We have established a new human myeloma cell line from the pleural effusion of a patient with an IgA lambda myeloma, using special tissue culture conditions and selection procedures to prevent the outgrowth of contaminating Epstein-Barr virus (EBV)-carrying normal B-lymphoblastoid cells present in the explant. The myeloma cell line, U-2030, is aneuploid and EBNA-negative and has morphological features, reactivity with cytochemical markers and cell-surface antigen expression typical of plasmablasts. The cell line thus appears to be representative of the malignant clone in vivo. However, functionally the line is a non-Ig-producer and must therefore be derived from a non-secretory variant cell present within the highly aneuploid myeloma cell clone in vivo. The U-2030 differs from previously established human myeloma cell lines in that it has a comparatively high growth rate, is clonable and can be made HAT-sensitive relatively easily. This, together with the facts that it is a non-Ig-producer and mycoplasma-free, suggests that the 6-thioguanine-resistant, HAT-sensitive subline, U-2030 TG, derived from this cell line may be used as a malignant fusion partner for the production of human-human hybridomas. An EBV-carrying lymphoblastoid cell line (U-2031) was also established. This line was diploid and had all the phenotypic properties of lymphoblastoid lines established from normal individuals.

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