Mouse B lymphocytes were fractioned from normal T lymphocyte-depleted spleen cell populations using discontinuous Percoll gradients and were stimulated with rabbit F(ab')2 anti-mouse μ-specific antibodies (anti-μ) plus the supernatant of Con A-stimulated rat spleen cells (SN) as a source of lymphokines. The responses of small (mean volume 120 μ3), dense (>1.087 specific gravity), resting (least spontaneous thymidine incorporation) B lymphocytes were augmented by irradiated (4000 rad), larger (mean volume >170 μ3), less dense (<1.081 specific gravity), activated (greater spontaneous thymidine incorporation) B lymphocytes. Proliferation was augmented 2- to 4-fold and polyclonal antibody-forming cell responses three- to sixfold. Maximal augmentation of the responses of 5 x 104 resting B cells was obtained with 104 activated B cells. Augmenting activity was specific for activated B lymphocytes in that responses were not augmented by irradiated thymocytes, T lymphoblasts, macrophages, or additional supernatant, B lymphocytes activated in vitro by LPA or anti-μ also had augmenting activity. Augmentation of responses was maximal only when activated B lymphocytes were added simultaneously with anti-μ. The interaction between activated and resting B lymphocytes did not appear to be genetically restricted. Interestingly, the augmenting activity of activated B cells could be reconstituted by a combination of supernatant and cell membranes from these cells but not by either alone, suggesting that two components are required, one soluble and the other membrane-bound. Thus, a functional interaction has been demonstrated between B lymphocyte subpopulations which differ in their state of activation, and this interaction appears to involve a novel mechanism of action.
|Number of pages||6|
|Journal||Journal of Immunology|
|Publication status||Published - jan. 1 1988|
ASJC Scopus subject areas
- Immunology and Allergy