Immunochromatography Test Kit for Paralytic Shellfish Toxins (PSTs) and Transition of PSTs in Scallops

MT test Immunochromato-PSP had been developed in a collaborative research project. In this kit, the previously developed mouse monoclonal antibody GT-13A designed against GTX2/3 is used. Since STX and its analogs (STXs) are small molecules, a competitive inhibition format with modified-STX is applied. The formation of Avidin Biotin complexes to trap modified-STX on the test line showed interference by the bivalve matrix, so we improved the kit with oligonucleotides trapping complementary strands. The affinity of the GT-13 antibody differs depending on the STX analogs present and does not correspond to relative toxicity. Therefore, it is necessary to accumulate data in advance on paralytic shellfish toxins (PSTs) toxin profiles for the local target species and area. Since this kit is intended to be used in screening, it is necessary to consider a dilution factor that will never lead to a false negative against the regulatory value. Although this kit is qualitative, it can be recorded and compared objectively as semi-quantitative data by imaging and quantifying. It can also be used to determine PSTs presence in seawater samples. In recent years, the problem of PSTs has become more serious in the east and north of Japan. We are considering using the kit for monitoring scallops in one prefecture and have confirmed that some of the samples could be assessed with the kit and applied to screening. However, we also observed transformation of PSTs after the shellfish became highly toxic, limiting the utility of the kit in these cases.