# Germ cell preservation of immunodeficient pigs utilizing embryo complementation approach

> **NIH NIH R21** · UNIVERSITY OF MISSOURI-COLUMBIA · 2020 · $195,469

## Abstract

Project summary/Abstract
Severe combined immunodeficient (SCID) pigs are a valuable resource in biomedicine. For instance, pigs lacking
RAG2 and IL2RG can be a useful model in stem cell transplantation, immunology, and infectious diseases
because they lack all major lymphocytes (B-T-NK-). However, application of the models has been limited
because the pigs cannot be propagated through natural breeding due to their immunodeficiency; no germ cells
(spermatozoa and oocytes) can be produced from these animals. Somatic cell nuclear transfer (i.e. cloning) or
bone marrow transplantation may be applied to overcome the shortcoming, but it is labor intensive and inefficient.
The embryo complementation (or blastocyst complementation) technique provides an opportunity to exhibit two
or more phenotypes in a single animal. The objective of this project is to establish a foundation system that can
be applied to produce germ cells from any type of immunodeficient pigs. Our hypothesis is that embryo
complementation of two embryo types, each carrying immunodeficient and germ-cell depleted phenotype, will
allow animals from the embryos to have a functional immune system while restricting germ-cell development
only from the immunodeficient genetic background. We will address our hypothesis by two specific aims. Aim1.
Establish chimeric pigs that produce spermatozoa carrying modified RAG2/IL2RG. Aim2. Establish chimeric pigs
that produce oocytes carrying modified RAG2/IL2RG. Novel germ-cell depleted pig models, which can expand
our understanding of germ cell development, will also be produced and characterized. By introducing targeted
modifications during embryogenesis through the use of CRISPR/Cas9 system, we will rapidly generate these
pig models within the timeframe of R21 and demonstrate their ability to produce germ cells. Our extensive
experience in using the CRISPR/Cas9 system in pigs, especially during embryogenesis, will ensure successful
completion of the proposed aims. The knowledge obtained from the project can expand the use of
immunodeficient pigs by establishing a strategy to share their germ cells with other institutes and help understand
mechanism of germ-cell development using large animal models preventing different stage of germ-cell
development. Because pigs are physiologically, anatomically, and immunologically similar to humans, they can
be a suitable model in biomedicine as a preclinical translational model. The success of this proposal will diversify
animal models that can be applied in a wide array of biomedical research areas such as HIV, X-linked
immunodeficiency, cell transplantation therapy, and autoimmune diseases.

## Key facts

- **NIH application ID:** 10304388
- **Project number:** 7R21OD027062-03
- **Recipient organization:** UNIVERSITY OF MISSOURI-COLUMBIA
- **Principal Investigator:** Kiho Lee
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $195,469
- **Award type:** 7
- **Project period:** 2019-03-15 → 2022-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10304388

## Citation

> US National Institutes of Health, RePORTER application 10304388, Germ cell preservation of immunodeficient pigs utilizing embryo complementation approach (7R21OD027062-03). Retrieved via AI Analytics 2026-05-26 from https://api.ai-analytics.org/grant/nih/10304388. Licensed CC0.

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