A simultaneous two-colour detection method of human IgG- and IgE-reactive proteins from lactic acid bacteria

•The described method is appropriate to detect immunoreactive bacterial proteins.•Bacterial proteins react with human antibodies of various classes.•L. casei and L. delbrueckii ssp. bulgaricus differ in immunoreactive proteins.

Whole cell extracts of two Lactobacillus strains were tested with primary antibodies from two pooled sera from allergic patients. Fluorescently labelled anti-human IgG and anti-human IgE secondary antibodies applied in Western blotting, together with an appropriate image acquisition protocol facilitated imagining bacterial proteins that reacted with human IgG and IgE.