Virus World

A method that provides cloned embryos with a healthy placenta could pave the way for more research involving the primates.  For the first time, a cloned rhesus monkey (Macaca mulatta) has lived into adulthood — surviving for more than two years so far. The feat, described today in Nature Communications1, marks the first successful cloning of the species. It was achieved using a slightly different approach from the conventional technique that was used to clone Dolly the sheep and other mammals, including long-tailed macaques (Macaca fascicularis), the first primates to be cloned. By replacing the placenta of the cloned embryo with that of embryos produced by an in vitro fertilization technique, scientists reduced developmental defects that can hinder embryo survival while using fewer embryos and surrogate mothers. The new technique could unlock possibilities for using cloned primates in drug testing and behavioural research. “We could produce a large number of genetically uniform monkeys that can be used for drug-efficacy tests,” says Mu-ming Poo, director of the Institute of Neuroscience in the Chinese Academy of Sciences in Shanghai.

Monkeys infected with SARS-CoV-2 were protected from subsequent exposures, a finding that has vital implications for vaccine design. 

Concerns about SARS-CoV-2 infection have reached an all-time high in the United States and around the globe. With increasing numbers of COVID-19 cases, hospitalizations, and deaths—and “social distancing” now a household word—the possibility of being infected is on everyone’s mind. As if that weren’t enough to worry about, the surfacing of multiple personal accounts—primarily out of China and Japan—of patients who recovered after infection only to fall ill a second time, have some worried about the possibility of reinfection. Now, a collaboration of Chinese scientists has dug deeper into whether or not reinfection with SARS-CoV-2 is possible with a small monkey study. The team looked at whether or not non-human primates, rhesus macaques, can become reinfected with SARS-CoV-2. The work was posted on the preprint server bioRxiv on March 14 in a paper titled, “Reinfection could not occur in SARS-CoV-2 infected rhesus macaques.” Their conclusion: there may be no reason to worry about reinfection.

The study used four, adult Chinese rhesus macaques. After intratracheal infection, the monkeys were analyzed on schedule, including measurements such as body weight, body temperature, lung x-rays, sampling of sera, nasal/throat/anal swabs, and primary tissues. The rhesus monkeys were successfully infected, as measured by weight loss, viral replication mainly in the nose, pharynx, lung, and gut, as well as moderate interstitial pneumonia....

Original Study available at bioRxiv  (March 14, 2020):

https://doi.org/10.1101/2020.03.13.990226

SARS-CoV-2 Omicron is highly transmissible and has substantial resistance to antibody neutralization following immunization with ancestral spike-matched vaccines. It is unclear whether boosting with Omicron-specific vaccines would enhance immunity and protection. Here, nonhuman primates that received mRNA-1273 at weeks 0 and 4 were boosted at week 41 with mRNA-1273 or mRNA-Omicron. Neutralizing antibody titers against D614G were 4760 and 270 reciprocal ID50 at week 6 (peak) and week 41 (pre-boost), respectively, and 320 and 110 for Omicron. Two weeks after boost, titers against D614G and Omicron increased to 5360 and 2980, respectively, for mRNA-1273 and 2670 and 1930 for mRNA-Omicron. Following either boost, 70-80% of spike-specific B cells were cross-reactive against both WA1 and Omicron. Significant and equivalent control of virus replication in lower airways was observed following either boost. Therefore, an Omicron boost may not provide greater immunity or protection compared to a boost with the current mRNA-1273 vaccine.

Preprint available in bioRxix (Feb.04, 2022):

https://doi.org/10.1101/2022.02.03.479037