Expression and quantification of IgG and IgM molecules on the surface of lymphocytes of cattle infected with bovine leukaemia virus

Abstract

Immunogold-labelled antibodies were used with scanning electron microscopy ( SEM) and fluorescent-labelled antibodies were used with flow cytometry ( FACS) to evaluate the expression and quantity of IgG and IgM molecules on the surface of the lymphocytes of cattle infected with bovine leukaemia virus ( BLV). The BLV-infected animals were divided serologically and haematologically into groups with ( BLV +PL + ) and without ( BLV +PL − ) persistent lymphocytosis ( PL). The percentage of IgM-bearing cells was significantly higher in the BLV +PL + group than in the BLV −PL − and BLV +PL − groups by FACS. There was a significantly higher percentage of IgG-bearing cells in the BLV +PL + group than in the BLV −PL − and BLV +PL − groups by SEM, but no differences were found by FACS. A significantly higher intensity of IgM expression was observed in the BLV +PL + group by SEM. A higher intensity of IgG expression in some animals was detected only by SEM. An increase in the number of larger IgM cells was observed in the BLV +PL − and BLV +PL + groups by SEM. The SEM analysis was more sensitive than FACS in this experiment.