EXPRESSION AND QUANTIFICATION OF IGG AND IGM MOLECULES ON THE SURFACEOF LYMPHOCYTES OF CATTLE INFECTED WITH BOVINE LEUKEMIA-VIRUS

Immunogold-labelled antibodies were used with scanning electron micros copy (SEM) and fluorescent-labelled antibodies were used with flow cyt ometry (FACS) to evaluate the expression and quantity of IgG and IgM m olecules on the surface of the lymphocytes of cattle infected with bov ine leukaemia virus (BLV). The BLV-infected animals were divided serol ogically and haematologically into groups with (BLV(+)PL(+)) and witho ut (BLV(+)PL(-)) persistent lymphocytosis (PL). The percentage of IgM- bearing cells was significantly higher in the BLV(+)PL(+) group than i n the BLV(-)PL(-) and BLV(+)PL(-) groups by FAGS. There was a signific antly higher percentage of IgG-bearing cells in the BLV(+)PL(+) group than in the BLV(-)PL(-) and BLV(+)PL(-) groups by SEM, but no differen ces were found by FAGS. A significantly higher intensity of IgM expres sion was observed in the BLV(+)PL(+) group by SEM. A higher intensity of IgG expression in some animals was detected only by SEM. An increas e in the number of larger IgM cells was observed in the BLV(+)PL(-) an d BLV(+)PL(+) groups by SEM. The SEM analysis was more sensitive than FAGS in this experiment.