Circulating anti-dsDNA antibody is a hallmark of SLE both in human patients and in many SLE mouse models. This protocol describes how to measure the frequency of plasma cells producing these antibodies in the spleen of lupus-prone mice. This protocol was developed or modified in Dr. Anne Davidson’s lab at Feinstein Institute for Medical Research.

To probe for a specific mRNA species by Northern blot, RNA from the agarose/formaldehyde gel needs to be transferred to a nylon membrane. RNA is detected by hybridization using a labeled probe. The probe is a DNA or RNA molecule that is chemically or radioactively labeled. In this protocol synthesis and preparation of a [32P]-dCTP-labeled probe is described.