding a protein of 487 amino acid residues. Construction of a CAT1-deficient mutant was achieved by using the Ura-blaster technique for sequential disruption of multiple alleles by integrative transformation using URA3 as a selectable marker. Resulting mutants exhibited normal morphology and comparable growth rates of both yeast and mycelial forms. Enzymatic analysis revealed an abundance of catalase in the wild-type strain but decreasing catalase activity in heterozygous mutants and no detectable catalase in a homozygous null mutant. In vitro assays showed the mutant strains to be more sensitive to damage by both neutrophils and concentrations of exogenous peroxide that were sublethal for the parental strain. Compared to the parental strain, the homozygous null mutant strain was far less virulent for mice in an intravenous infection model of disseminated candidiasis. Definitive linkage of CAT1 with virulence would require restoration of activity by reintroduction of the gene into mutants. However, initial results in mice, taken together with the enhanced susceptibility of catalase-deficient hyphae to damage by human neutrophils, suggest that catalase may enhance the pathogenicity of C. albicans.     

Distinctive alterations of invasiveness, drug resistance and cell-cell organization in 3D-cultures of MCF-7, a human breast cancer cell line, and its multidrug resistant variant

Growth of human tumor cells as three-dimensional (3D) multicellular spheroids modifies their invasive properties. Here we study the differences in the biological features of MCF-7, a human breast cancer cell line, and its multidrug resistant variant (MDR-MCF-7) cultured as spheroids or as monolayers. Three-dimensional culture decreased the proliferative rate of both cell lines, reduced the drug sensitivity of MCF-7 cells and did not affect the resistance of MDR-MCF-7 cells. Transmission electron microscopic studies and intercellular junctions labeling showed that MCF-7 spheroids had a junctional system involving E-cadherin, tight-junctions and desmosomes. In MDR-MCF-7 cell spheroids, cell cohesion was mostly due to membrane interdigitations. MDR-MCF-7 cells, but not their parental counterpart, displayed a higher invasive potential when cultured as spheroids, as shown in the Boyden chamber assay. 3D-induced invasiveness was correlated with serine protease and plasminogen activator (PA) secretion. MCF-7 cells did not show any tendency to invade, whatever the mode of culture. These results show that 3D-cultures as spheroids distinctively altered structural features of parental and MDR-MCF-7 cells. In MCF-7 cells, 3D-culture increased cell-cell contacts and drug resistance; in MDR-MCF-7 cells, it induced invasive properties.     

Immunodetection of apoptosis-regulating proteins in lymphomas from patients with and without human immunodeficiency virus infection.

The expression of the apoptosis-regulating genes Bcl-2, Bcl-x, Bax, Mcl-1, and p53 analyzed in 4 cases of human immunodeficiency virus (HIV)-associated Hodgkin's disease, in 36 cases of HIV-related non-Hodgkin's lymphomas (NHLs), and in 109 cases of non-HIV-related NHLs by using immunohistochemistry. HIV-associated Hodgkin's disease samples were positive for all markers. For the HIV-related NHL samples, 36, 66, 88, 100, and 94% of the cases were Bcl-2, Bcl-x, Bax, Mcl-1, and p53 were found to be expressed in 69, 65, 82, 83, and 42%, respectively. No significant differences were observed in Bax and Mcl-1 staining between HIV-unrelated NHLs of B cell and T cell types. In contrast, Bcl-2 was positive in 66/79 (83%) and 10/30 (33%) of B cell and T cell HIV-unrelated NHLs, respectively (P2 < 0.001). Peculiar patterns were observed for hairy cell leukemia (Bax+, Bcl-2+, Mcl-1-) and for anaplastic large cell lymphoma (Bax+, Mcl-1+, Bcl-2-) in HIV-unrelated NHLs. Of interest, all cases with a positive expression of Bax were also found to express either Mcl-1 and/or Bcl-2, suggesting that Mcl-1 and Bcl-2 may counteract the pro-apoptosis function of Bax in vivo by protein-protein interaction within the tumor cell, as demonstrated previously in vitro. These results suggest that apoptosis regulation may have a role in the pathogenesis of some HIV-related and HIV-unrelated NHLs.     

Tissue injury and repair in the rat kidney after exposure to cisplatin or carboplatin

Cisplatin (cis-diamminedichloroplatinum II) has emerged as an anticancer drug of considerable value for the chemotherapy of several human neoplasms. However, this agent often causes renal toxicity, which appears to be the dose-limiting untoward effect. The present animal study was undertaken to compare, with regard to kidney injury and renal tissue repair, cisplatin and carboplatin (cis-diammine-1,1-cyclobutane dicarboxylate platinum II), a platinum derivative more recently introduced in clinics. Female Sprague-Dawley rats (four animals per group) were treated ip with cisplatin (4 or 8 mg/kg, delivered in four consecutive daily injections) or carboplatin (40 mg/kg given in one injection) and terminated 4, 7, and 21 days after drug administration. One hour prior to sacrifice, each animal received ip 200 microCi of [3H]thymidine for the measurement of DNA synthesis and cell proliferation (frequency of S-phase cells in renal tissue, determined by histoautoradiography). Cisplatin, particularly at 8 mg/kg, caused severe tubular injury (acute tubular necrosis) culminating in a long-lasting cystic tubular dilatation in the outer stripe of outer medulla. Tubular damage was followed by a sharp proliferative response, indicative of tubular regeneration. However, the proliferative activity was still above basal level at the end of the observation period, suggesting that the tissue repair process had not reached completeness 3 weeks after cisplatin administration. In contrast, carboplatin only induced focal tubular necrosis in proximal tubules. Distal and collecting tubules also showed ultrastructural evidence of hydropic degeneration after exposure to the latter drug. Renal tubular injury associated with carboplatin was followed by a mild proliferative response. From this study, we can infer that carboplatin is less nephrotoxic than cisplatin, but still causes histopathological alterations in renal tissue. Furthermore, the lesser nephrotoxicity of carboplatin has a primary origin and is not due to a more efficient tissue repair reaction.     

An open,randomized single-centre study to compare the efficacy and convenience of follitropin beta administered by a pen device with follitropin alpha administered by a conventional syringe in women undergoing ovarian stimulation for IVF/ICSI

BACKGROUND: A pen device, similar to an insulin pen, has been recently marketed for the administration of follitropin beta in cartridges. A randomized controlled trial was performed to compare the efficacy and convenience of this pen device delivering follitropin beta with a conventional syringe delivering follitropin alpha. METHODS: A total of 200 patients needing IVF/ICSI treatment and willing to self-inject were enrolled in the study. All subjects had ovarian stimulation according to a long protocol and were randomized to the pen or the conventional syringe group during down-regulation by means of a computer-generated randomization list using random numbers. Patients were asked to fill in a daily local tolerance book after each injection. On the day of hCG the patients scored a Visual Analogue Scale (VAS) for pain and convenience. RESULTS: The average duration, total dose of recombinant FSH and number of cumulus oocyte complexes retrieved were 10.8/12.0 days (P = 0.001), 1880/2226 IU (P < 0.001) and 15.2/13.1 respectively in the pen device and conventional syringe groups; the presence of pain after the daily injection was significantly higher in the conventional syringe group (P = 0.027); the visual analogue scale score was similar for pain but significantly more convenient for the pen device (P < 0.001). The live birth rate per embryo transfer was 32.9 and 34.4% respectively in the pen device and conventional syringe groups. CONCLUSIONS: Self-injection with the pen device is safe and easy, more convenient and less painful for the patient, requires less FSH and shortens the treatment duration.     

Renal expression of Na+-phosphate cotransporter mRNA and protein: Effect of the Gy mutation and low phosphate diet

The X-linked Gy mutation is closely linked, but not allelic, to Hyp and is characterized by rickets, hypophosphatemia, decreased renal tubular maximum for phosphate (Pi) reabsorption (Tm_P) and a specific reduction in renal brush-border membrane (BBM) Na⁺-Pi cotransport. Gy mice, like their normal littermates, respond to a low-Pi diet with an increase in BBM Na⁺-Pi cotransport, but fail to show an adaptive increase in Tm_p. Using an antibody raised against the NH₂ terminal peptide of the rat renal-specific Na⁺-Pi cotransporter (NaPi-2) and a NaPi-2 cDNA probe, we examined the effect of the Gy mutation and low-Pi diet (0.03% Pi) on NaPi-2 protein and mRNA abundance. The reduction in BBM Na⁺-Pi cotransport in Gy mice (51 ± 5% of normal, P < 0.05) was associated with a decrease in NaPi-2 protein (46 ± 12% of normal, P < 0.05) and mRNA abundance (76 ± 5%, P < 0.05). The low-Pi diet elicited a two- to three-fold increase in Na⁺-Pi cotransport in both normal and Gy mice that was accompanied by a large increase in NaPi-2 protein (10.2-fold in normal and 16.9-fold in Gy mice) and a modest increase in NaPi-2 mRNA (1.3-fold in both mouse strains, P < 0.05). The present data demonstrate that (1) the renal defect in BBM Pi transport in Gy mice can be ascribed to a deficit in NaPi-2 protein and mRNA abundance, (2) both normal and Gy mice respond to low Pi with an adaptive increase in NaPi-2 protein that exceeds the increase in Na⁺-Pi cotransport activity and NaPi-2 mRNA, (3) the adaptive increase in NaPi-2 protein and mRNA are not sufficient for the overall increase in Tm_P following Pi restriction. Received: 27 October 1995 / Received after revision: 4 December 1995 / Accepted: 6 December 1995     

MUC1 expression is correlated with nuclear grade and tumor progression in pT1 renal clear cell carcinoma

We studied, by immunohistochemical analysis, the expression of MUC1 and epithelial membrane antigen in 44 stage pT1 renal cell carcinomas (RCCs). Six patients had a metastatic evolution. The percentage of stained cells was determined for each tumor. All tumors and normal adjacent renal parenchyma were stained. In normal kidney, distal convoluted tubules and collecting ducts stained strongly with an apical distribution. In tumors, there was a significant statistical correlation of the MUC1 expression level with the nuclear grade and with tumor progression. High-grade tumors had more stained cells than did low-grade tumors. Metastatic tumors also were more stained than nonmetastatic lesions. By using the Kaplan-Meier method and the log-rank test, we observed that patients with fewer than 10% of stained cells had no metastatic evolution. In contrast, patients with 70% or more stained cells had significantly lower metastasis-free survival rates. We conclude that MUC1 is expressed in RCC and is associated with tumor progression in pT1 RCC.