Human B cell lines can be triggered to secrete an interleukin 2-like molecule.
To determine whether human B cells can be triggered to secrete interleukin 2 (IL-2), 19 tumor cell lines derived from patients with undifferentiated lymphomas of Burkitt's and non-Burkitt's types and 6 normal lymphoblastoid cell lines were tested. Cells were grown in the presence or absence of the new tumor promoter teleocidin, and culture supernatants were assayed for IL-2 activity using the standard CTLL-2 assay. Teleocidin (10 ng/ml) triggered IL-2 secretion in 7/8 (87%) EBV-negative lymphoma cell lines of American origin and in 6/6 (100%) normal lymphoblastoid cell lines, but in only 1/6 (16%) EBV-positive tumor cell lines of American origin. Teleocidin had no effect on 5/5 (0%) African Burkitt's cell lines. IL-2 secretion was not detected in control supernatants. IL-2 secretion correlated with the induction of IgM secretion and was linked to both EBV status and karyotype. The following similarities in the functional biological characteristics of T cell and B cell IL-2 suggest that B cell IL-2 is not a factor which mimics IL-2 activity in the CTLL-2 assay: (i) neutralization of IL-2 by anti-IL-2 monoclonal antibody (DMS-1); (ii) elution of IL-2 following its adsorption to CTLL-2 cells; (iii) determination of the MW of IL-2 by SDS-PAGE and Western blot analysis; and (iv) ability of B cell IL-2 to support T cell proliferation and blocking of this activity by anti-tac monoclonal antibody. cDNA probes for T cell IL-2, however, did not detect IL-2 mRNA in B cells. The cell lines were also found to constitutively express IL-2 receptors detected by anti-tac monoclonal antibody, and to secrete soluble IL-2 receptors measured by ELISA. Our results imply that under certain circumstances, B cells can be triggered to secrete IL-2 or an IL-2-like molecule and thus influence T cell activation and proliferation.
Benjamin
D
D
Saint Francis Research Institute, University of Oklahoma Health Sciences Center, Oklahoma City 73190.
Hartmann
D P
DP
Bazar
L S
LS
Jacobson
R J
RJ
Gilmore
M S
MS
D000911:Antibodies, Monoclonal; D001402:B-Lymphocytes / Q000378:metabolism*; D006801:Humans; D007136:Immunoglobulins / Q000378:metabolism; D007376:Interleukin-2 / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D008213:Lymphocyte Activation; D008222:Lymphokines / Q000378:metabolism; D008235:Lyngbya Toxins / Q000494:pharmacology; D008970:Molecular Weight; D012333:RNA, Messenger / Q000302:isolation & purification; D015375:Receptors, Interleukin-2 / Q000096:biosynthesis / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D000911:Antibodies, Monoclonal; D007136:Immunoglobulins; D007376:Interleukin-2; D008222:Lymphokines; D008235:Lyngbya Toxins; D012333:RNA, Messenger; D015375:Receptors, Interleukin-2; C022176:teleocidins