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H Zola

Publications and source records attributed to H Zola.

At least 19 recordsLinked to original sources
PubMed2002

Penetration of engineered antibody fragments into the eye.

Antibodies are powerful immunotherapeutic agents but their use for treating ocular disorders is limited by their poor penetration into the eye. We hypothesized that antibody fragments of relatively small size might penetrate the cornea more readily. Monovalent single chain variable region (scFv) antibody fragments and divalent miniantibodies were engineered from existing monoclonal antibodies, expressed in a bacterial expression system, and purified by metal ion affinity chromatography. Corneoscleral preparations from normal pig and cat eyes were mounted in a corneal perfusion chamber. Intact antibodies and antibody fragments were applied topically to the anterior corneal surface over 12-h periods, and samples were collected from the artificial anterior chamber. Similar experiments were performed with whole enucleated pig and human eyes. Penetration of antibodies and fragments was quantified by high-sensitivity flow cytometry on appropriate target cells. Both monovalent scFv and divalent miniantibody fragments (but not whole immunoglobulin molecules) passed through de-epithelialized and intact corneas after topical administration, and could be detected by antigen binding. Addition of 0.5% sodium caprate facilitated penetration through intact corneas. Topically-applied scFv was found to penetrate into the anterior chamber fluid of rabbit eyes in vivo. The engineered fragments were stable and resistant to ocular proteases. Monovalent and divalent antibody constructs of molecular weight 28 kD and 67 kD, respectively, can penetrate through intact corneas into the anterior chamber, with retention of appropriate antigen-binding activity. Such constructs may form novel therapeutic agents for topical ophthalmic use.

Animals↗
PubMed2001

CD antigens 2001.

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Antigens, CD↗
PubMed2001

Increased yield and activity of soluble single-chain antibody fragments by combining high-level expression and the Skp periplasmic chaperonin.

The success of recombinant antibody fragments as diagnostic reagents and therapeutic agents depends on the availability of sufficient functional material. We have produced a bacterial expression vector that combines high-level expression driven by a modified Shine-Dalgarno sequence with the periplasmic chaperonin Skp. Using this vector, we are able to obtain higher yields of soluble antibody fragments from cultures without the need for supplementation of the culture medium during expression. The fragments produced in the presence of the Skp show improved antigen binding activity compared to when the chaperonin is absent.

Animals↗
PubMed2001

Antibody against CD20 in patients with B cell malignancy.

Cancer patients may make antibodies against antigens on the surface of their malignant cells due either to the expression of unique antigens or to dysregulated responses to self antigens. Patients with B cell malignancy frequently produce autoantibodies and may therefore be a source of immunoglobulin genes for the production of phage display antibody libraries directed against tumour-associated antigens. Patients with autoimmune disease have circulating antibodies against lymphocyte surface antigens, and may also provide a good starting point for the production of a library of lymphocyte-reactive antibody structures. In this study, plasma and serum samples from patients with B cell malignancy or Sjogren's syndrome and from healthy controls were screened for antibodies against the B cell membrane antigens CD20. While the majority of samples showed very low reactivity, some individuals did show significant and reproducible binding to CD20. To identify a good donor for library construction, it would be advisable to screen donors for antibody against the antigens of interest.

Antigens, CD20↗
PubMed2001

The Fc receptor for IgG (Fc gamma RII; CD32) on human neonatal B lymphocytes.

B cells express an Fc receptor for IgG (FcgammaRII; CD32) which is involved in feedback inhibition of antibody production. Engagement of FcgammaRII during ligation of the antigen receptor provides an inhibitory signal. FcgammaRII exists as several isoforms, with FcgammaRIIb (which carries an immunoreceptor tyrosine-based inhibition motif; ITIM) being predominant form on adult B cells. The inhibitory role of FcgammaRIIb may be unhelpful to the infant, since primary exposure to infectious agents is likely to be in the presence of maternal IgG. We hypothesized that neonatal B cells would be less susceptible to feedback inhibition by antibody, either through the expression of activation-competent FcgammaRII isoforms (FcgammaRIIa and FcgammaRIIc) or through reduced expression of the inhibitory FcgammaRIIb isoforms. Cord and adult B cells were examined for expression of FcgammaRII isoforms using monoclonal antibodies and RT-PCR. In vitro assays were performed to assess susceptibility of cord and adult cells to FcgammaRII-mediated suppression. Although there is no phenotypic difference in FcgammaRII expression (FcgammaRIIb predominating on both adult and cord B cells), FcgammaRIIb is expressed at lower levels on cord cells. This quantitative difference in FcgammaRIIb expression may explain the reduced susceptibility of cord B cells to antibody-mediated inhibition observed in these experiments.

Adult↗
PubMed2001

Immune modulation in suckling rat pups by a growth factor extract derived from milk whey.

Oral tolerance to foreign enteral antigens is not fully developed in early neonatal life. Epidemiological evidence supports a role for maternal milk in the development of immune responses, including oral tolerance. Formula fed infants have an increased susceptibility to food allergy and the later development of autoimmune disease. This may relate to the lack in infant formula of growth factors found in maternal milk. Bovine milk contains proteins, growth factors and cytokines. Various studies have outlined the immune modulating potential of bovine milk-derived products. Fractionated whey extracts have therapeutic potential in disease states where there is an excessive inflammatory reaction, and disease preventive potential for infants who are not breast-fed. We have shown that daily oral administration of a growth factor-enriched fraction from milk whey to naturally suckling rat pups between days 4-9 postnatal can down-regulate immune activation to a specific orally administered food antigen, ovalbumin, assessed by lymphocyte proliferation. In addition, non-specific down-regulation in the intestine was observed as assessed by the expression of MHC I. Treatment of rat pups with whey extract at the time of oral sensitisation to ovalbumin also resulted in an increased secretion of TGF-beta into the culture supernatant of spleen cells incubated with specific antigen. TGF-beta is an immuno-down-regulatory cytokine involved in tolerance induction. Immune modulation by extracts derived from milk whey could be of potential benefit for formula-fed and pre-term infants in reducing susceptibility to inappropriate activation to food antigens.

Animals↗
PubMed2001

CD antigens 2001.

The most recent Human Leucocyte Differentiation Antigen Workshop ("HLDA7") took place in 2000 in Harrogate, UK and the proceedings are about to be published (Leucocyte Typing VII). New Sections were introduced in this Workship (Dendritic cells, Stem/progenitor cells, Erythroid cells and Carbohydrate Structures) and monoclonal antibodies were selected for which at least some molecular data were already available (to avoid "blind" screening of reagents against known specificities). A total of more than 80 new CD specificities were established (previously the average was less than 30 new CD specificities per Workshop) and these are listed in this article. There is already evidence for the existence of many new leucocyte surface molecules for study at the next HLDA Workshop (in Adelaide in 2004), and we have listed in this article a number of such potential CD candidates (identified following the production of monoclonal antibodies or via gene cloning). There are also today an increasing number of lineage- and/or stage-restricted leucocyte-associated molecules localised within the cell cytoplasm (or nucleus): they will certainly prove of intense in the future for many laboratories studying human haematopoietic cells (regardless of whether a new "intracellular CD" categorisation scheme is devised for such molecules).

Antigens, CD↗
PubMed2001

CD antigens 2001.

Explore the source record for details and available documents.

Antibodies, Monoclonal↗
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.

Explore the source record for details and available documents.

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↗