Development of a Quantitative PCR Assay for Differentiating the Agent of Heartwater Disease,Ehrlichia ruminantium,from the Panola Mountain Ehrlichia

Panola Mountain Ehrlichia (PME) is an emerging Ehrlichia sp. reported in ten US states. Based on the sequence homology of all known genes, PME is closely related to Ehrlichia ruminantium (ER), the causative agent of heartwater. Heartwater is an economically important tick‐borne disease of cattle, sheep and goats responsible for stock losses in sub‐Saharan Africa. Unfortunately, ER was imported to the Caribbean islands in the 19th century, and the presence of this foreign animal disease in the Caribbean poses a threat to the US mainland. If introduced, a heartwater outbreak would cause massive losses of naïve livestock. The serologic assay of choice to diagnose heartwater is cross‐reactive with Ehrlichia spp., including PME, as we demonstrate here, which would confound disease surveillance in the event of a heartwater outbreak. The purpose of this study was to develop a diagnostic assay capable of rapidly distinguishing between these pathogens. Using synthetic MAP‐1B peptides for ER and PME, we tested the cross‐reactivity of this assay using sera from infected livestock. The MAP‐1B ELISA cannot distinguish between animals infected with PME and ER. Therefore, a dual‐plex Taqman^™ qPCR assay targeting the groEL gene of PME and ER was developed and validated. Primers were designed that are conserved among all known strains of ER, allowing for the amplification of strains from the Caribbean and Africa. The assay is highly sensitive (10 copies of DNA) and specific. This assay distinguishes between infection with PME and ER and will be a valuable tool in the event of heartwater outbreak on the US mainland, or for epidemiological studies involving either disease‐causing organism.     

Detection of Antibodies Against Capripoxviruses Using an Inactivated Sheeppox Virus ELISA

An indirect ELISA was developed to detect antibodies specific for capripoxviruses in goat, sheep and cattle sera. Heat‐inactivated Nigerian sheeppox virus was used as the ELISA antigen. Sera obtained from sheep and goats that were experimentally infected with different capripoxvirus isolates were used to develop and evaluate the sensitivity of the ELISA. Virus neutralization indexes were determined for the experimental sera in OA3.Ts cells. The specificity of the ELISA was determined using 231 sera from capripoxvirus naïve sheep and goats from Canada. In addition, the ELISA was tested for cross‐reactivity to anti‐orf virus antibodies using orf‐reactive sera and no cross‐reactivity was observed. Using experimentally generated sera obtained from animals infected with virulent sheeppox or goatpox virus isolates, the diagnostic sensitivity of the ELISA was 96% with a diagnostic specificity of 95%, where the diagnostic sensitivity of the virus neutralization assay was 96% with a diagnostic specificity of 100%. Further evaluation of this ELISA, using 276 cattle serum samples that were positive by virus neutralization assays, revealed a diagnostic sensitivity of 88% with a specificity of 97%. These results indicated that the inactivated capripoxvirus ELISA can detect capripoxvirus‐specific antibodies in sheep, goats and cattle that have been infected with virulent capripoxvirus isolates. Non‐virulent capripoxvirus isolates, in contrast, did not elicit positive (≥1.5 Log₁₀ neutralization index) antibody responses.     

Anti-pig antibody levels in naïve baboons and cynomolgus monkeys

Anti‐pig antibodies (APA) were analysed in serum from 28 naïve wild‐caught baboons (originating from Kenya) and 31 naïve captive‐bred cynomolgus monkeys (13 from the Philippines and 18 from Mauritius), using a haemolytic assay with pig erythrocytes (APA), flow cytometry on the porcine lymphoma T‐cell cell line L35, and enzyme linked immunosorbent assay (ELISA) using α‐Gal type II and type VI antigen. This was extended in baboon samples by the evaluation in two laboratories (Imutran, Cambridge, UK and Immerge, Boston, USA), and by antibody absorption using either immobilized α‐Gal type II or α‐Gal type VI. Anti‐porcine antibodies were demonstrated in all assays with substantial variability within and between the three non‐human primate groups. Immunoglobulin (Ig)M antibody levels tended to be similar to or higher than those in a pooled normal human standard serum while IgG levels tended to be lower. Highest antibody levels were recorded in Mauritius cynomolgus monkeys. There were statistically significant correlations between assays for IgM or IgG class anti‐Gal antibodies using either α‐Gal type II or α‐Gal type VI as antigen, both for different assays and two laboratories involved. Also, significant correlations were observed between the anti‐Gal and L35 binding assays. Baboon sera before and after absorption to immobilized α‐Gal type II or type VI were analysed for anti‐Gal type VI or type II antibody: levels were almost undetectable indicating that most anti‐Gal antibodies react to epitopes shared between α‐Gal type II and type VI oligosaccharides. Finally, the relation between APA and outcome of porcine heart xenotransplantation in cynomolgus monkeys and baboons showed no apparent relation between pre‐transplant APA levels and the occurrence of hyperacute rejection (HAR) when compared with non‐immunological cause of organ/recipient dysfunction or acute humoral xenograft rejection during the first 4 days post‐transplantation or survival exceeding 4 days post‐transplantation.     

Antigenic regions of African swine fever virus phosphoprotein P30

African swine fever (ASF) is one of the most complex and lethally haemorrhagic viral diseases of swine, affecting all breeds and ages of pigs. In the absence of ASF vaccines, reliable laboratory diagnosis and restricted biosecurity are critical for disease prevention and control. A detection of ASF‐specific antibodies in an unvaccinated pig is a good marker for the diagnosis of ASF. The immunoperoxidase test (IPT) is a sensitive test for detecting ASF virus (ASFV) antibodies. However, due to the complexity of the procedure, the IPT is only suitable to be used as a confirmatory test. The ASFV p30 protein‐based enzyme‐linked immunosorbent assay (ELISA) is widely used for ASFV antibody screening, but the sensitivity is not comparable to the IPT. It is essential to have a better understanding of the antigenic properties of ASFV p30 to improve p30‐based serologic tests. In this study, we developed a panel of 21 monoclonal antibodies (mAbs) against ASFV p30. With 14 out of the 21 mAbs, we defined 4 antigenic regions that contain at least 4 linear epitopes. Nine of the 14 mAbs mapped to antigenic regions 3 and 4 reacted with p30 in all serologic methods tested in this study, such as indirect immunofluorescence assay (IFA), ELISA and Western blot. The antigenic regions 3 and 4 are highly conserved and immunodominant in host antibody response. These mAbs and the defined p30 antigenic regions 3 and 4 provide valuable tools for the development and improvement of ASF serologic assays.     

Real‐world effectiveness of fulvestrant monotherapy as first endocrine treatment in patients with metastatic breast cancer

Fulvestrant monotherapy is approved for postmenopausal women with hormone receptor‐positive, metastatic breast cancer (MBC) who progressed following antiendocrine therapy, or those with hormone receptor‐positive, human epidermal receptor 2‐negative advanced breast cancer (BC) not previously treated with endocrine therapy (ET). However, real‐world data are lacking. Retrospective reviews of 10 United States community oncology practices identified patients diagnosed with MBC between 1 January 2011 and 31 December 2015 who received fulvestrant as the first ET, either as initial therapy for metastatic disease or after progression following one line of chemotherapy. Endpoints were progression‐free survival (PFS) and overall survival (OS). Patients were classified as ET‐naïve or by relapse status following adjuvant ET (“early” recurrence during or ≤12 months of completing adjuvant ET, or “late” >12 months after completing adjuvant ET). Outcomes were evaluated using Kaplan‐Meier methods. Among 121 patients, median PFS (95% confidence interval) was 8.3 months (4.8‐12.3) for early relapse, 15.4 months (10.2‐21.2) for late relapse, and 18.7 months (10.1‐20.8) among ET‐naïve patients (P = .018). Median OS was 39.8 months (25.0‐55.1) for early relapse and 61.4 months (47.1‐61.4) for late relapse, but was not reached (NR; 55.6–NR) for ET‐naïve patients (P = .002). Fulvestrant monotherapy as the first ET after MBC diagnosis demonstrates PFS comparable to clinical study results; outcomes appeared better in patients without prior ET exposure and in patients with disease recurrence >12 months following adjuvant ET. These findings support fulvestrant monotherapy in patients with hormone receptor‐positive MBC.     

Re‐emergence of genotype I of African swine fever virus in Ivory Coast

In July 2014, an outbreak of severe haemorrhagic disease in a domestic pig population, was reported in San‐Pedro, the second seaport city of Ivory Coast. Animals of all age groups developed clinical signs consistent with African swine fever (ASF). Tissue and serum samples from dead pigs were sent to the laboratory for diagnostic confirmation and molecular characterization based on the partial B646L (p72), the full E183L (p54) gene and the central variable region of the B602L gene. The PCR results confirmed the outbreak of ASF. Phylogenetic analyses based on p72 and p54 sequences showed that the San‐Pedro 2014 outbreak virus strain belongs to p72 genotype I. The Analysis of the tetrameric amino acid repeat regions of the B602L gene showed two repeat signatures which differ by an extra A = CAST in the second signature. The ASFV sequence of the San‐Pedro 2014 outbreak strain is closely related to historical and recent ASFV strains collected in Angola and Cameroon whose ships have repeatedly visited the seaport of San‐Pedro from March to June 2014. The 2014 viruses are distinct from the strains involved in the previous ASF wave in 1996 in Ivory Coast.     

Uremia‐associated immunological aging is stably imprinted in the T‐cell system and not reversed by kidney transplantation

The uremia‐induced inflammatory environment in end‐stage renal disease (ESRD) patients is associated with premature T‐cell aging resulting in a defective T‐cell immunity. As kidney transplantation (KTx) reduces the pro‐inflammatory environment, we hypothesized that KTx would rejuvenate the aged T‐cell system. As aging parameters, we determined in 70 KTx recipients the differentiation status by immunophenotyping, thymic output by the T‐cell receptor excision circle (TREC) content together with CD31⁺ naïve T‐cell numbers and the relative telomere length (RTL) as a measure for proliferative history at pre‐KTx, 3, 6 and 12 months post‐KTx. In addition, T‐cell function was determined by measuring the proliferative capacity and percentages of cytokine‐producing cells. Directly post‐KTx, memory T‐cell numbers were diminished but restored to pre‐KTx values at 12 months, except for CD4⁺EM T cells. The RTL of (memory) CD4⁺ and CD8⁺ T cells did not change. In contrast, TREC content and CD31⁺ naïve T‐cell numbers were stable post‐KTx although the RTL of naïve CD4⁺ and CD8⁺ T cells decreased implying homeostatic proliferation of naïve cells, in response to a temporary decrease in memory cells. The T‐cell function was not improved post‐KTx. Our findings demonstrate that the uremia‐associated aged phenotype is stably imprinted in the T‐cell system and not reversed by KTx.     

Persistence of Indirect but Not Direct T Cell Xenoresponses in Baboon Recipients of Pig Cell and Organ Transplants

We investigated the contributions of direct and indirect T cell antigen recognition pathways to the immune response to porcine antigens in naïve baboons and baboon recipients of pig xenografts. In naïve baboons, in vitro culture of peripheral blood T cells with intact pig cells (direct xenorecognition pathway) or pig cell sonicates and baboon antigen‐presenting cells (indirect xenorecognition pathway) induced the activation and expansion of xenoreactive T cells producing proinflammatory cytokines, interleukin‐2 and interferon‐γ. Primary indirect xenoresponses were mediated by preexisting memory T cells, whose presence is not typically observed in primary alloresponses. Next, baboons were conditioned with a nonmyeloablative regimen before short‐term immunosuppression and transplantation of xenogeneic peripheral blood progenitor cells and a kidney, heart, or pancreatic islets from a miniature swine. All transplants were rejected acutely within 30 days after their placement. Posttransplantation, we observed an inhibition of the direct xenoresponse but a significant expansion of indirectly activated proinflammatory T cells. These results suggest that additional treatment to suppress indirect T cell immunity in primates may be required to achieve tolerance of pig xenografts through hematopoietic chimerism.     

Fibrin glue mitigates the learning curve of microneurosurgical repair

Microneurosurgical technique has a steep learning curve. An alternative to microepineurial suture repair of peripheral nerves that circumvents this learning curve would be ideal. We investigated the effect of surgeon experience on suture versus fibrin glue coaptations in a mouse sciatic nerve graft model. Sixty‐four mice received sciatic nerve grafts with either suture or fibrin glue repair by either a naïve surgeon (medical student) or a surgeon with extensive microsurgical experience. Grafts underwent quantitative histomorphometry at 3 weeks postoperatively. Suture repairs performed by the naïve surgeon demonstrated significantly poorer distal regeneration than all other repairs. Histomorphometric parameters of suture and glue repairs performed by the experienced surgeon were not significantly different from the glue coaptation by the naïve surgeon. Fibrin glue may be considered as an alternative to microepineurial suture repair, particularly in the setting of relative surgeon inexperience with microsurgical technique. © 2010 Wiley‐Liss, Inc. Microsurgery 2010.     

Assessment of interactions between African swine fever virus,bushpigs (Potamochoerus larvatus), Ornithodoros ticks and domestic pigs in north‐western Madagascar

Since its introduction in Madagascar in 1998, African swine fever (ASF) has severely affected national pig production and persists as a common disease in that country. Two of its natural hosts in the African continent, the bushpig (Potamochoerus larvatus) and tick vectors of the Ornithodoros moubata complex, are reported in west and central regions of the island. However, their role in the maintenance and transmission of the virus has been insufficiently studied. In this work, we tried to assess their potential role in the epidemiology of the disease in Madagascar, by assessing the levels of interaction between (i) ASF virus (ASFV) and bushpigs and (ii) between soft ticks and domestic and wild suids in north‐western Madagascar. Twenty‐seven sera and 35 tissue samples from bushpigs were collected and analysed for the presence of anti‐ASF antibodies and viral DNA. In addition, the sera from 27 bushpigs and 126 domestic pigs were analysed with an ELISA test for the detection of antibodies against salivary antigens from Ornithodoros ticks. No circulation of ASFV or anti‐ASFV antibodies nor anti‐tick antibodies were detected in bushpigs. However, seven of the domestic pig sera (5.6% of the total sample population) were antibody positive for O. moubata antigens. The probability of freedom from ASFV in the bushpig population using Bayesian statistical methods ranged between 73% and 84%. The probabilities of absence of anti‐tick antibodies in domestic and wild pigs were estimated at 63% and 71%, respectively. These preliminary results suggest that bushpigs are unlikely to play a significant role in the maintenance and transmission of ASFV in Madagascar. Nevertheless, further ASFV surveys are needed on that species to confirm this assumption. In addition, the presence of antibodies against O. moubata in domestic pigs suggests that soft ticks may be able to maintain ASFV within a domestic pig cycle in areas of Madagascar where they remain present.     

Attitudes and Beliefs of Pig Farmers and Wild Boar Hunters Towards Reporting of African Swine Fever in Bulgaria,Germany and the Western Part of the Russian Federation

This study investigated the attitudes and beliefs of pig farmers and hunters in Germany, Bulgaria and the western part of the Russian Federation towards reporting suspected cases of African swine fever (ASF). Data were collected using a web‐based questionnaire survey targeting pig farmers and hunters in these three study areas. Separate multivariable logistic regression models identified key variables associated with each of the three binary outcome variables whether or not farmers would immediately report suspected cases of ASF, whether or not hunters would submit samples from hunted wild boar for diagnostic testing and whether or not hunters would report wild boar carcasses. The results showed that farmers who would not immediately report suspected cases of ASF are more likely to believe that their reputation in the local community would be adversely affected if they were to report it, that they can control the outbreak themselves without the involvement of veterinary services and that laboratory confirmation would take too long. The modelling also indicated that hunters who did not usually submit samples of their harvested wild boar for ASF diagnosis, and hunters who did not report wild boar carcasses are more likely to justify their behaviour through a lack of awareness of the possibility of reporting. These findings emphasize the need to develop more effective communication strategies targeted at pig farmers and hunters about the disease, its epidemiology, consequences and control methods, to increase the likelihood of early reporting, especially in the Russian Federation where the virus circulates.     

The Allo‐ and Viral‐Specific Immunosuppressive Effect of Belatacept,but Not Tacrolimus,Attenuates With Progressive T Cell Maturation

Tacrolimus impairs allo‐ and viral‐specific T cell responses. Belatacept, a costimulation‐based alternative to tacrolimus, has emerged with a paradoxical picture of less complete control of alloimmunity with concomitant impaired viral immunity limited to viral‐naïve patients. To reconcile these signatures, bulk population and purified memory and naïve lymphocytes from cytomegalovirus (CMV)‐seropositive (n = 10) and CMV‐seronegative (n = 10) volunteers were studied using flow cytometry, interrogating proliferation (carboxyfluorescein succinimidyl ester dilution) and function (intracellular cytokine staining) in response to alloantigens or CMV‐pp‐65 peptides. As anticipated, T cells from CMV‐experienced, but not naïve, individuals responded to pp‐65 with a small percentage of their repertoire (<2.5%) consisting predominantly of mature, polyfunctional (expressing interferon gamma, tumor necrosis factor alpha and IL‐2) T effector memory cells. Both CMV naïve and experienced individuals responded similarly to alloantigen with a substantially larger percentage of the repertoire (up to 48.2%) containing proportionately fewer polyfunctional cells. Tacrolimus completely inhibited responses of CMV‐ and allo‐specific T cells regardless of their maturation. However, belatacept's effects were decreasingly evident in increasingly matured cells, with minimal effect on viral‐specific triple cytokine producers and CD28‐negative allo‐specific cells. These data indicate that belatacept's immunosuppressive effect, unlike tacrolimus's, wanes on progressively developed effector responses, and may explain the observed clinical effects of belatacept.     

Assessing the Risk of African Swine Fever Introduction into the European Union by Wild Boar

The presence of African swine fever (ASF) in the Caucasus region and Russian Federation has increased concerns that wild boars may introduce the ASF virus into the European Union (EU). This study describes a semi‐quantitative approach for evaluating the risk of ASF introduction into the EU by wild boar movements based on the following risk estimators: the susceptible population of (1) wild boars and (2) domestic pigs in the country of origin; the outbreak density in (3) wild boars and (4) domestic pigs in the countries of origin, the (5) suitable habitat for wild boars along the EU border; and the distance between the EU border and the nearest ASF outbreak in (6) wild boars or (7) domestic pigs. Sensitivity analysis was performed to identify the most influential risk estimators. The highest risk was found to be concentrated in Finland, Romania, Latvia and Poland, and wild boar habitat and outbreak density were the two most important risk estimators. Animal health authorities in at‐risk countries should be aware of these risk estimators and should communicate closely with wild boar hunters and pig farmers to rapidly detect and control ASF.     

Clinical symptoms of African swine fever in domestic pig farms in the Republic of Korea, 2019

This study describes the clinical characteristics of the African swine fever (ASF) outbreaks in 14 domestic pig farms in the Republic of Korea. ASF outbreak was identified by farmers' notifications in 11 farms and by active surveillance in the remaining three. At the time of notification, farmers reported sudden death, abortion and anorexia in sows. Death was the primary symptom identified by farmers in fattener pigs. The number of animals exhibiting clinical symptoms did not exceed four heads at notification, and the number of asymptomatic virus positives was four heads per farm on average. As ASF virus was detected only in the same pig house (in a pen for fattener pigs) in each of 14 ASF outbreak farms, there has been no evidence of house‐to‐house viral spread within any of the ASF outbreak farms. This in turn supports our hypothesis that infection was successfully detected during its initial phase.     

Complex nature of the human antisperm antibody response in SCID mice

Human peripheral blood mononuclear (PBMs) cells were introduced into the peritoneal cavity of severely‐combined immunodeficient (SCID) mice in concentrations of 2.5–4.0 × 10⁷ cells per mouse. Whole mononuclear cell suspensions were used either unstimulated or following primary in vitro culture with human spermatozoa. In some experiments, immunodepletion of CD8⁺ cells was carried out prior to grafting. Lymphocytes were obtained from nonsensitized (to antigen) human subjects or from individuals who were primed in vivo (vasectomized individuals in case of sperm antigens). An enzyme‐linked immunosorbent assay was employed to assess total human immunoglobulin (G or M) levels as well as the specificity of the antibodies generated. We have been successful by generating primary and secondary immune responses with ‘naïve’ human lymphocytes, challenged with chlamydia or ovalbumin but without adjuvant or CD8⁺ immunodepletion; however, we were unable to induce specific antibodies to spermatozoa under this regime in SCID male mice. We then employed female SCID mice, treated with sperm antigen extracts (glycosylated or deglycosylated) encapsulated in liposomes and human lymphocytes obtained from ‘naïve’ or pre‐sensitized in vivo subjects. It was found that the most pronounced humoral response to sperm antigens was obtained with deglycosylated antigens and PBMs from vasectomized (in vivo pre‐primed to spermatozoa) individuals. A presented SCID mice model can be helpful at understanding of antisperm antibody development and the molecular nature of generated antibodies to modified sperm antigenic entities.     

The impact of serum incubation time on IgM/IgG binding to porcine aortic endothelial cells

The results of the assay for measuring anti‐non‐Gal antibodies (which affect pig xenograft survival) in recipients are important. Serum incubation time and concentration may be important factors in the extent of antibody binding to the graft. The aim of this in vitro study was to determine the optimal incubation time and serum concentration for measuring anti‐non‐Gal antibody binding to porcine aortic endothelial cells (pAECs). Pooled human , naive, and sensitized baboon sera were incubated with wild‐type, α1,3‐galactosyltransferase gene‐knockout (GTKO), and GTKO/human CD55 pAECs. IgM/IgG binding to pAECs after varying serum incubation times (0.5, 1, 2, and 3 hour) and concentrations (5, 10, 20, and 40 μL) was determined by flow cytometry. An increase in incubation time from 30 minutes to 2 hour was associated with increases in anti‐non‐Gal IgM/IgG binding to GTKO and GTKO/hCD55 pAECs of pooled human , naive and sensitized baboon sera (P<.05). Pooled human serum showed a significant increase in anti‐non‐Gal IgM (1.5 times) and a minimal increase in anti‐non‐Gal IgG antibody binding. IgM/IgG binding of sensitized baboon serum to GTKO pAECs after 2‐hour incubation was 1.5 times and 2 times greater than after 30‐minutes incubation, respectively, whereas naïve baboon sera showed minimal (non‐significant) increase in anti‐non‐Gal IgM/IgG antibody binding. With 2‐hour incubation, increasing the serum concentration from 5 μL to 20 μL significantly increased antibody binding to non‐Gal antigens in pooled human and sensitized baboon serum. With naïve baboon serum, only IgG was significantly increased. Increasing the serum incubation time contributed to improve the sensitivity of detecting anti‐non‐Gal antibodies, without affecting cell viability in vitro.     

In Vivo Development of Transplant Arteriosclerosis in Humanized Mice Reflects Alloantigen Recognition and Peripheral Treg Phenotype of Lung Transplant Recipients

Experimentally, regulatory T cells inhibit rejection. In clinical transplantations, however, it is not known whether T cell regulation is the cause for, or an epiphenomenon of, long‐term allograft survival. Here, we study naïve and alloantigen‐primed T cell responses of clinical lung transplant recipients in humanized mice. The pericardiophrenic artery procured from human lung grafts was implanted into the aorta of NODrag^?/?/IL‐2rγc^?/? mice reconstituted with peripheral blood mononuclear cells (PBMCs) from the respective lung recipient. Naïve or primed allogeneic PBMCs procured 21 days post–lung transplantation with or without enriching for CD4⁺CD25^high T cells were used. Transplant arteriosclerosis was assessed 28 days later by histology. Mice reconstituted with alloantigen‐primed PBMCs showed significantly more severe transplant arteriosclerosis than did mice with naïve PBMCs (p = 0.005). Transplant arteriosclerosis was equally suppressed by enriching for autologous naïve (p = 0.012) or alloantigen‐primed regulatory T cells (Tregs) (p = 0.009). Alloantigen priming in clinical lung recipients can be adoptively transferred into a humanized mouse model. Transplant arteriosclerosis elicited by naïve or alloantigen‐primed PBMCs can be similarly controlled by potent autologous Tregs. Cellular therapy with expanded autologous Tregs in lung transplantation might be a promising future strategy.     

The Role of Regulatory Cells in Miniature Swine Rendered Tolerant to Cardiac Allografts by Donor Kidney Cotransplantation

To determine the mechanism by which cotransplantation of a kidney allograft induces tolerance to a donor heart in miniature swine, we examined the role of CD25⁺ cells in heart/kidney recipients. Tolerance was induced to class‐I MHC mismatched hearts by cotransplanting a donor‐specific kidney with a 12‐day course of cyclosporine. Peripheral blood leukocytes (PBL) were isolated from tolerant heart/kidney recipients and used in cell‐mediated lympholysis (CML) coculture assays as either unmodified PBL, PBL enriched for CD25⁺ cells or PBL depleted of CD25⁺ cells to assess their ability to suppress CML responses of naïve recipient‐matched leukocytes against mismatched target cells. Primed PBL from tolerant heart/kidney recipients completely suppressed lysis by naïve cells. Complete suppression of the response of naïve recipient‐matched leukocytes against donor‐matched target cells was lost following the depletion of CD25⁺ cells from tolerant heart/kidney animal PBL, but it was reestablished by incubation of naïve cells with small populations of CD25⁺ cells from tolerant heart/kidney animals. These data suggest that peripheral blood from tolerant heart/kidney recipients contains regulatory cells that, upon priming, can suppress the response of naïve‐matched PBL in coculture CML assays, and that suppression appears to be dependent on cells expressing CD25.     

An Investigation into the First Outbreak of African Swine Fever in the Republic of Mauritius

Outbreaks of African swine fever (ASF) have been reported from many countries, particularly in Sub‐Saharan Africa, but until 2007 the disease had never been reported from the Republic of Mauritius. This is the first report describing field epidemiological and laboratory investigations into the outbreak of the lethal pig disease on the island. The official index case displayed clinical and necropsy signs suggestive of ASF. Serological and agent identification methods used to confirm and investigate the outbreak yielded negative and a few positive results respectively. Phylogenetic analysis based on DNA sequencing clustered the outbreak strain within genotype II viruses. The outbreak was controlled by modified stamping out and risk assessment revealed the possibility of disease endemicity in the country.     

Adoptive Transfer of Renal Allograft Tolerance in a Large Animal Model

Our recent studies in an inbred swine model demonstrated that both peripheral and intra‐graft regulatory cells were required for the adoptive transfer of tolerance to a second, naïve donor‐matched kidney. Here, we have asked whether both peripheral and intra‐graft regulatory elements are required for adoptive transfer of tolerance when only a long‐term tolerant (LTT) kidney is transplanted. Nine highly‐inbred swine underwent a tolerance‐inducing regimen to prepare LTT kidney grafts which were then transplanted to histocompatible recipients, with or without the peripheral cell populations required for adoptive transfer of tolerance to a naïve kidney. In contrast to our previous studies, tolerance of the LTT kidney transplants alone was achieved without transfer of additional peripheral cells and without strategies to increase the number/potency of regulatory T cells in the donor. This tolerance was systemic, since most subsequent, donor‐matched challenge kidney grafts were accepted. These results confirm the presence of a potent tolerance‐inducing and/or tolerance‐maintaining cell population within LTT renal allografts. They suggest further that additional peripheral tolerance mechanisms, required for adoptive transfer of tolerance to a naïve donor‐matched kidney, depend on peripheral cells that, if not transferred with the LTT kidney, require time to develop in the adoptive host.