Continuous growth of mitogen-reactive B lymphocytes

Area of Science:

• Immunology
• Cell Biology

Background:

• B-cell mitogens stimulate murine lymphocytes in suspension cultures.
• Continuous lymphocyte growth is achievable under specific culture conditions.

Purpose of the Study:

• To investigate the conditions supporting continuous B-cell growth in vitro.
• To understand the relationship between B-cell proliferation and maturation.

Main Methods:

• Culturing murine lymphocytes with B-cell mitogens.
• Maintaining low cell densities (<10^6 cells/ml) in renewed medium with beta-mercaptoethanol and fetal calf serum.
• Observing cell proliferation and immunoglobulin secretion.

Main Results:

• Continuous B-cell growth was observed at low cell densities.
• Prolonged growth occurred when B-cell maturation into Ig-secreting cells was inhibited.
• B-cell maturation and antibody class switching (IgM to IgG/IgD) were observed when cell division ceased.
• T cells were not required for continuous B-cell growth or antibody class switching.

Conclusions:

• Specific culture conditions, including low cell density and supplemented medium, support sustained B-cell proliferation.
• B-cell proliferation and maturation are distinct processes that can be regulated independently in vitro.
• The 'switch' to IgG- or IgD-like molecule secretion is independent of T cells.