Immunoglobulin expression in human lymphoblastoid cell lines with early B cell features

Area of Science:

• Immunology
• Cell Biology

Background:

• Human B cell lines Raji and T 5.1 exhibit a pre-B cell phenotype.
• Characterized by intracytoplasmic IgM, predominantly mu chains, and lack of surface immunoglobulins.

Purpose of the Study:

• To investigate immunoglobulin expression and secretion in Raji and T 5.1 cell lines.
• To analyze spontaneous phenotypic variations and potential B cell maturation.

Main Methods:

• Direct immunofluorescence assays.
• Biosynthesis experiments to study immunoglobulin chains.
• Analysis of secreted immunoglobulins and cell surface markers.

Main Results:

• Cells displayed abnormally large heavy and light chains.
• T 5.1 secreted pentameric IgM; Raji secreted subunits and free light chains.
• Spontaneous maturation observed: acquisition of mu, lambda, and delta chains, followed by loss of cytoplasmic mu chains.

Conclusions:

• The studied cell lines demonstrate dynamic B cell phenotype plasticity.
• Spontaneous variations can lead to transient mature B cell phenotypes.
• Further maturation induction attempts were unsuccessful in this model.