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H Zola

Publications and source records attributed to H Zola.

At least 37 records · Page 2Linked to original sources
PubMed2001

Identification of soluble transforming growth factor-beta receptor III (sTbetaIII) in rat milk.

Transforming growth factor-beta (TGF-beta) is present at high concentrations in maternal milk. In milk TGF-beta2 is the predominant isoform. For function TGF-beta2 requires TbetaRIII to facilitate efficient binding to the TGF-beta receptor types I and II signalling complex. We have shown that TGF-beta receptor types I (TbetaRI), II (TbetaRII) and III (TbetaRIII) are coexpressed in the suckling rat intestine. Immunostaining for TbetaRIII was also observed in the intestinal lumen prior to weaning. TbetaRIII (or betaglycan) has been reported in serum, cell culture medium and extracellular matrix. To determine whether a soluble form of TbetaRIII is present in milk, the rat milk aqueous phase was analysed by slot-blot and Western blot. Soluble TbetaRIII was detected in milk throughout lactation. Western blot analysis of rat milk revealed a high molecular weight band of glycosylated protein of >200 kDa, with a core protein of approximately 110-120 kDa that comigrated with recombinant TbetaRIII. Immunoabsorption of soluble TbetaRIII (sTbetaRIII) from milk resulted in partial depletion of active TGF-beta from milk, suggesting that the receptor may interact with ligand in milk. In addition rat pups suckled on mother's milk demonstrated an enhanced labelling of TbetaRIII in the gut, as compared with pups fed on a rat milk substitute (RMS). These findings suggest that milk sTbetaRIII is functional, and may modulate milk-derived TGF-beta function in the developing intestine.

Animals↗
PubMed2001

CD antigens 2001.

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Antigens, CD↗
PubMed2001

Human leukocyte differentiation antigens as therapeutic targets: the CD molecules and CD antibodies.

The cell membrane presents an attractive target in a number of different disease situations. Most obviously, malignant cells may be killed by damaging their cell membranes. There are also more subtle, though effective, ways of rendering cells harmless by engaging proteins at the cell surface. The cells of the immune system may be targeted, for example to stop a damaging immune reaction, such as acute inflammation or rejection of a transplanted organ. If we are to make the best use of the opportunities to modulate disease by targeting the cell membrane, we need a detailed understanding of the many proteins, glycoproteins and glycolipids that are attached to or inserted in the cell membrane. The CD (cluster of differentiation) Workshops, more properly known as the HLDA (Human Leukocyte Differentiation Antigens) Workshops have, since 1982, focussed on the study of the membrane molecules of leukocytes, including the major cells of the immune system and malignant cells derived from them. The scope has extended to molecules on endothelium which are important in interaction with leukocytes. Many of the molecules characterised as leukocyte antigens are also expressed on other tissue. The approaches developed by the HLDA Workshops are useful in the study of the molecular composition and function of cells of other organ systems. Some of the antibodies produced in order to study the CD molecules have proved useful as therapeutic agents. This review describes the CD system, how it has developed and what it means and introduces the field of therapy based on antibodies against CD or similar molecules. The author is responsible for organising the next (8th) HLDA Workshop and invites readers to suggest ways in which the therapeutic relevance of the Workshop may be enhanced.

Antibodies, Monoclonal↗
PubMed2001

CD antigens 2001.

This paper reviews the Seventh Human Leucocyte Differentiation Antigen (HLDA7) workshop. Due to the limitations of "blind" antibody screening, which had been evident at the previous meeting in 1996, participants at HLDA7 adopted a more selective approach to the choice of antibodies by identifying new CD specificities. This resulted in the addition of more than 80 new CD specificities. Plans for the eighth and subsequent workshops are also previewed.

Antibodies, Monoclonal↗
PubMed2000

Preparation of human-mouse heterohybridomas against an immunising antigen.

The production of murine monoclonal antibodies against specific antigens by hybridomas is a well utilised technique. The production of hybridomas secreting specific human antibodies would have many advantages in therapeutic applications of monoclonal antibodies. The immortalised human lymphocytes themselves would also provide valuable tools in research on lymphocyte development. Preparation of human-human hybridomas has been limited by a lack of suitable fusion partners. This protocol paper describes the production of human-mouse heterohybridomas by two independent laboratories. The purpose of this protocol is to provide a basis for the development of heterohybridoma technology in laboratories with limited hybridoma experience.

Adult↗
PubMed2000

Expression of the costimulator molecules, CD40 and CD154, on lymphocytes from neonates and young children.

Differential expression of the costimulator molecules CD40 and CD154 on neonatal lymphocytes may be one explanation for limited T-dependent antibody responses in human neonates. CD40 was expressed at similar levels on resting B cells from adults, young children (2-20 months of age) or cord blood. CD40 expression was higher on cord blood B cells compared to adult B cells after stimulation with PMA and ionomycin, but similar on adult and cord blood B cells activated by CD3-stimulated T cells. In contrast to previous reports, cord blood T cells stimulated with PMA and ionomycin expressed adult levels of CD154 initially, but this expression was more transient on cord blood T cells. When adult and cord blood mononuclear cells were stimulated with CD3 mAb, T cells from some cord blood specimens showed different kinetics of CD154 expression compared with adult T cells. However, some cord blood specimens showed adult patterns of T cell CD154 expression. When mononuclear cells were depleted of B cells and monocytes prior to stimulation with CD3 mAb, the MFI and percentage of T cells expressing CD154 increased, with adult and cord T cells showing similar patterns of expression. These results show some differences in expression of CD40 and CD154 between neonatal and adult lymphocytes, but do not directly account for the relative deficiencies of humoral immunity in neonates.

Adult↗
PubMed1999

Analysis of the cord blood T lymphocyte response to superantigen.

We have characterized the T lymphocyte population of the human neonate in respect of the expression of phenotypic profiles for naive, memory and differentiated populations. We have examined the response of the neonate T cell to the superantigen Staphylococcus enterotoxin B (SEB) and compared the response to T cells from healthy adults. We found that the primary response to SEB is equivalent in neonates and adults but that the secondary response demonstrates hyporesponsiveness in the neonate that is more profound than in adults. This response was associated with increased expression of CD25; the alpha chain of the IL-2 receptor, equivalent to that seen in responding cells from adults. A modest increased expression of CD122 and CD132, the beta and gamma chains of the IL-2 receptor, was also observed. There was no increase in the IL-4 receptor (CD124). The hyporesponsive neonate T cells proliferated in response to exogenous IL-2 but the response was less than none SEB treated cells. The neonate cells did not respond to IL-4. We also examined the expression of MHC class II molecules on SEB stimulated cells and found that both neonate and adult T cells upregulate MHC class II to a similar degree. The difference in the hyporesponsive cells appears to result in part from a lower production of IL-2 and in part from a lower ability of cord cells to respond to IL-2. Since the stimulated cord cells expressed IL-2 receptor at the same levels as similarly treated adult cells; there may be differences in down stream signaling pathways.

Adult↗
PubMed1999

Expression of the costimulator molecules, CD80, CD86, CD28, and CD152 on lymphocytes from neonates and young children.

The expression of CD80, CD86, CD28, and CD152 were examined on peripheral blood lymphocytes from adults, neonates (cord blood lymphocytes) and young children (2-20 months of age). There was no difference in the expression of CD80 or CD86 between adult and neonatal B cells, either resting or activated. A higher percentage of resting T cells expressed CD28 in neonates and young children compared to adults. CD28 expression was similar on adult and neonatal T cells activated with PMA and ionomycin. However, CD28 was expressed at greater intensity on a higher percentage of neonatal T cells than adult T cells stimulated with CD3. CD152 expression was lower on neonatal T cells than adult T cells stimulated with PMA and ionomycin and undetectable on neonatal T cells stimulated with CD3. In contrast, intracellular CD152 was equivalent in adult and neonatal T cells stimulated with PMA and ionomycin, suggesting trafficking of CD152 to the cell surface may be differentially regulated in neonatal T cells. Since the T cell response is determined by the balance of signals received from CD28 and CD152, high levels of CD28 expression and lower surface expression of CD152 on neonatal T cells may represent specialisation to promote activation of neonatal T cells.

Abatacept↗
PubMed1999

Localization of transforming growth factor-beta receptor types I, II, and III in the postnatal rat small intestine.

Transforming growth factor-beta2 (TGF-beta2) levels in rat milk are high in early lactation, whereas endogenous TGF-beta1 expression in the neonatal gut increases toward midweaning. Three types of transmembrane TGF-beta receptors have been identified in mammals. The receptor III (or betaglycan) binds and presents TGF-beta1 or beta2 to receptor II. Receptor I then interacts with receptor II, forming a signaling receptor complex, and propagates the signal. To determine whether TGF-beta receptor expression in the gut is also developmentally regulated, the present study assessed ontogeny of TGF-beta receptor expression in the postnatal rat small intestine. Jejunum and ileum tissues from rat pups at d 3, 10, 14, 21, and 28 of age were collected. Cryostat sections were stained with antibodies against TGF-bea receptors I, II, and III, and various cell markers by immunofluorescence. In both regions, receptor I staining was seen on apical and basolateral membranes of the villus and crypt epithelium at all ages, and staining on the apical membrane increased with age; receptor II was predominantly expressed in the crypt, and staining on the villi appeared after d 10; receptor III was distributed throughout the mucosa at early ages but diminished from the epithelium postweaning by d 28. T cells, B cells, and dendritic cells in the lamina propria expressed TGF-beta receptor III but lacked expression of receptor I and II. The pattern of TGF-beta receptor expression changes with age in a manner that may reflect the change in ligand from TGF-beta2 (milk-derived) to TGF-beta1 (endogenously produced).

Animals↗
PubMed1998

Removal of erythroid cells from umbilical cord blood mononuclear cell preparations using magnetic beads and a monoclonal antibody against glycophorin A.

Umbilical cord blood mononuclear cells isolated by density centrifugation are contaminated by erythrocytes and nucleated erythroid precursors which may exceed 50% of the total cell population, and thus interfere with phenotypic, functional and mRNA analyses. Lysis with hypotonic ammonium chloride can overcome this problem, but interferes with lysosomal function and should be avoided when cell preparations are intended for functional studies. The aim of this study was to develop a technique for removing erythroid cells from cord blood mononuclear cell preparations that would be as effective as ammonium chloride lysis but would not affect cellular function. This paper describes a method using 10F7, a mouse monoclonal antibody against human glycophorin A, and magnetic beads coated with anti-mouse immunoglobulin. The population of cord blood mononuclear cells recovered using this technique was of high purity, good yield and viability, and the cells responded appropriately to stimulation in vitro. To maximise cost-effectiveness, purification with magnetic beads could be performed after two density separations to reduce the quantity of beads required.

Ammonium Chloride↗
PubMed1998

Interleukin 2 receptor regulation and IL-2 function in the human infant.

IL-2 receptor is expressed at low levels on adult blood lymphocytes, and at lower levels on cord blood cells. IL-2 receptor alpha and beta chain expression increases gradually from 0-18 months of age. The level of soluble CD25 (IL-2 receptor alpha chain) has been reported to be elevated in cord blood. Quantitative RT-PCR showed that adult cells express 10 times as much CD25 mRNA as cord cells. Cord plasma showed only a marginal ability to strip CD25 from the membrane. To assess the functional consequences of low IL-2 receptor expression, cord and adult cells were activated in vitro. The response was stimulus-dependent, but cord cells upregulated CD25 readily. Cord and adult cells proliferated in an IL-2-dependent assay to a similar extent. Infants suffering acute infection showed marginally higher levels of membrane CD25 expression than infants without overt infection. Thus neonatal and infant lymphocytes express lower levels of IL-2 receptors than adult cells, reflecting lower mRNA concentrations at least for CD25; they are able to up-regulate receptors in response to in vitro stimulation and are able to respond in vitro to IL-2-dependent stimulation; however in vivo there may be a dampening down of the IL-2 system in infancy.

Adult↗
PubMed1998

Somatic mutation of immunoglobulin V(H)6 genes in human infants.

Infants respond to antigen by making antibody that is generally of low affinity for antigen. Somatic hypermutation of immunoglobulin genes, and selection of cells expressing mutations with improved affinity for antigen, are the molecular and cellular processes underlying the maturation of antibody affinity. We have reported previously that neonates and infants up to 2 months of age, including individuals undergoing strong immunological challenge, show very few mutated V(H)6 sequences, with low mutation frequencies in mutated sequences, and little evidence of selection. We have now examined immunoglobulin genes from healthy infants between 2 and 10 months old for mutation and evidence of selection. In this age group, the proportion of V(H)6 sequences which are mutated and the mutation frequency in mutated sequences increase with age. There is evidence of selection from 6 months old. These results indicate that the process of affinity maturation, which depends on cognate T-B cell interaction and functional germinal centres, is approaching maturity from 6 months old.

Adult↗
PubMed1998

Heterogeneity of CD44 expression among human B-cell subpopulations.

CD44 is a widely distributed cell surface glycoprotein that participates in a number of cellular adhesion and signal transduction processes. Germinal center B cells express very low levels of CD44, whereas their precursors and differentiation products express much higher levels. In immunofluorescence studies comparing 20 antibodies classified as being against the hematopoietic isoform of CD44, one antibody, A1G3, was unreactive with germinal center B cells, whereas the other antibodies showed low intensity but definite reactivity. Western blotting and sequential immunoprecipitation studies of lysates from density-separated lymphocyte fractions showed two bands that were differentially expressed and reacted differently with A1G3 compared with the other CD44 antibodies. These results suggest that germinal center B cells and non-germinal center B cells express different forms of CD44. Of 21 malignant B-cell populations examined, 5 showed reactivity with a "standard" CD44 reagent and significantly reduced reactivity with A1G3, while one sample showed the opposite pattern and the remainder were positive for both reagents. Of 10 cell lines studied, 5 were differentially stained by A1G3 and a standard CD44 antibody. PCR amplification of reverse transcribed mRNA from sorted human tonsil B-cell subpopulations and Southern blotting showed that B cells express a number of splice isoforms of CD44. These results demonstrate that B cells express multiple forms of CD44; both splice insert isoforms and variants distinguished by A1G3; the form of CD44 expressed depends on B-cell differentiation state.

Antibodies, Monoclonal↗
PubMed1998

Transforming growth factor-beta levels in maternal milk and expression in postnatal rat duodenum and ileum.

After birth, the gastrointestinal tract of the neonate is exposed to food and bacterial and environmental antigens. Maternal milk components may play a role in regulation of mucosal immune activity to luminal antigens. In this study we determine the ontogeny of transforming growth factor (TGF)-beta1-producing cells in the rat pup small intestine and assess maternal milk concentrations of TGF-beta. Intestinal tissue samples of duodenum and ileum were collected, processed, and stained for TGF-beta1, and in situ hybridization for TGF-beta1 mRNA was also performed on the duodenum. TGF-beta levels in milk were assayed by ELISA. TGF-beta2 levels in milk were high at d 6, and declined thereafter at d 10 and 19. TGF-beta1 was not detected. In contrast, the cell number and intensity of staining of TGF-beta1 peptide in the small intestine was low in 3- and 10-d-old rats and increased markedly by 19 d of life. In the duodenum mRNA levels mirrored this trend. TGF-beta1 expression in the lamina propria was absent before d 19, and increased progressively over time. Maternal milk TGF-beta2 levels are high in early milk and decrease during the weaning period. In contrast, endogenous TGF-beta production in the small intestine increases during the weaning period.

Aging↗