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V L Calder

Publications and source records attributed to V L Calder.

35 records · Page 2Linked to original sources
PubMed1994

Differential lymphokine expression by rat antigen-specific CD4+ T cell lines with antigen and mitogen.

Retinal soluble antigen (S-Ag) and purified protein derivative (PPD)-specific T cell lines established from Lewis rats were used to study the pattern of lymphokine expression to see if it varied with the inducing stimulus. Lymphokine mRNA expression was detected by PCR combined with Southern analysis after 6-hr stimulation and protein secretion assessed by bioassays at 24 hr poststimulation. S-Ag-specific T cell lines when stimulated with antigen expressed IL-2, IFN-gamma, and IL-4 mRNA, whereas only IL-2 and IFN-gamma could be detected in the supernatants. This is in contrast to the findings after stimulation of the PPD cell lines with PPD where IL-4 could be detected in the supernatants. The time course studies (3, 6, 24, 48, and 72 hr) with one of the S-Ag-specific T cell lines showed that S-Ag activation did not induce any detectable IL-4 bioactivity. However, when the S-Ag T cell line was stimulated by Con A or PMA, IL-4 was detected in the supernatants following Con A activation, suggesting that the way in which the T cell is activated has an effect on its resultant lymphokine secretion.

Animals↗
PubMed1993

Isolation of retinal lymphocytes in experimental autoimmune uveoretinitis: phenotypic and functional characterization.

Lymphocytes were obtained from the inflamed retinas of Lewis rats with S antigen (S-Ag)-induced experimental autoimmune uveoretinitis (EAU). In early disease 81% of these were CD4+ T cells. Thirty-four per cent of retinal CD4+ T cells expressed the interleukin-2 receptor (IL-2R) and 95% were CD45R-. These phenotypes contrast sharply with those of peripheral blood and lymph node CD4+ T cells isolated from EAU rats and confirm a high level of CD4+ T-cell activation in the retina in early disease. Although the relative proportions of CD8+ T cells increased in late disease, so did those of B cells and CD45R+ CD4+ T cells. We did not find clear evidence of a selective retention of CD8+ T cells in the retinas in late disease. Proliferation assays using retinal preparations demonstrated modest but significant responses to both S-Ag and the purified protein derivative of Mycobacterium tuberculosis (PPD) compared with lymph node preparations. The S-Ag response was abrogated by anti-major histocompatibility complex (MHC) class II monoclonal antibody (mAb). Lymphocyte preparations from inflamed retinas have not been examined previously in vitro but are likely to be useful in defining the precise function of CD4+ T cells during the course of EAU.

Animals↗
PubMed1993

Effects of CD8 depletion on retinal soluble antigen induced experimental autoimmune uveoretinitis.

During the later stages of soluble-antigen (sAg)-induced experimental autoimmune uveoretinitis (EAU), an increase in the relative number of CD8+ lymphocytes has been observed at the site of inflammation in the retina. It has been suggested that these late-appearing CD8+ cells might down-regulate this acute disease process. To determine the role of the CD8+ cells in EAU, Lewis rats were depleted of CD8+ cells prior to and during disease and the enucleated eyes examined histologically. The spleen cells from CD8-depleted rats were also examined for their ability to respond to concanavalin A (Con A) and to allogeneic targets as determined by mixed lymphocyte reaction (MLR) and cytotoxicity assays. The results suggest that depleting CD8+ cells had no effect on the course of disease and that CD8+ cells do not play a crucial role in the immunoregulation of EAU.

Animals↗
PubMed1993

Lymphocyte migration through cultured endothelial cell monolayers derived from the blood-retinal barrier.

Lymphocyte migration across endothelial monolayers, derived from the rat blood-retinal barrier, was recorded in vitro using time-lapse video microscopy. Syngeneic lymphocytes were plated out onto endothelial cell monolayers for 4 hr and their surface motility and transmonolayer migration recorded and quantified. Under resting conditions lymphocytes, obtained from peripheral lymph nodes (PLN), were small, rounded and static with less than 5% migrating across the monolayer. Activation of the lymphocytes with concanavalin A (Con A) increased their size and surface motility on both interferon-gamma (IFN-gamma)-treated and resting endothelia, but did not alter the number migrating across the monolayer. Similar results were also found for phytohaemagglutinin (PHA)-activated lymphocytes. Interleukin-2 (IL-2)-dependent CD4+ T-cell lines specifically recognizing either retinal soluble antigen (S-Ag) or bovine serum albumin (BSA) exhibited significantly greater surface motility over the endothelial monolayers than the mitogen-activated PLN lymphocytes. By 4 hr, in excess of 50% of the T-cell line lymphocytes had migrated across the endothelial monolayer. Treatment of the endothelial cells with IFN-gamma caused a small, but not significant, increase in the level of T-cell line lymphocyte migration. These results suggest that the migration of lymphocytes across central nervous system-derived endothelia is primarily dependent upon the state and mode of lymphocyte activation.

Animals↗
PubMed1993

B7/BB-1 is a leucocyte differentiation antigen on human dendritic cells induced by activation.

Activation of a primary T-lymphocyte response requires additional signals apart from interaction of the T-cell receptor (TcR)/CD3 complex with major histocompatibility complex (MHC) antigens on the antigen-presenting cell. The CD28 antigen on T lymphocytes provides an important co-stimulatory signal to T lymphocytes and we therefore searched for the presence of its ligand, the B7/BB-1 antigen, on blood and tonsil dendritic cells (DC). Blood DC, prepared from peripheral blood mononuclear cells with a minimal period of in vitro culture, did not stain with the monoclonal antibody BB-1 using flow cytometry analysis. In contrast, tonsil DC stained weakly for B7/BB-1 compared to positive control cell lines. Polymerase chain reaction (PCR) was used to amplify a 605 base pair (bp) fragment from human B7/BB-1 mRNA and demonstrated significant amounts of B7/BB-1 mRNA in tonsil DC but no specific product was obtained from blood DC, confirming the surface-staining results. Weak expression of B7/BB-1 antigen was detected by immunofluorescence analysis following culture of blood DC with either interferon-gamma (IFN-gamma) or granulocyte-macrophage colony-stimulating factor (GM-CSF). These data support the concept that blood DC give rise to tissue and/or lymphoid DC, which acquire co-stimulatory ligands as a result of activation and/or differentiation.

Antibodies, Monoclonal↗
PubMed1992

Nucleotide sequence analysis of the movement genes of resistance breaking strains of tomato mosaic virus.

The nucleotide sequences were determined for the movement genes, encoding 30K proteins, of two resistance breaking strains of tomato mosaic virus (ToMV), LII-ToMV and LIIA-ToMV. The putative amino acid sequences of the encoded proteins were compared with L-ToMV and with two previously published resistance breaking strains, Ltb1-ToMV and C32-ToMV. LII-ToMV, a Type 2 strain able to infect tomatoes containing the Tm-2 gene, has four amino acid changes relative to L-ToMV. One of these substitutions, Glu-Lys133, is also found in the other Type 2 strains, Ltb1-ToMV and C32-ToMV. LIIA-ToMV, a Type 2(2) strain able to overcome the resistance conferred by the tomato Tm-2(2) gene, has four amino acid differences from L-ToMV. The Type 2(2) strain has no substitutions in common with any of the Type 2 strains; however the predominance of amino acid substitutions that involve a change in the local charge (six out of the eight) suggests an electrostatic interaction between a host factor and the 30K protein may be intrinsic to the function of the movement gene and/or resistance breakage.

Amino Acid Sequence↗
PubMed1992

Experimental autoimmune uveoretinitis (EAU) versus experimental allergic encephalomyelitis (EAE): a comparison of T cell-mediated mechanisms.

EAU is a model of ocular inflammatory disease. EAU resembles another T cell-mediated autoimmune disease--experimental allergic encephalomyelitis--since both have increased expression of MHC class II molecules in the target tissue, can be adoptively transferred by activated CD4+ T cells and are inhibited by cyclosporin A. The immunological findings will be compared to find out if the same cellular mechanisms are involved in both diseases.

Animals↗
PubMed1992

Distribution of IL-2R and CD45Ro expression on CD4+ and CD8+ T-lymphocytes in the peripheral blood of patients with posterior uveitis.

Different lines of evidence support a major role for activated T-lymphocytes in the pathogenesis of posterior uveitis. The initial site of activation of these autoreactive T-cells, either locally in the eye or in the peripheral immune compartment, is still unknown. This study was undertaken to investigate whether with currently available techniques, it is possible to detect alterations in the levels and subsets of activated T-cells in the peripheral blood of patients with posterior uveitis. For this reason, 3-colour immunofluorescent staining was performed to assess the distribution of IL-2 receptors (IL-2R) and the CD45RO-antigen on CD4+ and CD8+ subsets of peripheral blood lymphocytes (PBLs) from patients with posterior uveitis (n = 29). Only the subgroup of patients with posterior uveitis as part of a systemic immune-mediated disease (sarcoidosis, Behçet's disease) (n = 9) showed a significant increase in IL-2R expression on peripheral blood lymphocytes (p less than 0.005) when compared to normals (n = 12). This increased expression was reflected much more significantly in the CD4+ (p less than 0.0005) rather than in the CD8+ subset (p less than 0.05) of lymphocytes. In contrast, no significant increase in CD45RO expression on either subset of T lymphocytes was found in any subgroup of posterior uveitis in comparison with normals.

Antibodies, Monoclonal↗
PubMed1992

Hodgkin's disease cell lines: a model for interleukin-1-independent accessory cell function.

The haemopoietic origins of the Hodgkin's disease (HD)-derived cell lines L428, KM-H2 and HDLM-2 remain controversial. Analysis of T-cell receptor (TcR) and Ig rearrangements cannot resolve this, and lineage promiscuity limits the interpretation of isolated surface antigen expression. Nonetheless the cell marker profile of L428 has similarities with human dendritic cells (DC), and L428 strongly stimulates in the mixed leucocyte reaction (MLR). We therefore undertook an extended immunophenotypic comparison of the HD lines with that recently defined for DC, prior to examining their ability to stimulate allogenic T lymphocytes, and comparing the molecular interactions involved with those of primary MLR stimulatory cells. The immunophenotype of the HD lines failed to establish either a lymphoid or monocytoid derivation. The profile of L428 appeared similar to the human DC. All three lines were potent stimulators in the primary MLR, and each expressed relevant adhesion and signal-transducing molecules important for co-stimulating T lymphocytes. Inhibition studies using monoclonal antibodies indicated similar contributions within HD line-T cell MLR to that documented in human tonsil DC-T cell MLR. The HD lines produced no detectable interleukin-1 (IL-1) by biological or immunological analysis. Moreover they stimulated allogeneic T lymphocytes in the presence of anti-IL-1 antibodies. Thus although IL-1 mRNA can be detected in both HDLM-2 and KM-H2 by polymerase chain reaction, these lines, and L428, share with DC the ability to stimulate allogeneic T lymphocytes in an IL-1-independent manner [corrected]. HD lines, particularly L428, may provide a standardized, reproducible, IL-1-independent model for dissection of the co-stimulatory requirements of the human primary MLR.

Antigens, CD↗
PubMed1990

Nucleotide sequence of the coat protein gene of pea seed-borne mosaic potyvirus.

The nucleotide sequence of a 1355 bp cDNA representing the 3'-terminal sequences of pea seed-borne mosaic virus (PSbMV) was determined. This sequence contained a single long open reading frame (ORF) of 1189 bp ending with a single TAA termination codon. Downstream from the ORF was an untranslatable region of 189 bp followed by eight bp of polyadenylate. The probable location of the PSbMV coat protein codons within the long ORF was determined by comparing the inferred amino acid sequence with other potyviral coat protein sequences and by examining the sequence for a potyviral polyprotein cleavage cassette sequence. Direct chemical sequencing of the PSbMV coat protein revealed it to be blocked at its amino terminus. A partial amino acid sequence representing the N terminus of the protease-resistant core of the coat protein was determined, however. Alignment of the PSbMV coat protein sequence and the sequences of seven other potyviral coat proteins revealed significant homology, ranging from 53.7% for potato virus Y strain D to 43.2% for tobacco vein mottling virus.

Amino Acid Sequence↗
PubMed1988

The differentiation of O-2A progenitor cells into oligodendrocytes is associated with a loss of inducibility of Ia antigens.

Current data suggest that some astrocytes, one of the 3 main types of macroglia in the central nervous system (CNS), can be induced by interferon-gamma (IFN-gamma) to express major histocompatibility complex class II antigens (immune-associated or Ia) and present antigen to T lymphocytes. In contrast, oligodendrocytes, another type of macroglia, cannot be induced to express Ia. The astrocytes which have been shown to express Ia are from a particular glial lineage and are called type-1 astrocytes. The oligodendrocyte-type-2 astrocyte (O-2A) lineage, which gives rise to oligodendrocytes, also gives rise to a second class of astrocytes called type-2 astrocytes and the ability of type-2 astrocytes or the common O-2A progenitor cell to express Ia is not known. We have now found that both type-2 astrocytes and O-2A progenitor cells can be induced to express Ia by IFN-gamma but Ia expression is not induced in oligodendrocytes in parallel cultures. Thus, it appears that differentiation of O-2A progenitor cells into oligodendrocytes is specifically associated with a loss of inducibility of Ia. This apparent loss of the capacity for Ia expression, and presumably antigen presentation, in oligodendrocytes (the cells which produce myelin in the CNS) is of particular interest in view of the ability of immunization of myelin components to produce autoimmune-mediated paralytic disease.

Age Factors↗
PubMed1988

Nervous and immune system disorders in multiple sclerosis.

Multiple sclerosis is probably an acquired infectious disease with an autoimmune response relating to damage to the white matter of the central nervous system. There is evidence of continued intrathecal synthesis of oligoclonal antibody and there are perivascular inflammatory cell infiltrates close to areas of demyelination in the central nervous system. Following adoptive transfer, cells sensitized to the myelin basic protein can cause demyelinating disease in rodent recipients. Unlike the peripherally-mediated immune changes in the experimental model it is argued that autoaggressive cells are generated within the CNS in multiple sclerosis. The possible mechanism of cellular demyelination is discussed and the implication for therapy is reviewed.

Animals↗
PubMed1987

Effects of cyclosporin A on expression of IL-2 and IL-2 receptors in normal and multiple sclerosis patients.

The effects of the immunosuppressant Cyclosporin A (CsA) on T cell activation in vivo and in vitro were examined using the monoclonal antibody, anti-Tac, for interleukin 2 (IL-2) receptors and 3.9C2, for a peptide fragment of human IL-2. Peripheral blood lymphocytes (PBL) were stimulated with PHA in the presence of CsA. The expression of IL-2 receptors and production of IL-2 were reduced. PBL from CsA-treated MS patients had significantly lower proportions of Tac+ cells compared with untreated patients. This inhibition was not reflected in the CSF lymphocyte populations from CsA-treated patients and indicates the urgent need for an immunosuppressant drug which can enter the CNS in sufficient concentrations to inhibit local T cell activation.

Cyclosporins↗
PubMed1985

The distribution of interleukin-2 receptor bearing lymphocytes in multiple sclerosis: evidence for a key role of activated lymphocytes.

The identification of T cells in the brain using monoclonal antibodies has suggested a role for T cells in the pathogenesis of multiple sclerosis (MS). In the present study the monoclonal antibody anti-Tac, shown to react with interleukin-2 (IL-2) receptors expressed on activated T cells, was used to determine levels of recently activated T cells in blood, cerebrospinal fluid (CSF) and brain sections from MS patients at different stages of disease. The CSF of MS patients contained much higher numbers of IL-2 receptor positive lymphocytes (up to 67%) than blood cells from the same patients, or the CSF of patients with non-inflammatory neurological diseases. In histological sections of the brain of MS patients with active disease, perivascular lymphocytes expressing IL-2 receptors were detected, as were lymphocytes containing IL-2. In contrast, these were absent in brain sections from patients with chronic MS, secondary demyelination or from normal controls. These observations in CSF and brain suggest that in multiple sclerosis, T-cell activation is occurring within the CNS and not in peripheral lymphoid tissue.

Antibodies, Monoclonal↗
PubMedDate not supplied

Lymphocyte adhesion to cultured endothelial cells of the blood-retinal barrier.

Microvascular endothelial cells derived from the blood-retinal barrier were grown in vitro and various factors affecting the adhesion of syngeneic lymphocytes to these monolayers was evaluated. Under resting conditions 5.3 +/- 0.4% of lymphocytes derived from peripheral lymph nodes (PLN) were found to adhere to the endothelia. Adhesion of resting lymphocytes increased significantly following endothelial treatment with interferon-gamma (IFN-gamma; 11.7 +/- 1.0%), interleukin-1 (IL-1; 14.9 +/- 1.2%), astrocyte conditioned medium (ACM; 12.7 +/- 0.9%) or forskolin (13.9 +/- 1.2%). Lymphocyte activation with concanavalin A (ConA) increased adhesion to 17.0 +/- 0.9% which could be augmented by activating the endothelia with IFN-gamma (22.3 +/- 1.0%), IL-1 (24.0 +/- 1.0%) and ACM (25.7 +/- 1.6%). An antigen-specific CD4+ T cell line exhibited the greatest degree of adhesion, 40.4 +/- 2.5% on resting endothelia, 60.0 +/- 3.0% on IFN-gamma-activated cells and 54.3 +/- 1.4% on IL-1-activated cells. Although CD4+ lymphocytes predominated in the PLN population by 2:1, significantly more CD8+ cells were found to adhere.

Animals↗