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M G Goodman

Publications and source records attributed to M G Goodman.

At least 73 records · Page 4Linked to original sources
PubMed1982

Bromination of guanosine and cyclic GMP confers resistance to metabolic processing by B cells.

The metabolic fates of 8-bromoguanosine (8BrGuo) and 8-bromoguanosine-3'5'-cyclic monophosphate (8Br-cGMP) were examined in cultures of murine B lymphocytes. These compounds exert striking immunostimulatory effects upon bone marrow-derived lymphoid cells in vitro. Both 8BrGuo and 8Br-cGMP were resistant to metabolic processing by these cells. That purine metabolic pathways are intact and operant in B cells was demonstrated by the ready degradation and phosphorylation of native guanosine and cyclic GMP. Inaccessibilty of the substrate to the relevant enzymes was ruled out as an explanation by the observation that the brominated compounds also were resistant to processing in broken cell preparations. Moreover, 8BrGuo did not interfere with the cellular machinery for metabolizing native guanosine. The implications of these observations for studying the actions of purine nucleotides, cyclic nucleotides, and their enzymatic processing in B cells are discussed.

Animals↗
PubMed1981

T cell regulation of polyclonal B cell responsiveness. III. Overt T helper and latent T suppressor activities from distinct subpopulations of unstimulated splenic T cells.

Polyclonal activation of murine splenic B lymphocytes by lipopolysaccharide was found to be subject to regulation by helper and suppressor influences from T lymphocytes. In the normal adult spleen, only helper influences were exercised over polyclonal B cell activation; this influence is a property of Lyt-l(+)23(-) slowly sedimenting T cells. Suppressive influence evidently is latent, for it exists at such a low level (or the cells are so few in number) that its effects are difficult to detect. Suppressor T cell function may be evoked by culturing spleen cells at high ratios of T:B cells, by activating splenic T cells with concanavalin A, or by sonicating unstimulated splenic T cells to liberate a suppressive potential that is not expressed by these unstimulated cells when intact. The soluble fraction of resident splenic T cell sonicates exerts both helper and suppressor regulatory influences. The soluble helper activity is derived from Lyt-l(+)23(-) slowly sedimenting T cells, whereas suppressor activity is generated from a distinct subpopulation of Lyt-l(-)23(+) rapidly sedimenting T cells. The thymus contains cells capable only of helping but not of suppressing polyclonal activation of splenic B cells. Helper and suppressor activities contained in splenic T cell sonicates were separated by gel chromatography; the suppressive activity was found to elute with a molecular weight between 68,000 and 84,000 and the helper activity eluted with a molecular weight between 15,000 and 23,000. The data indicate that helper and suppressor activities are distinct molecular entities derived from distinct splenic T lymphocyte subpopulations. The possibility that these molecules are precursors to or components of antigen- specific or nonspecific helper and suppressor factors described in the literature is discussed.

Animals↗
PubMed1981

Activation of lymphocytes by brominated nucleoside and cyclic nucleotide analogues: implications for the "second messenger" function of cyclic GMP.

The purine nucleoside guanosine, when derivatized at the C-8 position to give 8-bromoguanosine (8-BrGuo), acquires the capacity to stimulate high-level lymphocyte proliferation in the presence or absence of serum. Direct comparisons were undertaken to determine whether this activity is exerted only by virtue of the structural resemblance of 8-BrGuo to 8-bromo cyclic GMP (8-BrcGMP) (a known intracellular lymphocyte mitogen). They showed that, of the brominated guanosine derivatives studied, 8-BrGuo is the primary activator because (i) it is a far more potent lymphocyte activator than 8-BrcGMP, the order of mitogenic potency being 8-BrGuo greater than 8-bromo GMP (8-BrGMP) greater than 8-BrcGMP; (ii) it acts much more rapidly than 8-BrcGMP; (iii) it is not metabolized to 8-BrcGMP or cGMP; and (iv) it does not elevate intracellular cGMP content. cGMP is not likely to be the second messenger serving to activate B cells because (i) it does not induce significant proliferation unless brominated at the C-8 position; (ii) the brominated form is much less efficient than 8-BrGuo or 8-BrGMP; (iii) 8-BrGuo and many other mitogens do not increase intracellular cGMP; (iv) many agents that increase cGMP fail to initiate lymphocyte activation; (v) certain agents that increase cGMP (i.e., 15-hydroperoxyarachidonic acid, azide) inhibit lymphocyte activation; and (vi) addition of unbrominated cGMP to cultures stimulated with 8-BrGuo actually diminished stimulation. These data (i) indicate that, by interaction with cellular components, 8-BrGuo triggers high level lymphocyte activation and (ii) cast significant doubt on the role of cGMP as an intracellular second messenger in lymphocyte proliferation.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1980

Inability of the C3a anaphylatoxin to promote cellular lysis.

Investigation of the biological effects of the cleavage product, C3a, derived from the third component of complement has generally focused on the effects it exerts as an anaphylatoxin, that is, smooth muscle contraction and histamine release from mast cells and basophils. Therefore, reports that C3a exerts cytoxic effects on various cell types, and exhibits concentration-dependent specificity for malignant cells, excited great interest. The cytolytic activity mediated by macrophages which were activated in vitro may be attributed to their ability to generate C3a. The far-reaching implications of such a cytolytic role for C3a led us to pursue these observations further. We report here that we have been unable to duplicate the results reported by Ferluga et al. On the contrary, we find that C3a actually reduces spontaneous release of label below normal background levels.

Animals↗
PubMed1980

Inhibition of lymphocyte mitogenesis by an arachidonic acid hydroperoxide.

Incubation of murine spleen cells with the oxidation product of soybean lipoxidase-treated arachidonic acid results in profound inhibition of induction of proliferation and maturation of these cells. The active entity was shown to be the 15-hydroperoxide of arachidonic acid (15-HPAA). Inhibition of the enzymes of the cyclo-oxygenase pathway fails to disturb this effect, indicating that 15-HPAA is not a substrate for this series of enzymes. 15-HPAA produced in this manner interfered with RNA synthesis, DNA synthesis, and blastogenesis, while failing to exert cytotoxic effects on the cells themselves. A variety of lymphocyte subpopulations, distinguished by their responsiveness to a diverse group of mitogens, were all equally inhibited by the addition of 15-HPAA to culture. Addition of this agent even as late as 24 h after initiation of culture resulted in profound inhibition of the proliferative and differentiative responses of splenic B cells to bacterial lipopolysaccharide (LPS). Exposure of cells to 15-HPAA for 10-30 min was adequate to initiate inhibition, an event that exhibited marked temperature dependence. The effects of pre-incubation with 15-HPAA could not be reversed in its absence in recovery periods of up to 6 h prior to addition of LPS. The implications of these data with reference to cellular activation mechanisms are discussed.

Animals↗
PubMed1979

Nonspecific activation of murine lymphocytes. VI. Mediation of synergistic interaction between T and B lymphocytes by a cell-associated, reciprocally acting lymphocyte proliferation helper.

The mechanism by which B and T lymphocytes interact synergistically in the proliferative response to 2-mercaptoethanol (2-ME) as a mitogen was investigated in cultures of C3H/St spleen cells. The interaction between these cells required physical contact between the collaborating cell types, and was not mediated by the release of a soluble factor into the culture supernate. Sonicates of spleen cells which had been activated with optimal concentrations of 2-ME for 24 h and then washed extensively, stimulated the uptake of tritiated thymidine and morphological blast transformation of fresh, unstimulated cells. This activity was found to reside within the soluble fraction of the activated cells, and to activate cells optimally at a ratio of 1 naive cell: 1 activated cell-equivalent. This reciprocally-acting lymphocyte proliferation helper (RALPH) activity was produced by B cells as well as by T cells, with a kinetic peak at 48 h of culture. RALPH activity was produced by viable but not by nonviable cells incubated with 2-ME, and was nondialyzable. It could not be induced by the B-cell mitogens lipopolysaccharide, polyinosinic-polycytidilic acid, or purified protein derivative of tuberculin, or by the T-cell mitogen concanavalin A. RALPH isolated from T cells activated B cells exclusively, while that from B cells acted predominantly upon T cells, possibly with a nonspecific effect on B cells. A model for the cellular interactions involved in the amplification of the proliferative response to 2-ME is described.

Animals↗
PubMed1979

T cell regulation of polyclonal B cell responsiveness. II. Evidence for a deficit in T cell function in mice with an X-linked B lymphocyte defect.

In addition to the x-linked B cell maturation deficit previously reported in CBA/N mice, a functional T cell defect has now been observed. T lymphocyte regulation of the polyclonal PFC response was studied within the context of this x-linked immunodeficiency model. The ability of 1) B cells from (CBA X CBA/CaJ)F1, male mice to respond to nonspecific T cell helper signals and 2) T cells from NCF1 male mice to provide such signals was investigated under in vitro conditions by using bacterial lipopolysaccharide (LPS) as the polyclonal activator. B lymphocytes from both male and female NCF1 mice were receptive to T cell help rendered by NCF1 female T cells. Male T cells. however, were unable to augment polyclonal B cell responses of either NCF1 male or female B cells to LPS. Treatment with ATS + C reduced the polyclonal response of female but not male spleen cells to LPS. This deficit could not be overcome by the use of greater numbers of NCF1 male T cells. The observation that this deficiency in T cell regulation is not due to active suppression suggests that the results may be attributable to an intrinsic T cell defect.

Animals↗
PubMed1979

T cell regulation of polyclonal B cell responsiveness. I. Helper effects of T cells.

Polyclonal activation of murine splenic B lymphocytes to secrete immunoglobulin was shown to be subject to regulation by splenic T cells. By admixture of separated B and T cell populations it was demonstrated that normal fresh splenic T cells were able to augment polyclonal B cell responsiveness to LPS up to several-fold. Optimal collaboration between these two cell types ensued when they were co-cultured in equal numbers. T cell-mediated enhancement of polyclonal B cell responses was dependent upon the ability of T cells to divide and was manifested upon T cell interaction with B cells soon after culture initiation. Originally expounded as a one-signal phenomenon, polyclonal activation of lymphocytes by LPS is, under the circumstances described, attributable instead to two distinct, nonspecific signals acting in concert. The observation that T cells from LPS-nonresponder (C3H/HeJ) mice were deficient in the capacity to enhance polyclonal B cell responsiveness of B cells derived from responder (C3H/HeN) mice implied a direct action of LPS on the involved T cells as well as an active role for the T cell signal in this immunoregulatory event. The novel observation of a functional T cell defect in LPS responsiveness in the C3H/HeJ mouse is discussed in terms of its other cellular defects.

Animals↗
PubMed1978

Immunologic responsiveness of the C3H/HeJ mouse: differential ability of butanol-extracted lipopolysaccharide (LPS) to evoke LPS-mediated effects.

The lipopolysaccharide (LPS)-protein complex extracted from the cell wall of Escherichia coli K235 by the butanol-water technique has been shown to evoke a mitogenic response in bone marrow-derived (B) lymphocytes from the C3H/HeJ mouse strain. These mice are resistant to the effects of LPS extracted with phenol. Therefore, the ability of butanol-extracted LPS to modulate a spectrum of C3H/HeJ B-cell functions was investigated. Both butanol-extracted (LPS-B) and phenol-extracted (LPS-P) LPS preparations activated responder C3H/St spleen cell cultures to polyclonal antibody production, while only LPS-B activated C3H/HeJ spleen cells. Both LPS-P and LPS-B acted as adjuvants when injected after aggregated human gamma globulin (HGG) in C3H/St mice, but neither preparation was effective as a adjuvant in C3H/HeJ mice. LPS-P injected with deaggregated HGG (tolerogen) into LPS-sensitive mice has been shown previously to inhibit the induction of tolerance HGG. In the present studies, it was shown that LPS-B, but not LPs-p, was able to inhibit tolerance induction to HGG in the C3H/HeJ, whereas both preparations were effective in the C3H/St. LPS has also been shown to bypass tolerant T cells in LPS-sensitive mice late in tolerance to HGG at a time when B cells are responsive. However, in the C3H/HeJ, neither LPS-B nor LPS-P was capable of this function. The responsiveness of these B cells to HGG was demonstrated in transfer experiments. Thus, in the C3H/HeJ, LPS-B stimulates mitogenesis, polyclonal B-cell activation, and inhibition of tolerance induction, but cannot act as an effective adjuvant or as a bypass mechanism to activate B cells in the presence of tolerant T cells. The explanation for this pattern of responses may be attributable to yet another cellular defect in the C3H/HeJ mouse.

Adjuvants, Immunologic↗
PubMed1978

Nonspecific activation of murine lymphocytes. II. Parameters of the interaction between splenic lymphocytes and radiolabeled 2-mercaptoethanol in vitro.

Recent evidence has indicated that addition of 2-mercaptoethanol (2-ME) to culture medium is able to activate murine lymphocytes to undergo blastogenesis, to synthesize polyclonal antibody, and to develop cytotoxicity to both autologous and heterologous target cells. In order to explore the basis for these phenomena, a study of the physical interaction between the cell and 2-ME was undertaken by using a radiolabeled preparation of 2-ME. Uptake of labeled 2-ME increased over the initial 24 hr of culture, after which a steady state was achieved. Cells were found to have maximal susceptibility to activation by 2-ME after incubation for 24 hr in the absence of the thiol compound. This observation was not explicable in terms of any alteration in the kinetics of 2-ME uptake. The amount of labeled 2-ME taken up was a function of the 2-ME concentration with which the cell was incubated, with the exception of the concentration range that is optimal for mitogenesis. At this range, the curve was suggestive of a saturation effect. Uptake by B cell cultures was found to exceed that by T cell cultures. Uptake was shown to result from interaction with protein, to be independent of metabolic energy, to be governed by temperature-dependent kinetics, and to be highly specific.

Animals↗