Biological differences in a rat insulinoma cell line obtained from different laboratories do not affect binding of human anti-islet immunoglobulins.

An insulin-producing clone of rat insulinoma cells (RINm5F) has been used by several investigators as target cells for studies of both humoral and cell-mediated anti-islet immunity in diabetic animals and humans. We noted that the rate of proliferation of RINm5F cells obtained from different laboratories varied considerably, and, in the present study, we have compared the proliferation rates of RINm5F cells obtained from 3 laboratories (Uppsala, Sweden [UPP], Chicago [CHI] and New York [NY]). The cells were plated at 0.5 and 2.0 X 10(4)/cm2 and changes in cell number were measured over 5 days. Basal insulin release was also determined daily. In addition, binding of IgG from sera of human diabetics by each of the cell lines was also examined by a solid-phase, quantitative assay. Plating efficiency was significantly greater in the NY and CHI cells than UPP cells at both plating densities (p less than 0.025). When plated at 2 X 10(4)/cm2, the growth rate of the NY cells was faster than the others (NY: 100.1 +/- 7.8%/day, CHI: 72.2 +/- 8.1%/day, UPP: 78.3 +/- 14.0%/day, p less than 0.025). All growth rates were lower when cells were plated at 5 X 10(4)/cm2, and the differences in growth between the NY and the other cells was greater (NY: 94.1 +/- 12.2%/day, CHI: 61.8 +/- 5.8%/day, UPP: 58.1 +/- 5.6%/day). Insulin release also differed among the cells. More insulin was released by the NY cells than by the other cells on all days, and the CHI cells released more insulin than the UPP cells (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)