Sigma-Aldrich, the US life sciences and laboratory chemicals producer in the process of being acquired by Germany's Merck KGa for $17 billion, has agreed to buy Cell Marque, a manufacturer of antibody reagents, for an undisclosed sum.

Based at Rocklin, California, Cell Marque designs, develops and manufactures antibody reagents and kits, products that Sigma-Aldrich said complement its IHC product family. The portfolio includes validated, fit-for-purpose antibodies and IHC staining kits aimed at pathologists and clinicians focused on patient management.

Frank Wicks, president of Sigma-Aldrich's Applied Business unit, said he expects the California firm's strong in vitro diagnostic product lines and its "solid relationships" with pathologists and companies that provide automated staining instrumentation to broaden his company's diagnostic health reach.

Sigma-Aldrich expects the transaction to close by the end of 2014. Its own takeover by Merck is expected to take place in mid-2015, subject to regulatory approvals, approval by a special shareholder meeting at Sigma-Aldrich, and other customary closing conditions.