The adoptive transfer of antigen-specific B cells into mice that cannot recognize that specific antigen has two main advantages. The first is determining exactly when the B cells were transferred and exposed to antigen. The second is that all B cells that can bind that antigen are the ones that were transferred; no new antigen-specific B cells will emerge from the bone marrow. Thus all B cells that were exposed to the antigen and still alive after at least 4 weeks (8 weeks or more is ideal), are memory B cells. Splenic B cells from B1-8 mice were prepared with an EasySep Mouse B Cell Enrichment Kit according to the manufacturer's protocol. Single-cell suspensions were transferred intravenously into tail veins of recipient mice. Approximately 1 million NP+ B cells were transferred per mouse. Approximately 12-24 h after transfer, mice were immunized intra-peritoneally with 50 µg of NP-CGG precipitated in alum.