Continuous in vitro production of IgA by a human colostral immortalized cell line

Breast milk samples from 8 postpartum mothers were collected and incubated with Epstein-Barr virus, immortalizing their B-lymphocytes and giving rise to lymphoblastoid cell lines. Three samples showed no growing lymphocytes and five samples gave rise to transformed cell lines. IgA positive cells were selected from one such cell line by rosetting with anti-IgA-coated sheep erythrocytes. The emerging cell line was similarly reselected giving rise to an IgA-surface positive lymphoblastoid cell line. Monoclonal IgA-producing cell lines were obtained by cloning in the soft agar method. IgA is continuously secreted by the cell lines which have been growing in vitro for more than 24 mth.