Prevention of type 1 diabetes by inducing subclinical dermatitis on a small area

Detection of local inflammation induced by repeated exposure to contact allergens by use of IVIS SpectrumCT analyses

BACKGROUND

Contact allergy is characterized by local skin inflammation that, in some cases, can result in systemic immune activation.

OBJECTIVES

To investigate whether IVIS SpectrumCT analyses can be used to detect the immune response induced by contact allergens.

METHODS

Mice were repeatedly exposed to vehicle or allergens on the ears. The local and systemic responses were analysed at different times with the ProSense 750 FAST probe in IVIS SpectrumCT measurements. In addition, changes in ear thickness, cytokine profile in the skin and immunological phenotype in the draining lymph nodes and spleen were determined.

RESULTS

Local inflammation was detected by ProSense 750 FAST and correlated with changes in ear thickness, cytokine profile and immunological phenotype following exposure to the strong contact allergen 2,4-dinitrofluorobenzene. Analysis of the systemic response with ProSense 750 FAST did not show any difference between allergen-exposed and control mice, although fluorescence-activated cell sorting analysis of the spleen showed increased numbers of γδ T cells and CD11b⁺ CD11c⁺ MHCII⁺ cells in allergen-treated mice.

CONCLUSIONS

IVIS SpectrumCT analyses with ProSense 750 FAST as the probe can be used to detect local immune responses induced by contact allergens.

Impact of the gut microbiota on rodent models of human disease

Traditionally bacteria have been considered as either pathogens, commensals or symbionts. The mammal gut harbors 10¹⁴ organisms dispersed on approximately 1000 different species. Today, diagnostics, in contrast to previous cultivation techniques, allow the identification of close to 100% of bacterial species. This has revealed that a range of animal models within different research areas, such as diabetes, obesity, cancer, allergy, behavior and colitis, are affected by their gut microbiota. Correlation studies may for some diseases show correlation between gut microbiota composition and disease parameters higher than 70%. Some disease phenotypes may be transferred when recolonizing germ free mice. The mechanistic aspects are not clear, but some examples on how gut bacteria stimulate receptors, metabolism, and immune responses are discussed. A more deeper understanding of the impact of microbiota has its origin in the overall composition of the microbiota and in some newly recognized species, such as Akkermansia muciniphila, Segmented filamentous bacteria and Faecalibacterium prausnitzii, which seem to have an impact on more or less severe disease in specific models. Thus, the impact of the microbiota on animal models is of a magnitude that cannot be ignored in future research. Therefore, either models with specific microbiota must be developed, or the microbiota must be characterized in individual studies and incorporated into data evaluation.