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Activation of BCL 1 Cells by Polyclonal Activators and Inhibition of Growth and IgM Secretion by Anti‐IgM
Author(s) -
SEVERINSON E.,
TORRES A.,
MOLLER G.
Publication year - 1983
Publication title -
scandinavian journal of immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.934
H-Index - 88
eISSN - 1365-3083
pISSN - 0300-9475
DOI - 10.1111/j.1365-3083.1983.tb00852.x
Subject(s) - polyclonal antibodies , secretion , chemistry , microbiology and biotechnology , medicine , antibody , immunology , biology , biochemistry
Bacterial lipoprotein (LP) and lipopolysaccharide (LPS) both activated an in vitro line of the B‐cell tumour BCL 1 to IgM secretion, as determined by the protein A plaque assay. LPS but not LP activation was inhibited by polymyxin B. Activation with both LPS and LP resulted in a less than additive response. Several clones of BCL 1 were tested, and all responded to both LPS and LP. Both LPS and LP induced broad dose‐response curves in normal lymphocytes, recently cloned BCL 1 cells, and cloned and synchronized (G 1 phase) BCL, cells. This suggests that the dose‐response curve cannot be due to accumulation of responding cells with different threshold sensitivities for activation. We cannot exclude the possibility that the broad dose‐response curve is due to a heterogeneity of the LPS or LP preparation. The results indicate that LPS and LP induce similar signals in BCL, cells. Furthermore, binding to the cell membrane and activation of BCL 1 cells by LPS or LP seem to be separate events. An anti‐IgM antiserum inhibited spontaneous DNA synthesis and spontaneous and LP‐induced IgM secretion of BCL, cells. Equal inhibition was observed with F(ab′) 2 fragments but not with Fab fragments of the antiserum. suggesting that cross‐linking of IgM bound to the cell surface membrane‐induced inhibition. Supernatants from concanavalin A (Con A)‐activated spleen cells induced BCL 1 cells to secrete IgM. Fab anti‐IgM added alone to BCL, cells did not induce IgM secretion. Furthermore. Fab anti‐IgM plus Con A supernatant did not induce a higher response than the supernatant alone. This suggests that inductive signals via the IgM receptor do not occur in BCL, cells.