Research gaps and future needs for allergen prediction in food safety.

The allergenicity and protein risk assessments in food safety are facing new challenges. Demands for healthier and more sustainable food systems have led to significant advances in biotechnology, the development of more complex foods, and the search for alternative protein sources. All this has increased the pressure on the safety assessment prediction approaches anchored into requirements defined in the late 90's. In 2022, the EFSA's Panel on Genetically Modified Organisms published a scientific opinion focusing on the developments needed for allergenicity and protein safety assessments of new products derived from biotechnology. Here, we further elaborate on the main elements described in this scientific opinion and prioritize those development needs requiring critical attention. The starting point of any new recommendation would require a focus on clinical relevance and the development of a fit-for-purpose database targeted for specific risk assessment goals. Furthermore, it is imperative to review and clarify the main purpose of the allergenicity risk assessment. An internationally agreed consensus on the overall purpose of allergenicity risk assessment will accelerate the development of fit-for-purpose methodologies, where the role of exposure should be better clarified. Considering the experience gained over the last 25 years and recent scientific developments in the fields of biotechnology, allergy, and risk assessment, it is time to revise and improve the allergenicity safety assessment to ensure the reliability of allergenicity assessments for food of the future.

Biocompatibility and immunogenicity of elastin-like recombinamer biomaterials in mouse models.

Novel thermo-sensitive elastin-like recombinamers (ELRs) containing bioactive molecules were created for use as a biomimetic biomaterial for tissue regeneration. For effective use for in vivo applications, it is essential to ensure that they do not induce adverse inflammatory, immune, or allergic responses that inhibit tissue repair. Therefore, we sought to establish a pre-clinical approach to evaluate biocompatibility in experimental mice using ELRs as a prototype biomaterial. First, we measured in vitro proliferation and cytokine production from BALB/c and C57BL/6 mouse splenocytes incubated with ELRs. Second, we used a rapid, high throughput in vivo approach in which inflammatory cells and cytokines were measured following an intraperitoneal implantation. Lastly, a subchronic in vivo approach was used in which ELRs or positive controls were subcutaneously implanted and the implantation sites were assessed for inflammation and gene expression. We found that ELRs induced mild inflammation and minimal fibrosis compared to the intense response to Vitoss. Additionally, implantation increased antigen-specific antibody titers for both groups and gene expression profiling of the implantation sites revealed the upregulation of inflammation, fibrosis, and wound healing-related genes in ELR and positive control-implanted mice compared to sham controls. These data demonstrate that ELRs appear safe for use in tissue engineering. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 924-934, 2018.

Mimotope vaccination for therapy of allergic asthma: anti-inflammatory effects in a mouse model.

BACKGROUND: One of the concerns of allergen-specific immunotherapy is the possible boost of inflammatory allergen-specific T lymphocytes. To address this problem, treatment with B cell epitopes devoid of allergen-specific T cell epitopes would be a promising alternative. OBJECTIVE: In this study, we examined the therapeutic potency of a single mimotope, mimicking a structural IgE epitope of grass pollen allergen Phl p 5 in an established memory mouse model of acute allergic asthma. METHODS: In the experimental set-up, BALB/c mice were primed with intraperitoneal injections of recombinant Phl p 5a (rPhl p 5a) and subsequently aerosol challenged with the nebulized allergen. Mice developed signs of bronchial asthma including hypereosinophilia around bronchi, goblet cell hyperplasia and enhanced mucus production. RESULTS: When the mice were subsequently treated with the grass pollen mimotope coupled to keyhole limpet haemocyanin, bronchial eosinophilic inflammation and mucus hypersecretion decreased. Further, a decrease of Th2 cytokines IL-4 and IL-5 could be observed in the bronchoalveolar lavage (BAL). In contrast to rPhl p 5a, the mimotope was in vitro not able to stimulate splenocytes to proliferation or IL-5 production. Despite not affecting the levels of pre-existing IgE, vaccination with the single mimotope thus rendered anti-inflammatory effects in a mouse model of acute asthma. CONCLUSION: From our data, we conclude that vaccination with a mimotope peptide representing a single IgE epitope of the allergen Phl p 5a and being devoid of allergen-specific T cell epitopes is able to down-regulate inflammation in acute asthma.

Successful T cell priming in B cell-deficient mice.

B cells are an abundant population of lymphocytes that can efficiently capture, process, and present antigen for recognition by activated or memory T cells. Controversial experiments and arguments exist, however, as to whether B cells are or should be involved in the priming of virgin T cells in vivo. Using B cell-deficient mice, we have studied the role of B cells as antigen-presenting cells in a wide variety of tests, including assays of T cell proliferation and cytokine production in responses to protein antigens, T cell killing to minor and major histocompatibility antigens, skin graft rejection, and the in vitro and in vivo responses to shistosome eggs. We found that B cells are not critical for either CD4 or CD8 T cell priming in any of these systems. This finding lends support to the notion that the priming of T cells is reserved for specialized cells such as dendritic cells and that antigen presentation by B cells serves distinct immunological functions.

Selective deficiency in pneumococcal antibody response in children with recurrent infections.

BACKGROUND: Impaired ability to respond to polysaccharide capsular antigens of Streptococcus pneumoniae may be associated with an IgG subclass deficiency and recurrent respiratory infections. OBJECTIVE: To identify children over three years of age with recurrent otitis media, sinusitis, or pneumonia who had low or absent pneumococcal antibody titers as their sole manifestation of immune deficiency and to determine their response to the 23-valent pneumococcal vaccine. RESULTS: Of 100 children with low pneumococcal antibody titers, 87 generated a protective antibody response to the pneumococcal vaccine (> 300 ng/mL to the majority of the antigen serotypes), while 13 responded poorly or not at all. Repeated vaccination of nonresponders failed to produce a normal response. CONCLUSION: We have identified two clinically distinct subpopulations of children with recurrent respiratory infections characterized by their responsiveness to pneumococcal antigens: one group did not respond to pneumococcal vaccination, whereas the other group responded both clinically and serologically. The nonresponding 6.5% subpopulation has an apparent isolated defect in anti-pneumococcal antibody production associated with recurrent respiratory infections despite normal IgG2 subclass levels.

The usefulness of routine screening for salivary secretory component.

Secretory IgA is a dimeric immunoglobulin found in association with the J chain and secretory component (SC). It is secreted into saliva and other mucosal fluids and is involved in mucosal immunity. The absence of either SC or secretory IgA may be associated with recurrent sinopulmonary infections, diarrhea, and failure to thrive. We present a retrospective study of 1262 samples from 877 patients who were screened for salivary IgA, SC, and serum immunoglobulin levels. Forty-six patients (5.2%) of those tested were found to have absent salivary SC. Although only 19 of these patients (41.3%) could be retested, all were found to have SC on repeated testing. Of the patients whose initial samples of saliva exhibited no SC, 15% (6/46) had low or absent serum IGA (less than 10 mg/dl) in contrast to 8.6% (66/769) of patients whose saliva contained detectable SC, but this was not statistically significant (chi 2 = 1.93; p greater than 0.1). There was also no correlation between serum immunoglobulin levels and the absence of SC. Because of the rarity of salivary SC deficiency, routine screening is not valuable.

Inhibition of the metabolism of paracetamol by isoniazid.

1. The effect of isoniazid given daily for 7 days on paracetamol (acetaminophen) kinetics and metabolism was studied in 10 healthy volunteers. Paracetamol, 500 mg, was given before isoniazid, on day 7 of isoniazid administration, and 2 days after the last dose of isoniazid. 2. On day 7, isoniazid markedly inhibited the formation clearance of the glutathione and catechol metabolites by 69.7% and 62.2%, respectively. Total paracetamol clearance was lowered by 15.2%. There was no effect of isoniazid on the non-oxidative pathways of paracetamol elimination. 3. Two days after isoniazid was discontinued, paracetamol metabolism had returned to pre-isoniazid values.