Interleukin-2 (IL-2) production by human B-cell line.

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 (sIg) G+, 98% sIg kappa chain+, 100% HLA-DR+, 94% IL-2 receptor (IL-2R alpha), 98% IL-2R beta, 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-2R alpha mRNA, and IL-2R beta mRNA. These findings indicate that certain B-cells not only produce, but also respond to IL-2 in an autocrine fashion with increased proliferation.