Interleukin-2 (IL-2) Production by Human B-Cell Line

Abstract A human B-cell line (Hairy-BM) constitutively secreting interleukin-2 (IL-2) was established from tumor tissue resected surgically from a patient with breast cancer. Hairy-BM was found to be 100% CD20 + , 98% surface immunoglobulin (slg) G + , 98% slg κ chain + , 100% HLA-DR + , 94% IL-2 receptor (IL-2Rα), 98% IL-2Rβ, and devoid of T-cell, monocyte, and natural killer cell surface antigens. The B-cell origin of Hairy-BM was also confirmed by clonally rearranged Ig heavy- and Ig light-chain genes. The growth of Hairy-BM expressing IL-2R was promoted by recombinant IL-2 (rIL-2) and anti-CD25 antibody significantly blocked the growth enhancement. IL-2 secretion from Hairy-BM was confirmed by radioimmunoassay. By using a sensitive polymerase chain reaction technique, we demonstrated that Hairy-BM expressed IL-2 mRNA, IL-2Rα mRNA, and IL-2Rβ mRNA. These findings indicate that certain B-cells not only produce, but also respond to IL-2 in an autocrine fashion with increased proliferation.