Development of transplantable B-cell lymphomas in the MHC-defined miniature swine model

Swine models for translational oncological research: an evolving landscape and regulatory considerations

Swine biomedical models have been gaining in popularity over the last decade, particularly for applications in oncology research. Swine models for cancer research include pigs that have severe combined immunodeficiency for xenotransplantation studies, genetically modified swine models which are capable of developing tumors in vivo, as well as normal immunocompetent pigs. In recent years, there has been a low success rate for the approval of new oncological therapeutics in clinical trials. The two leading reasons for these failures are either due to toxicity and safety issues or lack of efficacy. As all therapeutics must be tested within animal models prior to clinical testing, there are opportunities to expand the ability to assess efficacy and toxicity profiles within the preclinical testing phases of new therapeutics. Most preclinical in vivo testing is performed in mice, canines, and non-human primates. However, swine models are an alternative large animal model for cancer research with similarity to human size, genetics, and physiology. Additionally, tumorigenesis pathways are similar between human and pigs in that similar driver mutations are required for transformation. Due to their larger size, the development of orthotopic tumors is easier than in smaller rodent models; additionally, porcine models can be harnessed for testing of new interventional devices and radiological/surgical approaches as well. Taken together, swine are a feasible option for preclinical therapeutic and device testing. The goals of this resource are to provide a broad overview on regulatory processes required for new therapeutics and devices for use in the clinic, cross-species differences in oncological therapeutic responses, as well as to provide an overview of swine oncology models that have been developed that could be used for preclinical testing to fulfill regulatory requirements.

Swine as biomedical animal model for T-cell research-Success and potential for transmittable and non-transmittable human diseases

Swine is biologically one of the most relevant large animal models for biomedical research. With its use as food animal that can be exploited as a free cell and tissue source for research and its high susceptibility to human diseases, swine additionally represent an excellent option for both the 3R principle and One Health research. One of the previously most limiting factors of the pig model was its arguably limited immunological toolbox. Yet, in the last decade, this toolbox has vastly improved including the ability to study porcine T-cells. This review summarizes the swine model for biomedical research with focus on T cells. It first contrasts the swine model to the more commonly used mouse and non-human primate model before describing the current capabilities to characterize and extend our knowledge on porcine T cells. Thereafter, it not only reflects on previous biomedical T-cell research but also extends into areas in which more in-depth T-cell analyses could strongly benefit biomedical research. While the former should inform on the successes of biomedical T-cell research in swine, the latter shall inspire swine T-cell researchers to find collaborations with researchers working in other areas - such as nutrition, allergy, cancer, transplantation, infectious diseases, or vaccine development.

Absence of porcine endogenous retrovirus (PERV) production from pig lymphoma cell lines

Porcine endogenous retroviruses (PERVs) -A and -B are integrated in the genome of all pigs, whereas PERV-C is found in many, but not all pigs. Some immortalized pig cell lines, among them lymphoma cells, but also mitogen activated primary lymphocytes have been shown to release virus particles, which were able to infect human cells and some of them were recombinant PERV-A/C. Since retroviruses can induce lymphomas, two newly established pig lymphoma cell lines and an older one (L23) were analysed for PERV expression. All three lines harboured PERV-A, PERV-B and PERV-C proviruses, but PERV-A/C recombinants were found only in the genome of L23 cells. The expression at the RNA level was very low and no protein expression and particle release was observed, suggesting that PERVs were not involved in the pathogenesis of these lymphomas. However, all three cell lines were infected with the porcine lymphotropic herpesvirus-3 (PLHV-3), which may have been involved in lymphoma development.

Beyond tradition and convention: benefits of non-traditional model organisms in cancer research

Traditional laboratory model organisms are indispensable for cancer research and have provided insight into numerous mechanisms that contribute to cancer development and progression in humans. However, these models do have some limitations, most notably related to successful drug translation, because traditional model organisms are often short-lived, small-bodied, genetically homogeneous, often immunocompromised, are not exposed to natural environments shared with humans, and usually do not develop cancer spontaneously. We propose that assimilating information from a variety of long-lived, large, genetically diverse, and immunocompetent species that live in natural environments and do develop cancer spontaneously (or do not develop cancer at all) will lead to a more comprehensive understanding of human cancers. These non-traditional model organisms can also serve as sentinels for environmental risk factors that contribute to human cancers. Ultimately, expanding the range of animal models that can be used to study cancer will lead to improved insights into cancer development, progression and metastasis, tumor microenvironment, as well as improved therapies and diagnostics, and will consequently reduce the negative impacts of the wide variety of cancers afflicting humans overall.

Establishment and characterization of a porcine B cell lymphoma cell line

The lack of available, well characterized, established, domestic porcine cell lines hinders the advancement of porcine cellular immunology. A case of multicentric lymphoma was diagnosed in a market weight pig at the time of slaughter. Affected lymph nodes and spleen were collected and used for single cell isolation and analysis. Cell lines were established by 3 rounds of limiting dilution from splenic and subiliac lymph node lymphomas. Surface marker staining identified the cells as CD21⁺, CD79a⁺, CD20⁺, PAX5⁺, and CD3^- and cells were grown and easily passaged in cell culture. Transcriptome analysis was carried out to further characterize these rapidly proliferating cells validating the initial cytometric findings, confirming their identity as B cell lymphomas, and suggesting that they arose from germinal center centroblasts with aberrant control of BCL6 expression. Functional analysis identified the cells as being involved in cancer, cell movement, cell survival, and apoptosis. These new porcine B cell lymphoma cell lines will be a valuable resource for more in-depth cellular investigations into the porcine immune system and cancer, as well as providing a potential tool for the growth of lymphotropic viruses of pigs and humans.