Ubiquitous LEA29Y Expression Blocks T Cell Co-Stimulation but Permits Sexual Reproduction in Genetically Modified Pigs

We have successfully established and characterized a genetically modified pig line with ubiquitous expression of LEA29Y, a human CTLA4-Ig derivate. LEA29Y binds human B7.1/CD80 and B7.2/CD86 with high affinity and is thus a potent inhibitor of T cell co-stimulation via this pathway. We have characterized the expression pattern and the biological function of the transgene as well as its impact on the porcine immune system and have evaluated the potential of these transgenic pigs to propagate via assisted breeding methods. The analysis of LEA29Y expression in serum and multiple organs of CAG-LEA transgenic pigs revealed that these animals produce a biologically active transgenic product at a considerable level. They present with an immune system affected by transgene expression, but can be maintained until sexual maturity and propagated by assisted reproduction techniques. Based on previous experience with pancreatic islets expressing LEA29Y, tissues from CAG-LEA29Y transgenic pigs should be protected against rejection by human T cells. Furthermore, their immune-compromised phenotype makes CAG-LEA29Y transgenic pigs an interesting large animal model for testing human cell therapies and will provide an important tool for further clarifying the LEA29Y mode of action

Avaliação imunofenotípica de subpopulações linfocitárias no sangue do cordão umbilical e periférico de suínos neonatos (Sus scrofa)

Considerando a importância do uso do sangue do cordão umbilical como fonte potencial de células tronco hematopoiéticas e o uso do suíno doméstico (Sus scrofa) como modelo para pesquisas biomédicas em medicina regenerativa, e por outro lado, visando dar um contributo sobre a quantificação das subpopulações linfocitárias no sangue do cordão umbilical e periférico, objetivou-se quantificar as células CD4+, CD5+ e CD8+ nas amostras de sangue de suínos neonatos. Analisaram-se as amostras do sangue do cordão umbilical e periférico de 48 leitões de linhagem Topigs, provenientes de porcas hígidas, inseminadas artificialmente e de parto natural. Foram coletadas amostras de sangue do cordão umbilical e periférico no momento do nascimento, por meio de venopunção da veia umbilical e seio venoso retro-oftálmico, respectivamente. As quantificações imunofenotípicas de células CD4+, CD5+ e CD8+ foram obtidas por citometria de fluxo. Os valores médios obtidos para as contagens das células CD4+, CD5+ e CD8+ do sangue do cordão umbilical e periférico apresentaram-se inferiores aos reportados para o sangue periférico de suínos adultos, sugerindo um componente imunológico imaturo. A proporção CD4+:CD8+ obtida no sangue do cordão umbilical (3,2±1,2%) e no sangue periférico (3,2±1,7%) ilustrou a predominância dos linfócitos TCD4+ com relação aos TCD8+. A quantidade relativa de células CD4+ e CD8+ no sangue do cordão umbilical e periférico foi de 1,37±0,86% e 1,15±0,57%, respectivamente

A model for homeopathic remedy effects: low dose nanoparticles, allostatic cross-adaptation, and time-dependent sensitization in a complex adaptive system

BACKGROUND: This paper proposes a novel model for homeopathic remedy action on living systems. Research indicates that homeopathic remedies (a) contain measurable source and silica nanoparticles heterogeneously dispersed in colloidal solution; (b) act by modulating biological function of the allostatic stress response network (c) evoke biphasic actions on living systems via organism-dependent adaptive and endogenously amplified effects; (d) improve systemic resilience. DISCUSSION: The proposed active components of homeopathic remedies are nanoparticles of source substance in water-based colloidal solution, not bulk-form drugs. Nanoparticles have unique biological and physico-chemical properties, including increased catalytic reactivity, protein and DNA adsorption, bioavailability, dose-sparing, electromagnetic, and quantum effects different from bulk-form materials. Trituration and/or liquid succussions during classical remedy preparation create “top-down” nanostructures. Plants can biosynthesize remedy-templated silica nanostructures. Nanoparticles stimulate hormesis, a beneficial low-dose adaptive response. Homeopathic remedies prescribed in low doses spaced intermittently over time act as biological signals that stimulate the organism’s allostatic biological stress response network, evoking nonlinear modulatory, self-organizing change. Potential mechanisms include time-dependent sensitization (TDS), a type of adaptive plasticity/metaplasticity involving progressive amplification of host responses, which reverse direction and oscillate at physiological limits. To mobilize hormesis and TDS, the remedy must be appraised as a salient, but low level, novel threat, stressor, or homeostatic disruption for the whole organism. Silica nanoparticles adsorb remedy source and amplify effects. Properly-timed remedy dosing elicits disease-primed compensatory reversal in direction of maladaptive dynamics of the allostatic network, thus promoting resilience and recovery from disease. SUMMARY: Homeopathic remedies are proposed as source nanoparticles that mobilize hormesis and time-dependent sensitization via non-pharmacological effects on specific biological adaptive and amplification mechanisms. The nanoparticle nature of remedies would distinguish them from conventional bulk drugs in structure, morphology, and functional properties. Outcomes would depend upon the ability of the organism to respond to the remedy as a novel stressor or heterotypic biological threat, initiating reversals of cumulative, cross-adapted biological maladaptations underlying disease in the allostatic stress response network. Systemic resilience would improve. This model provides a foundation for theory-driven research on the role of nanomaterials in living systems, mechanisms of homeopathic remedy actions and translational uses in nanomedicine

Development of γδ thymocyte subsets during prenatal and postnatal ontogeny

In this report, we describe 12 subpopulations of porcine γδ thymocytes based on their expression of CD1, CD2, CD4, CD8-isoforms and CD45RC. Our data suggest that γδ thymocytes can be divided into two major families: (a) one large family of CD4(−) γδ thymocytes that could be further subdivided according to the CD2/CD8αα phenotype and (b) a small family of CD4(+) γδ thymocytes bearing CD8αβ and possessing certain unusual features in comparison with other γδ thymocytes. Maturation of γδ thymocytes within the CD4(−) family begins with proliferation of the CD2(+) CD8(−) CD1(+) CD45RC(−) γδ common precursor. This developmental stage is followed by diversification into the CD2(+) CD8αα(+), CD2(+) CD8(−) and CD2(−) CD8(−) subsets. Their further maturation is accompanied by a loss of expression of CD1 and by increased expression of CD45RC. Therefore, individual subsets develop from CD1(+) CD45RC(−) through CD1(−) CD45RC(−) into CD1(−) CD45RC(+) cells. On the other hand, γδ thymocytes within the CD4(+) family bear exclusively CD8αβ, always express CD1, but may coexpress CD45RC. These cells have no counterpart in the periphery. Our observations suggest that all peripheral CD8(+) γδ T cells express CD8αα and that two subsets of these cells differing in major histocompatibility complex II expression, occur. We propose that one subset acquires CD8αα in the thymus while the second acquires CD8αα as a result of stimulation in the periphery