Llama antibodies for COVID-19
Nanobodies (single-domain antibodies) generated in llamas that can be produced in the laboratory can effectively target SARS-CoV-2, say researchers. The nanobodies could form a new treatment delivered directly to the respiratory tract via a nasal spray, are cheap to produce, and would not need cold storage. They were produced by injecting a portion of the SARS-CoV-2 spike protein into a llama and triggering the animal's immune system. From a blood sample, researchers purified four nanobodies able to bind to SARS-CoV-2. Three nanobody chains were able to neutralise both the original lineage and the alpha variant (B.1.1.7). A fourth nanobody chain was able to neutralise the beta variant (B.1.351).
Dose-sparing of mRNA-1273
The immune response to a low dose of Moderna's COVID-19 vaccine (mRNA-1273) lasts for at least 6 months, and there is no indication that a booster shot is needed, according to new research. All age groups vaccinated with mRNA-1273 were found to have strong CD4+ and CD8+ T-cell and antibody responses. The researchers compared immune responses between recovered COVID-19 patients and vaccine trial participants who received a 25-μg dose of mRNA-1273 during the phase 1 clinical trials. This dose is a quarter of the 100-μg dose given emergency use authorisation in the USA. Researchers do not know whether this smaller dose is as effective as the standard dose, but the study showed that the T-cell and antibody response to the smaller dose was still strong.
An antiviral for dengue
An ultrapotent antiviral that is active against all four known dengue variants has been developed, and researchers say that it could also be used for preventing infection with the mosquito-borne virus that kills thousands of people each year. No antiviral drug is currently available to prevent or treat dengue. The inhibitor prevents the interaction between two viral proteins that are part of a copier of the virus’ genetic material so that it can no longer produce new virus particles. A low dose of the inhibitor was effective in mice even when infection was at its peak.
New nairovirus in Japan
A novel infectious virus transmitted by tick bites, called Yezo virus, has been identified in Japan, where at least seven people have been infected since 2014, but no deaths have been confirmed. The new type of orthonairovirus causes fever and a decrease in blood platelets and leukocytes. The scientists named it Yezo virus after a historical Japanese name for Hokkaido, a large island in the north of the country where the virus was discovered. The novel virus is most closely related to Sulina virus and Tamdy virus, detected in Romania and Uzbekistan, respectively. Researchers screened samples collected from wild animals in Hokkaido between 2010 and 2020. They found antibodies for the virus in Hokkaido sika deer and raccoons. They also found the virus’ RNA in three species of ticks in Hokkaido and are planning to track its nationwide distribution.
Antibiotics in the breath
Scientists have for the first time used breath measurements to determine the level of antibiotics in the blood They tested a biosensor on blood, plasma, urine, saliva, and breath samples from pigs who had received antibiotics, and they were able to determine the smallest concentrations in breath condensate that correlated with blood values. The microfluidic biosensor is based on synthetic proteins that react to β-lactam antibiotics, and it generates a change in current similar to a battery. Human trials are planned, possibly using a conventional face mask. The biosensor would make personalised dosing easier and help in the fight against antibiotic resistance, say researchers.
A phage–antibiotic cocktail
Researchers have shown that it is possible to treat an antibiotic-resistant infection in zebrafish with bacteriophages—naturally occurring viruses that destroy bacteria—and they hope the process can be transferred to human trials. They studied a new combination therapy consisting of a bacteriophage and the antibiotic rifabutin to treat infections caused by Mycobacterium abscessus. This bacterium is particularly dangerous for cystic fibrosis patients, and it is resistant to many antibiotics. With this combination treatment, infections in zebrafish with the key genetic mutation that causes cystic fibrosis were much less severe and their survival rate increased to 70% compared with fish treated with only rifabutin, who had a 40% survival rate.
Maternal IgA production
Researchers have discovered that Peyer's patches, immune sensors found in the gastrointestinal tract, have a key role in making maternal antibodies, especially IgA, which is produced in mothers during lactation. These antibodies, transferred during breastfeeding, protect the gastrointestinal tracts of babies from infection. The researchers also identified two bacteria, Bacteroides acidifaciens and Prevotella buccalis, that cohabit the gastrointestinal tract of mothers and generate immune responses in Peyer's patches through antigen-sampling M cells, resulting in IgA-producing plasma cells migrating to the mammary glands. The discovery of this inter-organ network between the mammary glands and the small intestine will help immunological and microbiological approaches to increasing breastfeeding quality, say the researchers.
For more on llama antibodies see Nat Commun 2021; 12: 5469
For more on the new nairovirus see Nat Commun 2021; 12: 5539
For more on antibiotics in breath see Adv Mater 2021; published online Sept 21. https://doi.org/10.1002/adma.202104555
For more on a bacteriophage–antibiotic cocktail see Dis Model Mech 2021; 14: dmm049159
For more on maternal IgA production see Cell Rep 2021; 36: 109655