The V gene repertoire as revealed by polyclonal B cell activators

Area of Science:

• Immunology
• Cell Biology

Background:

• The one non-specific signal hypothesis proposes B lymphocyte activation via non-clonal receptors, distinct from Ig receptors.
• Protein A acts as a polyclonal B cell activator but not through Ig receptor Fc regions.

Purpose of the Study:

• To summarize evidence supporting the one non-specific signal hypothesis for B lymphocyte activation.
• To investigate the role of thymus-dependent antigens in B cell activation and tolerance.

Main Methods:

• Review of existing evidence on B cell activation mechanisms.
• Experimental induction of tolerance to thymus-dependent protein antigens.
• Activation of tolerant B cells using polyclonal B cell activators (e.g., LPS, PPD).

Main Results:

• Polyclonal B cell activators can activate B cells tolerant to thymus-dependent antigens, inducing autoantibody production.
• Experimentally induced tolerance in B cells mirrors self-antigen tolerance.
• LPS and PPD induced autoantibodies capable of lysing autologous cells.

Conclusions:

• B lymphocytes lack the ability to distinguish self from non-self antigens.
• T cells possess the capacity for self/non-self discrimination, unlike B cells.