Mouse spleen lymphoblasts generated in vitro. Their replication and differentiation in vitro

Abstract

For many years it has been known that mouse spleen B cells can be stimulated to proliferate and secrete antibody when cultured in the presence of such substances as lipopolysaccharide (LPS)' and fetal calf serum (FCS; 1, 2). This stimulation is said to be "nonspecific" or "polyclonar' because large numbers of cells are activated, and individual antibody-forming cells (AFC) exhibit many different, probably noncross-reactive, specificities. The phenomenon of polyclonal B-cell activation or B-cell mitogenesis is thought to be a useful model for studying the normal immune response even though smaller proportions of specific lymphoid cells are activated.Most studies of nonspocific B-lymphocyte activation have simply documented the behavior of whole cultures rather than individual cells. For example, we know little about the extent to which stimulated B cells divide in vitro; how many of the blasts mature into typical plasma cells as opposed to other cell types; or the life-span of the various cell types. We also have little information comparing the behavior of B cells in response to antigen-specific and nonspecific stimulation.In this study, we take advantage of the availability of enriched populations of presumptive B lymphoblasts, obtained by floatation on dense bovine plasma albumin (BPA) columns as described in the accompanying paper (3). These populations consist almost entirely of blasts. They can be recovered in high yield in their first cycle of cell division in response to either LPS or FCS stimulation. By using these enriched populations, often in combination with a nontoxic [SH]thymidine radiolabeling technique, we show that the majority of mitogen-stimulated blasts mature into typical plasma cells. Maturation occurs after just two cell divisions, after which the plasma cell appears to withdraw from proliferative activity. The mature plasma cells are similar to those produced in response to antigen in situ in their cytologic features, content of abundant cytoplasmic immunoglobulin, diminished proliferative activity, and short life-span.

Immunological memories of the bone marrow

“…It had been noted early on that they disappear from secondary lymphoid organs when immune reactions are finished,3, 4 an observation leading Astrid Fagraeus to state that the plasma cell is “a cell which has already passed its greatest functional activity” 3. A second observation apparently supported this view, in that plasma cells isolated from secondary lymphoid organs died rapidly in cell culture, unlike other lymphocytes 5, 6, 7, 8. The apparently short lifespan of plasma cells created a conceptual problem, namely how to explain the persistence of specific antibody titers in the blood, long after termination of an immune response 9.…”

“…3 A second observation apparently supported this view, in that plasma cells isolated from secondary lymphoid organs died rapidly in cell culture, unlike other lymphocytes. [5][6][7][8] The apparently short lifespan of plasma cells created a conceptual problem, namely how to explain the persistence of specific antibody titers in the blood, long after termination of an immune response. 9 One solution to this problem would be if immune reactions would not terminate, but continue to smolder, driven by residual antigen, at very low to undetectable concentrations.…”

Cell Development in Primary Culture of Porcine Bone Marrow

“…The myelopoetic cells don't need macrophages to regulate their cell cycle and that's why they can complete it. The lymphoid cells ability to division in the in vitro conditions is known for a long time [16] [17].…”

A System for In Vitro Generation of Mature Murine Plasma Cells Uncovers Differential Blimp-1/Prdm1 Promoter Usage

“…ASCs generated in culture typically express the differentiation-associated marker CD138 and maintain the B cell marker B220 (27), however fail to terminally differentiate into plasma cells characterized by loss of the B220 marker (Fig. 1A) and exit from cell cycle.…”