Swine platelet antigens: section report

Miniature Swine for Preclinical Modeling of Complexities of Human Disease for Translational Scientific Discovery and Accelerated Development of Therapies and Medical Devices

Noncommunicable diseases, including cardiovascular disease, diabetes, chronic respiratory disease, and cancer, are the leading cause of death in the world. The cost, both monetary and time, of developing therapies to prevent, treat, or manage these diseases has become unsustainable. A contributing factor is inefficient and ineffective preclinical research, in which the animal models utilized do not replicate the complex physiology that influences disease. An ideal preclinical animal model is one that responds similarly to intrinsic and extrinsic influences, providing high translatability and concordance of preclinical findings to humans. The overwhelming genetic, anatomical, physiological, and pathophysiological similarities to humans make miniature swine an ideal model for preclinical studies of human disease. Additionally, recent development of precision gene-editing tools for creation of novel genetic swine models allows the modeling of highly complex pathophysiology and comorbidities. As such, the utilization of swine models in early research allows for the evaluation of novel drug and technology efficacy while encouraging redesign and refinement before committing to clinical testing. This review highlights the appropriateness of the miniature swine for modeling complex physiologic systems, presenting it as a highly translational preclinical platform to validate efficacy and safety of therapies and devices.

Membrane markers of the immune cells in swine: an update

Besides their breeding value, swine are increasingly used as biomedical models. As reported in three international swine clusters of differentiation (CD) workshops and in the animal homologue section of the last workshop for the determination of human leukocyte differentiation antigens (HLDA 8), characterisation of leukocyte surface antigens by monoclonal antibodies and other molecular studies have determined the cell lineages and blood leukocyte subsets implicated in the immune response, including cell adhesion molecules involved in cell trafficking. This review focusses on the current state of knowledge of porcine leukocyte differentiation and major histocompatibility complex (SLA) molecules. Examples of porcine particularities such as the double-positive T lymphocytes with the phenotype CD(4+)CD8(low) and CD(4-)CD8(low) alphabeta T cell subsets and the persistence of SLA class II after T-lymphocyte activation are illustrated, as well as the shared characteristics of the Artiodactyla group, such as the high proportion of gammadelta TcR (T cell receptor) T cells in blood and other lymphoid tissues. Furthermore, discrepancies between swine and humans, such as CD16 expression on dendritic cells and CD11b (wCD11R1) tissue distribution are outlined. The rapidly growing information should facilitate manipulation of the swine immune system towards improving disease control, and open new avenues for biomedical research using the pig as a model.

Molecular cloning and functional characterization of the pig homologue of integrin-associated protein (IAP/CD47)

We report the cloning of cDNA encoding the pig homologue of human integrin-associated protein (IAP or CD47). A pig CD47-specific probe was generated by polymerase chain reaction (PCR) amplification of pig leucocyte cDNA, using primers based on consensus regions among the known sequences of CD47 from different species. Screening of a pig aorta smooth muscle cDNA library identified seven clones, all containing identical sequences. The clones contained an open reading frame (ORF) that encoded an 18 amino acid putative signal peptide, a 122 amino acid sequence consisting of a single extracellular immunoglobulin variable (IgV)-like domain followed by a 147 amino acid region containing five membrane-spanning domains and a 16 amino acid cytoplasmic tail. The amino acid sequence of the clones was 73% homologous to human IAP and therefore it was termed pig IAP or CD47. Reverse transcription-polymerase chain reaction (RT-PCR) showed that pig CD47 was expressed in a wide range of tissues and detected different alternatively spliced forms. The monoclonal antibody (mAb) BRIC 126, anti-human CD47, was shown, by flow cytometry, to stain pig platelets as well as Chinese hamster ovary (CHO) cells transfected with the cDNA encoding pig CD47. Western blot analysis of pig erythocytes and platelets showed a molecular weight (MW) of 43 000-50 000 and of 55 000-65 000, respectively, under non-reducing conditions. Pig CD47 was stably expressed on CHO cells and shown to bind human thrombospondin (TSP). BRIC126 antibody inhibited the binding of platelets and of CD47-transfected cells to human TSP and to pig fibrinogen, whereas no effect was observed on control CHO cells.