aequorin is a photoprotein isolated from the bioluminescent jellyfish "aequorea victoria". upon addition of calcium ions (ca2+) and coelenterazine, a reaction occurs whose end result is the generation of blue light in the 460 - 470 nm range. aequorin has been incorporated into human b cell lines for the detection of pathogenic bacteria and viruses in what is referred to as the cell canary assay (cellular analysis and notification of antigen risks and yields). the b cells are genetically engineered to produce aequorin. upon exposure to antigens of different pathogens, the recombinant b cells emit light as a result of activation of an intracellular signaling cascade that releases calcium ions inside the cell.