Federally Funded ‘Humanized Mouse Core’ at UCLA Transplanted Fetal Tissue into Mice

Micky Wootten | November 1, 2022 | 12:57pm EDT
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(CNS News) –  A federally funded “Humanized Mouse Core” at the University of California-Los Angeles created “humanized mice” by transplanting human fetal tissue into the mice.

Multiple journal articles published by federally funded researchers working at UCLA have described or summarized how these mice were constructed using tissue taken from human fetuses. Additional journal articles reference UCLA as the provider of humanized mice in studies funded by the National Institutes of Health.

For example, a 2016 article entitled “Propagating Humanized BLT Mice for the Study of Human Immunology and Immunotherapy,” published by Stem Cells and Development and co-authored by multiple UCLA researchers, provides a description of how “humanized BLT mice” are constructed.

“The humanized bone marrow-liver-thymus (BLT) mouse model harbors a nearly complete human immune system, therefore providing a powerful tool to study human immunology and immunotherapy,” says the article’s introduction. “However, its application is greatly limited by the restricted supply of Human CD34+ hematopoietic stem cells and fetal thymus tissues that are needed to generate these mice.”

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The article includes a section carrying the subhead “Generation of humanized BLT Mice.” In explaining the generation of these mice, it says “1–2 fragments of human fetal thymus (~1mm3), as well as donor-matched fetal liver CD34- cells, when available (~4.5x106 ), were implanted under the kidney capsule of each recipient NSG mouse.”

In the “acknowledgements” section, the authors thank “the UCLA AIDS Institute/CFAR Virology Core/Gene and Cell Therapy Core/Humanized Mouse Core for providing human cells/tissues and humanized mice services.”

The authors note that their work “was supported by an UCLA Center for AIDS Research Grant (NIH/NIAID AI028697, to J.Z.),” as well as “a National Institutes of Health (NIH) Director’s New Innovator Award (DP2 CA196335, to L.Y.).”

Another article, published on Jan. 10, 2022 in the journal Nature Communications and entitled “Latency reversal plus natural killer cells diminish HIV reservoir in vivo,” was co-authored by multiple UCLA researchers, as well as researchers from the University of California, Irvine, Stanford University, and a researcher associated with both UCLA and the University of Hong Kong.

The article described research funded by the National Institutes of Health that used “humanized mice” constructed by “the UCLA humanized mouse core” using fetal tissue.

“All mice were maintained in the animal facility at UCLA,” said the article. “All experiments were performed in ethical compliance with the study protocol approved by the UCLA Animal Research Committee.”

“Humanized bone marrow liver thymus (BLT) mice were constructed by the UCLA humanized mouse core using techniques described previously,” it said.

“In brief, NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ or NSG mice or C57BL/6 Rag2−/−γc−/−CD47−/− or TKO mice were obtained from Jackson Laboratories and bred at UCLA,” it said.

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“Male and female mice were age-matched and between 6 and 8 weeks old were irradiated with 270 rads, and then pieces of fetal thymus and liver tissue were transplanted under the kidney capsule. Mice were then injected intravenously with 5 × 104 human fetal liver-derived CD34+ cells isolated by immunomagnetic separation.”

The journal article acknowledged the support of the NIH.

“We acknowledge support from the National Institutes of Health (AI155232 to J.T.K., K08CA235525 to C.S.S., AI131294 to J.A.Z. and M.D.M., AI124743 to J.A.Z. and P.A.W., and AI145038 to R.S.) […] and the UCLA Center for AIDS Research (AI28697).”

A page on the NIH Reporter website on the UCLA project, “Defining Factors Controlling HIV Rebound,” that did the research described in this journal article, says the project was funded by the NIH’s National Institute of Allergy and Infectious Diseases (NIAID).

The NIAID grant had a “Project Start Date” of Aug. 10, 2017 and a “Project End Date” of July 31, 2022. The NIAID’s “Total Funding’ for the project, according to the NIH Reporter, was $1,540,000.  

One of the sub-projects of “Defining Factors Controlling HIV Rebound,” is called “Mouse Core.”

A page on the UCLA Health website briefly describes the division of the Center for AIDS Research that makes humanized mice. It is called “Core D: Humanized Mouse and Gene Therapy.” The brief description says the core “[p]rovides humanized mice, access to BSL2+ vivarium facilities, expertise in humanized mouse models, and further development of improved humanized mouse models.”

Another website maintained by the entire University of California system includes a brief description of what it calls the “UCLA CFAR Humanized Mouse Core.”

“The overall goal of this Core laboratory is to provide the infrastructure, materials, animals, technical expertise and support that will facilitate the use of humanized immunodeficient mice in studies examining the pathogenesis and treatment of HIV-induced disease,” it says.

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“Recent advances have enabled the recapitulation of human immune cell development and function in immunodeficient mice,” it says. “Human hematopoietic tissue is placed in the mice where it undergoes multlineage hematopoiesis into multiple types of human immune cells.  The human tissue utilized in these studies is capable of a high degree of experimental manipulation prior to and subsequent to implantation in the mouse and is further susceptible to infection with HIV. This provides a powerful surrogate in vivo model to examine human hematopoiesis, the pathogenic effects of HIV infection, and ways to protect the human system from HIV.”

The final sentence in this description of the UCLA CFAR Humanized Mouse Core says: “Develop and supply mice and ‘humanized’ mouse models to facilitate progress in HIV/AIDS and oncology based research.” 

The NIH RePorter website lists multiple journal articles associated with the project “Mouse Core” that indicated the program used humanized mice in its federally funded research.

These include:

  1. Characterization of designed, synthetically accessible bryostatin analog HIV latency reversing agents. (July 2018)

“Characterization of designed, synthetically accessible bryostatin analog HIV latency reversing agents,” was published in July of 2018 and funded by multiple NIH grants. On page three, in the Introduction, there is a summary of the use of humanized mice in the study:

“We further established that one particularly efficacious bryolog (SUW133) could induce HIV from latency ex-vivo from CD4 + T cells derived from HIV-infected ART-treated patients and in vivo in humanized BLT mice (Marsden et al., 2017).”

Page 12 includes an additional reference to humanized mice, which also parenthetically cites the same Marsden et al study:

“Subsequently, one particularly potent bryolog termed SUW133 was further tested ex vivo in ART-treated patient-derived cells and in vivo in a humanized mouse model of HIV latency (Marsden et al., 2017), the outcome of which provided further support for this approach and its clinical potential.”

The 2017 Marsden et al. study cited here is called “In vivo activation of latent HIV with a synthetic bryostatin analog effects both latent cell ‘kick’ and ‘kill’ in strategy for virus eradication.” The first author listed in this 2017 study was a researcher at UCLA at the time the article was published.  Three other co-authors are listed as researchers at UCLA. 

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“Humanized bone marrow liver thymus (BLT) mice were constructed by the UCLA humanized mouse core using techniques described previously,” said this article.

“In brief, NOD.Cg-Prkdcscid IL2rgtm1Wjl (Nod-SCID-common gamma chain knockout [NSG]) mice were first irradiated with 270 rads and then transplanted under the kidney capsule with pieces of fetal thymus and liver tissue. Mice were then infused intravenously by retro-orbital injection with 5x105 human fetal liver-derived CD34+ cells isolated by immunomagnetic separation as previously described.”

A footnote in this passage referred to a 2012 journal article, co-authored by the same UCLA researcher, entitled “HIV Latency in the Humanized BLT Mouse,” which explicitly states that BLT mice are made with fetal tissue.

It says,

“Several alternative murine models for HIV infection, including humanized Rag2-/- yc-/- mice (4, 40) and the recently developed BLT (bone marrow-liver-thymus) mouse, now exist. The BLT mouse represents a significant improvement over the SCID-hu (Thy/Liv) mouse by providing robust peripheral reconstitution with multiple human hematopoietic lineages. These BLT mice are produced by transplanting human fetal liver and thymus tissue under the kidney capsule of a nod-SCID-common gamma chain-knockout (NSG) mouse. Endogenous hematopoietic progenitors are then depleted by irradiation or chemical treatment, and new human CD34+ hematopoietic stem cells are introduced by intravenous injection. Human immune cells in BLT mice are present in multiple organs, including the Thy/Liv implant, peripheral blood, lymph nodes, gut, lungs, bone marrow, and liver. Moreover, the human CD4+ cells in these mice can also be infected with HIV.”

In a subsection, “Construction of BLT mice,” it states,

“Fetal tissue for these studies was obtained from either the UCLA CFAR Gene and Cellular Therapy Core or Advanced Biosciences Resources Inc.”

  1. Tracking HIV Rebound following Latency Reversal Using Barcoded HIV (Dec 22, 2020)

Another journal article co-authored by researchers from UCLA (along with researchers from UC Irvine, Stanford, and the School of Medicine at Zhejiang University in Hangzhou, China), also includes references to humanized mice. It is titled “Tracking HIV Rebound following Latency Reversal Using Barcoded HIV.” Published on Dec. 22, 2020, the research cited in this publication was funded by a series of NIH grants (including P01 AI131294 to J.A.Z., CA31845 to P.A.W., AI124763 to M.D., AI124743 to J.A.Z. and P.A.W.).

According to page two of the study:

“These mice were constructed by implanting fetal liver and thymus tissues under the kidney capsule of an immunodeficient (typically Nod-SCID-common gamma chain knockout) mouse, followed by irradiation and then transfusion of hematopoietic stem cells. This results in the generation of multilineage immune reconstitution with human cells including CD4+ and CD8+ T cells, natural killer (NK) cells, monocytes, macrophages, and dendritic cells. We and others have shown that the BLT mouse model can be efficiently infected with HIV and forms authentic post-integration latency in resting CD4+ T cells.” 

  1. Robust CAR-T memory formation and function via hematopoietic stem cell delivery (Apr 17, 2021)

Another journal article published by UCLA researchers was “Robust CAR-T memory formation and function via hematopoietic stem cell delivery.” It was published on April 17, 2021 and funded by NIH grants (NIH U19AI117941, 1R21AI122390, R01CA239261 to SGK; CIRM DISC2-10748 to SGK; NIH U19AI149504 to SGK and IC, NIH 1R01AI140775 to OOY and SGK; CIRM TR4-06845, NIH P01AI131294 to JAZ; NIH P30AI28697 to UCLA CFAR Virology Core, Gene and Cell Therapy Core, and Humanized Mouse Core); (NIH IRACDA K12 GM106996 to MC; NIH 1R21AI140866 to AZ).

The publication includes an “ethics statement” that reads,

“For humanized mice, all surgeries were performed under ketamine/xylazine and isofluorane anesthesia and all efforts were made to minimize animal pain and discomfort.”

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It also states, “To examine if D1D2CAR also suppresses endogenous TCR expression, we constructed humanized bone marrow-liver-thymus (BLT) mice with HSCs transduced with lentiviral vectors expressing either the CD4CAR or D1D2CAR as described above.”

“Humanized BLT mice,” it said, “were transplanted with donor matched fetal thymus and liver derived HSC (CD34+) transduced with either CD4CAR, D1D2CAR, CD4CAR-41BB, D1D2CAR-41BB, CD4CARCD28 or D1D2CAR-CD28” 

  1. Latency reversal plus natural killer cells diminish HIV reservoir in vivo (Jan 10, 2022)

Another journal article published by UCLA researchers along with researchers from UC Irvine, Stanford, and the University of Hong Kong, was entitled “Latency reversal plus natural killer cells diminish HIV reservoir in vivo.” It was published on Jan. 10, 2022 and funded by NIH grants (NIH AI155232 to J.T.K., K08CA235525 to C.S.S., AI131294 to J.A.Z. and M.D.M., AI124743 to J.A.Z. and P.A.W., and AI145038 to R.S).

A section of this journal article carried the headline, “Methods.” A subsection of this “Methods” section was headlined “Mice.” It states:

“All mice were maintained in the animal facility at UCLA. All experiments were performed in ethical compliance with the study protocol approved by the UCLA Animal Research Committee (ARC # 1996–058). Humanized bone marrow liver thymus (BLT) mice were constructed by the UCLA humanized mouse core using techniques described previously8,61. In brief, NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ or NSG mice or C57BL/6 Rag2−/−γc−/−CD47−/− or TKO mice58 were obtained from Jackson Laboratories and bred at UCLA. Male and female mice were age-matched and between 6 and 8 weeks old were irradiated with 270 rads, and then pieces of fetal thymus and liver tissue were transplanted under the kidney capsule. Mice were then injected intravenously with 5 × 104 human fetal liver-derived CD34+ cells isolated by immunomagnetic separation.”

Despite the multiple references in these journal articles to the use of fetal tissue in the construction of humanized mice, the articles do not indicate whether or not the fetal tissue used to create these mice came from elective abortions.

CNSNews.com repeatedly reached out to UCLA Medical School’s press spokesmen, NIAID spokesman, and the doctors involved with the UCLA humanized mice core and asked, among other things, if any of the fetal tissue used to create these humanized mice came from elective abortions.

Neither UCLA nor NIAID responded.

CNSNews.com specifically asked, “Does any of the fetal tissue used to create the humanized mice in the NIAID-funded UCLA Mouse Core come from elective abortions?”

In 2019, the Congressional Research Service published a report entitled, “Human Fetal Tissue Research: Frequently Asked Question.”  This report states:

“Fetal tissue used in research is mostly obtained from elective (induced) abortions. Though statute (PHISA Section 498A(g)) also permits the collection of human fetal tissue from spontaneous abortions (e.g., miscarriages) or stillbirths for subsequent use in federally funded research, these events often occur during unpredictable circumstances where it is difficult to preserve the tissue for research purposes. In addition, the tissue from spontaneous abortions or stillbirths is more likely to have genetic or other abnormalities that preclude its use for research purposes.”

A “background paper” sent by Harvard to the House Energy and Commerce Committee on July 7, 2016 explained why “obtaining fetal material from elective pregnancy termination is far superior to obtaining whatever material might be recoverable following spontaneous miscarriage.” It stated:

“Mice that have human immune systems are an invaluable scientific resource, but these mice are engineered to this condition only by means of the use of human fetal material. … If human fetal tissue is needed, why can it not be obtained from miscarriages instead of abortion? Here, timing is very important.  Almost all miscarriages happen at home or in locations in which fetal material is not recovered and, importantly, preserved in a usable state. Just as obtaining tissue during a scheduled surgery or an in-hospital autopsy soon after death provides tissue that is untainted by decay relative to obtaining those same tissues from the morgue or a funeral home, obtaining fetal material from elective pregnancy termination is far superior to obtaining whatever material might be recoverable following spontaneous miscarriage, even assuming a mechanism existed for the collection of such material.”

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“Fresh fetal tissue or tissue shipped overnight on ice from various organ procurement agencies can be used,” says a 2012 publication authored by a group of UCLA researchers that is titled “Using the BLT Humanized Mouse as a Stem Cell based Gene Therapy Tumor Model.”

The same publication includes a video showing the procedure by which these mice are humanized with fetal tissue.

The UCLA Medical School requires those requesting NIH funding to conduct research with the use of fetal tissue to go through a special approval process. On the UCLA Medical School website, a document called “NIH Proposals with Human Fetal Tissue (HFT)” states that “applications proposing HFT that do not address these requirements will be administratively withdrawn.”

The application form includes a required field that says “if the proposed project involves the use of human fetal tissue obtained from elective abortions (HFT), check ‘Yes’ and complete the rest of the ‘Human Fetal Tissue’ section.”

Applicants who check “Yes,” are then instructed to provide the medical school with the HFT Compliance Assurance, the HFT Sample IRB Consent Form, R & R Budget Form including a Budget Justification, as well as a Research Plan. 

In 2020, the director of UCLA’s Center for AIDS Research told the Washington Post that “work with humanized mice ‘was a flagship technique of ours.’” After the Trump administration issued stricter guidelines on the use of fetal tissue in NIH-funded projects, the same researcher told the Post that he was then reluctant to assign students to projects using humanized mice. “I might not put them on a humanized mouse project,” said the researcher. “Even if the mice were standing in front of you, you can’t do it if the grant says you can’t do it.”

“It is not a small thing,” he told the Post. “My career has been based on using these tissues.”

Under these guidelines, when the UCLA Center for AIDS Research applied to NIH to renew its grant in 2019, the director of the mouse core “made the wrenching decision to leave out the usual request to provide money for the humanized mice.”

Another researcher explained the reasoning behind this decision, saying: “We didn’t want to risk sinking the entire grant.”

 
 

According to the Washington Post, the UCLA Humanized Mouse Core Laboratory “was the first of its kind when it was created in the early 1990s and now provides such mice to 70 scientists on campus and around the country.” Citing one of the UCLA researchers, the Post said that “[a]bout three-fourths of the researchers who buy mice from the lab rely on NIH grants.” 

Under the Biden administration, federally funded fetal tissue research has resumed without the Ethics Advisory Board put into place by the 2019 HHS policy under the Trump administration, reported Forbes.

A new project at UCLA called “Core D-Humanized Mouse and Gene Therapy Core” began on April 8, 2022 and ends on March 31, 2027. The project is funded by NIAID and led by the same researcher who led the previous NIAID-funded mouse core at UCLA.

According to NIH RePorter, “The overall goal of the UCLA-CDU CFAR Humanized Mouse and Gene Therapy (HMGT) Core (Core D) is to provide support and expertise for HIV/AIDS-related research requiring stem cells, gene therapy, and humanized mice for in vitro and in vivo experimentation.” 

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