A new chapter for anti-idiotypes in low molecular weight compound immunoassays

There is an increasing demand for rapid, affordable, in-field screening methods for low molecular weight (LMW) compound detection. Anti-idiotypes (Ab2s) are biologically derived surrogates that can replace LMW compounds and their protein conjugates in immunoassays. Substitution with anti-idiotypes can improve assay standardisation, reduce cost, and contribute to environmental safety. Their application has been limited by difficult generation processes and varied effects on assay performance. This review examines a recent resurgence in the use of Ab2s within LMW compound detection, driven by the application of phage display and nanobodies. The methods used for Ab2 production are critically discussed and their potential role in improving LMW compound immunoassays is highlighted. Finally, forward-looking ideas for the production of anti-idiotypes are provided, along with barriers to their generation.