Biopolymers and cell. 1988. Volume 4. № 6. 303 - 309

S. V. Komissarenko

MOUSE B LYMPHOCYTE ACTIVATION OF PROLIFERATION AND CYCLIC NUCLEOTIDES AT EARLY STAGES OF ACTIVATION

Summary

    Splenocytes and isolated mouse spleen B lymphocytes were activated in culture by: anti¬bodies to u,-chains of mouse immunoglobulins, Fab and F(ab')2 fragments of such anti¬bodies, LPS from E. coll and interleukin 2(/L-2). Cell activation was monitored by [3H]-incorporation and by flow cytofluorimetry. The latter permitted detecting cell-cycle pha¬ses distribution of cells stained by acridine orange. It was shown that anti-n antibodies were cytotoxic to mouse splenocytes and B lymphocytes. Isolated B cell could not be stimulated by Fab or F(ab')2 anti-u, fragments but were activated by LPS and by F(ab')i -\-IL-2, though F(ab')2 were stimulative to mouse splenocytes. In most cases activated cells passed GI phase and were arrested at the GrS bo¬undary. LPS or F(ab')2 anti-u, addition to isolated B cells in culture caused a Ca2+-de-pendent increase in cGMP but not cAMP levels in these cells. Methylene bisphosphonic acid being administered to mice 24 hours before B cells isolation did not change cAMP or cGMP levels in LPS of F(ab')2 activated B lymphocytes. These data show that du¬ring the first minutes of B cell activation by LPS or F(ab')2 anti-jj, fragments there occurs a Ca2+-dependent increase in the cGMP level which is not sufficient for these cells proliferation and progression through the whole cell-cycle. The cells are usual¬ly arrested in GI phase.