Induction of mouse IgA B cell differentiation by phorbol ester in the absence of proliferation.
Previously, we have demonstrated that protein kinase C-activating phorbol esters selectively induce IgA synthesis by mouse B cells whether stimulated or not by lipopolysaccharide (LPS). In this study, we investigated in detail whether this maturation into IgA-secreting cells is preceded by cell proliferation. T-depleted spleen B cell suspensions were fractionated by Percoll gradient into a dense fraction that contained a majority of small resting B cells, and a hypodense fraction relatively enriched in large B cells. Phorbol 12-myristate, 13-acetate (PMA) induced IgA synthesis in both types of cells, though to a greater extent in large B cells. The phorbol ester accelerated and increased DNA synthesis in LPS-stimulated B cells but did not induce any DNA synthesis in small or large B cells, while at the same time decreasing the percentage of cells in the S, G2/M phases of the cell cycle. Inhibition of proliferation by colcemid, a cell cycle blocker, did not prevent PMA-induced IgA synthesis. The number of IgA secreting cells determined by the enzyme-linked immunospot reached a maximum at 24 h, by which time more than 50% of IgA B cells showed morphological features characteristic of plasma cells. No increase in percentage of large or blastic IgA cells was observed. Collectively the data indicate that PMA induces the terminal differentiation of mIgA+ B lymphocytes into IgA plasma cells without any DNA synthesis and cell proliferation.
Li
Y S
YS
Laboratoire d'Immunologie, INSERM U-80, UCBL, Lyon, France.
Dearden-Badet
M T
MT
Revillard
J P
JP
D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology* / Q000187:drug effects / Q000276:immunology; D002453:Cell Cycle / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects*; D002478:Cells, Cultured; D004247:DNA / Q000096:biosynthesis; D005434:Flow Cytometry; D007124:Immunoenzyme Techniques; D007070:Immunoglobulin A / Q000032:analysis / Q000096:biosynthesis*; D008213:Lymphocyte Activation; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D011493:Protein Kinase C / Q000378:metabolism; D013154:Spleen / Q000276:immunology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D013936:Thymidine / Q000378:metabolism
D007070:Immunoglobulin A; D004247:DNA; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate; D013936:Thymidine