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D Maurer

Publications and source records attributed to D Maurer.

At least 91 records · Page 5Linked to original sources
PubMed1990

A single laser flow cytometry method to evaluate the binding of three antibodies.

Here we describe a flow cytometry method which permits the collection of data regarding three staining parameters of a single cell from a suitable combination of dual parameter stainings using PE- and FITC-labelled mAbs and a single argon laser. The technique neither requires a third dye with non-overlapping emission spectra nor a second light source. In order to test the accuracy of this method, we compared data calculated using this triple parameter analysis with data obtained by double staining a presorted population homogeneously positive for one parameter. In experiments using either resting or in vitro activated T cells, the percentages obtained with both methods were identical (P greater than 0.05). Using this method we tested which T cell sub-subpopulation is responsible for the weak CD25 (IL-2R alpha) expression constantly associated with freshly isolated human T cells and concluded that it is predominantly expressed on the CD4+ CD45RO+ (CD4 positive memory) T cell subpopulation.

Adult↗
PubMed1990

IL-3 promotes basophilic differentiation of KU812 cells through high affinity binding sites.

The myeloid precursor cell line KU812 exhibits a constitutive potential to differentiate into basophilic cells. In the present study, the influence of recombinant human (rh)IL-2, rhIL-3, and recombinant human granulocyte-macrophage-CSF on basophilic differentiation of KU812-F cells was studied. Of all cytokines tested, rhIL-3 induced a significant increase in formation of metachromatically granulated cells (from 10% in control cultures up to 30% in cultures supplemented with 100 U/ml of rhIL-3) as well as dose-dependent (1.5- to 3 fold) increase in cellular histamine in KU812-F cell cultures. In addition, KU812-F cells exposed to rhIL-3 bound more IgE antibody than cells cultured in control medium with up to 3.3-fold increases in the mean fluorescence intensity on days 2 and/or 5 compared with control (p less than 0.001). RhIL-3 failed to induce significant changes in expression of the Tac-reactive subunit of the IL-2R (CD25), surface aminopeptidase N (CD13), ICAM-1 Ag (CD54), or CD40 Ag on KU812-F cells. To investigate the mechanism of IL-3 action on KU812-F cells, receptor analyses were performed by using 125I-radiolabeled rhIL-3. Quantitative binding studies and Scatchard plot analyses revealed the presence of a single class of 1910 to 2460 high affinity IL-3-binding sites per KU812-F cell with an apparent dissociation constant of 1.22 to 2.35 x 10(-9) M. Together, these results show that rhIL-3 promotes basophilic differentiation of KU812-F cells through a specific receptor.

Antigens, CD↗
PubMed1990

Activated human T lymphocytes express MHC class I heavy chains not associated with beta 2-microglobulin.

We present here the molecular characterization of a new activation-induced surface structure on human T lymphocytes, termed LA45, with high homology (93% at protein level) to MHC class I molecules. Antigen modulation and sequential immunoprecipitation experiments revealed that LA45 and HLA class I proteins do not crossreact with the corresponding antibodies. Furthermore, LA45 is not associated with beta 2-m. On the other hand, we could show that the separation of HLA-A,B,C and beta 2m molecules, induced by SDS-denaturation, leads to a conformational change in the heavy chain in such a way that it becomes reactive with LA45. The 90/45 kD LA45 proteins thus appear to be non-beta 2m-associated MHC class I alpha chains that are selectively expressed by activated but not by resting human T lymphocytes.

Amino Acid Sequence↗
PubMed1990

CD27 expression by a distinct subpopulation of human B lymphocytes.

CD27 is present on the surface of a major subset of peripheral blood T lymphocytes. In this report we show that CD27 is also expressed on a subpopulation of the normal human B cell lineage which is absent from cord blood but present in tonsils and in the peripheral blood of adult individuals. CD27+ B lymphocytes are characterized by the following criteria: (a) in terms of physical properties, the CD27+ B cells form a population with an increased cell size combined with a decreased cell density; (b) the CD27 expression of tonsillar B lymphocytes is postively correlated with mIgA but negatively correlated with membrane IgM/membrane IgD positivity; (c) CD27 on B cells can be induced selectively by the combination of Staphylococcus aureus plus interleukin 2, but not by either treatment alone, and (d) CD27+ B lymphocytes express high levels of the adhesion structures LFA-1 (CD11a), ICAM-1 (CD54), LFA-3 (CD58) and of the lymphocyte homing receptor CD44. These latter findings suggest that CD27+ B cells are predispose to form cell-cell interactions. Accordingly, within 3 h of cell culture CD27+, but not CD27-, B lymphocytes were found to form LFA-1-mediated homotypic B cell clusters.

Antibodies, Monoclonal↗
PubMed1990

The influence of stimulus size on newborns' discrimination of chromatic from achromatic stimuli.

We used an habituation procedure to explore newborns' ability to detect successive changes in luminance and based on those data, their ability to discriminate chromatic from achromatic stimuli. Newborns were very insensitive to successive changes in luminance: after habituating to a white square of given luminance, they showed no evidence of dishabituating when the luminance of the square increased or decreased by 0.37 log cd/m2, but dishabituated only to the next larger difference of 0.53 log cd/m2. Moreover, after newborns were habituated to a series of white squares that varied widely in luminance, they did not react when the luminance of the square was increased as much as 0.71 log cd/m2. In the color vision experiments, infants were habituated to a series of white squares of varying luminance and then tested with a chromatic square and with a white square of novel luminance. The size of the squares was also varied. The results showed that newborns discriminated 8 deg red (lambda peak = 650 nm) and 16 deg green (lambda peak = 540 nm) squares from white but required a larger stimulus (16 deg) to demonstrate the discrimination of yellow (lambda peak = 585 nm) from white. In addition, newborns showed no evidence of discriminating a 32 deg blue (lambda peak = 470 nm) square from white. Thus, although the results imply that newborns are at least dichromats, they also show that their color vision mechanisms are immature, particularly those operating in the blue and yellow spectral regions.

Color Perception↗
PubMed1990

M5, a phosphoinositol-linked human myelomonocytic activation-associated antigen.

When investigating the previously described monoclonal antibody (MoAb) VIM-5, raised against THP1 cells and binding to human monocytes and granulocytes, we found that the antigen detected by this antibody, designated M5, becomes very strongly expressed on monocytes after overnight culture with phorbol myristate acetate (PMA) or lipopolysaccharide (LPS) but not with recombinant human interferon-gamma (rhIFN-gamma). Granulocytes stimulated with formyl-methionyl-leucyl-phenylalanine (FMLP) become negative for binding VIM-5. Immature granulocytes from bone marrow do not express M5, thus its expression on granulocytes is differentiation linked. The antigen bound by VIM-5 is sensitive to hydrolysis by phosphoinositol-specific phospholipase C (PI-PLC). The immunoprecipitated M5 antigen on monocytes is a broad band, with a peak of 50 kD (unreduced) and two bands of 53 kD and 44 kD (reduced). We have therefore detected an antigen that is upregulated on stimulated monocytes but, conversely, down-regulated on FMLP-stimulated granulocytes.

Antigens, Differentiation, Myelomonocytic↗
PubMed1990

Further characterization of surface membrane structures expressed on human basophils and mast cells.

Recently, we were able to establish the immunologic surface marker profile of human basophils and mast cells. In the present study, the characterization of these cell types was extended by the use of monoclonal antibodies (mAbs) to hemopoietic differentiation antigens. Basophils and mast cells were enriched by mAbs and complement from chronic myeloid leukemia blood (n = 5) and dispersed lung tissue (n = 4), respectively. A panel of 80 mAbs was tested for being reactive with purified cell populations using flow cytometry and/or a combined toluidine blue-immunofluorescence staining procedure. In addition to previous findings, basophils were found to react with mAbs directed against the 126-kilodalton dipeptidylpeptidase IV (CD26), platelet glycoprotein IIa (CD31), CD40 antigen known to share sequence homology with nerve growth factor receptor, leukosialin (CD43), CD44 antigen, the ICAM-1 antigen (CD54) and VIM2-reactive gangliosides involving the sialofucooligosaccharide sequence (CDw65L). Bsp-1 was found to be a specific marker for human basophils, whereas mast cells were not stained by this reagent. Basophils apparently lack CD22 antigen, gangliosides detected by CDw65 mAbs (except CDw65L) and CD71 antigen (transferrin receptor). Mast cells were found to express CD43 and CD44 antigen. In contrast, mast cells lack CD22, CD26, CD31, CD40 and CDw65 antigen. These results provide further evidence that both blood basophils and mast cells express a unique immunologic surface marker profile including binding sites for a variety of immunomodulating ligands and adhesion molecules.

Antibodies, Monoclonal↗
PubMed1989

Interleukin-3 is a differentiation factor for human basophils.

The effect of recombinant human (rh) cytokines, interleukin-1 alpha (IL-1 alpha), interleukin-2 (IL-2), interleukin-3 (IL-3), interleukin-4 (IL-4), granulocyte/macrophage colony stimulating factor (GM-CSF), granulocyte colony stimulating factor (G-CSF), monocyte/macrophage colony stimulating factor (M-CSF), interferon-alpha (IF-alpha), interferon-gamma (IF-gamma), and the tumor necrosis factor-alpha (TNF-alpha) on differentiation and function of metachromatic cells (MCS) was studied. Among all cytokines tested, rh interleukin-3 (rhIL-3) selectively induced a significant formation of MCS (IL-3: 1.1 +/- 0.6 x 10(5) v control: 0.02 +/- 0.15 x 10(5) MCS/mL suspension) and dose dependent increase in formation of intracellular histamine (IL-3, 100 U/mL: 95 +/- 23 ng/mL v control: 1.8 +/- 0.8 ng/mL) in a bone marrow suspension culture system (analyzed on day 14 of culture). Besides MCS, formation of eosinophils was observed in this culture system in the continuous presence of rhIL-3, whereas IL-3 pulse-stimulation for three hours and subsequent exposure to control medium induced growth of MCS but not of eosinophils. By combined immunofluorescence/toluidine blue staining, MCS were found to express a cell surface marker profile that corresponds to the immunological phenotype of peripheral blood basophils (MY-7(CD13)+, VIM12(CD11b)+, VIM2+, MAX1-, MAX24- and YB5B8-). Furthermore, cultured MCS expressed surface membrane receptors for IgE and could be triggered for nontoxic histamine release by a monoclonal anti-IgE antibody. To evaluate a possible influence of IL-3 on basophil function, studies were extended to freshly obtained blood basophils (healthy volunteers, n = 3). However, like all other cytokines tested, rhIL-3 failed to induce basophil histamine release. Taken together, our studies demonstrate that IL-3 is a differentiation factor for human basophils.

Antibodies, Monoclonal↗
PubMed1989

Optokinetic nystagmus in normal and visually deprived children: implications for cortical development.

Ten years ago we proposed that the limitations on young infants' vision might be caused by an immature Y-pathway through the cortex, while their abilities might be mediated by an X-pathway to the cortex and by Y- and/or W-pathways to the superior colliculus and pretectum (Maurer & Lewis, 1979). Although that explanation was too simple overall, it fits well with what is known about asymmetrical optokinetic nystagmus, viz. the difficulty in eliciting OKN to patterns moving from the nasal field toward the temporal field. In this paper, we describe the development of symmetrical OKN, its alteration by early deprivation from cataract, and its physiological basis. We then suggest that, for primates, an explanation based on projections through the magnocellular versus parvocellular layers of the lateral geniculate nucleus may be more appropriate than one based on X-, Y-, and W-cells.

Animals↗
PubMed1989

A new test of luminous efficiency for babies.

We used the minimum motion method devised by Anstis and Cavanagh (1983) to measure the luminous efficiency of red and green and of yellow and blue for "normal" 1- 3-month-old babies and for one 3-month-old boy destined to be color-deficient because of a deutan mother. Subjects watched a display which created apparent motion, the direction of which depended on the relative luminance of the colors. To determine the equiluminant points, we observed the optokinetic nystagmus elicited by the display as the relative luminance of the colors was varied. The equiluminant points of the normal mothers and their infants were similar to each other but different from those of the deutan mother and her son. Our new method demonstrates the early maturation of input from red and green cones into achromatic pathways. It can also be used to identify some color-deficient infants.

Color Perception↗
PubMed1987

Emergence of the ability to discriminate a blue from gray at one month of age.

Two different methods which minimize achromatic cues were used to test the ability of 1-month-olds to discriminate gray from broadband blue (lambda peak = 475-480 nm). Unlike the newborns we tested previously, 1-month-olds demonstrated the discrimination with both methods. In Experiment 1 they showed preferences for each of four blue-and-gray checkerboards over gray squares of the same mean luminance, even though the luminance of the gray checks was varied in small steps over a wide range. In Experiment 2 they looked longer at a blue square than at a gray square, after they had been habituated to five other gray squares of varying luminance. Compared to previous results, these data imply an improvement between birth and 1 month of age in the discrimination of gray from broadband blue. Possible physiological changes underlying this improvement are discussed.

Child Development↗