BackgroundA comparative characterization of the oral mucosa in various animals is needed to identify the best animal model(s) for nonclinical evaluation of sublingual immunotherapy products. With this aim, we studied the histological characteristics and immune cell infiltrates of oral mucosae from common animal species.MethodsThree oral regions (i.e. ventral surface of the tongue, mouth floor and cheek) obtained from eight animal species, including rodents (i.e. mice, rats, hamsters, guinea pigs) and non-rodents (i.e. rabbits, dogs, minipigs and monkeys) were characterized by histology and immunohistology in comparison with a human tongue.ResultsRodents exhibit a thin keratinized epithelium with low epithelial extensions, whereas non-rodents, most particularly minipigs and monkeys, display a non-keratinized epithelium with larger rete ridges, similarly to humans. Glycogen-rich cells in the superficial epithelial layers are observed in samples from both minipigs, monkeys and humans. Comparable immune subpopulations detected in the 3 oral regions from rodent and non-rodent species include MHC-II+ antigen presenting cells, mostly CD163+ macrophages, located in the lamina propria (LP) and muscle tissue in the vicinity of resident CD3+CD4+ T cells. Limited numbers of mast cells are also detected in the LP and muscle tissue from all species.ConclusionThe oral mucosae of minipigs and monkeys are closest to that of humans, and the immune networks are quite similar between all rodents and non-rodents. Taking into account the ethical and logistical difficulties of performing research in the latter species, rodents and especially mice, should preferentially be used for pharmacodynamics/efficacy studies. Our data also support the use of minipigs to perform biodistribution and safety studies of sublingual immunotherapy products.

The Notch signaling pathway controls several cell fate decisions during lymphocyte development, from T-cell lineage commitment to the peripheral differentiation of B and T lymphocytes. Deltex-1 is a RING finger ubiquitin ligase which is conserved from Drosophila to humans and has been proposed to be a regulator of Notch signaling. Its pattern of lymphoid expression as well as gain-of-function experiments suggest that Deltex-1 regulates both B-cell lineage and splenic marginal-zone B-cell commitment. Deltex-1 was also found to be highly expressed in germinal-center B cells. To investigate the physiological function of Deltex-1, we generated a mouse strain lacking the Deltex-1 RING finger domain, which is essential for its ubiquitin ligase activity. Deltex-1 ⌬/⌬ mice were viable and fertile. A detailed histological analysis did not reveal any defects in major organs. T-and B-cell development was normal, as were humoral responses against T-dependent and T-independent antigens. These data indicate that the Deltex-1 ubiquitin ligase activity is dispensable for mouse development and immune function. Possible compensatory mechanisms, in particular those from a fourth Deltex gene identified during the course of this study, are also discussed.

A 6-year-old female pony died after 2 days of prostration. Clinical signs included hyperthermia and abnormal pulmonary auscultation sounds. Necropsy revealed diffuse severe necrohaemorrhagic colitis and splenitis, multiple visceral ecchymoses, petechial haemorrhages in the brain and lungs. Microscopical examination showed acute necrohaemorrhagic colitis, encephalitis, pneumonia and splenitis associated with fibrinoid vasculitis, thrombosis and fungal hyphae within and around vessels. Immunohistologically, concomitant aspergillosis (caused by Aspergillus fumigatus) and mucormycosis (causde by Absidia corymbifera) were identified in the colonic and pulmonary lesions, whereas pure mucormycosis was observed in cerebral and splenic lesions. Dual mycotic infections are very rarely described, and the present case emphasizes the need of immunohistochemistry in order to obtain a clear-cut diagnosis of mixed fungal infections.

Protealg ® is the dried and ground whole biomass of Galdieria sulphuraria, a microalga naturally rich in protein and phycocyanin, and contains carotenoids. It is expected that Protealg will be consumed as a food ingredient or supplement by the general public. The safety of Protealg was evaluated in an Ames bacterial reverse mutation test, in vitro mammalian cell micronucleus test, and 13-week oral toxicity study in rats at the dose levels of 500, 2000, and 5000 mg/kg/day. The 13week toxicity study included a 4-week treatment-free period to evaluate recovery. A functional observation battery and ophthalmology examinations were performed, and hematology, blood biochemistry, thyroid hormone, and urinalysis parameters were determined. Seminology parameters and estrus cycle staging were investigated. A macroscopic necropsy examination was performed and tissues were examined microscopically. Protealg showed no evidence of mutagenicity or clastogenic activity. It was well tolerated by rats and no clinical findings indicative of toxicity were observed. There were no significant findings in the in-life or post-mortem investigations. In conclusion, no toxicity was observed after administration of Protealg at dose levels up to 5000 mg/kg/day to rats for 13 weeks, supporting the safety of Protealg for use as a high protein food supplement. The NOAEL was established as 5000 mg/kg/day. Allowing for a margin of exposure of 100-fold, the corresponding anticipated daily intake will be 50 mg/kg/day equivalent to 3.5 g/day for a 70 kg subject. Incorporation levels in various foods will be defined on the basis of appropriate exposure estimations using official recommendations.