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  • Julie Collorafi

More Details on the Saskatoon BLT-L Humanized Mouse Project

Updated: Dec 14, 2021

Two NIH-trained researchers in Saskatoon


I recently listened again to NIH researcher Kerry Lavender's interview (see video below) where she gives further information about the ongoing BLT-L humanized COVID-19 vaccine test mice project at the University of Saskatchewan and discovered some significant details about Darryl Falzarano, another NIH researcher with whom she is collaborating on this project and how they are now doing what their NIH training prepared them to do.


UPDATE: It appears this video has been taken down. Kerry Lavender's interview is available on a podcast here.


Coronavirus won't infect a mouse lung; human lung needed

As discussed in a previous article, NIH researcher Kerry Lavender began making a continuous supply of Ralph Baric's BLT-L mice in Saskatoon in March, 2020, for COVID-19 vaccine research to avoid the Trump Administration's ban on fetal tissue research.


In the interview above viral immunologist Kerry Lavender explains that COVID researchers needed a specialized mouse that would support a coronavirus infection so they could test therapeutics that they couldn't properly and completely test on any other kind of mouse.


The coronavirus pathogen will not infect a mouse lung, so this model of mice features patches of human fetal lung tissue subcutaneously implanted on their backs which can be infected with the virus.


Kerry Lavender is a BLT mouse expert

Kerry claims, "I was the only one who could do it, and they were relying on me." She recalls how she was getting calls from "very important people from around the world" asking for her mice.


Kerry Lavender has a great deal of experience working with BLT mice for HIV research and has co-authored several key studies involving the use of fetal liver and thymus obtained from ABR, including this Dec. 12, 2013 study and this Jan. 2, 2019 study, conducted at Rocky Mountain Lab in Hamilton, Montana. One of the authors in both studies is Ronald Messer, who was identified in the Judicial Watch documents as having purchased fetal organs from ABR.


"My little babies"

Kerry describes the process of surgically implanting "balls" 1 cm in diameter of human (fetal) lung tissue under the shoulder blades of each mouse and watching them grow. Four weeks after surgery the implants begin to grow and the mice look like they are sprouting wings. The mice, she says are so "cute" running around with their human lung patches which look like "water wings" or "little backpacks."


Kerry refers to the mice with almost maternal pride as "my little babies." They are a special strain of black mice ("black mice, pink ears and tail") which she developed at the NIH Rocky Mountain Lab in Hamilton, MT, which matches the diagram of Ralph Baric's BLT-L mouse which was developed at University of North Carolina in 2019 as shown in this diagram from a 2019 Nature Biotechnology article:




Further investigation reveals that this strain of mice is known as the Rag2−/−γc−/−CD47−/− strain, or the Triple Knockout (TKO) mouse which has three genetic mutations and was developed especially to be used in making BLT mice. Her 2013 BLT mouse study reports that "the TKO-BLT mouse has advantages over current humanized mouse models and is a valuable tool for studying human pathogens." More information on this strain of mice here.


These mice models are available from Jackson Laboratory for $255 for each mouse, and $510 for a breeder pair.


This strain of mice, Kerry says, is originally from California, but she developed them further at the NIH Rocky Mountain Lab in Montana. When she came to University of Saskatchewan two years ago she originally worked with a different strain of mice that didn't work so well so she had her mice transferred from Montana and is breeding them there.


Small, medium and large human lung patches

The BLT-L mice take three months after surgery to be ready for testing. Her team began developing the first batch of mice in March, 2020, and by the time of the interview in August, they had 150 mice ready for testing. Two batches failed because the lung patches did not grow.


Kerry Lavender's part in this BLT-L COVID-19 vaccine project is working on animal model development while Darryl Falzarano, a Research Scientist at VIDO-InterVac, an international vaccine research center at the University of Saskatchewan, is working on coronavirus vaccine design. Coincidentally, Darryl completed his post-doctoral training at NIH's Rocky Mountain Lab in Hamilton, MT, where Kerry Lavender was a researcher. Kerry claims she was pleasantly surprised to find out that Darryl was also at in Saskatoon at VIDO-InterVac.


Initially, her team prepared mice with three different sizes of human lung patches, small, medium and large for Darryl Falzarano's team at VIDO-InterVac to inject with coronavirus. Because Darryl and his team are working in a BSL-3 lab with potentially lethal human pathogens, they are encumbered with a great deal of personal protective equipment so the smallest patches were too small for them to manipulate, but the medium and large lung patches turned out to be the best sizes.


The virus is injected directly in the lung patches, since there is a chance the virus would die if before it got to the lung if they put it in any other way. They want to give the virus the best chance to infect the lung right away so they inject it directly into the human lung cells.


Saskatoon "Dream Team" making a pan-coronavirus vaccine

"A lot of people are interested" in Kerry's BLT-L mice, and "150 won't go very far" so they have to be very choosy about the researchers who will receive the mice. One of the recipients who will receive the mice have a candidate drug already tested on COVID patients in compassionate use studies which doesn't have the toxic side effects of Remdesivir. (Could this be dexamethasone?)


(Kerry never mentions also implanting liver and thymus into her mice, but, as explained in my previous article, the grants she received from the Canadian Institute of Health Research required that she make BLT-L (bone marrow, liver, thymus and lung) mice.)


Kerry concludes her interview by referring enthusiastically referring to herself and Darryl as a "dream team" who are doing exactly what their NIH training prepared them to do.


It is worth mentioning that the larger goal of this project is to make a pan-coronavirus vaccine that could provide protection against multiple strains or cluster of viruses.


Possibly 600 babies have been sacrificed so far

One of the things I realized after listening to Kerry's interview is that my initial estimate of aborted babies required for Kerry Lavender's project is too low. It would appear that she had made 300 mice in 5 months, not 150, since two batches failed, so the numbers would have to be doubled. At that rate of production, 1200 mice would have been produced by now, 15 months later. If the ratio of mice to aborted babies is two to one, it would appear that close to 600 babies have been sacrificed for this grisly project in Saskatoon.

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