Orf Virus-Based Therapeutic Vaccine for Treatment of Papillomavirus-Induced Tumors.

Orf virus (ORFV) represents a suitable vector for the generation of efficient, prophylactic antiviral vaccines against different pathogens. The present study investigated for the first time the therapeutic application of ORFV vector-based vaccines against tumors induced by cottontail rabbit papillomavirus (CRPV). ORFV-CRPV recombinants were constructed expressing the early CRPV gene E1, E2, E7, or LE6. In two independent experiments we used in total 23 rabbits which were immunized with a mixture of the four ORFV-CRPV recombinants or empty ORFV vector as a control 5 weeks after the appearance of skin tumors. For the determination of the therapeutic efficacy, the subsequent growth of the tumors was recorded. In the first experiment, we could demonstrate that three immunizations of rabbits with high tumor burden with the combined four ORFV-CRPV recombinants resulted in significant growth retardation of the tumors compared to the control. A second experiment was performed to test the therapeutic effect of 5 doses of the combined vaccine in rabbits with a lower tumor burden than in nonimmunized rabbits. Tumor growth was significantly reduced after immunization, and one vaccinated rabbit even displayed complete tumor regression until the end of the observation period at 26 weeks. Results of delayed-type hypersensitivity (DTH) skin tests suggest the induction of a cellular immune response mediated by the ORFV-CRPV vaccine. The data presented show for the first time a therapeutic potential of the ORFV vector platform and encourage further studies for the development of a therapeutic vaccine against virus-induced tumors.IMPORTANCE Viral vectors are widely used for the development of therapeutic vaccines for the treatment of tumors. In our study we have used Orf virus (ORFV) strain D1701-V for the generation of recombinant vaccines expressing cottontail rabbit papillomavirus (CRPV) early proteins E1, E2, LE6, and E7. The therapeutic efficacy of the ORFV-CRPV vaccines was evaluated in two independent experiments using the outbred CRPV rabbit model. In both experiments the immunization achieved significant suppression of tumor growth. In total, 84.6% of all outbred animals benefited from the ORFV-CRPV vaccination, showing reduction in tumor size and significant tumor growth inhibition, including one animal with complete tumor regression without recurrence.

Local and systemic eosinophil activation in allergic fungal sinusitis.

BACKGROUND: In allergic fungal sinusitis diagnostic and monitoring criteria are not firmly established, and the role of eosinophils in pathogenesis is not clear. OBJECTIVE: To determine whether assessment of eosinophil activation by measurement of eosinophil cationic protein in serum or allergic mucin would be useful in distinguishing patients with allergic fungal sinusitis from patients with chronic sinusitis of other etiologies. METHODS: Thirteen patients referred for possible allergic fungal sinusitis were evaluated and given a definite allergic fungal sinusitis diagnosis if they met five of the following six criteria: (1) history and physical not suggesting another etiology, (2) sinus computed tomography consistent with allergic fungal sinusitis, (3) typical allergic mucin, (4) fungus isolated from allergic mucin, (5) presence of fungal-specific IgE, and (6) elevated total IgE. Eosinophil cationic protein, a marker of eosinophil activation, was measured in serum and allergic mucin. RESULTS: Nine patients met criteria for allergic fungal sinusitis. All patients had nasal polyps and were atopic. Eight of the patients had allergic rhinitis and three had asthma. Mean total IgE at surgery was 1,385 IU/mL. A fungus was isolated from allergic mucin of eight patients. All patients demonstrated fungal-specific IgE. Mean allergic mucin eosinophil cationic protein levels obtained at surgery were significantly higher in patients with allergic fungal sinusitis than in four patients not meeting strict diagnostic criteria, and in 16 control patients having sinus surgery for other indications. There was no significant difference in serum eosinophil cationic protein levels between the three groups. Serial allergic mucin eosinophil cationic protein levels appeared to correspond with disease activity in some allergic fungal sinusitis patients. CONCLUSIONS: Eosinophils in allergic mucin are activated. Measuring eosinophil cationic protein may be useful in diagnosis of allergic fungal sinusitis and in monitoring response to therapy.

Laboratory evaluation of a commercial immunoassay for fire ant allergen-specific IgE antibodies.

BACKGROUND: In vitro testing for fire ant sensitization would be useful for research purposes and in special clinical situations. METHODS: Laboratory performance of a commercial assay (Pharmacia CAP System, [PCS]), for specific IgE to Solenopsis invicta whole body extract was studied in 46 persons. Assay results were compared with those of venom skin testing, RAST, and ELISA. The manufacturer's global cutoffs were compared with cutoffs set by using methods derived from analytical detection limit theory. RESULTS: Thirty-two study subjects had positive skin test results, and 14 had negative results. Raw PCS data demonstrated a high level of correlation with RAST (rho = 0.941) and ELISA (rho = 0.931), and showed good correlation with skin testing (rho = -0.769). Analysis of binormal receiver operating characteristic curves, using skin test results as the reference standard, demonstrated no difference in performance among the three assays. The fixed global quantitative cutoff of 0.35 kUa/L was relatively insensitive. Use of the manufacturer's qualitative alternate scoring method cutoff substantially increased sensitivity without loss of specificity, as did lower limit of detection set by use of diluent. CONCLUSIONS: In situations in which skin testing for fire ant sensitization is not feasible, PCS appears to be an acceptable in vitro alternative method for determination of fire ant allergen-specific IgE.

Acute eosinophilic pneumonia with respiratory failure: a new syndrome?

Acute, noninfectious, eosinophilic pneumonia with respiratory failure has been described in adults. This new form of eosinophilic lung disease differs from the previously described types of eosinophilic pneumonia. Patients with this entity develop rapid progressive respiratory failure, which seems to respond to corticosteroid therapy. Eosinophilia in lung biopsy specimen, or in bronchoalveolar lavage fluid seems to be a common denominator. We present the first pediatric case of this new, distinct form of eosinophilic lung disease and review the pertinent literature.