Exploring molecular determinants and pharmacokinetic properties of IgG1-scFv bispecific antibodies

Bispecific antibodies (BsAbs) capable of recognizing two distinct epitopes or antigens offer promising therapeutic options for various diseases by targeting multiple pathways. The favorable pharmacokinetic (PK) properties of monoclonal antibodies (mAbs) are crucial, as they directly influence patient safety and therapeutic efficacy. For numerous mAb therapeutics, optimization of neonatal Fc receptor (FcRn) interactions and elimination of unfavorable molecular properties have led to improved PK properties. However, many BsAbs exhibit unfavorable PK, which has precluded their development as drugs. In this report, we present studies on the molecular determinants underlying the distinct PK profiles of three IgG1-scFv BsAbs. Our study indicated that high levels of nonspecific interactions, elevated isoelectric point (pI), and increased number of positively charged patches contributed to the fast clearance of IgG1-scFv. FcRn chromatography results revealed specific scFv-FcRn interactions that are unique to the IgG1-scFv, which was further supported by molecular dynamics (MD) simulation. These interactions likely stabilize the BsAb FcRn interaction at physiological pH, which in turn could disrupt FcRn-mediated BsAb recycling. In addition to the empirical observations, we also evaluated the impact of in silico properties, including pI differential between the Fab and scFv and the ratio of dipole moment to hydrophobic moment (RM) and their correlation with the observed clearance. These findings highlight that the PK properties of BsAbs may be governed by novel determinants, owing to their increased structural complexity compared to immunoglobulin G (IgG) 1 antibodies.

Donor-side and user-side evaluation of the Atlantic blue crab invasion on a Mediterranean lagoon

The recent invasion of Callinectes sapidus in the Lesina Lagoon has raised great concern about its potential impacts on the ecosystem and on local fisheries. The effects of the blue crab presence on the receiving ecosystem were evaluated from both a donor-side perspective, through the application of emergy analysis, and a user-side perspective, by means of interviews to the local fishermen. While emergy analysis showed that C. sapidus brings to an increase of both natural capital and ecosystem functions values, results from interviews highlighted that the major problem caused by the presence of the blue crab in the lagoon concerned the local economy. As the first quantitative assessment of the ecological and economic impact of C. sapidus in invaded habitats, the present investigation provided original and useful information for a comprehensive risk assessment of the species in European waters and in Mediterranean Sea.

Integrating supply, flow and demand to enhance the understanding of interactions among multiple ecosystem services

A comprehensive understanding of the relationships among ecosystem services (ES) is important for landscape management, decision-making and policy development, but interactions among multiple ES remain under-researched. In particular, earlier studies often did not clearly distinguish between supply, flow and demand. Furthermore, the underlying mechanisms in complex socio-ecological systems remain less examined. In this study, we therefore aimed to assess interactions among eight key ES, adopting a multistep approach. For all ES, we mapped ES supply, flow and demand at the municipality level in the Alpine Space area. We applied correlation analysis and cluster analysis in order to analyse the linkages between ES and to identify bundles of ES. We used random forest analysis to explain the distribution of the ES bundles and to identify important drivers based on socio-ecological variables (e.g. land use/cover, climate, topography and population density). Our results demonstrate that trade-offs and synergies varied greatly for supply, flow and demand. We identified five ES bundles, distinguishing hotspots of ES supply and demand. Twelve socio-ecological variables correctly predicted the membership of 81% of the municipalities to the ES bundles. Our results suggest that a limited number of socio-ecological variables can explain the majority of the distribution of ES bundles in the landscape. Considering the spatial relationships between mountain regions and their surrounding lowlands, regional and transnational governance frameworks need to connect areas of multiple ES supply to areas of ES demand, and should account for the different levels and types of ES relationships.