bluuebunny/crossref_metadata_2025_split huggingface dataset:
ON THE RELATION OF PRODUCTS OF ACTIVATED LYMPHOCYTES TO CELL-MEDIATED CYTOLYSIS
Authors: Henney Christopher S. , Gaffney Judith , Bloom Barry R. 
Published: June 2004

Experiments have been designed to test the hypothesis that soluble mediator production and T-cell-mediated cytotoxicity are necessarily related phenomena, and that soluble mediators may be involved in the mechanism of cytolysis. To this end, agents known to inhibit T-cell-mediated lysis in vitro have been studied for their effects on the production of two lymphocyte-derived mediators, lymphotoxin (LT) and migration inhibitory factor (MIF).
A clear dissociation between mediator production and cell-mediated cytolysis was found using inhibitors of protein synthesis. Pactamycin and emetine, in doses of 10–7 M to 10–6 M, suppressed production of MIF and LT with only slight effect on killing of mastocytoma cells by immune T cells. On the other hand colchicine and vinblastine inhibited T-cell-mediated cytolysis in a dose-related manner but had no significant effect on either MIF or LT production, A striking dichotomy was also observed after augmentation of intracellular cyclic 3'5' adenosine monophosphate (cAMP) levels with cholera enterotoxin. Increased cAMP levels were associated with abrogation of direct lytic activity, but were without significant effect on MIF or LT production in guinea pigs or mice. These findings indicate that mediator production and direct lymphocyte-mediated cytolysis can be experimentally dissociated and represent independent cell-mediated immune functions.
ISOLATION OF ANTIGEN-BINDING CELLS FROM UNPRIMED MICE
Authors: Julius Michael H. , Herzenberg Leonard A. 
Published: June 2004

Cells binding DNP groups conjugated to fluoresceinated mouse gamma globulin (FDNP-MGG) were isolated from spleens of unprimed mice using a fluorescence-activated cell sorter (FACS). The isolated cells were specifically enriched at least 100-fold for anti-DNP precursor activity in an adoptive transfer assay as compared to unfractionated spleen. The fraction depleted of binding cells, although depleted of anti-DNP precursor activity, responded as well as unfractionated spleen when assayed for anticarrier (keyhole limpet hemocyanin [KLH]) precursor activity.
High avidity binding cells were stained using low concentrations of FDNP-MGG. Medium and low avidity binding cells were stained using high concentrations of FDNP-MGG in the presence of free hapten which selectively blocked staining of the high avidity binding cells. Cells were supplemented with an excess of carrier-primed (KLH), nylon-purified splenic T cells and transferred to irradiated recipients. DNP-KLH was given at transfer and 5 days later. The anti-DNP plaque-forming cell (DNP-PFC) response and the avidities of the DNP-PFC in the irradiated recipients were measured by hapten inhibition of direct PFC plaque formation 12 days after transfer. At this time, very few indirect PFC were found.
There was a positive correlation between the avidity of the DNP-binding cells and the avidity of the anti-DNP antibody secreted by their progeny. High avidity DNP-binding cells gave rise to predominantly high avidity anti-DNP-PFC. Medium and low avidity binding cells gave rise to medium and low avidity DNP-PFC.
INDUCTION OF MACROPHAGE PLASMINOGEN ACTIVATOR BY ENDOTOXIN STIMULATION AND PHAGOCYTOSIS
Authors: Gordon Saimon , Unkeless Ay C. , Cohn Z. A. 
Published: June 2004

The injection of thioglycollate medium into the peritoneal cavity of the mouse induces high levels of macrophage fibrinolytic activity due to the production and secretion of a plasminogen activator, a trypsinlike serine protease, which is absent in unstimulated macrophages. Intraperitoneal injection of endotoxin or mineral oil can stimulate only a fraction (&lt;10%) of the fibrinolytic activity of thioglycollate cells, similar to the partial stimulation (&lt;10%) seen 1–2 days after phagocytosis of latex or SRBC by unstimulated macrophages. The endotoxin-stimulated macrophages contain and release relatively low levels of plasminogen activator, but these primed cells can be triggered to produce and secrete high levels of enzyme, by phagocytosis of latex. Under conditions where the plasminogen activator is induced and secreted, there are no effects on the production and/or release of lysozyme or intracellular acid hydrolases,
Discovery of a two-stage procedure for inducing macrophage plasminogen activator made it possible to study the role of cell priming and phagocytosis separately. Endotoxin was a more effective priming agent, weight for weight, than lipid A:BSA complex. Secretion of the plasminogen activator was induced only by thioglycollate, or endotoxin and latex. In situ fibrinolysis was induced by these agents and mineral oil, BCG, and fetal calf serum, in decreasing order of effectiveness. Phagocytosis of latex in all cases except thioglycollate stimulation, increased fibrinolytic activity from three- to sixfold.
Latex and a variety of other particles such as M. lysodeikticus, aggregated γ-globulin and immune complexes showed dose-dependent stimulation of fibrinolysis by endotoxin-primed macrophages. Although the initial phagocytic trigger was not specific for the substance employed, the ability to induce a sustained response depended on the persistence of the phagocytized particle within the cell. Fibrinolysis and secretion of plasminogen activator continued at high levels for at least 9 days after uptake of latex, a nondigestible particle, whereas plasminogen activator was secreted only transiently after ingestion of rapidly digested M. lysodeikticus. The induction of plasminogen activator secretion provides a mechanism by which the activated macrophage can exert a selective effect on its extracellular environment.
STUDIES ON MEDIATOR PRODUCTION BY HIGHLY PURIFIED HUMAN T AND B LYMPHOCYTES
Authors: Rocklin Ross E. , MacDermott Richard P. , Chess Leonard , Schlossman Stuart F. , David John R. 
Published: June 2004

Highly purified populations of T and B lymphocytes obtained by affinity column separation were stimulated by antigen and their ability to produce two mediators, migration inhibitory factor (MIF) and lymphocyte mitogenic factor (LMF) was assessed. Both T- and B-cell populations made MIF; the production of MIF was antigen-specific using purified protein derivative of tuberculin, streptokinase-streptodornase, and Candida antigens. The MIF activity from both populations could not be attributed to antigen-antibody complexes as the inhibitory activity eluted from Sephadex G-100 columns in the same region corresponding to mol wt 23,000 daltons. Further studies indicate that the T cells producing MIF are proliferating cells whereas the B cells producing this mediator are not.
In contrast, LMF was made only by T cells and not B cells when these populations were stimulated by antigen. The LMF induced the [3H]thymidine incorporation into both T and B cells obtained from donors lacking sensitivity to the antigens used to elicit the factor. Chromatographic studies indicate that LMF eluted from Sephadex G-100 in a fraction of mol wt 23,000 daltons where MIF is also found; however, since B cells produce MIF but not LMF, these two factors appear to be distinct from one another.
Some of the implications of these findings are discussed. The explanation for the production or lack of production of MIF by lymphocytes obtained from patients with immunodeficiency disorders requires reinterpretation.
DISTRIBUTION OF FIBROBLAST SURFACE ANTIGEN
Authors: Wartiovaara Jorma , Linder Ewert , Ruoslahti Erkki , Vaheri Antti 
Published: June 2004

The localization of a cell type-specific, soluble fibroblast surface antigen (SFA) was studied by immunofluorescence and by scanning electron microscopy of the same cells. The antigen had an uneven distribution forming streaks on chick embryo fibroblasts. It was localized to membrane processes and ridges, with a diameter of 50–200 nm. The processes extended from the periphery of the cells to the substratum or to other cells. Trypsin treatment completely removed detectable amounts of SFA. The antigen was detectable within 1 h after trypsin-treated cells were reseeded. The reappearance of SFA correlated with the restoration of membrane processes.
Fibroblasts transformed by Rous sarcoma virus (RSV) showed loss of all or most SFA. When normal cells were transformed without subcultivation and trypsinization a fibrillar extracellular network of SFA remained under the transformed fibroblasts while the cells themselves were negative in immunofluorescence. When fibroblasts infected by RSV mutants were transferred to nonpermissive temperature for transformation new SFA was detected within 2 h. These data lead us to propose that loss of stabilizing and anchoring effect of SFA molecules in fibrillar cell surface structures may be critical in altered growth control and malignant transformation.
The capacity of mitogen-responsive T cells to home to their tissue of origin, analyzed by means of chromosome markers
Authors: Doenhoff MJ , Davies AJS 
Published: June 2004

Lance and Taub (1) showed that when radioactively labeled lymphocytes were injected into a syngeneic mouse and the lymph node cells of this animal transferred to a second syngeneic recipient, the proportion of radioactivity found in the lymph node relative to the amount present in the spleen of the secondary recipient had increased markedly. The interpretation of this result was that some lymphocytes have the capacity to home to their organ of origin.
The purpose of the experiments described here was to test the homing copacity of T cells by a method that did not involve radioactive labeling. It has been shown elsewhere that some or all mouse T cells are stimulated to divide in culture by the mitogens phytohemagglutinin (PHA) and concanavalin A (Con A) (2). We therefore elected to inject karyotypically distinct lymphocytes into syngeneic recipients and to follow their subsequent distribution by culture of lymph node and spleen cells of the recipient with PHA or Con A. In this manner the homing capacities of spleen and lymph node T cells could be determined, and furthermore, the effects of labeling with chromium-51 ((51)Cr) could be assayed with respect to the persistence of mitogen responsiveness in the injected cells.
Genetic control of specific immune suppression. IV. Responsiveness to the random copolymer L-glutamic acid(50)-L-tyrosine(50) induced in BALB/c mice by cyclophosphamide
Authors: Debre P , Waltenbaugh C , Dorf ME , Benacerraf B 
Published: June 2004

Previous reports from our laboratory have demonstrated the stimulation of specific suppressor T cells in genetic nonresponder mice after immunization with the terpolymer of L- glutamic acid, L-alanine, and L-tyrosine (GAT) (1,2) and with the copolymer of L-glutamic acid and L-tyrosine (GT) (3-5). These findings raise two important questions: (a) do the specific suppressor T cells inhibit an antibody response which would otherwise develop in nonresponder mice; and, (b) can specific helper T cells inhibit an antibody response which would otherwise develop in nonresponder mice; and, (b) can specific helper T-cell activity be detected in these animals. Responsiveness appears to be completely dominant over suppression in (responder x suppressor)F(1) hybrids, therefore, we have been unable to detect suppressor cells in these hybrids after conventional immunization with GAT (2). However , using special conditions of antigen administration, GAT helper activity could be demonstrated in nonresponder DBA/1 (suppressor) mice. Thus, GAT-specific helper activity was not detected in these nonresponder animals after immunization with GAT irrespective of the adjuvant used, but could be stimulated by macrophage-bound GAT or by GAT complexed with methylated bovine serum albumin GAT-MBSA (6).
In the current report we have taken advantage of the fact that suppressor T-cell activity is more sensitive to cyclophosphamide treatment than T-cell helper activity (7) to demonstrate the presence of GT-specific helper activity in nonresponder BALB/c mice. We describe: (a) the dose of cyclophosphamide and conditions of treatment which inhibits the well-documented stimulation of specific suppressor T cells in BALB/c mice injected with GT previous to immunization with GT-MBSA, and (b) the ability of cyclophosphamide to permit the development of primary PFC responses to GT in these nonresponder mice.
These cyclophosphamide-induced responses are not characterized by the high levels of antibody detected in genetic responder animals.
Isolation of a lipid a bound polypeptide responsible for LPS- initiated mitogenesis of C3H/HeJ spleen cells
Authors: Morrison DC , Betz SJ , Jacobs DM 
Published: June 2004

The experiments by Sultzer and Nilsson (1), and later by Watson and Riblet (2), established that spleen cells from the C3H/HeJ strain of mouse were refractory to the mitogenic effects of bacterial lipopolysaccharides (LPS). More recently, however, experiments from our laboratory (3) demonstrated that spleen cells from C3H/HeJ mice were in fact responsive to some preparations of LPS but not to others, and that the method of extraction played a critical role in determining activity. In particular, preparations of LPS prepared by extraction with aqueous butanol had potent mitogenic activity. Our data showed that the mitogenic activity of such positive preparations of LPS coisolated with the LPS during gel filtration chromatography and subsequent equilibrium banding on CsCl. In addition, lipid A isolated from positive preparations of LPS was also capable of stimulating C3H/HeJ spleen cells. Taken together, these experiments provided rather convincing data that it was the LPS (in particular the lipid A) itself, or some contaminant very tightly bound to the lipid A, which was responsible for its biological activity.
We further demonstrated that treatment of positive preparations of LPS with hot phenol rendered such preparations nonmitogenic for C3H/HeJ spleens, yet activity for other strains was only moderately decreased. These experiments would suggest either that the phenol treatment chemically alters the lipid A region of the LPS molecule or that such treatment removes the putative tightly bound contaminant responsible for C3H/HeJ mitogenesis.
In the experiments reported here, we have explored in greater detail the role of lipid A in the stimulation of C3H/HeJ spleen cells. For these experiments we have utilized our earlier observations that the antibiotic polymyxin B forms a highly stable molecular complex with the lipid A region of LPS (4), and that such polymyxin B-LPS complexes are unable to mitogenically stimulate B lymphocytes (5). In addition, we have attempted to distinguish between the two potential modes of action of phenol on LPS, namely, the chemical alteration of the lipid A or the removal of a tightly bound contaminant by phenol treatment. The results of the experiments we report here support the interpretation that mitogenic activity of positive preparations of LPS is associated with a low mol wt phenol soluble polypeptide of approximately 10,000 mol wt. After partial purification, this polypeptide intitiates a significant mitogenic response at concentrations as low as 10 μg/ml. We conclude that the C3H/HeJ strain of mouse is a true nonresponder to the stimulatory effects of the lipid A region of LPS.
The specificity of T-cell helper factor in man
Authors: Geha RS , Mudawwar F , Schneeberger E 
Published: June 2004

Supernates of human T cells stimulated with TT antigen contain a factor that induces mitogenesis and immunoglobulin synthesis in autologous as well as allogeneic B cells. A fraction of the IgG produced has specificity against TT. The T-cell-derived LMF-TT eluted after albumin on Sephadex G 200 and did not contain immunoglobulin heavy chain determinants. LMF-TT was active on B cells from TT immune as well as TT- nonimmune individuals but in the latter instance the IgG secreted had no specificity against TT. B cells incubated with LMF-TT in the presence of a second antigen (DT) made IgG with specifity to that antigen provided the B-cell donor was immune to that second antigen.
LMF-TT-containing supernates were depleted of TT antigen by Sephadex G 200 chromatography followed by passage over anti-TT immunosorbent columns. The antigen-free supernates were able to induce mitogenesis and IgG synthesis in B cells but the IgG produced failed to exhibit specificity against TT unless the TT antigen was readded to the B-cell cultures.
The optimal concentration of LMF-TT (50 percent) inducing B-cell mitogenesis was different from the optimal concentration (20 percent) causing IgG synthesis by B cells. At low LMF concentrations (less than or equal 10 percent) addition of a second antigen to which the cell donor was immune caused an increase in the degree of B-cell mitogenesis. Submitogenic concentrations of LMF-TT (less than or equal to 5 percent) were still capable of inducingimmunoglobulin synthesis in B cells At these low concentrations of LMF-TT the proportion of anti-TT IgG over total IgG increased sharply.
B cells from TT immune donors were separated on TT immunosorbent columns. Cells that bound to the column were more sensitive to the mitogenic and IgG synthetic effects of LMF-TT than unfractionated B cells.
Thus, LMF is a nonspecific human T-cell helper factor which behaves like a polyclonal B-cell activator. However, in the presence of specific antigen (TT) the antigen-specific B cell is preferentially triggered by LMF. The experimental design of the present study does not rule out the additional presence of an antigen-specific helper factor in the supernates of TT-stimulated human T cells.
Carrier-directed anti-hapten responses by b-cell subsets
Authors: Lewis GK , Goodman JW 
Published: June 2004

The capacity of the trinitrophenyl (TNP) haptenic group, coupled to a series of chemically dissimilar carriers, to cross-stimulate putative T- dependent and T-independent murine B-cell subpepulations was determined by using an in vitro limiting dilution technique to generate primary IgM responses. It was found that TNP-Ficoll and TNP-dextran, two T- independent antigens with little or no polyclonal mitogenicity, stimulate the same population of anti-TNP precursors, which is distinct from the precursor population activated by TNP-bacterial lipopolysaccharide (LPS), a T-independent polyclonal mitogen, or TNP-horse erythrocytes (HRBC), a T-dependent antigen. On the other hand, TNP-LPS and TNP-HRBC activate the same precursor population, indicating that LPS can substitute for the T- cell signal in T-dependent B-cell responses, whereas nonmitogenic T- independent antigens cannot. However, the cumulative evidence from this and other laboratories strongly indicates that LPS and T-dependent antigens activate B cells by different mechanisms. Of particular interest, LPS is incapable of activating B cells responsive to weakly- or nonmitogenic T-independent antigens.
Based on clonal burst size, T-dependent antigens are capable of inducing greater antigen-specific B-cell proliferation than T-independent antigens. However, TNP conjugates of Ficoll and dextran, which are relatively poor inducers of polyclonal B-cell activation, induced larger anti-TNP clones than did TNP-LPS, a strong polyclonal mitogen.
The findings reinforce the evidence favoring existence of multiple B- cell subpopulations with distinctive activation pathways. They also strengthen the proposition that a given B-cell subset can be activated by more than one mechanism.
Differentiation of memory T cells to virus plaque-forming cells and cytotoxic T lymphocytes
Authors: Senik A , Bloom BR 
Published: June 2004

The aims of this study were to define the T-cell subpopulation(s) detected by the virus plaque assay, and particularly to determine whether the virus plaque assay could be used to enumerate cytotoxic T lymphocytes. In addition, studies were undertaken to ascertain whether cell proliferation was required for development of cytotoxic effector function and virus plaque formation by these subpopulations. The results of experiments with a secondary mouse mixed lymphocyte culture (MLC) model indicated that 70 percent of virus plaque-forming cells bore the Ly 1 phenotype and 30 percent the Ly 2,3 phenotype. Three lines of evidence suggested that cytotoxic T lymphocytes (CTL) can be detected by this assay: the fact that some virus plaque-forming cells (V-PFC) bear the same Ly phenotype as CTL; the use of an inhibitor of DNA synthesis indicated that proliferating cells could be eliminated with no effect on V-PFC production and cytotoxic activity of the Ly 2,3 cell population; and that infection of primed lymphocyteswith vesicular stomatitis virus before (MLC) stimulation eliminated cytotoxic activity.
In primary MLC, development of V-PFC and CTL was completely abolished by cytosine arabinoside. In contrast, in secondary MLC, some CTL and V- PFC were generated by antigenic stimulation in the absence of proliferation. However, the development of both functions became progressively more susceptible to cytosine arabinoside as the time between primary immunization and in vitro boosting is increased. It is suggested that there may be a considerable disparity between the number of existing effector cells at any given time and the cytotoxic potential, i.e. the number of cells capable of being generated by antigenic stimulation.
Regulatory functions of hapten-reactive helper and suppressor T lymphocytes. II. Selective inactivation of hapten-reactive suppressor T cells by hapten-nonimmunogenic copolymers of D-amino acids, and its application to the study of suppressor T-cell effect on helper T-cell development
Authors: Hamaoka T , Yoshizawa M , Yamamoto H , Kuroki M , Kitagawa M 
Published: June 2004

An experimental condition was established in vivo for selectively eliminating hapten-reactive suppressor T-cell activity generated in mice primed with a para-azobenzoate (PAB)-mouse gamma globulin (MGG)-conjugate and treated with PAB-nonimmunogenic copolymer of D-amino acids (D- glutamic acid and D-lysine; D-GL). The elimination of suppressor T-cell activity with PAB-D-GL treatment from the mixed populations of hapten- reactive suppressor and helper T cells substantially increased apparent helper T-cell activity. Moreover, the inhibition of PAB-reactive suppressor T-cell generation by the pretreatment with PAB-D-GL before the PAB-MGG-priming increased the development of PAB-reactive helper T-cell activity. The analysis of hapten-specificity of helper T cells revealed that the reactivity of helper cells developed in the absence of suppressor T cells was more specific for primed PAB-determinants and their cross-reactivities to structurally related determinants such as meta-azobenzoate (MAB) significantly decreased, as compared with the helper T-cell population developed in the presence of suppressor T lymphocytes. In addition, those helper T cells generated in the absence of suppressor T cells were highly susceptible to tolerogenesis by PAB-D- GL.
Similarly, the elimination of suppressor T lymphocytes also enhanced helper T-cell activity in a polyclonal fashion in the T-T cell interactions between benzylpenicilloyl (BPO)-reactive T cells and PAB- reactive T cells after immunization of mice with BPO-MGG-PAB. Thus inhibition of BPO-reactive suppressor T-cell development by the BPO-v-GL- pretreatment resulted in augmented generation of PAB-reactive helper T cells with higher susceptibility of tolerogenesis to PAB-D-GL.
Thus, these results support the notion that suppressor T cells eventually suppress helper T-cell activity and indicate that the function of suppressor T cells related to helper T-cell development is to inhibit the increase in the specificity and apparent affinity of helper T cells in the primary immune response. The hapten-reactive suppressor and helper T lymphocytes are considered as a model system of T cells that regulate the immune response, and the potential applicability of this system to manipulating various T cell-mediated immune responses is discussed in this context.