Differential recognition of Dirofilaria immitis antigens by human IgG and IgM positive sera. Preliminary data based on EITB analysis.

Preliminary data are presented on the differential recognition of Dirofilaria immitis antigens by sera positive for IgG and IgM (detected by enzyme linked immunosorbent assay, ELISA) using the enzyme-linked immunoelectrotransfer technique (EITB). The sera were followed prospectively over a year to detect seasonal variations. IgG mainly recognized antigens with a molecular weight (MW) lower than 74 kDa, while IgM recognized those with a MW higher than 43 kDa. The antigens with MW between 74 and 61 kDa were recognized by both isotypes. In IgG positive sera all bands were recognized throughout the year, albeit more mildly in summer. For IgM it is noteworthy that antigens with a MW between 43 and 20 kDa were not recognized in spring. These data are in accordance with those obtained with ELISA in the seasonal follow-up of positive sera.