scholarly journals ACTIVE SUPPRESSION AS A POSSIBLE MECHANISM OF TOLERANCE IN TETRAPARENTAL MICE

1973 ◽  
Vol 137 (2) ◽  
pp. 291-300 ◽  
Author(s):  
S. Michael Phillips ◽  
Thomas G. Wegmann
Keyword(s):  
Experimental System ◽  
Cell Types ◽  
Parental Cell ◽  
Spleen Cells ◽  
Cell Stage ◽  
Self Tolerance ◽  
Blocking Antibodies ◽  
Mixed Lymphocyte Reactions

Previous work has indicated that tetraparental mice, chimeric since the eight-cell stage because of embryo fusion using histoincompatible strain combinations, possess autospecific immune cells and blocking antibodies. Although this phenomenon has been demonstrated in vitro, it may have relevance to the self-tolerance shown by these mice in vivo. The experiments described here indicate that spleen cells from tetraparental mice can block mixed lymphocyte reactions between the two parental cell types, but not between unrelated strains. Furthermore, this suppressive ability is not affected by an otherwise effective treatment of the tetraparental spleen cells with anti-θ antibody and complement. The in vitro experimental system elaborated here should help to characterize the cell type responsible for the suppression.

scholarly journals Regulatory mechanisms in cell-mediated immune responses. II. A genetically restricted suppressor of mixed lymphocyte reactions released by alloantigen-activated spleen cells.

1975 ◽  
Vol 142 (6) ◽  
pp. 1391-1402 ◽  
Author(s):  
S S Rich ◽  
R R Rich
Keyword(s):  
Immune Responses ◽  
Mixed Lymphocyte Reaction ◽  
Antigenic Specificity ◽  
Spleen Cells ◽  
Suppressor Factor ◽  
Homology Relationship ◽  
Cell Suppression ◽  
Mixed Lymphocyte Reactions

The mechanism of alloantigen-activated spleen cell suppression of mixed lymphocyte reaction (MLR) is explored in this report. Activated murine suppressor spleen cells elaborated a soluble noncytotoxic factor which suppressed MLR responses by 55-95%. Generation of suppressor factor required both in vivo alloantigen sensitization and specific in vitro restimulation. Suppressor factor was not produced by activated spleen cells which had been treated with anti-Thy-1.2 serum and complement. Antigenic specificity toward alloantigens of the stimulator cells was not demonstrable. In contrast, suppressor factor effectively inhibited MLR response only of responder cells of those strains that shared the D-end and the I-C subregion of the H-2 complex with the cells producing suppressor factor. Therefore, active suppression appears to require an MHC-directed homology relationship between regulating and responder cells in MLR.

Analysis of clonal restriction of cell mingling in Xenopus

1985 ◽  
Vol 312 (1153) ◽  
pp. 57-65 ◽  
Keyword(s):  
Horseradish Peroxidase ◽  
Cell Types ◽  
Cell Group ◽  
Cell Stage ◽  
Wide Range ◽  
Cell Groups ◽  
Cell Layers ◽  
Single Blastomeres

Cell fates were traced by injecting horseradish peroxidase into single blastomeres of Xenopus embryos at 2- to 512-cell stages. At later stages the number, types and locations of all labelled progeny were observed. Progeny of a single labelled ancestral cell divided coherently until the 12th cell generation, the onset of gastrulation, and then dispersed and mingled with unlabelled cells. Cell mingling was restricted at mediolateral and anterior—posterior boundaries. These boundaries were always respected by progeny of any blastomere labelled at the 512-cell stage but they were frequently crossed by progeny of blastomeres labelled at the 256-cell or earlier stages. The boundaries defined seven morphological compartments each populated exclusively by a group of ancestral cells at the 512-cell stage. Each blastomere that contributed progeny to the nervous system also gave rise to a wide range of cell types in all three primary germ cell layers but the clone was restricted to a single compartment. Analysis of clonal restriction of cell mingling was done in vitro . Twenty to thirty blastomeres were excised from one ancestral cell group at the 512-cell stage and combined in vitro with 20-30 blastomeres from another group. One group of blastomeres labelled with horseradish peroxidase was placed in contact with another group of unlabelled blastomeres, maintained in vitro for up to 2 days, and then processed histologically to show the distribution of labelled and unlabelled cells. Mingling was significantly greater in combinations of two of the same ancestral cell groups than in combinations of two different ancestral cell groups. A similar result was observed when a single labelled cell was combined with either the same or different ancestral cells. In all experiments the cells were significantly larger in combinations of different ancestral cell groups, indicating that they had undergone fewer divisions. These results are consistent with the hypothesis that boundaries observed in vivo are lines of clonal restriction formed by mutual inhibition of cell motility and cell division following contact between progeny of different ancestral cell groups.

The allocation of early blastomeres to the ectoderm and endoderm is variable in the sea urchin embryo

Development ◽  
1997 ◽  
Vol 124 (11) ◽  
pp. 2213-2223 ◽  
Author(s):  
C.Y. Logan ◽  
D.R. McClay
Keyword(s):  
Sea Urchin ◽  
Low Frequency ◽  
Initial Step ◽  
Cell Types ◽  
Lytechinus Variegatus ◽  
Cell Fates ◽  
Cell Stage ◽  
Sea Urchin Embryo

During sea urchin development, a tier-to-tier progression of cell signaling events is thought to segregate the early blastomeres to five different cell lineages by the 60-cell stage (E. H. Davidson, 1989, Development 105, 421–445). For example, the sixth equatorial cleavage produces two tiers of sister cells called ‘veg1′ and ‘veg2,’ which were projected by early studies to be allocated to the ectoderm and endoderm, respectively. Recent in vitro studies have proposed that the segregation of veg1 and veg2 cells to distinct fates involves signaling between the veg1 and veg2 tiers (O. Khaner and F. Wilt, 1991, Development 112, 881–890). However, fate-mapping studies on 60-cell stage embryos have not been performed with modern lineage tracers, and cell interactions between veg1 and veg2 cells have not been shown in vivo. Therefore, as an initial step towards examining how archenteron precursors are specified, a clonal analysis of veg1 and veg2 cells was performed using the lipophilic dye, DiI(C16), in the sea urchin species, Lytechinus variegatus. Both veg1 and veg2 descendants form archenteron tissues, revealing that the ectoderm and endoderm are not segregated at the sixth cleavage. Also, this division does not demarcate cell type boundaries within the endoderm, because both veg1 and veg2 descendants make an overlapping range of endodermal cell types. The allocation of veg1 cells to ectoderm and endoderm during cleavage is variable, as revealed by both the failure of veg1 descendants labeled at the eighth equatorial division to segregate predictably to either tissue and the large differences in the numbers of veg1 descendants that contribute to the ectoderm. Furthermore, DiI-labeled mesomeres of 32-cell stage embryos also contribute to the endoderm at a low frequency. These results show that the prospective archenteron is produced by a larger population of cleavage-stage blastomeres than believed previously. The segregation of veg1 cells to the ectoderm and endoderm occurs relatively late during development and is unpredictable, indicating that later cell position is more important than the early cleavage pattern in determining ectodermal and archenteron cell fates.

scholarly journals PARTICIPATION OF THREE CELL TYPES IN THE ANTI-SHEEP RED BLOOD CELL RESPONSE IN VITRO

1971 ◽  
Vol 133 (3) ◽  
pp. 520-533 ◽  
Author(s):  
Teresita Tan ◽  
Julius Gordon
Keyword(s):  
Blood Cell ◽  
Red Blood Cell ◽  
Cell Types ◽  
Culture Conditions ◽  
Cotton Wool ◽  
Spleen Cells ◽  
C57bl Mice ◽  
Combined Cultures

Spleen cells of unprimed CBA mice were shown to produce anti-sheep red blood cell antibodies comparable in amount in vivo and in vitro. Under identical culture conditions spleen cells of C57BL mice did not respond. CBA spleen cells, passed through columns of cotton wool (CBAf), were equally inactive in vitro. However combined cultures containing both CBAf and C57BL cells yielded as many or more plaque-forming cells than the same number of unfractionated CBA spleen cells. Analysis of the contribution of each cell population to the synthesis of antibody in the combined cultures has disclosed the participation of three cell types. A thymus-dependent, radiosensitive cell was derived from the CBAf population, while the C57BL was the source of the precursor of the antibody-forming cell and of a radioresistant cell. The latter two were partially separated in a Staput apparatus.

2 THE IN VIVO DEVELOPMENTAL POTENTIAL OF PORCINE SKIN-DERIVED PROGENITORS

2012 ◽  
Vol 24 (1) ◽  
pp. 112 ◽  
Author(s):  
M. T. Zhao ◽  
X. Yang ◽  
K. Lee ◽  
J. Mao ◽  
J. M. Teson ◽  
...  
Keyword(s):  
Stem Cells ◽  
Cell Lineage ◽  
Pcr Amplification ◽  
Cell Types ◽  
Blastocyst Stage ◽  
Cell Stage ◽  
Germ Layers ◽  
Developmental Potential

Skin-derived progenitors (SKP) are capable of generating both neural and mesodermal progeny in vitro: neurons, Schwann cells, adipocytes, osteocytes and chondrocytes, thus exhibiting characteristics similar to embryonic neural crest stem cells. SKP show distinct transcriptional profiles when compared with neurospheres/neural stem cells in the central nervous system (CNS) and skin-derived fibroblasts, indicating a novel type of multipotent stem cell derived from the dermis of the skin. However, it remains unclear whether SKP cells can produce ectoderm and mesoderm lineages or other germ layers in vivo, although oocyte-like structures can be induced from porcine SKP in vitro. Embryonic chimeras are a well-established tool for investigating cell lineage determination and cell potency through normal embryonic development. Thus the purpose of this study was to investigate the in vivo developmental potential of porcine SKP by chimera production. Porcine SKP cells and fibroblasts were isolated from the back skin of Day 35 to 50 GFP transgenic fetuses. Individual cells or clusters of male GFP transgenic SKP and skin-derived GFP-expressing fibroblasts were injected into pre-compact in vitro-fertilized (IVF) embryos, respectively and then transferred into corresponding surrogates 24 h post-injection. Additional injected embryos were cultured in PZM3 medium for another 2 days until the blastocyst stage and subsequently stained with Hoechst 33342. Interestingly, in some of the chimeras the injected SKP cells migrated and dispersed into different locations of the host blastocysts, whereas in others they remained as a cluster of cells within the chimeric blastocysts. In contrast, the fibroblast cells were not observed to spread around the host blastocysts. Two chimeric fetuses were recovered at the middle of gestation and a litter of viable piglets was born. Genomic DNA was extracted from various tissues of chimeric piglets and subjected to PCR amplification. Two chimeric fetuses and 2 out of 6 piglets carried the GFP transgene in SKP-derived chimeras, but GFP was not present in the fibroblast-derived chimeric fetuses (n = 6). Surprisingly, the GFP transgene was present in various tissues of two SKP-derived chimeric piglets, including lung, heart, liver, artery, kidney, brain, skin, muscle, gut, ovary, pancreas and stomach, thus representing the 3 germ layers (ectoderm, mesoderm and endoderm). In addition, SRY was detected in several tissues of the two GFP-positive female chimeric piglets, confirming the chimerism of these piglets. Therefore, it appears that porcine SKP can contribute to various cell types of the 3 germ layers and have a broader developmental potency than previously expected. Alternatively, pre-compact (4-cell and 8-cell stage) embryos may provide a unique environment for reprogramming skin-derived progenitors into a more primitive state by the process of embryonic compaction. This study was funded by NIH National Center for Research Resources (R01RR013438) and Food for the 21st Century at the University of Missouri.

Ultrastructural observations on the in vitro cytoadherence of Plasmodium falciparum infected red blood cells

1990 ◽  
Vol 48 (3) ◽  
pp. 914-915
Author(s):  
D.J.P. Ferguson ◽  
A.R. Berendt ◽  
J. Tansey ◽  
K. Marsh ◽  
C.I. Newbold
Keyword(s):  
Plasmodium Falciparum ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Umbilical Vein ◽  
Cell Types ◽  
Amelanotic Melanoma ◽  
Cytoplasmic Process ◽  
Umbilical Vein Endothelial Cells

In human malaria, the most serious clinical manifestation is cerebral malaria (CM) due to infection with Plasmodium falciparum. The pathology of CM is thought to relate to the fact that red blood cells containing mature forms of the parasite (PRBC) cytoadhere or sequester to post capillary venules of various tissues including the brain. This in vivo phenomenon has been studied in vitro by examining the cytoadherence of PRBCs to various cell types and purified proteins. To date, three Ijiost receptor molecules have been identified; CD36, ICAM-1 and thrombospondin. The specific changes in the PRBC membrane which mediate cytoadherence are less well understood, but they include the sub-membranous deposition of electron-dense material resulting in surface deformations called knobs. Knobs were thought to be essential for cytoadherence, lput recent work has shown that certain knob-negative (K-) lines can cytoadhere. In the present study, we have used electron microscopy to re-examine the interactions between K+ PRBCs and both C32 amelanotic melanoma cells and human umbilical vein endothelial cells (HUVEC).We confirm previous data demonstrating that C32 cells possess numerous microvilli which adhere to the PRBC, mainly via the knobs (Fig. 1). In contrast, the HUVEC were relatively smooth and the PRBCs appeared partially flattened onto the cell surface (Fig. 2). Furthermore, many of the PRBCs exhibited an invagination of the limiting membrane in the attachment zone, often containing a cytoplasmic process from the endothelial cell (Fig. 2).

Epithelial Organotypic Cultures: A Viable Model to Address Mechanisms of Carcinogenesis by Epitheliotropic Viruses

2018 ◽  
Vol 18 (4) ◽  
pp. 246-255 ◽  
Author(s):  
Lara Termini ◽  
Enrique Boccardo
Keyword(s):  
Three Dimensional ◽  
Cell Types ◽  
Experimental Models ◽  
Biological Research ◽  
Specific Gene ◽  
Specific Cell ◽  
Organotypic Cultures ◽  
Skin Physiology

In vitro culture of primary or established cell lines is one of the leading techniques in many areas of basic biological research. The use of pure or highly enriched cultures of specific cell types obtained from different tissues and genetics backgrounds has greatly contributed to our current understanding of normal and pathological cellular processes. Cells in culture are easily propagated generating an almost endless source of material for experimentation. Besides, they can be manipulated to achieve gene silencing, gene overexpression and genome editing turning possible the dissection of specific gene functions and signaling pathways. However, monolayer and suspension cultures of cells do not reproduce the cell type diversity, cell-cell contacts, cell-matrix interactions and differentiation pathways typical of the three-dimensional environment of tissues and organs from where they were originated. Therefore, different experimental animal models have been developed and applied to address these and other complex issues in vivo. However, these systems are costly and time consuming. Most importantly the use of animals in scientific research poses moral and ethical concerns facing a steadily increasing opposition from different sectors of the society. Therefore, there is an urgent need for the development of alternative in vitro experimental models that accurately reproduce the events observed in vivo to reduce the use of animals. Organotypic cultures combine the flexibility of traditional culture systems with the possibility of culturing different cell types in a 3D environment that reproduces both the structure and the physiology of the parental organ. Here we present a summarized description of the use of epithelial organotypic for the study of skin physiology, human papillomavirus biology and associated tumorigenesis.

scholarly journals Heme Oxygenase-1 Deficiency and Oxidative Stress: A Review of 9 Independent Human Cases and Animal Models

2021 ◽  
Vol 22 (4) ◽  
pp. 1514 ◽  
Author(s):  
Akihiro Yachie
Keyword(s):  
Oxidative Stress ◽  
Animal Models ◽  
Heme Oxygenase ◽  
Inflammatory Diseases ◽  
Cell Types ◽  
Pharmacological Intervention ◽  
Heme Oxygenase 1 ◽  
Inflammatory Reactions

Since Yachie et al. reported the first description of human heme oxygenase (HO)-1 deficiency more than 20 years ago, few additional human cases have been reported in the literature. A detailed analysis of the first human case of HO-1 deficiency revealed that HO-1 is involved in the protection of multiple tissues and organs from oxidative stress and excessive inflammatory reactions, through the release of multiple molecules with anti-oxidative stress and anti-inflammatory functions. HO-1 production is induced in vivo within selected cell types, including renal tubular epithelium, hepatic Kupffer cells, vascular endothelium, and monocytes/macrophages, suggesting that HO-1 plays critical roles in these cells. In vivo and in vitro studies have indicated that impaired HO-1 production results in progressive monocyte dysfunction, unregulated macrophage activation and endothelial cell dysfunction, leading to catastrophic systemic inflammatory response syndrome. Data from reported human cases of HO-1 deficiency and numerous studies using animal models suggest that HO-1 plays critical roles in various clinical settings involving excessive oxidative stress and inflammation. In this regard, therapy to induce HO-1 production by pharmacological intervention represents a promising novel strategy to control inflammatory diseases.

scholarly journals MyD88 Is Not Required for Muscle Injury-Induced Endochondral Heterotopic Ossification in a Mouse Model of Fibrodysplasia Ossificans Progressiva

Biomedicines ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 630
Author(s):  
Huili Lyu ◽  
Cody M. Elkins ◽  
Jessica L. Pierce ◽  
C. Henrique Serezani ◽  
Daniel S. Perrien
Keyword(s):  
Heterotopic Ossification ◽  
Muscle Injury ◽  
Cell Types ◽  
Fibrodysplasia Ossificans Progressiva ◽  
Inflammatory Signaling ◽  
Conditional Deletion ◽  
Pathway Crosstalk ◽  
Multiple Cell

Excess inflammation and canonical BMP receptor (BMPR) signaling are coinciding hallmarks of the early stages of injury-induced endochondral heterotopic ossification (EHO), especially in the rare genetic disease fibrodysplasia ossificans progressiva (FOP). Multiple inflammatory signaling pathways can synergistically enhance BMP-induced Smad1/5/8 activity in multiple cell types, suggesting the importance of pathway crosstalk in EHO and FOP. Toll-like receptors (TLRs) and IL-1 receptors mediate many of the earliest injury-induced inflammatory signals largely via MyD88-dependent pathways. Thus, the hypothesis that MyD88-dependent signaling is required for EHO was tested in vitro and in vivo using global or Pdgfrα-conditional deletion of MyD88 in FOP mice. As expected, IL-1β or LPS synergistically increased Activin A (ActA)-induced phosphorylation of Smad 1/5 in fibroadipoprogenitors (FAPs) expressing Alk2R206H. However, conditional deletion of MyD88 in Pdgfrα-positive cells of FOP mice did not significantly alter the amount of muscle injury-induced EHO. Even more surprisingly, injury-induced EHO was not significantly affected by global deletion of MyD88. These studies demonstrate that MyD88-dependent signaling is dispensable for injury-induced EHO in FOP mice.

scholarly journals Adipose and Muscle Cell Co-Culture System: A Novel In Vitro Tool to Mimic the In Vivo Cellular Environment

Biology ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 6
Author(s):  
Palaniselvam Kuppusamy ◽  
Dahye Kim ◽  
Ilavenil Soundharrajan ◽  
Inho Hwang ◽  
Ki Choon Choi
Keyword(s):  
Drug Development ◽  
Culture System ◽  
Cell Types ◽  
Culture Cell ◽  
In Vitro Techniques ◽  
Culture Systems ◽  
Complex Interactions ◽  
Cellular Environment

A co-culture system allows researchers to investigate the complex interactions between two cell types under various environments, such as those that promote differentiation and growth as well as those that mimic healthy and diseased states, in vitro. In this paper, we review the most common co-culture systems for myocytes and adipocytes. The in vitro techniques mimic the in vivo environment and are used to investigate the causal relationships between different cell lines. Here, we briefly discuss mono-culture and co-culture cell systems and their applicability to the study of communication between two or more cell types, including adipocytes and myocytes. Also, we provide details about the different types of co-culture systems and their applicability to the study of metabolic disease, drug development, and the role of secretory factors in cell signaling cascades. Therefore, this review provides details about the co-culture systems used to study the complex interactions between adipose and muscle cells in various environments, such as those that promote cell differentiation and growth and those used for drug development.

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