Positive selection of antigen-specific B lymphocytes by means of immunomagnetic particles.

This paper presents a method for the isolation of highly enriched antigen-specific B lymphocytes from peripheral blood mononuclear cells (PBMC) by means of an immunomagnetic procedure. The method is illustrated by the isolation of B cells positive for rheumatoid factors (RF) from patients with rheumatoid arthritis and healthy blood donors. After Epstein-Barr virus transformation of isolated cells, more than 90% of the generated immunoglobulin-secreting cells produced RF in several experiments. Compared to the low frequency of B cells positive for RF in PBMC, this represents a 10(3)- to 10(4)-fold enrichment of antigen-specific B cells.