Are the Mast Cells Antigen Presenting Cells?

Mast cells have an important role in allergic reactions secreting histamine and other mediators of immediate hypersensitivity. In the present study we evaluated major histocompatibility complex (MHC) class II antigen expression in mast cells and their possible role in antigen presentation. In rats, 10% of mast cells isolated from the pleural cavity expressed MHC class II antigen; after incubation with gamma interferon (INF) 80% of the cells were positive. These findings suggest that mast ceils, in addition to their secretory function in allergic reactions, may also function as antigen presenting cells.     

CD4+CD7− T Cells: A Separate Subpopulation of Memory T Cells?

The CD7 molecule is apparently involved in T cell activation but is absent in a substantial subpopulation of human T cells under physiological and certain pathological conditions. The majority of CD7^– T cells expresses TCR / and is of CD4⁺ helper and CD45R0⁺CD45RA^– memory phenotype. After birth, percentages and absolute numbers of circulating CD7^– T cells increase significantly during aging. A number of molecules thought to be involved in organ-specific T cell homing are preferentially expressed within the subset of CD4⁺CD7^– T cells. Specific absence of CD7 antigen expression on T cells is observed in a variety of pathologic conditions such as cutaneous T cell lymphoma, HIV infection, rheumatoid arthritis, and kidney transplantation. Current in vitro results suggest that specific downregulation of CD7 antigen expression in T cells reflects a separate and stable differentiation state occurring late in the immune response. Expansion of CD7^– T cells in vivo has been found in certain diseases associated with chronically repeated T cell stimulation. The potential pathophysiological significance of this T cell subset in certain human diseases is discussed.     

Do Mesenchymal Stem Cells Modulate the Milieu of Reconstructed Bladder Wall?

To evaluate the mesenchymal stem cells (MSCs) influence on cytokines and matrix metalloproteinases (MMPs) expression in rat bladder wall regeneration. MSCs cultures from the bone marrow were established. Acellular matrices from the bladder submucosa were prepared. Bladders were reconstructed using cell-seeded (n = 5) and unseeded (n = 5) grafts. MSCs were injected into the bladder wall (n = 5), bladders were incised and MSCs were injected into the circulation (n = 5) or were left intact (n = 5). Animals were killed after 3 months. Bladder histology and immunohistochemical staining of IL-2, IL-4, IL-6, IL-10, TNF-α, TGF-β1, IFN-γ, MMP-2, and MMP-9 were done. Bladders reconstructed with cell-seeded grafts mimicked native tissue, while unseeded grafts revealed shrinkage and morphological irregularities. There were no morphological changes in bladders of other groups. Different pattern of cytokine and MMP expression was observed. Increased expression of anti-inflammatory cytokines and MMPs in bladder promotes detrusor regeneration.     

COVID-19 and T Cells: Do T Cells Really Matter?

How to cite this article: Gajjala C, Jindal, A. COVID-19 and T Cells: Do T Cells Really Matter? Indian J Crit Care Med 2023;27(1):75.     

Application of iPS in Assisted Reproductive Technology: Sperm from Somatic Cells?

Infertility is an emotionally charged problem, and it is a condition of increasing incidence. In addition, in 40% to 60% of all infertile couples, it was the male who had a problem that led to infertility. Among the male fertility problems, non-obstructive azoospermia (NOA) (caused by testis failure or impaired spermatogenesis) is the most prevalent. Despite enormous clinical and experimental efforts, treatment of this disorder—assistant reproduction technique (ART) with donor spermatozoa remains controversial. We present the hypothesis that induced pluripotent stem (iPS) cell derived spermatozoa can be a potential source for male gametes for patients with NOA; we support this with the following three evidence: the first is the generation of viable, live-born, fertile mature organism from iPS cells; the second is the successful induced differentiation of male gametes from pluripotent cells in vitro; and the last is the wide use of intracytoplasmic sperm injection (ICSI) in human assisted reproduction. If the hiPS derived spermatozoa prove practical in the generation offspring with ICSI, this method might be able to grant a new chance for NOA patients to have their genetic children with fewer emotional, ethical and legislative problems. To ensure the safety of the technology itself and the production of healthy offspring, further investigations are needed. We also suggest several laboratory and clinical approaches for testing our hypothesis.     

Chemical Reprogramming of Somatic Cells in Neural Direction: Myth or Reality?

Bulletin of Experimental Biology and Medicine - In in vitro experiments on cultures of human multipotent stem cells from the human bone arrow and dental pulp, we studied direct reprogramming...     

Application of Stem Cells in Tissue Engineering

Stem cells have become an important source of seed cells for tissue engineering because they are relatively easy to expand in vitro and can be induced to differentiate into various cell types in vitro or in vivo. In the current stage, most stem cell researches focus on in vitro studies, including in vitro induction and phenotype characterization. Our center has made a great deal of effort in the in vivo study by using stem cells as seed cells for tissue construction. We have used bone marrow s…     

How do Regulatory T Cells Work?

CD4⁺ T cells are commonly divided into regulatory T (Treg) cells and conventional T helper (Th) cells. Th cells control adaptive immunity against pathogens and cancer by activating other effector immune cells. Treg cells are defined as CD4⁺ T cells in charge of suppressing potentially deleterious activities of Th cells. This review briefly summarizes the current knowledge in the Treg field and defines some key questions that remain to be answered. Suggested functions for Treg cells include: prevention of autoimmune diseases by maintaining self-tolerance; suppression of allergy, asthma and pathogen-induced immunopathology; feto-maternal tolerance; and oral tolerance. Identification of Treg cells remains problematic, because accumulating evidence suggests that all the presently-used Treg markers (CD25, CTLA-4, GITR, LAG-3, CD127 and Foxp3) represent general T-cell activation markers, rather than being truly Treg-specific. Treg-cell activation is antigen-specific, which implies that suppressive activities of Treg cells are antigen-dependent. It has been proposed that Treg cells would be self-reactive, but extensive TCR repertoire analysis suggests that self-reactivity may be the exception rather than the rule. The classification of Treg cells as a separate lineage remains controversial because the ability to suppress is not an exclusive Treg property. Suppressive activities attributed to Treg cells may in reality, at least in some experimental settings, be exerted by conventional Th cell subsets, such as Th1, Th2, Th17 and T follicular (Tfh) cells. Recent reports have also demonstrated that Foxp3⁺ Treg cells may differentiate in vivo into conventional effector Th cells, with or without concomitant downregulation of Foxp3.     

Neuropilin-1: The Glue between Regulatory T Cells and Dendritic Cells?

The interaction between dendritic cells and regulatory T cells is critical for the maintenance of self-tolerance. In this issue of Immunity, Sarris et al. (2008) find that Neuropilin-1 contributes to the prolonged interaction of regulatory T cells with dendritic cells.     

Do Regulatory T Cells Play a Role in the Control of Homeostatic Proliferation?

The control of peripheral lymphocyte numbers is a fundamental aspect of the immune system. Regulatory T cells are involved in the suppression of autoimmune, antitumor, allergic, and other inflammatory responses, as well as in facilitating graft acceptance. In this paper, we discuss whether the control of homeostatic proliferation is another facet of the immune system that is controlled by regulatory T cells. A review of the published data connecting regulatory T cells with the control of homeostatic proliferation indicates that several key questions remain open. One of these relates to the stage at which regulatory T cells could play a role (i.e., T-cell proliferation vs. survival).     

The Source of Neointimal Cells in Vein Grafts: Does the Origin Matter?

The focus of this Commentary is the existing plasticity in the origin of neointimal vascular smooth muscle cells and endothelial cells after vein grafting.     

Secretome of Mesenchymal Bone Marrow Stem Cells: Is It Immunosuppressive or Proinflammatory?

Bulletin of Experimental Biology and Medicine - Mesenchymal stem cells (MSC) are characterized by tolerogenic potential and therefore, are used in the treatment of autoimmune diseases such as...     

Application of Serum-Free Culture Medium for Preparation of A-NK Cells

To compare the differences between proliferation and cytotoxicity of adherent natural killer （A-NK） cells cultured with serum-free medium AIMV and standard serum-containing medium in vitro, and also observe the assisting effect of IL-12 on the activation and the morphology character of IL-2-treated A-NK cells, cellular proliferation was evaluated by MTT method in vitro. The morphology of the target cells killed by A-NK cells was observed through electroscope. All of the A-NK cells cultured in serum-free medium AIMV could rapidly proliferate and keep high cytotoxicity compared with that in standard serum-containing medium. A-NK cells activated by both moderate-dose IL-2 and IL-12 were superior to the high-dose IL-2-treated A-NK cells. These data indicated that serum-free medium AIMV could replace standard serum-containing medium for culturing A-NK cells, and moderate-dose IL-2 and IL-12 could reduce side effects caused by high-dose IL-2. The study provided a new experimental basis for experimental and clinical preparation of A-NK cells. Cellular ＆ Molecular Immunology.     

Role of Natural Interferon-α Producing Cells (Plasmacytoid Dendritic Cells) in Autoimmunity

The type I interferons (IFNs) have antiviral, cytostatic and prominent immunomodulatory effects, which all are of great importance during viral infections. However, prolonged exposure of the immune system to type I IFN can break tolerance and initiate an autoimmune reaction, eventually leading to autoimmune disease. Recent observations in patients with systemic lupus erythematosus (SLE) have revealed that such individuals have endogenous IFN-α inducers, causing an ongoing IFN-α production and consequently a continuous stimulation of the immune system. These IFN-α inducers consist of small immune complexes (IC) containing DNA or RNA and act on the principal IFN-α producing cell, the natural IFN-α producing cell (NIPC), also termed the plasmacytoid dendritic cell (PDC). The NIPC/PDC is a key cell in both the innate and adaptive immune response but can also, either directly or via produced IFN-α, have a pivotal role in autoimmunity. In this review we summarize recent data concerning NIPC/PDC, including their activation, regulation, function and possible role in autoimmune diseases, especially SLE.     

Plasticity of Ectomesenchymal Stem Cells and its Ability of Producing Tissue Engineering Tooth by Recombining with Dental Epithelial Cells

1 IntroductionRecently, it has been found that human dental pulp stem cells could generate dentin-pulp complex-like structures in nude mice, but studies on tissue engineering tooth-like structures by cultured human dental epithelial and mesenchymal stem cells are still reported rarely. Ectomesenchyme is an unique structure of vertebrates embryo compose of postmigratory cephalic neural crest cells (NCC) and its derivatives. The aim of the present study was to identify and isolate the ectomesen…     

Culture of Neural Stem Cells in Calcium-alginate Microbeads

1 Introduction Recent research shows that neural stem cells may play an important role in the nerve injury reparation and nerve disease treatment. The shortage of the source and the number of NSCs, however, is the main challenge for its clinic application. In this situation, expansion of NSCs in large scale and culture in three dimensional environment are very worth of exploration. Notablely, the shear stress existed in bioreactors can cause serious cell injury especially for the shear sens…