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It was a tale of two very different complaints Monday as a San Diego-based biotech tools maker sued Regeneron Pharmaceuticals Inc. for patent infringement in the Southern District of New York and Pfizer Inc. and BioNTech in the Southern District of California.

Allele Biotechnology and Pharmaceuticals Inc. contends that it patented a leading fluorescent protein, embodied as mNeonGreen, which it has licensed to hundreds of universities and medical research institutions around the world and which Regeneron, Pfizer and BioNTech have openly acknowledged using in their work developing a promising antibody therapy and vaccine candidate for COVID-19.