Mould extracts increase the allergic response to ovalbumin in mice

Authors


Christine Instanes, Norwegian Institute of Public Health, Division of Environmental Medicine, Box 4404 Nydalen, NO-0403 Oslo, Norway. E-mail: christine.instanes@fhi.no

Summary

Background Exposure to moulds in indoor air is thought to induce asthma in susceptible persons. Moulds may contain several potent allergens. However, more importantly, moulds may increase the allergic response to other allergens (adjuvant effect). Previously, we have found that a β-1,3-glucan from the cell wall of the fungus Sclerotinia sclerotiorum increases the allergic response to the model allergen ovalbumin (OVA) in a mouse model.

Objective In the present study, we wanted to confirm the adjuvant effect of another β-1,3-glucan, MacroGard® (MG) from baker's yeast in this model. More importantly, we wished to explore the putative effects of extracts from the moulds Cladosporium herbarum (CH) and Penicillium chrysogenum (PC) using the very same model as used to explore effects of β-glucans.

Methods Groups of eight Balb/c mice were injected with OVA alone, OVA+extract or OVA+MG, into one footpad. On day 21, all mice were reinjected with OVA, before exsanguination on day 26. The levels of OVA-specific IgE, IgG1 and IgG2a in serum were measured by ELISA.

Results Compared with OVA alone, OVA+MG, OVA+CH extract and OVA+PC extract increased OVA-specific IgE and IgG1 levels significantly. For all groups, the levels of IgG2a anti-OVA remained similar to those of the OVA-alone group.

Conclusions Our results show that extracts from CH and PC, and the β-1,3/1,6-glucan from baker's yeast have adjuvant effects on the allergic response in mice.

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