Creating effective biocontainment facilities and maintenance protocols for raising specific pathogen-free, severe combined immunodeficient (SCID) pigs

Abstract

Severe combined immunodeficiency (SCID) is defined by the lack of an adaptive immune system. Mutations causing SCID are found naturally in humans, mice, horses, dogs, and recently in pigs, with the serendipitous discovery of the Iowa State University SCID pigs. As research models, SCID animals are naturally tolerant of xenotransplantation and offer valuable insight into research areas such as regenerative medicine, cancer therapy, as well as immune cell signaling mechanisms. Large-animal biomedical models, particularly pigs, are increasingly essential to advance the efficacy and safety of novel regenerative therapies on human disease. Thus, there is a need to create practical approaches to maintain hygienic severe immunocompromised porcine models for exploratory medical research. Such research often requires stable genetic lines for replication and survival of healthy SCID animals for months post-treatment. A further hurdle in the development of the ISU SCID pig as a biomedical model involved the establishment of facilities and protocols necessary to obtain clean SPF piglets from the conventional pig farm on which they were discovered. A colony of homozygous SCID boars and SPF carrier sows has been created and maintained through selective breeding, bone marrow transplants, innovative husbandry techniques, and the development of biocontainment facilities.

Survival of human cadaver skin on severe combined immune deficiency pigs: Proof of concept

“…A colony of homozygous SCID boars and specific pathogen free (SPF) carrier sows has been created and maintained through selective breeding and bone marrow transplants on the male side. SPF SCID pigs are kept in a special “barrier facility” designed to minimize human‐to‐pig pathogen transfer …”

“…SPF SCID pigs are kept in a special "barrier facility" designed to minimize human-to-pig pathogen transfer. 10…”

Novel engraftment and T cell differentiation of human hematopoietic cells inArt-/-IL2RG-/SCID pigs

“…We previously described the discovery of naturally occurring Art -/- SCID pigs 3 , which we have been able to raise and breed 14,32 for research purposes. We started with this genetic background for IL2RG site-directed mutagenesis.…”

“…Both cell lines shared the same SLA haplotype of 26.6/68.19a. Among those transferred, four gilts were confirmed pregnant and two carried their piglets to full term and produced five live male piglets via Cesarean section that were reared in biocontainment facilities 14 ( Supplemental Table 3 ). All five piglets were confirmed to have the 120 bp loss in IL2RG and the established mutation in exon 10 of Artemis 3 ( Art12 allele information found in Materials and Methods).…”

“…After removal, the uterus was immediately rinsed in chlorohexidine and then surgically opened to remove the piglets. All piglets had their cords clamped before being immediately placed into sterile polystyrene boxes and delivered into biocontainment facilities 14 . All piglets were fed approximately 250 mL of pasteurized porcine colostrum within the first 24 hours of life.…”