Search bioRxivSearch

Biology subjects

Warner, B. M.

Publications and source records attributed to Warner, B. M..

2 recordsLinked to original sources

North American deer mice are susceptible to SARS-CoV-2

The zoonotic spillover of the pandemic SARS-coronavirus 2 (SARS-CoV-2) from an animal reservoir, currently presumed to be the Chinese horseshoe bat, into a naive human population has rapidly resulted in a significant global public health emergency. Worldwide circulation of SARS-CoV-2 in humans raises the theoretical risk of reverse zoonosis events with wildlife, reintroductions of SARS-CoV-2 into permissive non-domesticated animals, potentially seeding new host reservoir species and geographic regions in which bat SARS-like coronaviruses have not historically been endemic. Here we report that North American deer mice (Peromyscus maniculatus) and some closely related members of the Cricetidae family of rodents possess key amino acid residues within the angiotensin-converting enzyme 2 (ACE2) receptor known to confer SARS-CoV-2 spike protein binding. Peromyscus rodent species are widely distributed across North America and are the primary host reservoirs of several emerging pathogens that repeatedly spill over into humans including Borrelia burgdorferi, the causative agent of Lyme disease, deer tick virus, and Sin Nombre orthohantavirus, the causative agent of hantavirus pulmonary syndrome (HPS). We demonstrate that adult deer mice are susceptible to SARS-CoV-2 infection following intranasal exposure to a human isolate, resulting in viral replication in the upper and lower respiratory tract with little or no signs of disease. Further, shed infectious virus is detectable in nasal washes, oropharyngeal and rectal swabs, and viral RNA is detectable in feces and occasionally urine. We further show that deer mice are capable of transmitting SARS-CoV-2 to naive deer mice through direct contact. The extent to which these observations may translate to wild deer mouse populations remains unclear, and the risk of reverse zoonosis and/or the potential for the establishment of Peromyscus rodents as a North American reservoir for SARS-CoV-2 is unknown. Nevertheless, efforts to monitor wild, peri-domestic Peromyscus rodent populations are likely warranted as the SARS-CoV-2 pandemic progresses.

microbiology

ImmunoPET as Stoichiometric Sensor for Glypican-3 in Models of Hepatocellular Carcinoma

BackgroundHepatocellular carcinoma (HCC) is the fifth most common cancer worldwide. While conventional imaging approaches like ultrasound, CT, and MRI play critical roles in the diagnosis and surveillance of HCC, improved methods for detection and assessment of treatment response are needed. One promising approach is the use of radiolabeled antibodies for positron emission tomography (immunoPET) imaging. Glypican-3 (GPC3) is a proteoglycan that is highly expressed in the majority of HCC tumors. GPC3-specific antibodies are used to diagnose HCC histopathologically, and have been proposed as a treatment of HCC. Here, we design, synthesize and demonstrate that our humanized immunoPET agent, [89Zr]Zr-DFO-TAB-H14, can stoichiometrically bind to models of human liver cancer with varied GPC3 expression. Methods: The GPC3-specific monoclonal humanized IgG1, TAB-H14, was used as a scaffold for engineering our immunoPET agent. Fluorescent and deferroxamine (DFO) chelate conjugates of TAB-H14 were characterized using mass spectrometry. Binding affinity of TAB-H14 and conjugates for GPC3 was determined in cell-free biolayer interferometry, and cell-based radioimmunoassays. GPC3-expression was assessed by flow cytometry and immunofluorescence using commercially available anti-GPC3 antibodies and TAB-H14 in GPC3-(A431) and GPC3+ cell lines including an engineered line (A431-GPC3+, G1) and liver cancer lines (HepG2, Hep3B, and Huh7). DFO-TAB-H14, was radiolabeled with Zr-89. Mice were subcutaneously engrafted with the aforementioned cell lines and in vivo target engagement of the immunoPET agent [89Zr]Zr-DFO-TAB-H14 was determined using PET/CT, quantitative biodistribution, and autoradiography. Results: TAB-H14 demonstrated subnanomolar to nanomolar affinity for human GPC3. Fluorescently tagged TAB-H14 was able to bind to GPC3 on cell membranes of GPC3-expressing lines by flow cytometry. These results were confirmed by immunofluorescence staining of A431, G1 HepG2, Hep3B, and Huh7 tumor sections. ImmunoPET imaging with [89Zr]Zr-DFO-TAB-H14 showed stoichiometric tumor uptake corresponding to the cell surface expression levels. Autoradiography and immunostaining confirmed in vivo findings. Conclusion: We systematically demonstrate that the humanized immnoPET agent [89Zr]Zr-DFO-TAB-H14 specifically and stoichiometrically binds to GPC3 in several models of human liver cancer, serving as a promising in vivo GPC3 sensor. This agent may provide utility in HCC diagnosis and surveillance, and the selection of candidates for GPC3-directed therapies.

cancer biology