Neutralizing antibody persistence in pediatric travelers from non-JE-endemic countries following vaccination with IXIARO® Japanese encephalitis vaccine: An uncontrolled, open-label phase 3 follow-up study.

BACKGROUND: In an initial study among children from non-Japanese encephalitis (JE)-endemic countries, seroprotection rates remained high 6 months after completion of the primary series with IXIARO®. METHODS: In this open-label follow-up study, a subset of 23 children who received a 2-dose primary series of IXIARO® in the parent study, were evaluated for safety and neutralizing antibody persistence for 36 months. RESULTS: Seroprotection rates (SPRs) remained high but declined from 100% one month after primary immunization to 91.3% at month 7 and 89.5% at month 36. Geometric mean titers (GMTs) declined considerably from 384.1 by day 56-60.8 at month 36. No long-term safety concerns were identified. CONCLUSIONS: The substantial decline in GMT observed in this study, together with previously published data on children vaccinated with IXIARO® support the recommendation for a booster dose in children who remain at risk of JE from 1 year after the primary series of IXIARO®, consistent with the recommendation for adults. CLINICAL TRIAL REGISTRY NUMBER: NCT01246479.

No adjuvant effect of Bacillus thuringiensis-maize on allergic responses in mice.

Genetically modified (GM) foods are evaluated carefully for their ability to induce allergic disease. However, few studies have tested the capacity of a GM food to act as an adjuvant, i.e. influencing allergic responses to other unrelated allergens at acute onset and in individuals with pre-existing allergy. We sought to evaluate the effect of short-term feeding of GM Bacillus thuringiensis (Bt)-maize (MON810) on the initiation and relapse of allergic asthma in mice. BALB/c mice were provided a diet containing 33% GM or non-GM maize for up to 34 days either before ovalbumin (OVA)-induced experimental allergic asthma or disease relapse in mice with pre-existing allergy. We observed that GM-maize feeding did not affect OVA-induced eosinophilic airway and lung inflammation, mucus hypersecretion or OVA-specific antibody production at initiation or relapse of allergic asthma. There was no adjuvant effect upon GM-maize consumption on the onset or severity of allergic responses in a mouse model of allergic asthma.

Genetically modified α-amylase inhibitor peas are not specifically allergenic in mice.

Weevils can devastate food legumes in developing countries, but genetically modified peas (Pisum sativum), chickpeas and cowpeas expressing the gene for alpha-amylase inhibitor-1 (αAI) from the common bean (Phaseolus vulgaris) are completely protected from weevil destruction. αAI is seed-specific, accumulated at high levels and undergoes post-translational modification as it traverses the seed endomembrane system. This modification was thought to be responsible for the reported allergenicity in mice of the transgenic pea but not the bean. Here, we observed that transgenic αAI peas, chickpeas and cowpeas as well as non-transgenic beans were all allergenic in BALB/c mice. Even consuming non-transgenic peas lacking αAI led to an anti-αAI response due to a cross-reactive response to pea lectin. Our data demonstrate that αAI transgenic peas are not more allergenic than beans or non-transgenic peas in mice. This study illustrates the importance of repeat experiments in independent laboratories and the potential for unexpected cross-reactive allergic responses upon consumption of plant products in mice.

Comparison of the α-amylase inhibitor-1 from common bean (Phaseolus vulgaris) varieties and transgenic expression in other legumes--post-translational modifications and immunogenicity.

The seeds of peas (Pisum sativum) and chickpeas (Cicer arietinum) expressing a gene for α-amylase inhibitor-1 (αAI) from the common bean (Phaseolus vulgaris) are protected from damage by old world bruchids (pea and cowpea weevils). Here, we used electrospray ionization time-of-flight mass spectrometry to compare the post-translational modifications of αAI from transgenic sources with the processed forms of the protein from several bean varieties. All sources showed microheterogeneity with differences in the relative abundance of particular variants due to differences in the frequency of addition of glycans, variable processing of glycans, and differences of C-terminal exopeptidase activity. The structural variation among the transgenics was generally within the range of the bean varieties. Previously, mice showed allergic reactions following ingestion of transgenic pea αAI but not bean αAI. Here, only minor differences were observed following intraperitoneal sensitization. Both of the transgenic pea and bean forms of αAI elicited Th1 and Th2 antibody isotype responses, suggesting that both proteins are immunogenic and could potentially be allergenic.