Monoclonal antibodies defining markers with apparent selectivity for particular haemopoietic cell types may also detect antigens on cells of neural crest origin.

Monoclonal antibodies described as reacting with particular subsets of haemopoietic cells were screened against a variety of neuronal cell lines to further investigate their true specificity. While some reagents, e.g., monoclonal anti-cALL (J5), were found only reactive with haemopoietic cells, other monoclonals, e.g., BA1, BA2, NA134, OKT6, and OKT9, also bound to neuronal cells. Further investigation into the cross-reactivity of these antibodies to a variety of neural crest derived cell lines indicated that, with the exception of OKT9, differential binding patterns to different lines were obtained. This suggests that haemopoietic cell subsets and neural crest derived tissues can share similar differentiation antigens. For monoclonals OKT9 and BA2 this observation was confirmed biochemically, showing that it is not just antigenic determinants but similar molecular weight cell surface antigens that are shared between subsets of the two major cell types. A similar analysis using monoclonal antibodies raised against human neuronal cells or cell lines again indicates that some antigens appear unique to neural tissue while others are shared by haemopoietic cell subsets.