A novel recombinant vaccine protecting mice against abrin intoxication

A monolithically integrated microcantilever biosensor based on partially depleted SOI CMOS technology

This paper presents a monolithically integrated aptasensor composed of a piezoresistive microcantilever array and an on-chip signal processing circuit. Twelve microcantilevers, each of them embedded with a piezoresistor, form three sensors in a Wheatstone bridge configuration. The on-chip signal processing circuit consists of a multiplexer, a chopper instrumentation amplifier, a low-pass filter, a sigma-delta analog-to-digital converter, and a serial peripheral interface. Both the microcantilever array and the on-chip signal processing circuit were fabricated on the single-crystalline silicon device layer of a silicon-on-insulator (SOI) wafer with partially depleted (PD) CMOS technology followed by three micromachining processes. The integrated microcantilever sensor makes full use of the high gauge factor of single-crystalline silicon to achieve low parasitic, latch-up, and leakage current in the PD-SOI CMOS. A measured deflection sensitivity of 0.98 × 10-6 nm-1 and an output voltage fluctuation of less than 1 μV were obtained for the integrated microcantilever. A maximum gain of 134.97 and an input offset current of only 0.623 nA were acquired for the on-chip signal processing circuit. By functionalizing the measurement microcantilevers with a biotin-avidin system method, human IgG, abrin, and staphylococcus enterotoxin B (SEB) were detected at a limit of detection (LOD) of 48 pg/mL. Moreover, multichannel detection of the three integrated microcantilever aptasensors was also verified by detecting SEB. All these experimental results indicate that the design and process of monolithically integrated microcantilevers can meet the requirements of high-sensitivity detection of biomolecules.

A Novel Humanized Anti-Abrin A Chain Antibody Inhibits Abrin Toxicity In Vitro and In Vivo

Abrin, a type-II ribosome inactivating protein from the seed of Abrus precatorius, is classified as a Category B bioterrorism warfare agent. Due to its high toxicity, ingestion by animals or humans will lead to death from multiple organ failure. Currently, no effective agents have been reported to treat abrin poisoning. In this study, a novel anti-abrin neutralizing antibody (S008) was humanized using computer-aided design, which possessed lower immunogenicity. Similar to the parent antibody, a mouse anti-abrin monoclonal antibody, S008 possessed high affinity and showed a protective effect against abrin both in vitro and in vivo, and protected mice that S008 was administered 6 hours after abrin. S008 was found that it did not inhibit entry of abrin into cells, suggesting an intracellular blockade capacity against the toxin. In conclusion, this work demonstrates that S008 is a high affinity anti-abrin antibody with both a neutralizing and protective effect and may be an excellent candidate for clinical treatment of abrin poisoning.

Integration of transcriptomics, proteomics and metabolomics data to reveal the biological mechanisms of abrin injury in human lung epithelial cells

BACKGROUND

Abrin toxin (AT) is a potent plant toxin that belongs to the type Ⅱ ribosome inactivating protein family and is recognized as an important toxin agent for potential bioweapons. Exposure to AT by way of aerosol is the most lethal route, but the mechanism of injury requires further investigation.

MATERIALS AND METHODS

In the present study, we performed a comprehensive analysis of transcriptomics, proteomics and metabolomics on the potential mechanism of abrin injury in human lung epithelial cells.

RESULTS

In total, 6838 genes, 314 proteins and 178 metabolites showed significant changes in human lung epithelial cells after AT treatment. Using molecular function, pathway, and network analysis, the genes and proteins regulated in AT-treated cells were mainly attributed to amino acid metabolism, lipid metabolism, and genetic information processing. Furthermore, a comprehensive analysis of the transcripts, proteins, and metabolites was performed. The results revealed that the correlated genes, proteins, and metabolism pathways regulated in AT-treated human lung epithelial cells were involved in tryptophan metabolism, biosynthesis of amino acids, and protein digestion and absorption.

CONCLUSION

This study provides large-scale omics data to develop new strategies for the prevention, rapid diagnosis, and treatment of AT poisoning, especially AT from aerosol.

A chimeric protein of abrin and Abrus precatorius agglutinin that neutralizes abrin mediated lethality in mice

Abrin, a type II ribosome inactivating protein from the Abrus precatorius plant, is extremely toxic. It has been shown to be 75 times more potent than its infamous sister toxin, ricin and their potential use in bio-warfare is a cause of major concern. Although several vaccine candidates are under clinical trials for ricin, none are available against abrin. The present study proposes a chimeric protein, comprising of 1-123 amino acids taken from the A chain of abrin and 124-175 amino acids from Abrus precatorius agglutinin A chain, as a vaccine candidate against abrin intoxication. The design was based on the inclusion of the immunogenic region of the full length protein and the minimal essential folding domains required for inducing neutralizing antibody response. The chimera also contains the epitope for the only two neutralizing antibodies; D6F10 and A7C4, reported against abrin till now. Active immunization with the chimera protected all the mice challenged with 45 X LD₅₀ of abrin. Also, passive transfer of antibodies raised against the chimera rescued all mice challenged with 50 X LD₅₀ of toxin. Hence the chimeric protein appears to be a promising vaccine candidate against abrin induced lethality.