We report here a factor (B cell growth factor) found in induced supernatants of the mouse thymoma EL4 that co-stimulates with anti-IgM antibodies in short-term cultures of purified B lymphocytes to induce polyclonal B cell proliferation but not antibody-forming cell production. The factor is not mitogenic for resting B cells and interacts with anti-IgM-activated B cells in a non-H-2-restricted manner. Absorption studies and molecular weight analysis reveal the factor is distinct from interleukin 2. This factor synergises with antigen, interleukin 2, and an interleukin 2-free, B cell growth factor-free T cell supernatant that contains T cell-replacing factor to produce erythrocyte-specific plaque-forming cells in cultures of highly purified B cells.

https://rupress.org/jem/article-pdf/155/3/914/1393671/914.pdf

Identification of a T cell-derived b cell growth factor distinct from interleukin 2.

We previously reported that osteoclast-like cells were formed in cocultures of a mouse marrow-derived stromal cell line (ST2) with mouse spleen cells in the presence of 1 alpha, 25-dihydroxyvitamin D3 and dexamethasone. In this study, we developed a new coculture system to determine the origin of osteoclasts. When relatively small numbers of mononuclear cells (10(3)-10(5) cells per well) obtained from mouse bone marrow, spleen, thymus, or peripheral blood were cultured for 12 days on the ST2 cell layers, they formed colonies with a linear relationship between the number of colonies formed and the number of hemopoietic cells inoculated. Tartrate-resistant acid phosphatase (TRAPase)-positive mononuclear and multinucleated cells appeared in the colonies (TRAPase-positive colonies) in response to 1 alpha, 25-dihydroxyvitamin D3 and dexamethasone. When hemopoietic cells suspended in a collagen-gel solution were cultured on the ST2 cell layers to prevent their movement, TRAPase-positive colonies were similarly formed, indicating that each colony originated from a single cell. All of the colonies consisted of nonspecific esterase-positive cells. The monocyte-depleted population prepared from peripheral blood failed to form colonies, whereas the monocyte-enriched population produced a large number of TRAPase-positive colonies. In addition, alveolar macrophages formed TRAPase-positive colonies most efficiently on the ST2 cell layers in the presence of the two hormones. Salmon 125I-labeled calcitonin specifically bound to the TRAPase-positive cells. Resorption lacunae were formed on dentine slices on which cocultures were performed. When direct contact between the peripheral blood cells and the ST2 cells was inhibited by a collagen-gel sheet, no TRAPase-positive cells were formed. These results indicate that osteoclasts are also derived from the mature monocytes and macrophages when a suitable microenvironment is provided by bone marrow-derived stromal cells.

https://www.pnas.org/content/pnas/87/18/7260.full.pdf

Origin of osteoclasts: mature monocytes and macrophages are capable of differentiating into osteoclasts under a suitable microenvironment prepared by bone marrow-derived stromal cells.

https://www.cell.com/cell/pdf/0092-8674(78)90101-0.pdf

Functional macrophage cell lines transformed by Abelson leukemia virus.

To evaluate cellular and protein components in the lower respiratory tract of patients with idiopathic pulmonary fibrosis (IPF) and chronic hypersensitivity pneumonitis (CHP), limited broncho-alveolar lavage was done in 58 patients (19 IPF, 7 CHP, and 32 controls). Analysis of the cells and protein in the lavage fluids from patients with IPF revealed an inflammatory and eosinophilic response and a significant elevation of IgG in the lungs. With corticosteroid therapy, inflammation diminished but eosinophils remained. Lavage fluid from patients with CHP also had eosinophils and elevated levels of IgG. However, in contrast to IPF, lavage fluid from CHP patients contained IgM, fewer inflammatory cells, and a strikingly increased number (38-74%) of lymphocytes. Identification of lavage lymphocytes in CHP showed that T lymphocytes were significantly elevated and B lymphocytes were decreased compared to peripheral blood. These studies suggest nthat the lung in IPF and CHP may function as a relatively independent immune organ, and that analysis of cells and proteins in broncho-alveolar lavage fluid may be of diagnostic, therapeutic, and investigative value in evaluating patients with fibrotic lung disease.

/pdf/analysis-of-cellular-and-protein-content-of-broncho-alveolar-2ddvqyv9cc.pdf

Analysis of cellular and protein content of broncho-alveolar lavage fluid from patients with idiopathic pulmonary fibrosis and chronic hypersensitivity pneumonitis.

Interleukin 2 (IL 2) (Aarden et at. 1979) is a genetically unrestricted, soluble immunoenhancing factor which is produced by helper T cells following stimulation with either T cell mitogens or allogeneic cells. Presumably, IL 2 is also produced and secreted following specific antigen stimulation, although this question has not been carefully evaluated. The definitive biological assay for IL 2 measures the factor's ability to maintain the growth of factor-dependent cytotoxic T cell lines. However, a broad spectrum of biological activities has been ascribed to IL 2. The factor has been reported to induce thymocyte proliferation either in the presence (Chen & DiSabato 1976, Paetkau et al. 1976) or absence (Farrar et al. 1978) of a suboptimal concentration of T cell mitogen. Additionally, IL 2 has been shown to augment the proliferation and generation of cytotoxic cells by alloantigenstimulated T cell populations (Wagner & Rollinghoff 1978, Farrar et al. 1978) and, in the process, induce the synthesis of immune interferon (IFNji) by the alloantigen-stimulated T cells (Farrar et al. 1981a). IL 2 has also been reported

Iris A. Ly

Papers

Separation of mouse spleen cells by passage through columns of sephadex G-10.