Publications by authors named "Sieckmann D"

Unlabelled: While perfluorocarbons (PFCs) may be useful in some clinical situations, previous studies have shown that interferences with chemistry analytes can occur with blood samples containing PFCs. This in vitro study focused on how the PFC Oxycyte may affect hematology measurements in blood samples. Swine blood diluted with Oxycyte or saline (Controls) were analyzed for Hemoglobin (Hb), Mean Corpuscular Volume (MCV),Hematocrit (Hct) and Fluorocrit (Fct) using a HemaVet, ABL-735 (ABL), or microhematocrit.

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Plasma from hibernating (HIB) woodchucks (Marmota monax) or 13-lined ground squirrels (Ictidomys tridecemlineatus) suppressed (3)H-thymidine uptake in mouse spleen cell cultures stimulated with Concanavalin A (ConA); plasma from non-hibernating animals were only slightly inhibitory. Maximum inhibition occurred when HIB plasma was added to the cultures prior to ConA. After HPLC size exclusion chromatography of the HIB ground squirrel plasma, a single fraction (fraction-14) demonstrated inhibitory activity.

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Four rat x mouse hybridomas secreting monoclonal anti-idiotypic (anti-Id) antibodies (MAb) specific for the transgene-encoded antibody of the 207-4 transgenic mouse line, which carries the VH1/V kappa 24 gene segments of the IgA, phosphocholine-(PC) specific MOPC167 myeloma, were developed from a fusion of Ag8-X63.653 mouse cells with spleen cells from a rat immunized with MOPC167 and HPCM27 anti-PC antibodies. The anti-Id MAb were shown by ELISA to be specific for PC-binding proteins of VH1/V kappa 24 H and L chains of various isotypes.

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X-linked immune deficient (Xid) mice fail to produce anti-phosphocholine (PC) antibodies even after immunization with Streptococcus pneumoniae. Consequently, Xid mice are extremely susceptible to infection with S. pneumoniae, PC-specific B cells appear to undergo clonal deletion in Xid mice; however, a new thymus-dependent form of PC, 6-(O-phosphocholine)hydroxyhexanoate (EPC), can rescue PC-specific B cells from the bone marrow presumably by providing T cell help before clonal deletion.

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Severe combined immunodeficient (SCID) mice reconstituted with human peripheral blood lymphocytes (hu-PBL) were evaluated as an animal model for demonstrating dengue (DEN) viral infection. Reconstituted mice (hu-PBL-SCID) that demonstrated successful engraftment by the presence of serum titers of human immunoglobulin (Ig) were inoculated intraperitoneally with DEN virus serotype 1 (DEN-1). Serial blood samples were taken postinoculation and assayed for virus in C6/36 cells.

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The transgenic (TG) mouse strain 207-4, carries mu a + kappa transgenes ligated to the anti-phosphocholine (PC) VH1 and V kappa 24 V region genes from the MOPC-167 myeloma. Although B cells from mice carrying these transgenes respond both in vivo and in vitro to thymus-dependent Ags, they failed to proliferate in response to soluble goat anti-mu Ab or other soluble anti-Ig reagents. On the other hand, B cells from the Sp6 mu kappa anti-trinitrophenyl TG mouse line proliferated normally after stimulation with soluble anti-mu.

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A Western blot (immunoblot) assay was used to detect Campylobacter-specific immunoglobulin A in urine. Acute-phase urine samples from six children with Campylobacter diarrhea had titers ranging from 2 to 8. The highest titer was detected 4 days postonset.

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Flow cytometric analysis of antigen-specific, idiotype-positive (id+), B cell development in transgenic mice expressing a rearranged M167-mu gene shows that large numbers of phosphocholine (PC)-specific, M167-id+ B cells develop in the spleen and bone marrow of these mice. Random rearrangement of endogenous V kappa genes, in the absence of a subsequent receptor-driven selection, should give rise to equal numbers of T15- and M167-id+ B cells. The observed 100-500-fold amplification of M167-id+ B cells expressing an endogenous encoded V kappa 24]kappa 5 light chain in association with the M167 VH1-id transgene product appears to be an antigen driven, receptor-mediated process, since no amplification of non-PC-binding M167 VH1/V kappa 22, T15-id+ B cells occurs in these mu-only transgenic mice.

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The combined expression of the M167 mu/kappa anstiphosphocholine (PC) transgenes with the x-linked immunodeficiency gene, xid, results in an almost total failure to develop B cells in the peripheral lymphoid organs of such mice. Although there is no significant difference between the normal transgene positive (TG+) female offspring and the immunodeficient TG+ xid males with respect to the number of B220+ pre-B cells and IgM+B220+B cells that develop in their bone marrow, the hemizygous xid males have 85% fewer B cells in their spleens than the phenotypically normal heterozygous F1 females. In xid M167-mu-transgenic mice, PC-specific B cells also fail to develop in the spleen; however, numerous B cells bearing the mua+VH1(+)-transgene product associated with endogenous kappa L chains that do not give rise PC-specific antibodies are present.

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An IgG1 mouse monoclonal antibody (MAb) specific for a mouse IgM allotypic determinant in the a, c, f, g, h, and j haplotypes was derived from a fusion of SP2/O-Ag14 mouse myeloma cells with C57BL/6 mouse spleen cells (Igh-Cb) immune to TC31, a MAb of the IgMa allotype. MAb from one hybridoma derived from this fusion (designated DS1) was demonstrated to bind in an ELISA to immunoglobulin bearing the IgMa allotype (TC31, MOPC104E), but not to immunoglobulin bearing the IgMb allotype (C.BPC112).

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In pursuing the mechanism of endotoxin action, we examined the effect of lipopolysaccharide (LPS) and its chemically defined components, lipid A and lipid X on cultured bovine endothelial cells. We report that LPS and lipid A caused detachment and altered morphology of endothelial cells while lipid X did not. Phorbol myristate acetate, a compound known to activate protein kinase C, also caused endothelial cell detachment.

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Transgenic mice carrying immunoglobulin genes coding for mu heavy chain and kappa light chain have been used to study the mechanisms involved in allelic and isotypic exclusion. We report here that individual cells from transgenic mice carrying a functionally rearranged mu heavy chain gene (capable of generating both membrane and secreted forms of IgM) can rearrange an endogenous mu heavy chain gene and simultaneously produce both transgenic and endogenous IgM. These "double-producing" cells express both endogenous and transgenic IgM in the cytoplasm (detected by immunohistology) and on the cell surface (detected by multiparameter fluorescence-activated cell sorter analysis).

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Mouse spleen cells were stimulated to proliferate in vitro by soluble affinity-purified heterologous antibodies to mouse delta. Antibodies from goat or rabbit antisera to TEPC 1017, a mouse IgD myeloma protein, were purified on an affinity column of TEPC 1033, a second mouse IgD myeloma protein. Maximum uptake of [3H]thymidine in the range of 60,000 cpm was obtained after 48 hr of culture with anti-delta at concentrations of 50 micrograms/ml.

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Mice expressing the xid gene exhibit an altered immune response to phosphocholine (PC)-conjugated keyhole limpet hemocyanin (KLH). Less than 25% of their anti-PC-KLH response is PC specific, and most of these antibodies lack the normally predominant T15 idiotype. These findings suggested that immune defective mice might employ different variable region genes than normal mice in their anti-PC response.

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A method for the rapid separation of murine spleen cells into subpopulations on the basis of their size has been developed using counterflow centrifugation. Upon separation of normal spleen cells with a mean cell volume of 125.5 +/- 6.

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B lymphocyte-enriched cell populations cultured with mitogens in initial suspension cultures formed colonies in soft agar when the same mitogenic agent was present in the lower layer of a two-layer soft agar system. Colony formation depended upon the presence of T cells in the initial culture, and was optimal after an initial 72-h culture with phytohemagglutinin (PHA; 12.5 microliters/ml), pokeweed mitogen (PWM; 2.

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Two monoclonal rat anti-mouse IgM antibodies, Bet 1 and Bet 2, are described in this paper. Bet 1 defines a new allotypic determinant, Igh-6.5, expressed on IgM molecules in serum and on B lymphocytes, whereas Bet 2 recognizes a determinant on IgM molecules of all mouse strains tested.

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The T cell dependence of the in vivo and in vitro immune response to TNP-Ficoll was re-examined. It was found that after extensive T cell depletion, the in vitro response to TNP-Ficoll was significantly reduced and could be restored with T cells. Despite the apparent T cell dependence, TNP-Ficoll was able to elicit responses by congenitally athymic BALB/c mice in vivo and by spleen cells from these mice in vitro.

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The ability of various cell populations to bind and present the thymus-independent antigen TNP-Ficoll to a responding cell population was assessed. The in vitro antibody response to TNP-Ficoll depends upon the presence of B lymphocytes and plastic-adherent accessory cells, but does not require T lymphocytes. Purified B cells were the most effective population in binding and presenting TNP-Ficoll, and adherent cells did not perform this function.

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