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D T McKenzie

Publications and source records attributed to D T McKenzie.

12 recordsLinked to original sources
PubMed1991

Role of T cells in the B-cell response: glutaraldehyde-fixed T-helper hybridoma cells synergize with the lymphokine IL-4 to induce B-cell activation and proliferation.

Antigen-unselected helper T-cell hybridomas (Th) which activate normal resting B cells to RNA synthesis and proliferation in the presence of concanavalin A (Con A) have been developed. The response is completely Th cell dependent, and not restricted by the haplotype of the B-cell major histocompatibility complex (MHC). Culture supernatants from the Con A-stimulated Th hybridomas contain interleukin-4 (IL-4) and IL-2, but undetectable level of IL-5. The supernatant alone, however, does not induce B-cell activation or proliferation. Although the Con A-mediated Th cell-dependent B-cell response occurs in an MHC-unrestricted manner, the response of resting B cells can be blocked by monoclonal Ia antibody specific for the surface class II molecules of the responding B cell. The response is also blocked by monoclonal antibody to L3T4. Significant activation and proliferation of resting B cells can also be triggered by glutaraldehyde-fixed Th hybridomas and Con A when exogenous IL-4 is added. The stimulation with fixed Th hybridomas plus IL-4 can be inhibited by monoclonal anti-L3T4 or anti-Ia. These results suggest that maximal B-cell activation requires a direct helper T cell-B cell interaction which depends on availability of Ia on the B cell and L3T4 on the T cell, even when Con A overcomes the requirement for MHC-restricted T-cell recognition. We suggest that this signal, in conjunction with T-cell produced lymphokine IL-4, is responsible for the activation and subsequent proliferation of the B cells which occurs following interaction with T cells.

Animals↗
PubMed1989

IL-5-dependent conversion of normodense human eosinophils to the hypodense phenotype uses 3T3 fibroblasts for enhanced viability, accelerated hypodensity, and sustained antibody-dependent cytotoxicity.

Human peripheral blood-derived eosinophils were assessed for their viability, density, and functional properties after 7 days of culture with purified mouse IL-5 and mouse 3T3 fibroblasts. Whereas none of the eosinophils remained viable after 7 days of culture in the absence of IL-5, 38 +/- 12% and 61 +/- 14% (n = 6, mean +/- SD) of the eosinophils survived in the presence of 1 pM IL-5 alone or 1 pM IL-5 in the presence of 3T3 fibroblasts, respectively (p less than 0.05). Direct contact between the fibroblasts and the eosinophils was not needed for this enhanced IL-5-dependent viability. After 7 days, 66 +/- 7% (n = 6) of the cocultured eosinophils were viable when the two cell types were separated by a 0.4-microns filter. As assessed by density-gradient centrifugation after 7 days of IL-5 exposure, all of the original normodense eosinophils became hypodense. The time course of this conversion was accelerated by the presence of 3T3 fibroblasts. Enhanced helminthic cytotoxicity was maintained by the 7-day cultured eosinophils only if they had been cocultured with fibroblasts. Eosinophils killed 10 +/- 11% (n = 5), 48 +/- 17%, and 31 +/- 15% of the larvae when they were cultured for 7 days in IL-5 alone, in IL-5 in direct contact with 3T3 fibroblasts, or in IL-5 with filter separation of the fibroblasts and the eosinophils, respectively. The ability of IL-5 to induce progenitor cells to differentiate selectively into eosinophils, and of 3T3 fibroblasts to facilitate the IL-5-mediated conversion of normodense eosinophils to hypodense eosinophils with increased viability and antibody-dependent cytotoxicity suggests a role for both hematopoietic and tissue factors in determining the presence and pathobiologic function of activated hypodense eosinophils in patients with hypereosinophilic conditions.

Animals↗
PubMed1989

Regulation of isotype production by IL-4 and IL-5. Effects of lymphokines on Ig production depend on the state of activation of the responding B cells.

The effects of IL-4 and IL-5 on the production of Ig of different isotypes was investigated. We compared B cells from spleen and from Peyer's patches either stimulated with LPS or without added polyclonal stimulation. We also compared high density (small) and low density (large) B cells. The effect of lymphokines depended on the size and source of the B cells as well as on whether LPS was added. As expected, small B cells from either lymphoid compartment responded to LPS alone and IL-4 suppressed IgM and IgG3 production and enhanced IgG1. In contrast, when large B cells were examined, the suppressive effects of IL-4 were much less apparent but the enhancement of IgG1 was still marked. IL-5 alone had only minimal effects in LPS-stimulated cultures but the combination of IL-4 plus IL-5 appeared to overcome much of the IL-4-mediated suppression of IgM, and IgA production was enhanced. In the absence of LPS, a quite different profile is seen. First, small B cells make little if any response. Second, there is dramatic synergy between IL-4 and IL-5 in the response of large B cells, which is independent of isotype. Third, IL-4 does not suppress any isotype in the absence of LPS. Fourth, IL-4 plus IL-5 stimulate large Peyer's patch B cells to produce 10 times more IgA but three times less IgM than large spleen B cells. Fifth, Th2 cells directly stimulate both large and small B cells.

Adjuvants, Immunologic↗
PubMed1989

Interleukin 5 is a differentiation factor for IgA B cells.

Interleukin 5 (IL5) stimulates murine B cells to IgA production in vitro. The present study examined the B cell target of IL5 activity, and asked whether IL5 acts as an isotype switch factor, a growth factor, or a differentiation factor on B cells that produce the IgA isotype. Lipopolysaccharide-activated surface IgM-positive, surface IgA-positive or surface IgA-negative B cell populations from spleen or Peyer's patches were stimulated with IL5, after which the expression of cell surface IgA, IgA secretion, and numbers of IgA-secreting cells were determined. IL5 increased the IgA response by acting on B cells that are already committed to IgA expression. Thus, with regard to the IgA response, IL5 acts as a differentiation factor, rather than a growth or IgA isotype switch factor.

Animals↗
PubMed1989

Interleukin 4 acts on both high- and low-density murine B cell subpopulations to induce IgE and IgG1 synthesis in vitro.

Murine B cells were activated for 24 h with either lipopolysaccharide (LPS) or polyribosyl-ribitol-phosphate (PRP), followed by addition of interleukin 4 (IL-4) and the immunoglobulin isotypes secreted into the supernatant quantitated. Without IL-4, both LPS and PRP induced mainly IgM and IgG3 and no IgE secretion. Addition of IL-4 to both LPS- and PRP-activated cells decreased the IgM and IgG3 secretion and induced a large IgG1 production. In contrast to IgG1, only LPS-activated cells secreted large amounts of IgE, demonstrating that the nature of the polyclonal B cell activator also plays an important role in the IL-4 induced IgE formation. The effect of LPS and IL-4 on high- and low-density sIgM+/sIgD+ cells was also investigated. LPS and IL-4 induced IgG1 and IgE secretion by both populations. Low-density B cells from mice infected with the parasite Nippostrongylus brasiliensis formed more IgE than low-density B cells from normal mice, presumably because these mice have more in vivo preactivated B cells committed to IgE formation. The data show that IL-4 can act on both small high-density resting B cells as well as on in vivo preactivated low-density B cells to induce IgG1 and IgE secretion.

Animals↗
PubMed1988

Characterization of T helper 1 and 2 cell subsets in normal mice. Helper T cells responsible for IL-4 and IL-5 production are present as precursors that require priming before they develop into lymphokine-secreting cells.

We have shown that the requirements for the production of IL-4 and IL-5 by normal L3T4+T cells from murine spleen are very different from those for the production of IL-2. Secretion of detectable quantities of IL-4 and IL-5 and induction of the mRNA for each lymphokine occurs in vitro only after cells are primed and re-stimulated. This priming can be achieved by mitogens (Con A), by antibodies to the TCR (anti-T3) or by stimulation with alloantigen. In contrast, requirements for induction of lymphokine production after priming resemble those for initial production of IL-2. Thus the majority of T cells of helper phenotype that have the potential to become IL-4- and IL-5-secreting T cells, exist in the form of precursors requiring stimulation and several days of culture as well as re-stimulation with mitogen or Ag before they become detectable as lymphokine-secreting cells. In contrast, among fresh CD4+T cells, secretion of IL-2, IL-3, granulocyte/macrophage CSF, and IFN-gamma is easily detected within 24 h of stimulation with mitogen or Ag. These observations establish that distinct phenotypes of Th cells are found at different times after stimulation and support the concept that synthesis and secretion of different lymphokines or groups of lymphokines are regulated independently. Furthermore the patterns of lymphokines secreted by fresh vs primed Th cells, which largely correspond to the patterns that have been used to define the Th1 and Th2 subsets among Th cell lines, provides evidence that different subsets of normal T cells exist that may correspond to these designations. Secretion of different lymphokines by two subsets of Th cells at different times in an immune response, and perhaps in different places, suggests a model in which the ratio of the two T cell subsets (Th1 vs Th2) and state of differentiation of each (precursor vs effector), influence or determine the direction of the response, with variations in these parameters leading to differing responses.

Animals↗
PubMed1987

B cell stimulatory factor 1 (interleukin 4) is sufficient for the proliferation and differentiation of lectin-stimulated cytolytic T lymphocyte precursors.

In this report, we demonstrate that IL-4 is sufficient to stimulate both the proliferation and differentiation of Lyt-2+, Ia- splenic CTL precursors stimulated with the mitogenic lectin Con A. The response to IL-4 and Con A was not dependent on a putative endogenous production of IL-2 within the cultures, as demonstrated by an absence of an inhibitory effect by an anti-IL-2-R blocking mAb. Our results indicate that IL-2 and IL-4 can support an equivalent proliferative response by lectin-stimulated Lyt-2+ T lymphocytes, while IL-4 is more efficacious in stimulating their differentiation into mature cytolytically active cells.

Animals↗
PubMed1987

Purification and partial sequence analysis of murine B cell growth factor II (interleukin 5).

Murine B cell growth factor II (BCGF-II/interleukin 5) was purified from the conditioned media of the helper T cell line D10 . G4 . 1. The purification scheme consisted of sequential batch adsorption onto trimethylsilyl-controlled pore glass beads, high pressure ion exchange chromatography, and reverse phase high pressure liquid chromatography. The purified BCGF-II had a relative molecular weight of 45,000 when analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis under nonreducing conditions. Identical analysis of BCGF-II under reducing conditions yielded a m.w. of 22,500, suggesting that native BCGF-II exists as a homodimer. The NH2-terminal amino acid sequence of the purified lymphokine was determined by automated Edman degradation. A single amino acid sequence of 24 residues was obtained that, upon comparison, was contained within the cDNA pSP6K-mTRF23 recently described as encoding murine BCGF-II/T cell-replacing factor. The NH2-terminal methionine in mature BCGF-II is found at position 21 of the amino acid sequence predicted from the cDNA pSP6K-mTRF23. This finding supports the contention of Kinashi et al. (Kinashi, T., N. Harada, E. Severinson, T. Tanabe, P. Sideras, M. Konishi, C. Azuma, A. Tominaga, S. Bergstedt-Lindqvist, M. Takahashi, F. Matsuda, Y. Yaoita, K. Takatsu, and T. Honjo. 1986. Nature 324:70) that amino acids 1-20 serve as the signal sequence for the BCGF-II gene. The ability of BCGF-II to stimulate the proliferation of the B cell lymphoma BCL1 was used to assess the potency of the lymphokine. BCGF-II at 13.5 pM induced 50% of the maximal proliferative response in the BCL1 cells; concentrations as low as 2 pM were still effective in stimulating the growth of the cells. Assuming that the amount of BCGF-II necessary to mount a 50% response in the BCL1 assay is defined as one unit of activity, then the purified BCGF-II has a specific activity of 16.5 U/ng of protein.

Amino Acid Sequence↗
PubMed1987

Interleukin 5 and interleukin 4 produced by Peyer's patch T cells selectively enhance immunoglobulin A expression.

Considerable evidence suggests that the high frequency of B cells committed to the IgA isotype in Peyer's patches is regulated by T lymphocytes. To understand more accurately the mechanism of this immunoregulation, an autoreactive T cell line from Peyer's patches was generated by culturing L3T4+ Peyer's patches T cells with syngeneic B cell blasts. The resulting T cell line, designated PT-1, and a clone derived from this line, PT-1.14, stimulated immunoglobulin secretion in spleen B cells with a preferential enhancement of IgA and IgG1 isotypes. Supernatant derived from concanavalin A-stimulated PT-1 or PT-1.14 cells could also enhance IgA secretion if spleen B cells were preactivated with lipopolysaccharide. Peyer's patches T cell supernatant did not contain IgA-specific binding factors. PT-1 supernatant scored positive in lymphokine assays for interleukin (IL)-2, IL-4 (B cell stimulatory factor 1), IL-5 (B cell growth factor II), and interferon-gamma, whereas PT-1.14 supernatant was positive for IL-4 and IL-5 and negative for IL-2 and interferon-gamma. Only IL-5 enhanced IgA secretion in lipopolysaccharide-activated B cells and this response was increased two- to three-fold by IL-4. These results suggest that the type 2 T helper subset which produces both IL-5 and IL-4 plays a primary role in regulating IgA expression.

Animals↗
PubMed1983

Isoprinosine and NPT 15392: immunomodulation and cancer.

These data demonstrate that both Isoprinosine and NPT 15392 are active nontoxic biological response modifiers that qualify for studies in cancer patients. Because of their immunomodulating properties, these agents are expected to be most appropriate in the treatment of immunosuppressed patients who are prone to infection or recurrence following cytoreductive therapy.

Adjuvants, Immunologic↗
PubMed1981

Detergent extraction of a presumptive gating component from the voltage-dependent sodium channel.

A physiologically characterized radiolabeled neurotoxin complex obtained from venom of the scorpion Leiurus quinquestriatus has been used to identify detergent-solubilized presumptive sodium channel components in sucrose gradients. This toxin-binding component is found in extracts prepared from three sources of excitable membrane but appears to be absent from similar extracts prepared from nonexcitable membrane or from Torpedo californica membrane. Procedures that destroy the physiological activity of the Leiurus neurotoxin lead to a corresponding loss of toxin binding to the putative sodium channel component. The major component recognized by the Leiurus toxin sediments at 6.5 S. Scatchard analysis of quantitative binding experiments carried out in sucrose gradients shows approximately linear plots and indicates that the toxin recognizes a relatively small number of sites with a dissociation constant near 10 nM. Once formed, the channel element--toxin complex is quite stable. Experiments show diphasic dissociation kinetics with half-times near 70 hr and greater than 200 hr.

Animals↗