Viable pigs exhibiting robust and ubiquitous expression of pCTLA4-Ig were produced on both a WT and GTKO background. Expression of pCTLA4-Ig resulted in acute susceptibility to opportunistic pathogens due at least in part to a significantly compromised humoral immune status. As this molecule is known to have immunosuppressive activity, high levels of pCTLA4-Ig expression in the blood, as well as defective development related to exposure to pCTLA4-Ig in utero, may contribute to this reduced immune status. Prophylactic treatment with antibiotics may promote survival of disease-free transgenic pigs to a size optimal for organ procurement for transplantation. Additional genetic modifications and/or tightly regulated expression of pCTLA4Ig may reduce the impact of this transgene on the humoral immune system.

Background The increasing availability of genetically-engineered pigs is steadily improving the results of pig organ and cell transplantation in nonhuman primates (NHPs). Current techniques offer knock-out of pig genes and/or knock-in of human genes. Knowledge of normal values of hematologic, biochemical, coagulation, and other parameters in healthy genetically-engineered pigs and NHPs is important, particularly following pig organ transplantation in NHPs. Furthermore, information on parameters in various NHP species may prove important in selecting the optimal NHP model for specific studies. Methods We have collected hematologic, biochemical, and coagulation data on 71 α1,3-galactosyltransferase gene-knockout (GTKO) pigs, 18 GTKO pigs additionally transgenic for human CD46 (GTKO.hCD46), 4 GTKO.hCD46 pigs additionally transgenic for human CD55 (GTKO.hCD46.hCD55), and 2 GTKO.hCD46 pigs additionally transgenic for human thrombomodulin (GTKO.hCD46.hTBM). Results We report these data and compare them with similar data from wild-type pigs, and the 3 major NHP species commonly used in biomedical research (baboons, cynomolgus, and rhesus monkeys) and humans, largely from previously published reports. Conclusions Genetic modification of the pig (e.g., deletion of the Gal antigen and/or the addition of a human transgene) (i) does not result in abnormalities in hematologic, biochemical, or coagulation parameters that might impact animal welfare, (ii) seems not to alter metabolic function of vital organs, though this needs to be confirmed after their xenotransplantation, and (iii) possibly (though by no means certainly) modifies the hematologic, biochemical, and coagulation parameters closer to human values. The present study may provide a good reference for those working with genetically-engineered pigs in xenotransplantation research and eventually in clinical xenotransplantation.

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Ultrasound-guided transvaginal follicular aspiration was used to obtain oocytes from Holstein cows to study follicular development and oocyte morphology during early lactation. A single aspiration was conducted on each of the 120 cows during wk 1 to 12 postpartum. On the day of aspiration, the number of follicles and their sizes were recorded. The collected oocytes were morphologically classified into four grades. Blood and follicular fluid samples were collected for hormone and metabolite assays. Greater serum nonesterified fatty acids concentrations for first- and second-parity cattle on d 7 implied a more negative energy balance status than for third-parity cattle. The numbers of follicles and oocytes retrieved were affected by linear days postpartum x parity interactions, with second-parity cattle having increases compared with decreases for third-parity cattle. Oocyte quality score was affected by the quadratic days postpartum x parity interaction. First- and second-parity cattle had greater oocyte quality scores from d 20 to 70 postpartum compared with third-parity cattle, but third-parity cattle had greater quality oocytes near the end of the 12-wk period. In contrast to cattle subjected to multiple aspirations, first- and second-parity cattle had higher estradiol and insulin-like growth factor I concentrations in follicular fluid associated with greater numbers of oocytes retrieved than third-parity cattle. This study demonstrated that conditions related to early lactation have a negative effect on oocyte quality and endocrine measures of dairy cattle and that animals of various parities may be differentially affected.

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Xenotransplantation research has made considerable progress in recent years, largely through the increasing availability of pigs with multiple genetic modifications, effective immunosuppressive therapy, and anti‐inflammatory therapy to protect pig tissues from the primate immune and inflammatory responses and correct molecular incompatibilities. Further study is required regarding identification and investigation of physiological incompatibilities. Although the exact cause remains uncertain, we and others have observed relatively rapid growth of kidney xenografts after transplantation into nonhuman primates (NHPs). There has also been some evidence of growth, or at least ventricular hypertrophy, of the pig heart after orthotopic transplantation into NHPs. Rapid growth could be problematic, particularly with regard to the heart within the relatively restricted confines of the chest. It has been suggested that the problem of rapid growth of the pig organ after transplantation could be resolved by growth hormone receptor (GHR) gene knockout in the pig. The GHR, although most well‐known for regulating growth, has many other biological functions, including regulating metabolism and controlling physiological processes. Genetically modified GHRKO pigs have recently become available. We provide data on their growth compared to comparable pigs that do not include GHRKO, and we have reviewed the literature regarding the effect of GHRKO, and its relevance to xenotransplantation.

Fang J, Walters A, Hara H, Long C, Yeh P, Ayares D, Cooper DKC, Bianchi J. Anti‐gal antibodies in α1,3‐galactosyltransferase gene‐knockout pigs. Xenotransplantation 2012; 19: 305–310. © 2012 John Wiley & Sons A/S. Abstract  Serum anti‐galactose‐α1,3‐galactose (Gal) IgM and IgG antibody levels were measured by ELISA in α1,3‐galactosyltransferase gene‐knockout (GTKO) pigs (78 estimations in 47 pigs). A low level of anti‐Gal IgM was present soon after birth, and rose to a peak at 4–6 m, which was maintained thereafter even in the oldest pigs tested (at >2 yr). Anti‐Gal IgG was also present at birth, peaked at 3 m, and after 6 m steadily decreased until almost undetectable at 20 m. No differences in this pattern were seen between pigs of different gender. Total IgM followed a similar pattern as anti‐Gal IgM, but total IgG did not decrease after 6m. The data provide useful baseline data for future experimental studies in GTKO pigs, e.g., relating to the antibody response to WT pig allografts.