Infection of cultured human pancreatic B cells with reovirus type 3.

The capacity of reovirus type 3 to infect insulin-producing B cells was studied in human pancreatic cell cultures. Antibody to reovirus was labelled with fluorescein isothiocyanate and antibody to insulin was labelled with tetramethyl rhodamine isothiocyanate. By using a double-labelled immunofluorescent antibody technique, it was shown that only about 6% of the insulin-containing human B cells in culture became infected when inoculated with unpassaged reovirus type 3. However, by repeated passage of the virus in human pancreatic B cell cultures, the percentage of infected B cells increased to 27%, and the virus titre in cultures rose from 8.0 X 19(4) pfu/ml in the first passage, to 4.9 X 10(6) pfu/ml in the 5th passage. As measured by radioimmunoassay, the intracellular immunoreactive insulin began to decrease at 24 h after infection. This decrease roughly paralleled the increase in virus titre. In contrast, there was relatively little change in immunoreactive insulin in cultures inoculated with unpassaged reovirus type 3. These studies show that the ability of reovirus type 3 to infect human B cells is enhanced by serial passage in human pancreatic cell cultures and that the infection resulted in the destruction of B cells and release of insulin.