Virological and Parasitological Characterization of Mini-LEWE Minipigs Using Improved Screening Methods and an Overview of Data on Various Minipig Breeds.

Sabrina Halecker,Julia Metzger,Benedikt Kaufer,Christina Strube,Joachim Denner,Ludwig Krabben

doi:10.3390/microorganisms9122617

Abstract

Minipigs play an important role in biomedical research and have also been used as donor animals in xenotransplantation. To serve as a donor in xenotransplantation, the animals must be free of potential zoonotic viruses, bacteria and parasites. Porcine endogenous retroviruses (PERVs) are integrated in the genome of all pigs and cannot be eliminated as most of the other pig viruses can. PERV-A and PERV-B infect human cells in cell culture and are integrated in all pigs, whereas PERV-C infects only pig cells and it is found in many, but not all pigs. Minipigs are known for a high prevalence of recombinant PERV-A/C viruses able to infect human cells (Denner and Schuurman, Viruses, 2021;13:1869). Here, Mini-LEWE minipigs are screened for the first time for pig viruses including PERV. Peripheral blood mononuclear cells (PBMCs) from 10 animals were screened using PCR-based methods (PCR, RT-PCR, and real-time PCR). In comparison with our previous screening assays, numerous improvements were introduced, e.g., the usage of gene blocks as a PCR standard and foreign RNA to control reverse transcription in RT-PCR. Using these improved detection methods, Mini-LEWE pigs were found to be negative for porcine cytomegalovirus (PCMV), porcine lymphotropic herpesviruses (PLHV-1, -2 and -3), porcine circoviruses (PCV1, 2, 3 and 4), porcine parvovirus (PPV) and hepatitis E virus (HEV). All animals carried PERV-A, PERV-B and PERV-C in their genome. PERV-A/C was not found. In contrast to all other minipig breeds (Göttingen minipigs, Aachen minipigs, Yucatan micropig, Massachusetts General Hospital miniature pigs), Mini-LEWE minipigs have less viruses and no PERV-A/C. Parasitological screening showed that none of the Mini-LEWE minipigs harbored ecto- and gastrointestinal parasites, but at least one animal tested positive for anti-Toxoplasma gondii antibodies.

Highlights

IntroductionPigs (Sus scrofa) have great potential as biomedical models for studying developmental processes, congenital diseases and pathogen response mechanisms and can be used as xenotransplant organ donors and tools for vaccine and drug design [1,2]
The ten Mini-Lehnitz and Wendefeld (LEWE) minipigs were positive for the polymerase gene of Porcine endogenous retroviruses (PERVs), indicating that PERV is present in the genome of the Mini-LEWE minipigs as expected
At that time Gregor et al [58] reported that the animals kept under specified pathogen-free conditions were serologically free of brucellosis, caused by Brucella bacteria; transmissible gastro-enteritis (TGE), caused by the coronavirus TGEV; leptospirosis, caused by Leptospira bacteria; Aujeszky’s disease, caused by the Suid alphaherpesvirus 1 (SuHV-1), called pseudorabies virus; and that the animals were clinically free of dysentery; salmonellosis, caused by Salmonella bacteria; Teschen disease and Talfan disease, both caused by teschoviruses; swine vesicular disease, caused by the swine vesicular disease virus, an enterovirus; foot-and-mouth disease, caused by the foot-and-mouth disease virus, an aphthovirus; classical swine fever caused by pestivirus C; porcine enzootic pneumonia, caused by Mycoplasma hyopneumoniae; pleuropneumonia due to Haemophilus pleuropneumoniae; and rhinitis atrophicans, caused by Pasteurella multocida

Summary

Introduction

Pigs (Sus scrofa) have great potential as biomedical models for studying developmental processes, congenital diseases and pathogen response mechanisms and can be used as xenotransplant organ donors and tools for vaccine and drug design [1,2]. Minipigs are broadly used in several fields of biomedicine, e.g., experimental surgery, pharmacology, toxicology and basic research (for review see [3,4,5,6]). This particular group of miniature size pigs (called minipigs, micropigs or miniature swine) has moved into focus as a model animal with many well-documented similarities to humans.

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