CD8(low)CD28(-) T Cells: A Human CD8 T-Suppressor Subpopulation With Alloantigen Specificity Induced by Soluble HLA-A2 Dimer In Vitro

Design and Optimization of PLGA Particles to Deliver Immunomodulatory Drugs for the Prevention of Skin Allograft Rejection

Background: Recent advancements in therapeutic strategies have attracted considerable attention to control the acute organs and tissues rejection, which is the main cause of mortality in transplant recipients. The long-term usage of immunosuppressive drugs compromises the body immunity against simple infections and decrease the patients' quality of life. Tolerance of allograft in recipients without harming the rest of host immune system is the basic idea to develop the therapeutic approaches after induction of donor-specific transplant. Methods: Controlled and targeted delivery system by using biomimetic micro and nanoparticles as carriers is an effective strategy to deplete the immune cells in response to allograft in an antigen-specific manner. Polylactic-co-glycolic acid (PLGA) is a biocompatible and biodegradable polymer, which has frequently being used as drug delivery vehicle. Results: This review focuses on the biomedical applications of PLGA based biomimetic micro and nano-sized particles in drug delivery systems to prolong the survival of alloskin graft. Conclusion: We will discuss the mediating factors for rejection of alloskin graft, selective depletion of immune cells, controlled release mechanism, physiochemical properties, size-based body distribution of PLGA particles and their effect on overall host immune system.

Anti-human Interleukin(IL)-4 Clone 8D4-8 Cross-Reacts With Myosin-9 Associated With Apoptotic Cells and Should Not Be Used for Flow Cytometry Applications Querying IL-4 Expression

Interleukin(IL)-4 is produced by T cells and other leukocytes and is a critical mediator of monocyte and B cell responses. During routine flow cytometry panel validation for the investigation of intracellular cytokines, we observed unique IL-4 expression patterns associated with the widely available monoclonal antibody 8D4-8. Namely, IL-4 (8D4-8) expression was observed in the absence of cellular activation and enhanced following staurosporine exposure. Mass spectrometry analysis of immunoprecipitates from peripheral blood lymphocytes (PBL) revealed that 8D4-8 cross-reacts with the ubiquitous cytoskeletal protein myosin-9. We confirmed these results by western blotting immunoprecipitates, using immunofluorescence among staurosporine-treated Caco-2 cells, and by surface-labeling PBL for 8D4-8 and myosin-9 and analyzing by flow cytometry. Although previously reported from several independent groups, we found no evidence to support the hypothesis that IL-4 is produced by apoptotic cells. Rather, this appears to have been myosin-9. Our data indicate clone 8D4-8 should not be used in the flow cytometric study of IL-4. Furthermore, our work calls for a reevaluation of previous flow cytometric studies that have used this clone for IL-4 analysis and highlights the importance of validation in antibody-based assays.

Advances on CD8+ Treg Cells and Their Potential in Transplantation

Although cluster of differentiation (CD)8 regulatory T (Treg) cells have been in the last 20 years more studied since evidences of their role in tolerance as been demonstrated in transplantation, autoimmune diseases and cancer, their characteristics are still controversial. In this review, we will focus on recent advances on CD8 Treg cells and description of a role for CD8 Treg cells in tolerance in both solid organ transplantation and graft-versus-host disease and their potential for clinical trials.

Puerarin alleviates delayed-type hypersensitivity via cytokine inhibition by modulating Th1/Th2 balance

Puerarin has long been used as a traditional Chinese medicine, which possesses various physiological properties, including anti-inflammation, anti-oxidative, anti-diabetic and anti-cancer activities. The aim of the current study was to investigate the effect of puerarin on delayed-type hypersensitivity (DTH) induced by ovalbumin (OVA) in mice and explore its underlying mechanisms. The results showed that puerarin significantly attenuated DTH, resulting from a decrement in footpad swelling, reduction in inflammatory cell as well as a decline in anti-OVA IgG in serum. In the homogenized supernatant of footpad tissues, the classic Th1-cytokines, including interferon (IFN)-γ was suppressed following puerarin treatment. Furthermore, a high dose of puerarin inhibited interleukin (IL)-4 production, the classic Th2-cytokine. The concanavalin A stimulation and MTT assays indicated a suppressive effect of puerarin on Th1 response via decreasing IFN-γ production in OVA-primed lymphocytes. Detailed studies revealed that puerarin modulated the Th1/Th2 balance in DTH responses, attributing to lower T-bet/GATA binding protein-3 mRNA and protein level ratios, which led to the shift change of IFN-γ/IL-4 with puerarin treatment. These findings demonstrate that puerarin alleviated inflammation in DTH triggered by OVA application via curbing inflammatory cytokines by modulating the Th1/Th2 balance. These results suggest that puerarin may be an alternative therapeutic option for the treatment of DTH.

CD28- and CD28lowCD8+ Regulatory T Cells: Of Mice and Men

Since the rebirth of regulatory (formerly known as suppressor) T cells in the early 1990s, research in the field of immune-regulation by various T cell populations has quickly gained momentum. While T cells expressing the transcription factor Foxp3 are currently in the spotlight, several other T cell populations endowed with potent immunomodulatory capacities have been identified in both the CD8⁺ and CD4⁺ compartment. The fundamental difference between CD4⁺ and CD8⁺ T cells in terms of antigen recognition suggests non-redundant, and perhaps complementary, functions of regulatory CD4⁺ and CD8⁺ T cells in immunoregulation. This emphasizes the importance and necessity of continuous research on both subpopulations of regulatory T cells (Tregs) so as to decipher their complex physiological relevance and possible synergy. Two distinct CD8-expressing Treg populations can be distinguished based on expression of the co-stimulatory receptor CD28. Here, we review the literature on these (at least in part) thymus-derived CD28^low and peripherally induced CD28^-CD8⁺ Tregs.