Abstract
In order to establish clonal human lymphoblastoid cell lines, human tonsillar lymphocytes infected with Epstein-Barr virus were directly seeded in semi-solid agar. After four weeks, resulting colonies were randomly isolated and transferred to suspension culture. At around three months after the initiation of the culture, immunoglobulin (Ig) production of 17 clones thus established was determined. Cytoplasmic and membrane Ig were detected by immunofluorescence staining and secretory Ig in the culture supernatants was detected by double immunodiffusion. The patterns of Ig production by these cell lines were clear-cut. Each clone produced and secreted one class of heavy chains and one type of light chains, i. e., a single Ig. Of 17 clones, 13 clones were IgM producers, 3 clones were IgA producers and one clone was an IgG producer. Membrane Ig of these clones was also identical with cytoplasmic/secretory Ig with the exceptions of three IgM producers in which membrane IgD as well as IgM was detected and the one IgG producer in which no membrane Ig was detected.
