Triggering of monoclonal human lymphoma B cells with antibodies to IgM heavy chains: differences of response obtained with monoclonal as compared to polyclonal antibodies.

A comparative study of human B lymphoma cells activation by monoclonal (murine hybridoma) antibodies to μ heavy chains (Ma-μ) as compared to polyclonal (rabbit) antibodies to μ heavy chains (Ra-μ) has been carried out. Early events related to calmodulin activation such as ⁸⁶Rb influx and changes in cell volume at 4 h could be induced by Ma-μ. One antibody (AF6) approached Ra-μ with regard to the strength of response obtained-However. Ma-μs including AF6 were deficient in inducing DNA synthesis underconditions where this was achieved with Ra-μ, Studies in one lymphoma, where stimulation of re-expressed surface IgM could be studied, revealed that Ma-μ was deficient m stimulating re-expressed sIgM. These findings raise questions with regard to polyclonal antibody to surface Ig as a model for B cell triggering by antigen and suggest that antigen-induced B cell triggering may be more complex Mum indicated by previous studies with polyclonal antibody. [ABSTRACT FROM AUTHOR]