Ehrlichia are zoonotic obligate intracellular alpha-proteobacteria of the family Ehrlichiaceae. Ticks serve as as the main reservoir and as vectors of ehrlichiosis while feeding on both humans and animals. The antibody response to infections by Ehrlichia chaffeensis, Ehrlichia canis and Ehrlichia muris is primarily directed against outer-membrane protein antigens and is most often detected using standard IFA and MIF methods.
Our IFA slides contain infected cells in a traditional format, while our 2-antigen MIF (depicted below) pairs purified Anaplasma phagocytophilum with purified Ehrlichia chaffeensis in each slide well. The MIF format removes the vast majority of host cell cytoplasmic, nuclear and membrane constituents that are common sources of "non-specific" fluorescence.Without the need to penetrate the host cell membrane, the IgM antibody assay has the same incubation timing (30 minutes) as the IgG assay. To produce a distict marix for these antigens, we use a sonicated chicken cell suspension that absorbs the Evans' blue counterstain. The goal of this approach is to produce a reaction that can be immediately classified as either positive or negative, saving valuable technician time and avoiding erroneous results cause by irrelevant fluorescence.