Elevating student potential: creating digital video to teach neurotransmission.

Students today have unprecedented access to technology, the Internet, and social media. Their nearly ubiquitous use of these platforms is well documented. Given that today's students may be primed to learn using a different medium, incorporating various technological elements into the classroom in a manner compatible with traditional approaches to teaching becomes a challenge. We recently designed and implemented a strategy that capitalized on this knowledge. Students in their first neuroscience course were required to create a 3-5 minute digital video using video-making freeware available on any Mac or PC. They used images, text, animation, as well as downloaded music to describe the fundamental process of neurotransmission as it applies to a topic of their choice. In comparison to students taught using other more traditional approaches to demonstrate the process of neurotransmission, we observed that students who took part in the video-making project exhibited better understanding of the neurological process at multiple levels, as defined by Bloom's revised taxonomy. This was true even of students who had no aspirations of pursuing a Neuroscience career, thus suggesting that there was an overall increased level of student engagement regardless of personal career interests. The utility of our approach was validated by both direct and indirect assessments. Importantly, this particular strategy to teaching difficult concepts offers a high degree of flexibility allowing it to potentially be incorporated into any upper-level Neuroscience course.

Lung resident mesenchymal stem cells isolated from human lung allografts inhibit T cell proliferation via a soluble mediator.

Development of allograft rejection continues to be the major determinant of morbidity and mortality postlung transplantation. We have recently demonstrated that a population of donor-derived mesenchymal stem cells is present in human lung allografts and can be isolated and expanded ex vivo. In this study, we investigated the impact of lung resident mesenchymal stem cells (LR-MSCs), derived from allografts of human lung transplant recipients, on T cell activation in vitro. Similar to bone marrow-derived MSCs, LR-MSCs did not express MHC II or the costimulatory molecules CD80 or CD86. In vitro, LR-MSCs profoundly suppressed the proliferative capacity of T cells in response to a mitogenic or an allogeneic stimulus. The immunosuppressive function of LR-MSCs was also noted in the absence of direct cell contact, indicating that LR-MSCs mediated their effect predominantly via a soluble mediator. LR-MSCs isolated from lung transplant recipients demonstrated PGE(2) secretion at baseline (385 +/- 375 pg/ml), which increased in response to IL-1beta (1149 +/- 1081 pg/ml). The addition of PG synthesis inhibitors (indomethacin and NS-398) substantially abrogated LR-MSC-mediated immunosuppression, indicating that PGE(2) may be one of the major soluble mediators impacting T cell activity. This is the first report to demonstrate that human tissue-derived MSCs isolated from an allogeneic environment have the potential to mediate immunological responses in vitro.

Regulation of alloimmune Th1 responses by the cyclin-dependent kinase inhibitor p21 following transplantation.

BACKGROUND: The cyclin-dependent kinase (cdk) inhibitor p21 inhibits cellular proliferation of many cell types, including T cells. Autoimmune models, however, have yielded conflicting results regarding the role of cdk inhibitors and T-cell function. The role of p21 in T-cell function after transplantation has not been investigated directly. We hypothesized that p21 plays an important role in alloantigen-driven responses in vitro in mixed lymphocyte cultures (MLC) and in vivo using the heterotopic murine cardiac allograft model. METHODS: Wild type (WT) and p21-deficient (p21-/-) mice were used as recipients, and the effects of p21 overexpression were assessed by transplanting p21 adenoviral-transfected cardiac allografts. Enzyme-linked immunospot (ELISPOT) and 3H-thymidine incorporation were used to evaluate for T-cell priming and proliferation in vitro, whereas graft histology was evaluated for rejection. RESULTS: When stimulated with alloantigens in vitro, splenocytes from p21-/- mice mounted enhanced proliferative responses and decreased Th2 responses relative to their WT counterparts. No differences in Th1 responses were noted when p21-/- cells were stimulated with alloantigens in vitro; however, after cardiac transplantation, Th1 responses were enhanced in p21-/- recipients relative to WT mice. This enhanced in vivo Th1 response was associated with exacerbated graft rejection in p21-/- recipients. Interestingly, p21 transfection of WT allografts inhibited graft rejection and Th1 priming. CONCLUSIONS: p21 controls the intensity of the immune response posttransplantation, with overexpression inhibiting allograft rejection. Our data demonstrate that p21 controls T-cell priming and suggest that p21 and other cdk inhibitors may serve as potential targets for therapeutic manipulation of alloimmune responses.

CD40/CD154 interactions at the interface of tolerance and immunity.

Development of the acquired immune response is dependent on the signaling of CD40 by its ligand, CD154. These molecules govern both the magnitude and quality of humoral- and cell-mediated immunity. A litany of studies have conclusively documented that blockade of this ligand-receptor pair can prevent, and also intervene in, the progression of antibody- and cell-mediated autoimmune diseases, and can instill long-lived allogeneic and xenogeneic graft tolerance. Many effector mechanisms of inflammation are abolished as a result of CD154 blockade, but we are now beginning to understand that CD154 blockade may, in some instances, engender long-lived, antigen-specific tolerance. In the context of transplantation tolerance, we present a hypothesis that alpha CD154 blockade is most effective at inducing long-lived allospecific tolerance if anergy and regulation can be elicited prior to the onslaught of inflammation that is induced by grafting (preemptive tolerance). This facet of alpha CD154-induced tolerance appears to co-opt the normal processes of peripheral tolerance induced by immature DCs and can be exploited to induce long-lived antigen-specific tolerance. The underlying science and the prospects for inducing long-lived antigen-specific tolerance in a model of allograft tolerance through CD154 blockade are presented and discussed.

CD154 on the surface of CD4+CD25+ regulatory T cells contributes to skin transplant tolerance.

BACKGROUND: It is known that the infusion of whole blood from donors (donor-specific transfusion) into recipients combined with anti-CD154 therapy can prolong allograft survival. It has generally been agreed that the effectiveness of anti-CD154 therapy is caused by the inactivation of alloreactive CD4+ and CD8+ effector T cells. The recent literature has implicated CD4+CD25+ regulatory T cells in the suppression of autoimmunity and graft rejection, and we therefore examined whether CD154 blockade is effective because of its blockade of inflammatory T-cell activation or because of a direct impact on the regulatory T cells. METHODS: RAG(-/-) mice were adoptively transfused with CD4+ T cells or a subset of the population (CD4+CD25+ or CD4+CD25- T cells) alone or in combination with donor-specific transfusion and anti-CD154 and given an allo-skin transplant. The longevity of the transplant was determined over time. CD154(-/-)CD4+ T cells were used to assess the importance of CD154 in graft rejection and acceptance. RESULTS: CD154 blockade (or loss of CD154) on CD4+CD25+ regulatory T cells enhanced their immunosuppressive activities and was a contributing factor to anti-CD154-induced immune suppression in vivo. In a model of allograft tolerance, suppression was elicited by antigen and anti-CD154 or antigen alone if the CD4+CD25+ regulatory T cells were deficient in CD154 expression. CONCLUSIONS: Neutralizing the function of CD154 on regulatory T cells upon antigen exposure induces heightened levels of suppressive activities and is likely a contributing factor to the long-lived therapeutic effects of anti-CD154 treatment.

Mechanisms of donor-specific transfusion tolerance: preemptive induction of clonal T-cell exhaustion via indirect presentation.

Induction of transplantation tolerance to alloantigens without general immunosuppression remains an enduring challenge. Injecting a donor-specific transfusion (DST) of spleen cells together with blocking alphaCD154 antibody prior to graft transplantation is an effective way to induce long-lived graft acceptance. Using a novel T-cell receptor (TCR) transgenic (Tg) model of CD4+ T-cell-mediated rejection, this study sheds new insights into the cellular basis for enhanced graft survival induced by DST and alphaCD154. The study shows that DST and alphaCD154 induce an early, robust, abortive expansion of the Tg T cells that results in profound anergy. This is contrasted with the more delayed, regional, productive response elicited by an allogeneic graft. Studies show that the induction of tolerance to the allograft induced by DST is mediated by indirect presentation by host antigen-presenting cells. Based on these observations, we conclude that DST and alphaCD154 preemptively tolerize the alloreactive T-cell compartment to prohibit subsequent responses to the immunogenic allograft.

Immunization of rabbits against a bacterial pathogen with an alginate microparticle vaccine.

Pasteurella multocida is an important bacterial pathogen of domestic rabbits. To evaluate the ability of a thiocyanate extract (PTE) of P. multocida to stimulate an immune response and protect against infection with P. multocida, rabbits were immunized subcutaneously or intranasally on Days 7, 21 and 35. Cholera toxin, a potent mucosal adjuvant, was included in one treatment group. Rabbits immunized subcutaneously (SC) or intranasally (IN) had significant increases in serum anti-PTE IgG but not IgA. In contrast, only rabbits immunized IN with PTE developed significant titers of nasal lavage anti-PTE IgA and cholera toxin significantly enhanced this response. In a second study rabbits were immunized via the drinking water with PTE incorporated into alginate microparticles on Days 7, 14 and 21. Mild increases in serum IgG were noted in rabbits immunized with PTE in microparticles, with or without cholera toxin, and this increase was significant (P