Detection of antibodies against Actinobacillus pleuropneumoniae serotypes 1, 2, 5 and 7 using the immunohistochemical staining.

Whole cells of Actinobacillus pleuropneumoniae (A. pleuropneumoniae) serotype 1, 2, 5 or 7 attached to fibrins were fixed in 10% neutral buffered formalin and embedded in paraffin. The sections on a slide glass were stained by the avidin-biotin complex immunoperoxidase (ABC) method. Test sera were applied to sections as primary antibodies. The serum antibodies against A.pleuropneumoniae (serotypes 1, 2, 5 and 7) were measured by the ABC method and complement fixation (CF) test. There was good correlation between the ABC and CF tests. The present results indicate that the immunohistochemical staining is as useful as the CF test for the detection and quantification of antibody in swine sera.