To determine whether NZB/W MCs are capable of producing more MCP-1 and OPN than the DBA/W MC controls, when exposed to LPS (S. minnesota, the same source of LPS that was used to induce the accelerated LN model [3]) the cells were arrested in 2% FBS medium for 2 hours, and were then incubated with LPS (10 μg/ml) for 0–12 hours. This evidence concerns the gene SPP1 and lobular neoplasia.