Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0029713 (immaturity)
 4,335 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

IgG, IgA, and IgE production by newborn B cells is limited both in vivo and in vitro in various activation conditions, whereas IgM production is readily detectable. It has been suggested that the Ig heavy chain switch inability could be the consequence of T and B cell immaturity. As the interaction between CD40 (expressed on B cells) and its ligand CD40-L (expressed on activated T cells) triggers a key signal required for isotype switching, we studied the expression and function of these two components in normal fetuses, newborns, and infants, compared with adults. CD40-L expression was not inducible in 28 of 30 specimens of newborn cord-blood T cells following incubation with PMA and ionomycin, whereas activation markers such as CD69 were inducible. CD40-L expression was triggered by activation of T cells from infants > 3 wk of age. Surprisingly, T cells from 19- to 28-wk-old fetuses also expressed CD40-L following activation. CD40-L expression on newborn T lymphocytes was induced on T cell lines generated in the presence of PHA and maintained with IL-2 following further stimulation with PMA and ionomycin. CD40-L mRNA transcripts and intracytoplasmic protein expression following activation of newborn T cells were strongly decreased, leading to undetectable protein membrane detection. These results point to a possible transcriptional down-regulation of CD40-L expression by neonatal T lymphocytes. In addition, fetal and cord-blood B cells were poorly able to switch to IgG or IgA by stimulation with CD40 agonists (Ab or soluble CD40-L) in the presence of IL-4 or IL-10 as also detected with surface IgD+ adult B cells. Both phenomena could contribute to the neonatal Ig switch inability, although distinct underlying regulatory mechanisms are probably involved, as suggested by different in vivo time courses.
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PMID:Undetectable CD40 ligand expression on T cells and low B cell responses to CD40 binding agonists in human newborns. 753 Jul 39

The physiologically low or absent IgG2 responses of infants have been attributed to T or B cell functional immaturity. We have analyzed the capacity of adult and neonatal T lymphocytes to secrete IgG2 switch factor (IgG2-SF) and the capacity of neonatal B cells to respond to such factors. The IgG2-SF capacity was assessed on CD40-activated naive B cells, measuring IgG2 by ELISA in supernatants of cultures performed in the presence of IL-10. T cells secreted IgG2-SF together with IL-2 and IFN-gamma, after activation with a combination of anti-CD2, anti-CD28 and phorbol myristate acetate (Th1-like activation). In contrast, activation with anti-CD3 and anti-CD28, which yielded IL-4 and IL-10 but neither IL-2 nor IFN-gamma (Th2-like activation), did not result in the secretion of IgG2-SF. The supernatant of activated neonatal T cells contained IgG2-SF. Neonates' B cells produced almost as much IgG2 as did naive adult B cells. The effect of IgG2-SF was further demonstrated by its ability to induce 3-15% of CD40-activated naive B cells to express cytoplasmic IgG2 regardless of the presence of IL-10. This study demonstrates that: (i) IgG2 switch can be T cell dependent in humans, (ii) IgG2-SF is produced with Th1-like cytokines and (iii) low IgG2 responses in infants do not result from either an inability of T cells to produce IgG2-SF or an inability of B cells to undergo IgG2 switch in vitro.
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PMID:Delayed IgG2 humoral response in infants is not due to intrinsic T or B cell defects. 892 28

Aspirin is the most commonly used analgesic and antiinflammatory agent. In this study, at physiological concentrations, it profoundly inhibited CD40, CD80, CD86, and MHC class II expression on murine, GM-CSF + IL-4 stimulated, bone marrow-derived myeloid dendritic cells (DC). CD11c and MHC class I expression were unaffected. The inhibitory action was dose dependent and was evident at concentrations higher than those necessary to inhibit PG synthesis. Experiments with indomethacin revealed that the effects of aspirin on DC maturation were cyclooxygenase independent. Nuclear extracts of purified, aspirin-treated DC revealed a decreased NF-kappaB DNA-binding activity, whereas Ab supershift analysis indicated that aspirin targeted primarily NF-kappaB p50. Unexpectedly, aspirin promoted the generation of CD11c+ DC, due to apparent suppression of granulocyte development. The morphological and ultrastructural appearance of aspirin-treated cells was consistent with immaturity. Aspirin-treated DC were highly efficient at Ag capture, via both mannose receptor-mediated endocytosis and macropinocytosis. By contrast, they were poor stimulators of naive allogeneic T cell proliferation and induced lower levels of IL-2 in responding T cells. They also exhibited impaired IL-12 expression and did not produce IL-10 after LPS stimulation. Assessment of the in vivo function of aspirin-treated DC, pulsed with the hapten trinitrobenzenesulfonic acid, revealed an inability to induce normal cell-mediated contact hypersensitivity, despite the ability of the cells to migrate to T cell areas of draining lymphoid tissue. These data provide new insight into the immunopharmacology of aspirin and suggest a novel approach to the manipulation of DC for therapeutic application.
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PMID:Aspirin inhibits in vitro maturation and in vivo immunostimulatory function of murine myeloid dendritic cells. 1139 Apr 49

In a search for genes expressed by dendritic cells (DC), we have cloned cDNAs encoding different forms of an asialoglycoprotein receptor (ASGPR). The DC-ASGPR represents long and short isoforms of human macrophage lectin, a Ca(2+)-dependent type II transmembrane lectin displaying considerable homology with the H1 and H2 subunits of the hepatic ASGPR. Immunoprecipitation from DC using an anti-DC-ASGPR mAb yielded a major 40-kDa protein with an isoelectric point of 8.2. DC-ASGPR mRNA was observed predominantly in immune tissues. Both isoforms were detected in DC and granulocytes, but not in T, B, or NK cells, or monocytes. DC-ASGPR species were restricted to the CD14-derived DC obtained from CD34(+) progenitors, while absent from the CD1a-derived subset. Accordingly, both monocyte-derived DC and tonsillar interstitial-type DC expressed DC-ASGPR protein, while Langerhans-type cells did not. Furthermore, DC-ASGPR is a feature of immaturity, as expression was lost upon CD40 activation. In agreement with the presence of tyrosine-based and dileucine motifs in the intracytoplasmic domain, mAb against DC-ASGPR was rapidly internalized by DC at 37 degrees C. Finally, intracellular DC-ASGPR was localized to early endosomes, suggesting that the receptor recycles to the cell surface following internalization of ligand. Our findings identify DC-ASGPR/human macrophage lectin as a feature of immature DC, and as another lectin important for the specialized Ag-capture function of DC.
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PMID:Immature human dendritic cells express asialoglycoprotein receptor isoforms for efficient receptor-mediated endocytosis. 1169 50

The neonate typically exhibits an immature immune response compared with the adult, yet the fetus is able to generate antigen-specific responses from around 20-22 weeks of gestation. Although antigen-presenting cells (APCs) must have attained the necessary level of maturity to support this, very little is known about the phenotype and function of these populations during human fetal development. Whole blood flow cytometry was, therefore, utilised to phenotype fetal/neonatal circulating monocytes and B cells throughout the third trimester of pregnancy. The percentage of B cells (CD19+) expressing MHC Class II was comparable to the adult at all gestations, whereas the percentage of MHC Class II-positive monocytes (CD14+) increased significantly over gestation (P=0.0008) but remained lower than the adult at term. In contrast, the percentage of CD40+ or CD86+ fetal/neonatal monocytes at all gestations was comparable to the adult, but there was a maturational increase in the percentage of CD40+ or CD86+ B cells (P=0.007) to adult levels by term. The expression of CD14 itself (mean fluorescence intensity, MFI) showed a trend to increase over gestation (P=0.062) and, although all CD14+ cells expressed other receptors associated with innate immune responses (CD11b and CD35), there was fluctuation in the intensity of expression over gestation. Functional immaturity of neonatal antigen-specific immune responses could be associated with reduced co-stimulation provided by both monocytes (via reduced MHC Class II) and B cells (via reduced CD40 and CD86); altered innate responsiveness of monocytes could also contribute.
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PMID:Phenotype of fetal monocytes and B lymphocytes during the third trimester of pregnancy. 1210 83

There are reports of immaturity of the neonatal immune system, which may explain the low incidence of graft-versus-host-disease (GVHD) after cord blood transplantation. The CD40 ligand (CD40L)-CD40 interaction is important in regulating the cellular immune response. We hypothesized that the neonatal immune system may show immaturity in this interaction. We studied the function of the CD40L-CD40 interaction in the T-cell interaction with B cells and monocytes in cord blood compared with adult blood in vitro. Consistent with previous reports, CD4+ T cells do not express CD40L after T-cell activation. In whole blood, adult monocytes, but not neonatal monocytes, were activated following T-cell activation. However, the activation of adult monocytes was not dependent on the CD40L-CD40 interaction. Using the CD40L trimer (Lt), we showed that cord B cells have comparable responses to CD40 ligation to those of the adult B cells. Both cord and adult monocytes do not respond as well as B cells and this is probably related to low density of expression of CD40. However, interferon-gamma up-regulated CD40 on adult monocytes but not on cord monocytes. This potentiated the adult monocyte response to CD40 ligation by CD40Lt. Our findings suggest that the neonatal CD40L-CD40 pair is immature in the cellular immune response involving monocytes and that interferon-gamma fails to activate neonatal monocytes for a response to CD40L. These findings suggest that in the inflammatory microenvironment of cord blood transplantation neonatal monocytes may play a minor role in the effector arm of the immune response. This finding may be one of several mechanisms for the low incidence of GVHD that is observed following cord blood transplantation. Also the ligand-receptor immaturity may contribute to the increased susceptibility of newborns to certain infections.
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PMID:Potential immaturity of the T-cell and antigen-presenting cell interaction in cord blood with particular emphasis on the CD40-CD40 ligand costimulatory pathway. 1531 33

Monocyte-derived dendritic cells (DCs) were used as an in vitro model of myeloid DCs in order to determine a minimum marker pattern with which to characterize and distinguish different stages of DC activation and maturation. Phenotypic changes induced on immature DCs by two prototypic stimuli, poly I:C and CD40 ligation, were first examined. Both elicited HLA-DR, CD40, CD86 and CXCR4 upregulation, and CCR5 downregulation, but only CD40 ligand-stimulated DCs became CD83(+)\CCR7(+), whereas poly I:C-stimulated DCs expressed lower CD83 levels and were mostly CCR7(--). CD40 ligation and poly I:C elicited increased production of inflammatory cytokines interleukin (IL)-6 and tumor necrosis factor-alpha, of IL-10 and the CCL5 chemokine, but profiles differed as to higher IL-10, IL-12 and CCL22 (a CCR4 ligand important for T cell recruitment) levels for the former, and of CCL4 and CCL5 for the latter. Thus, a limited set of phenotypic markers, cytokine and chemokine production assays, may be used to distinguish the three stages in the life of DCs: immaturity, activation and full maturation. The ability of purified protein derivative-loaded DCs to stimulate autologous T cells to produce IL-2, IL-4 and interferon-gamma indeed depended on their activation stage and endocytic activity, which decreased upon maturation. We then examined whether ligation of CD4, CCR5 and\or CXCR4, the receptor and coreceptors of human immunodeficiency virus envelope gp120, respectively, affected DC activation or maturation, neither a monoclonal antibody to the gp120-binding site on CD4 nor CCL5 nor CXCL12, the natural ligands of CCR5 and CXCR4, respectively, nor gp120 altered the DC activation and maturation processes.
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PMID:Double-stranded RNA stimulation or CD40 ligation of monocyte-derived dendritic cells as models to study their activation and maturation process. 1531 72

Phenotypically "immature" dendritic cells (DCs), defined by low cell surface CD40, CD80, and CD86 can elicit host immune suppression in allotransplantation and autoimmunity. Herein, we report the most direct means of achieving phenotypic immaturity in NOD bone marrow-derived DCs aiming at preventing diabetes in syngeneic recipients. CD40, CD80, and CD86 cell surface molecules were specifically down-regulated by treating NOD DCs ex vivo with a mixture of antisense oligonucleotides targeting the CD40, CD80, and CD86 primary transcripts. The incidence of diabetes was significantly delayed by a single injection of the engineered NOD DCs into syngeneic recipients. Insulitis was absent in diabetes-free recipients and their splenic T cells proliferated in response to alloantigen. Engineered DC promoted an increased prevalence of CD4(+)CD25(+) T cells in NOD recipients at all ages examined and diabetes-free recipients exhibited significantly greater numbers of CD4(+)CD25(+) T cells compared with untreated NOD mice. In NOD-scid recipients, antisense-treated NOD DC promoted an increased prevalence of these putative regulatory T cells. Collectively, these data demonstrate that direct interference of cell surface expression of the major costimulatory molecules at the transcriptional level confers diabetes protection by promoting, in part, the proliferation and/or survival of regulatory T cells. This approach is a useful tool by which DC-mediated activation of regulatory T cells can be studied as well as a potential therapeutic option for type 1 diabetes.
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PMID:Antisense oligonucleotides down-regulating costimulation confer diabetes-preventive properties to nonobese diabetic mouse dendritic cells. 1538 62

It is highly desirable that immature dendritic cells (DC) used for tolerance induction maintain steady immature state with predominant interleukin (IL)-10 production. In this study, we attempted to develop DC with durable immaturity and other tolerogenic features by using dexamethasone (Dex). We found DC derived from human monocytes in the presence of 10(-7) m Dex were negative for CD1a. Compared with control transduced DC (Ctrl-DC), Dex-DC expressed lower CD40, CD80 and CD86 but equivalent human leucocyte antigen-DR. Both immature Dex- and Ctrl-DC did not express CD83. Nevertheless, upon stimulation of lipopolysaccharide (LPS) or CD40 ligand, the expression of CD40, CD80, CD83 and CD86 was upregulated on Ctrl-DC but not on Dex-DC. The immaturity of Dex-DC was durable following Dex removal. Interestingly, Dex-DC maintained production of large amount of IL-10 and little IL-12 five days after Dex removed. Further study indicated that high-level IL-10 production by Dex-DC was associated with high-level phosphorylation of extracellular signal-regulated kinase (ERK) as blockade of this enzyme markedly attenuated IL-10 production. Furthermore, Dex-DC sustained the capability of high phosphorylation of ERK and IL-10 production 5 days after Dex removal. In addition, Dex-DC had significantly lower activity in stimulating T-cell proliferation. Neutralization of IL-10, to some extent, promoted DC maturation activated by LPS, as well as T-cell stimulatory activity of Dex-DC. The above findings suggest that IL-10-producing Dex-DC with durable immaturity are potentially useful for induction of immune tolerance.
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PMID:Dexamethasone induces IL-10-producing monocyte-derived dendritic cells with durable immaturity. 1609 Nov 24

Bone marrow-derived mesenchymal stem cells (BM-MSC) are currently being investigated in preclinical and clinical settings because of their self-renewal and multipotent differentiative capacity or their immunosuppressive function. However, BM may be detrimental because of the highly invasive donation procedure and BM-MSC decline with age. Therefore, MSC derived from other sources have been considered as an alternative. However, there is only limited knowledge on their immunomodulatory properties. Human umbilical cord blood (UCB) cells are good substitutes for BM-MSC because of the immaturity of newborn cells. In this study, we successfully isolated MSC from UCB. The morphological phenotypes, cell cycle status, surface markers and differentiation potential of these clonally expanded cells are consistent with BM-MSC. Furthermore, UCB-MSC expanded in vitro retain low immunogenicity and an immunomodulatory effect. Flow cytometry analysis showed that UCB-MSC did not express CD40, CD40 ligand, CD80, CD86 and major histocompatibility complex class II molecules. We have demonstrated that UCB-MSC are incapable of inducing allogeneic peripheral blood mononuclear cell (PBMC) proliferation and have a dose-dependent inhibition of PBMC immune responses in mixed lymphocyte reactions (MLR) and phytohaemagglutinin activation assays, even after interferon-gamma treatment. Additionally, we have found that UCB-MSC can suppress the function of mature dendritic cells. Using transwell systems, we have demonstrated an inhibition mechanism that depends on both cell contact and soluble factors. Based on the findings we conclude that banked UCB could serve as a potential alternative source of MSC for allogeneic application in the future.
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PMID:The immunomodulatory activity of human umbilical cord blood-derived mesenchymal stem cells in vitro. 1862 25


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