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A W Butch

Publications and source records attributed to A W Butch.

26 records · Page 2Linked to original sources
PubMed1991

Germinal center T cells are distinct helper-inducer T cells.

Germinal centers (GCs) contain a significant number of CD4+ T cells, but what role these T cells may play in the development of GC B cells has not been determined. To gain insight into their role, we studied the phenotype of GC T cells and the lymphokines secreted by GC T cells isolated from human tonsils obtained after tonsillectomies. In addition to confirming that a large fraction of GC T cells are Leu-7(CD57)+ and Leu-8-, we found that they have no binding sites for peanut agglutinin. Furthermore, we found that they are CD45RA- and CD45R0+, the phenotype of helper-inducer T cells. We also found that Leu-7(CD57)+ cells display CD69, a phenotypic marker of very early cell activation, but do not display three other markers of cell activation: CD25 [interleukin-2 (IL-2) receptor], CD71 (transferrin receptor), and DR. When isolated, Leu-7(CD57)+ cells were stimulated in vitro with a mitogen that can induce peripheral blood T cells with the helper-inducer phenotype to produce various cytokines, Leu-7(CD57)+ cells did not produce IL-2, interleukin-4 (IL-4), interferon-gamma (IFN-gamma) or tumor necrosis factor-alpha (TNF-alpha) in significant amounts. Taken together, GC T cells from a distinct subpopulation of T cells with helper-inducer phenotype by their histologic location, by their surface phenotype, and by their ability to produce lymphokines. This finding is consistent with the possibility that GC T cells have been selectively recruited to actively help B cells develop in GCs.

Antigens, CD↗
PubMed1990

Production, characterization and use of five monoclonal antibodies to human IL-4.

We describe five murine monoclonal antibodies that are specific for human IL-4. At least three spatially distinct epitopes on the hIL-4 molecule are recognized by this panel of antibodies which allowed development of a sensitive sandwich EIA specific for hIL-4. The EIA is capable of detecting 200 pg/ml of hIL-4 and exhibits no detectable crossreactivity to seven other human cytokines examined. In addition to the EIA these antibodies are also useful in a number of other techniques for investigating hIL-4. Recombinant hIL-4 can be easily and efficiently purified by affinity chromatography using these mAbs. Western blotting with two of the antibodies detects as little as 1.8 ng/ml of hIL-4 in a 50 microliters sample. Finally, we present a method for cytoplasmic localization of hIL-4 by a fluorescence staining method utilizing a hIL-4 specific mAb.

Animals↗
PubMed1989

CD8 suppressor cell activity and its effect on CD4 helper cell-dependent growth of SJL/J B-cell lymphomas.

CD8 cells, flow cytometrically sorted from the lymph nodes of tumor-bearing and normal SJL/J mice, suppressed in vitro proliferation of syngeneic CD4 cells in response to concanavalin A, two independent SJL/J lymphomas, and LPS-activated syngeneic B-cell blasts. The data confirm earlier reports that nonspecific suppressor cells are generated as a consequence of SJL/J lymphoma-stimulated T-cell proliferation. Earlier reports are extended, in that the suppressor cell is identified as expressing CD8, and the suppressor activity is shown to decrease the tumor-stimulated CD4 cell proliferation which is essential to growth of these CD4-dependent murine B-cell lymphomas. In three separate experiments, anti-CD8 treatment of mice, in which CD4 cells were made limiting by injection with anti-CD4, increased growth of transplantable SJL/J lymphomas with corresponding increases in numbers of CD4 cells. The data imply that, under certain conditions, CD8 suppressor cells measurably influence growth of SJL/J lymphomas by regulating the tumor-stimulated CD4 cell proliferation essential to maximum growth of SJL/J lymphomas.

Animals↗
PubMed1989

Mitogen-induced human IgG subclass expression. II. IgG1 and IgG3 subclasses are preferentially stimulated by a combination of Staphylococcus aureus Cowan I and pokeweed mitogen.

Mitogens generally stimulate human IgG subclass production in amounts proportional to their abundance in serum (IgG1 greater than IgG2 greater than IgG3 greater than IgG4). We report here that a combination of Staphylococcus aureus Cowan strain I and pokeweed mitogen consistently stimulates human peripheral blood lymphocytes in vitro to preferentially produce more IgG1 and IgG3 than IgG2. This preferential stimulation can be measured by increases in the number of immunoblasts (cells with detectable cytoplasmic immunoglobulin) as well as in secreted immunoglobulin. The preferential stimulation pattern is established by the fourth day of culture and is maintained at least until the tenth day. Removal of T cells and subsequent stimulation of B cells with S. aureus Cowan I and interleukin 1 (IL-1) interleukin 2 (IL-2), interleukin 4 (IL-4), or interferon-gamma (IFN-gamma) failed to enhance any IgG subclass production, indicating the requirement for multiple lymphokines in IgG subclass production. The significance of these findings is discussed with respect to B-cell regulatory molecules and the coordinate expression of IgG subclasses.

Enzyme-Linked Immunosorbent Assay↗
PubMed1989

Stratus automated creatine kinase-MB assay evaluated: identification and elimination of falsely increased results associated with a high-molecular-mass form of alkaline phosphatase.

We compared the performance of an automated assay of creatine kinase MB isoenzyme (CK-MB) mass (Stratus) with that of a CK-MB enzymatic assay routinely used at our institutions. Both of these assays use the same CK-MB-specific monoclonal antibody to immunocapture CK-MB, thus providing a direct means of comparing a mass assay with an activity assay. Routine CK-MB measurements for 206 samples within the analytical range of both assays revealed the following relationship: Stratus (micrograms/L) = 0.67 (activity U/L) + 0.18 (r = 0.95, Sx.y = 4.45). The linearity, sensitivity, and precision of the Stratus assay were acceptable for routine clinical use. Icteric, lipemic, and hemolyzed samples do not interfere with the assay. During our evaluation we identified a single, clinically significant false-positive sample. Because this patient had alkaline phosphatase values greater than 1100 U/L, we investigated additional samples with increased activities of alkaline phosphatase and found that samples from 12 of 23 patients selected for alkaline phosphatase values greater than 460 U/L produced falsely increased CK-MB values. We determined that a membrane-associated, high-molecular-mass form of alkaline phosphatase was a cause of these falsely increased values and instituted an approach to identify falsely increased Stratus CK-MB values. Samples from 23 of 1933 patients were falsely increased, the increase being clinically significant in samples from 14 of these patients. Consultation with the manufacturer resulted in the successful reformulation of the substrate/wash solution to minimize interferences from high-molecular-mass forms of alkaline phosphatase.

Alkaline Phosphatase↗
PubMed1985

Comparative growth of SJL/J lymphomas in irradiated and normal SJL/J mice: cell cycle distribution and tumor cell quantification.

Flow cytometric and biological quantification of tumor cells revealed that 650 rad gamma-radiation 1 day prior to iv injection of H-2Ds negative lymphoma cells into SJL/J mice resulted in approximately a fourfold (day 3) to twelvefold (day 7) decrease in the tumor cell content of lymphoid organs as compared to that in unirradiated mice. Approximately 1.6-fold less tumor growth was noted (day 7) in 700-rad gamma-irradiated as compared to growth in unirradiated (SJL/J X CBA/J)F1 mice. Distributions of tumor cells in S-phase of the cell cycle were comparable at days 3, 5, and 7 in irradiated and unirradiated mice. Although approximately 26% of splenic tumor cells were in S-phase at days 5 and 7 in irradiated SJL/J mice, splenic tumor cell content did not increase during this time period. The data indicate that early (prior to day 3) and late (after day 5) events are responsible for decreased tumor growth in irradiated mice.

Animals↗
PubMedDate not supplied

Induction of IL-4 and IL-6 synthesis in vitro: variation in signaling requirements and kinetics are dependent on the anatomic source of the responding mononuclear cells.

We have shown differences in regulation of cytokine mRNA expression in human tonsil, spleen, and peripheral blood. After PHA stimulation of peripheral blood, IL-2, IL-4, and IL-6 mRNA were expressed with similar kinetics: peak expression occurred after four hours and subsequently declined over 48 hr. In PHA-stimulated splenic and tonsillar MNC, IL-2 and IL-6 mRNA were expressed later, with peak expression occurring after eight hours of stimulation and no mRNA detectable after 40 hr of stimulation. The intensity of the IL-6 mRNA signal and the amount of IL-6 secreted was much greater in MNC from peripheral blood than in spleen and tonsil and correlated with the percentage of monocytes in MNC from each tissue. IL-4 mRNA expression differed in all three tissues: PHA-stimulated tonsillar MNC expressed IL-4 mRNA with a major peak at eight hours and a minor peak at 24 hr after stimulation. The kinetics of mRNA were not due to effects of mixed cell populations. The same bimodal peak was observed in purified tonsillar T lymphocytes, and the minor 24-hr peak was dependent on IL-4 mRNA synthesis by cells expressing high amounts of VLA-beta 1 antigen (CDw29) on their surface and which lacked the CD45 epitope recognized by the mAb 2H4. Splenic MNC did not express IL-4 mRNA when stimulated with a number of mitogens and only exhibited IL-4 mRNA expression when stimulated with the combination of PHA and PMA or anti-CD3. Thus, IL-4 mRNA has markedly different kinetics and intensity of expression in spleen, peripheral blood, and tonsil.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗