Phase II study on the efficacy and safety of Lapatinib administered beyond disease progression and combined with vinorelbine in HER-2/neu- positive advanced breast cancer: results of the CECOG LaVie trial.

BACKGROUND: Vinorelbine constitutes effective chemotherapy for metastatic breast cancer (MBC) and acts synergistically with trastuzumab in HER-2/neu positive disease. The present study was set out to evaluate the efficacy and safety of vinorelbine when combined with lapatinib, an anti-HER2 tyrosine-kinase inhibitor, as late-line regimen administered beyond previous disease progression on prior lapatinib in patients with HER-2/neu- positive MBC. METHODS: The CECOG LaVie study was designed as open-labeled, single-arm, multicenter phase II trial. Patients had to be pretreated with lapatinib plus chemotherapy, and received lapatinib at a daily dose of 1250 mg in combination with vinorelbine 20 mg/m(2) i.v. on days 1 and 8 of a three-week cycle until disease progression, intolerable toxicity or withdrawal of consent. Progression-free survival (PFS) was defined as primary study endpoint; secondary endpoints included overall survival (OS), response rate according to RECIST 1.1, and safety. The study was terminated early due to poor accrual. RESULTS: A total number of nine patients were included; lapatinib administered beyond disease progression combined with vinorelbine resulted in a median PFS of 7.7 months (95% CI 0.56-14.91) and a median OS of 23.4 months (95% CI 16.61-30.13), respectively. Partial remission was seen in one of nine patients, three patients had stable disease of > six months, whereas the remaining five patients had primary disease progression. In two patients, modification of vinorelbine dose due to toxicity became necessary; no dose modification was needed for lapatinib. The majority of reported adverse events (AE) were grade 1 and 2 in severity with diarrhea being the most commonly observed AE CONCLUSION: In this heavily pretreated patient population, combination of vinorelbine plus lapatinib showed encouraging activity and was characterized by an acceptable safety profile. Despite the low patient number, lapatinib plus vinorelbine may constitute a potential treatment option in heavily pretreated patients with HER-2/neu-positive MBC previously exposed to lapatinib. TRIAL REGISTRATION: EudraCT number 2009-016826-15, (15. 10.2009).

FOLFOX4 Plus Cetuximab for Patients With Previously Untreated Metastatic Colorectal Cancer According to Tumor RAS and BRAF Mutation Status: Updated Analysis of the CECOG/CORE 1.2.002 Study.

BACKGROUND: This updated analysis of the CECOG/CORE 1.2.002 study investigated the association between clinical outcome and RAS and BRAF mutations in metastatic colorectal cancer (mCRC) patients treated with FOLFOX4 plus cetuximab. PATIENTS AND METHODS: Available DNA samples from CECOG/CORE 1.2.002 study patients with KRAS exon 2 wild type (wt) (at codons 12 and 13) tumors were screened for mutations at other loci in the KRAS and NRAS (RAS) coding regions by Sanger sequencing, and for BRAF codon 600 mutations by Sanger sequencing and pyrosequencing. Clinical outcome was compared among different mutation subgroups. RESULTS: Of 152 KRAS wt mCRC patients, 148 were evaluable for RAS and BRAF mutation status. Eleven RAS mutations were detected in 10 patients' tumors (7%). BRAF mutations were detected in 14 patients' tumors (9%). RAS and BRAF tumor mutations were mutually exclusive. Compared with patients with RAS wt/BRAF wt tumors (n = 124; median overall survival, 28.5 months), those with RAS mutations (n = 10; median, 16.3 months; hazard ratio, 0.43; 95% confidence interval, 0.20-0.89; P = .020) or BRAF mutations (n = 14; median, 11.7 months; hazard ratio, 0.23; 95% confidence interval, 0.12-0.41; P < .0001) had worse overall survival, which remained significant (P < .04) when adjusting for differences in baseline characteristics among the mutation subgroups. CONCLUSION: These findings support those from recent studies that RAS and BRAF mutations are associated with poor outcome in patients receiving an epidermal growth factor receptor-targeted monoclonal antibody in combination with oxaliplatin-based chemotherapy. Furthermore, mutation testing should not only include RAS codons 12 and 13 but should also be extended to the entire coding regions.

Impact of the specific mutation in KRAS codon 12 mutated tumors on treatment efficacy in patients with metastatic colorectal cancer receiving cetuximab-based first-line therapy: a pooled analysis of three trials.

PURPOSE: This study investigated the impact of specific mutations in codon 12 of the Kirsten-ras (KRAS) gene on treatment efficacy in patients with metastatic colorectal cancer (mCRC). PATIENTS: Overall, 119 patients bearing a KRAS mutation in codon 12 were evaluated. All patients received cetuximab-based first-line chemotherapy within the Central European Cooperative Oncology Group (CECOG), AIO KRK-0104 or AIO KRK-0306 trials. RESULTS: Patients with KRAS codon 12 mutant mCRC showed a broad range of outcome when treated with cetuximab-based first-line regimens. Patients with tumors bearing a KRAS p.G12D mutation showed a strong trend to a more favorable outcome compared to other mutations (overall survival 23.3 vs. 14-18 months; hazard ratio 0.66, range 0.43-1.03). An interaction model illustrated that KRAS p.G12C was associated with unfavorable outcome when treated with oxaliplatin plus cetuximab. CONCLUSION: The present analysis suggests that KRAS codon 12 mutation may not represent a homogeneous entity in mCRC when treated with cetuximab-based first-line therapy.

Cetuximab-based or bevacizumab-based first-line treatment in patients with KRAS p.G13D-mutated metastatic colorectal cancer: a pooled analysis.

KRAS p.G13D mutant metastatic colorectal cancer (mCRC) has been identified as representing a cetuximab-sensitive subtype of KRAS mutant mCRC. This analysis aims to answer the question of whether first-line treatment of p.G13D mCRCs should include cetuximab or bevacizumab. Fifty-four patients with p.G13D mutant mCRC were pooled in this analysis. All patients underwent systemic first-line treatment with a fluoropyrimidine and oxaliplatin/irinotecan that was combined with either cetuximab or bevacizumab. The analysis of cetuximab-based and bevacizumab-based regimens in mCRC patients with p.G13D-mutated tumours indicated comparable data for the overall response rate (58 vs. 57%) and progression-free survival (8.0 vs. 8.7 months; hazard ratio: 0.96, P=0.9). Overall survival (OS) was 20.1 months in patients treated with cetuximab-based first-line therapy compared with 14.9 months in patients receiving bevacizumab-containing regimens (hazard ratio: 0.70, P=0.29). Logistic regressions modelling OS revealed oxaliplatin-based first-line treatment to correlate with a poor outcome (P=0.03). Moreover, a strong trend in favour of capecitabine compared with infusional 5-FU (P=0.06) was observed. Response to treatment correlated with OS in patients receiving cetuximab-based, but not bevacizumab-based regimens. This retrospective pooled analysis suggests comparable efficacy of cetuximab-based and bevacizumab-based first-line therapy in patients with p.G13D mutant mCRC. The combination with capecitabine and irinotecan was associated with a more favourable outcome compared with infusional 5-FU and oxaliplatin.

Anti-idiotypic Fab Fragments Image a Conserved N-terminal Epitope Patch of Grass Pollen Allergen Phl p 1.

BACKGROUND AND AIMS: Naturally occurring anti-idiotypic antibodies structurally mimic the original antibody epitope. Anti-idiotypes, therefore, are interesting tools for the portrayal of conformational B-cell epitopes of allergens. In this study we used this strategy particularly for major timothy grass pollen (Phleum pratense) allergen Phl p 1. METHODS AND RESULTS: We used a combinatorial phage display library constructed from the peripheral IgG repertoire of a grass pollen allergic patient which was supposed to contain anti-idiotypic Fab specificities. Using purified anti-Phl p 1 IgG for biopanning, several Fab displaying phage clones could be isolated. 100 amplified colonies were screened for their binding capacity to anti-Phl p 1-specific antibodies, finally resulting in four distinct Fab clones according to sequence analysis. Interestingly, heavy chains of all clones derived from the same germ line sequence and showed high homology in their CDRs. Projecting their sequence information on the surface of the natural allergen Phl p 1 (PDB ID: 1N10) indicated matches on the N-terminal domain of the homo-dimeric allergen, including the bridging region between the two monomers. The resulting epitope patches were formed by spatially distant sections of the primary allergen sequence. CONCLUSION: In this study we report that anti-idiotypic specificities towards anti-Phl p 1 IgG, selected from a Fab library of a grass pollen allergic patient, mimic a conformational epitope patch being distinct from a previously reported IgE epitope area.

Nitration of the egg-allergen ovalbumin enhances protein allergenicity but reduces the risk for oral sensitization in a murine model of food allergy.

BACKGROUND: Nitration of proteins on tyrosine residues, which can occur due to polluted air under "summer smog" conditions, has been shown to increase the allergic potential of allergens. Since nitration of tyrosine residues is also observed during inflammatory responses, this modification could directly influence protein immunogenicity and might therefore contribute to food allergy induction. In the current study we have analyzed the impact of protein nitration on sensitization via the oral route. METHODOLOGY/PRINCIPAL FINDINGS: BALB/c mice were immunized intragastrically by feeding untreated ovalbumin (OVA), sham-nitrated ovalbumin (snOVA) or nitrated ovalbumin (nOVA) with or without concomitant acid-suppression. To analyze the impact of the sensitization route, the allergens were also injected intraperitoneally. Animals being fed OVA or snOVA under acid-suppressive medication developed significantly elevated levels of IgE, and increased titers of specific IgG1 and IgG2a antibodies. Interestingly, oral immunizations of nOVA under anti-acid treatment did not result in IgG and IgE formation. In contrast, intraperitoneal immunization induced high levels of OVA specific IgE, which were significantly increased in the group that received nOVA by injection. Furthermore, nOVA triggered significantly enhanced mediator release from RBL cells passively sensitized with sera from allergic mice. Gastric digestion experiments demonstrated protein nitration to interfere with protein stability as nOVA was easily degraded, whereas OVA and snOVA remained stable up to 120 min. Additionally, HPLC-chip-MS/MS analysis showed that one tyrosine residue (Y(107)) being very efficiently nitrated is part of an ovalbumin epitope recognized exclusively after oral sensitization. CONCLUSIONS/SIGNIFICANCE: These data indicated that despite the enhanced triggering capacity in existing allergy, nitration of OVA may be associated with a reduced de novo sensitizing capability via the oral route due to enhanced protein digestibility and/or changes in antibody epitopes.

Mimotope vaccination--from allergy to cancer.

BACKGROUND: Mimotopes are peptides mimicking protein, carbohydrates or lipid epitopes and can be generated by phage display technology. When selected by antibodies, they represent exclusively B-cell epitopes and are devoid of antigen/allergen-specific T-cell epitopes. Coupled to carriers or presented in a multiple antigenic peptide form mimotopes achieve immunogenicity and induce epitope-specific antibody responses upon vaccination. OBJECTIVE/METHODS: In allergy IgG antibodies may block IgE binding to allergens, whereas other IgG antibody specificities enhance this and support the anaphylactic reaction. In cancer, inhibitory antibody specificities prevent growth signals derived from overexpressed oncogenes, whereas growth-promoting specificities enhance signalling and proliferation. Therefore, the mimotope concept is applicable to both fields for epitope-specific vaccination and analysis of conformational B-cell epitopes for the allergen/antigen. RESULTS/CONCLUSIONS: Mimotope technology is a relatively young theme in allergology and oncology. Still, proof of concept studies testing allergen and tumour mimotope vaccines suggest that mimotopes are ready for clinical trials.

Characterisation of an engineered trastuzumab IgE antibody and effector cell mechanisms targeting HER2/neu-positive tumour cells.

Trastuzumab (Herceptin), a humanized IgG1 antibody raised against the human epidermal growth factor receptor 2 (HER2/neu), is the main antibody in clinical use against breast cancer. Pre-clinical evidence and clinical studies indicate that trastuzumab employs several anti-tumour mechanisms that most likely contribute to enhanced survival of patients with HER2/neu-positive breast carcinomas. New strategies are aimed at improving antibody-based therapeutics like trastuzumab, e.g. by enhancing antibody-mediated effector function mechanisms. Based on our previous findings that a chimaeric ovarian tumour antigen-specific IgE antibody showed greater efficacy in tumour cell killing, compared to the corresponding IgG1 antibody, we have produced an IgE homologue of trastuzumab. Trastuzumab IgE was engineered with the same light- and heavy-chain variable-regions as trastuzumab, but with an epsilon in place of the gamma-1 heavy-chain constant region. We describe the physical characterisation and ligand binding properties of the trastuzumab IgE and elucidate its potential anti-tumour activities in functional assays. Both trastuzumab and trastuzumab IgE can activate monocytic cells to kill tumour cells, but they operate by different mechanisms: trastuzumab functions in antibody-dependent cell-mediated phagocytosis (ADCP), whereas trastuzumab IgE functions in antibody-dependent cell-mediated cytotoxicity (ADCC). Trastuzumab IgE, incubated with mast cells and HER2/neu-expressing tumour cells, triggers mast cell degranulation, recruiting against cancer cells a potent immune response, characteristic of allergic reactions. Finally, in viability assays both antibodies mediate comparable levels of tumour cell growth arrest. These functional characteristics of trastuzumab IgE, some distinct from those of trastuzumab, indicate its potential to complement or improve upon the existing clinical benefits of trastuzumab.

Characterization of intrinsic and extrinsic risk factors for celery allergy in immunosenescence.

Recent studies indicated an underestimation of allergies in elderly. In our experimental food allergy model of protein feeding under acid-suppression we aimed to assess whether food allergy can be induced in immunosenescent mice. Furthermore, the impact of gastric digestion on celery allergenicity was evaluated in aged patients. Measurements of serum zinc and iron levels in senescent and adult BALB/c mice for definition of the nutritional status indicated a possible alteration of the immune response in the aged animals due to reduced zinc and iron levels. Feedings of mice with digestion-sensitive celery proteins under physiological gastric conditions induced IgG1 and IgG2a in the aged and preferentially IgG1 in the adult animals. In contrast, incomplete digestion due to acid-suppression rendered celery-specific IgE, positive skin tests and elevated IL-5 levels in both age groups. Also in aged celery allergic patients (mean age 72 years) properly digested celery showed decreased capacity to bind and crosslink IgE as evaluated by skin tests and IgE immunoblot. Thus, in the geriatric murine model, celery allergy was induced only if gastric digestion was hindered. Accordingly, gastric proteolysis decreased in vitro and in vivo IgE-reactivity against celery proteins in aged allergic patients.

Immunization with mimotopes prevents growth of carcinoembryonic antigen positive tumors in BALB/c mice.

PURPOSE: The carcinoembryonic antigen (CEA) is a glycoprotein that is overexpressed in nearly 50% of all human and veterinarian tumors. At present, anti-CEA antibodies are being tested in clinical studies as passive immunotherapeutics. This study aims to establish an active immunotherapy for the poorly immunogenic CEA glycoprotein by generating antigen surrogates. EXPERIMENTAL DESIGN: We used the monoclonal anti-CEA antibody Col-1 and the biopanning method to generate peptide mimics (mimotopes) of the Col-1 epitope. The peptide showing the highest specificity and mimicry was synthesized as an octameric multiple antigenic mimotope (MAM). Subsequently, immunogenicity of the selected mimotope was examined in BALB/c mice. We assessed antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity mediated by the induced antibodies on CEA-expressing HT29 tumor cells. Furthermore, after immunization, the BALB/c mice were transplanted s.c. with Meth-A/CEA tumor cells. RESULTS: When BALB/c mice were immunized with this MAM, they generated a specific humoral immune response against CEA. The mimotope-induced polyclonal and poly-isotypic antibodies induced antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity in vitro. Furthermore, when MAM-immunized mice were transplanted s.c. with Meth-A/CEA cells expressing human CEA, a suppressed tumor growth was observed. CONCLUSION: From our results, we can conclude that the Col-1 epitope of the glycoprotein CEA can be translated into an immunogenic peptide mimic. The mimotope-induced antibodies recognize CEA and do effectively inhibit growth of CEA-positive tumors. Based on these finding, we suggest that the generated mimotopes are candidates for active immunotherapy of CEA-expressing tumors.

Active induction of tumor-specific IgE antibodies by oral mimotope vaccination.

A role of IgE antibodies in cancer surveillance has been implicated for a long time. Studies dealing with IgE antibodies directly targeted to tumor antigens have shown marked anticancer effects mediated by this antibody class. Thus, the basic function of IgE antibodies may be to control tumor growth. Thus far, cancer-specific IgE has only been applied passively. Consequently, the aim of this study was to establish an active vaccination protocol to induce tumor antigen-specific IgE antibodies, and to evaluate functional properties. We previously generated epitope mimics, so-called mimotopes, for the epitope recognized by the anti-HER-2 antibody trastuzumab. Upon i.p. immunizations, IgG antibodies with trastuzumab-like properties could be elicited. In the present study, we immunized BALB/c mice via the oral route with these trastuzumab mimotopes, under simultaneous neutralization and suppression of gastric acid. As shown in preceding experiments, this feeding regimen effectively induces Th2 immune responses. Oral immunizations with trastuzumab mimotopes under hypoacidic conditions indeed resulted in the formation of IgE antibodies towards the HER-2 antigen. Moreover, anti-HER-2 IgE-sensitized effector cells mediated SK-BR-3 target cell lysis in an antibody-dependent cytotoxicity assay. We conclude that directed and epitope-specific induction of IgE against tumor antigens is feasible with an oral mimotope vaccination regimen, and that these antibodies mediate anticancer effects.

Anti-ulcer treatment during pregnancy induces food allergy in mouse mothers and a Th2-bias in their offspring.

The treatment of dyspeptic disorders with anti-acids leads to an increased risk of sensitization against food allergens. As these drugs are taken by 30-50% of pregnant women due to reflux and heartburn, we aimed here to investigate the impact of maternal therapy with anti-acids on the immune response in the offspring in a murine model. Codfish extract as model allergen was fed with or without sucralfate, an anti-acid drug, to pregnant BALB/c mice during pregnancy and lactation. These mothers developed a codfish-specific allergic response shown as high IgG1 and IgE antibody levels and positive skin tests. In the next step we analyzed whether this maternal sensitization impacts a subsequent sensitization in the offspring. Indeed, in stimulated splenocytes of these offspring we found a relative Th2-dominance, because the Th1- and T-regulatory cytokines were significantly suppressed. Our data provide evidence that the anti-acid drug sucralfate supports sensitization against food in pregnant mice and favors a Th2-milieu in their offspring. From these results we propose that anti-acid treatment during pregnancy could be responsible for the increasing number of sensitizations against food allergens in young infants.

Internal images: human anti-idiotypic Fab antibodies mimic the IgE epitopes of grass pollen allergen Phl p 5a.

BACKGROUND: The role of anti-idiotypic antibodies in allergic disease is still poorly understood. According to Jerne, anti-idiotypic antibodies to IgE should represent internal images of an allergen. Our aim was to ultimately prove whether this hypothesis holds true in allergy. Here, we describe the selection of anti-idiotypic antibodies against Phl p 5a-specific IgE directly from the B-cell repertoire of a grass pollen allergic individual. METHODS: Taking Phleum pratense grass pollen allergen Phl p 5 as a model, we selected anti-idiotypic antibodies against allergen-specific IgE directly from the B-cell repertoire of an allergic individual. We screened a combinatorial phage display library of human monovalent antibody heavy and light chain fragments (Fabs) with anti-Phl p 5a-IgE to identify and characterize Fabs with anti-idiotypic specificity. RESULTS: Five different Fab clones with anti-idiotypic specificity for anti-Phl p 5a-IgE were identified. Their hypervariable regions revealed partial sequence homology with solvent accessible antigenic sites of Phl p 5a, which have been identified by our previous mimotope approach. Phagemid DNA derived from the phage clones was used to produce two soluble recombinant anti-idiotypic Fab clones in E. coli. As a proof of molecular mimicry, both Fabs induced anti-Phl p 5a-specific antibodies in immunized BALB/c mice. Molecular modeling of the heavy and light chain hypervariable loops of the anti-idiotypic Fabs illustrated structural similarity with dominant IgE epitopes of Phl p 5a. CONCLUSION: In this straightforward phage technology approach, antibodies with anti-idiotypic specificities could be isolated from a human allergic's repertoire. As predicted by the immune network hypothesis, their hypervariable domains mimic IgE epitopes like internal images and, more importantly, induce allergen-specific immune responses in the absence of the allergen.

Dimerization of the major birch pollen allergen Bet v 1 is important for its in vivo IgE-cross-linking potential in mice.

In type I allergy, the cross-linking of membrane IgE on B lymphocytes and of cytophilic IgE on effector cells by their respective allergens are key events. For cross-linking two IgE molecules, allergens need at least two epitopes. On large molecules, these could be different epitopes in a multivalent, or identical epitopes in a symmetrical, fashion. However, the availability of epitopes may be limited on small allergens such as Bet v 1, the major birch pollen allergen. The present work analyzes whether dimerization is required for the cross-linking capacity of this allergen. In immunoblots, murine monoclonal and polyclonal human Bet v 1-specific Abs detected, besides a Bet v 1 monomer of 17 kDa, a dimer of 34 kDa. In dynamic light scattering, Bet v 1 appeared as dimers and even multimers, but a single condition could be defined where it behaved exclusively monomerically. Small-angle x-ray scattering of the monomeric and dimeric samples resulted in diagrams agreeing with the calculated models. Circular dichroism measurements indicated that the structure of Bet v 1 was preserved under monomeric conditions. Skin tests in Bet v 1-allergic mice were positive with Bet v 1 dimer, but remained negative using the monomer. Furthermore, in contrast to dimeric Bet v 1, the monomer was less capable of activating murine memory B cells for IgE production in vivo. Our data indicate that the presentation of two identical epitopes by dimerized allergens is a precondition for cross-linking of IgE on mast cells and B lymphocytes.

The Fc gammaRIIa polymorphism R/H131, autoantibodies against the platelet receptors GPIb alpha and Fc gammaRIIa and a risk for thromboembolism in lupus anticoagulant patients.

There is a clear propensity of individuals with lupus anticoagulant (LA) for thromboembolic disease (TE). Yet, it is not clear how individuals at risk for TE can be differentiated from those who are not. The Fc gammaRIIa receptor is the only Fc receptor expressed by platelets. As platelets can be activated via this receptor, we have compared gene frequencies of the Fc gammaRIIa polymorphism R/H131 in 46 and 27 patients with (LA/TE+) and without TE (LA/TE-), respectively, in an exploratory study. Furthermore, we investigated the presence of autoantibodies against Fc gammaRIIa and/or GPIb alpha, which is in close proximity to the Fc gammaRIIa and interacts with it functionally, and a possible linkage of antibody formation to HLA class II alleles. The Fc gammaRIIa-R/R131 genotype was significantly less frequent in patients with LA compared to controls (p<0.025). These findings were due to an increased frequency of heterozygous patients in the LA/TE+ cohort (odds ratio 6.76, 95% confidence interval 1.55-62.03, p<0.008). For the first time, heterozygosity, rather than homozygosity, can be linked to disease, which may be explained by the dual function of the Fc gammaRIIa, namely binding of antibodies to platelets and thereby their activation, and, on the other hand, clearance of antibody coated platelets by the phagocyte system. There was no correlation between the presence of anti-Fc gammaRIIa or anti-GPIb alpha autoantibodies and the Fc gammaRIIa-R/H131 polymorphism, nor the incidence of TE, nor HLA class II alleles.

Mapping of conformational IgE epitopes on Phl p 5a by using mimotopes from a phage display library.

BACKGROUND: Phl p 5 represents a major allergen of timothy grass pollen (Phleum pratense). Detailed knowledge about the structures responsible for IgE binding would allow the design of a novel generation of allergy vaccines. OBJECTIVE: We aimed to characterize the IgE epitopes of Phl p 5a using phage display combined with a molecular modeling approach. METHODS: Phl p 5a-specific IgE from sera of patients with grass pollen allergy was used for screening of a random peptide phage library displaying constrained decamers. RESULTS: Fifteen phage clones that shared sequence motifs and could be grouped into families were selected by using Phl p 5a-specific IgE. Peptide alignment with the solvent-accessible amino acids of Phl p 5a revealed 3 sequence sections with frequent hits of identical or similar amino acids. On the surface of Phl p 5a, these sections assembled in compact patches, most likely representing conformational IgE epitopes, whereas no matching clusters were found on the back sides of the 2 Phl p 5a halves. In surface plasmon resonance experiments, the high-affinity interaction between IgE and Phl p 5 could be competed by phage-displayed peptides up to 24%, indicating that they represent true epitope mimics (ie, mimotopes). Allergen-specific immunogenicity of the mimotopes was proved in Biozzi mice. CONCLUSION: The selected mimotopes facilitated the localization of conformational IgE epitopes of Phl p 5. We suggest them to be suitable candidates for the development of an epitope-specific immunotherapy.