bluuebunny/crossref_metadata_2025_split huggingface dataset:
Regulation of delayed‐type hypersensitivity. III. Effect of cyclophosphamide on the suppressor cells for delayed‐type hypersensitivity to sheep erythrocytes in mice
Authors: Gill H. K. , Liew F. Y. 
Published: February 2007

AbstractA previous study (Eur. J. Immunol. 1977. 7: 714) has shown that mice injected intravenously (i.v.) with 1 × 109 sheep red blood cells (SRBC) produce cells which suppress delayed‐type hypersensitivity (DTH). These suppressor cells are Θ‐positive, antigen‐specific and act via a soluble factor which does not bear immunoglobulin determinants (Eur. J. Immunol. 1978. 8: 168). The present paper demonstrates that these suppressor cells are inhibitable by cyclophosphamide (CY). Mice injected with graded amounts of CY two days prior to SRBC injection, showed maximum augmentation of DTH at 200 mg/kg body weight, a dose which completely suppressed the appearance of splenic plaque‐forming cells (PFC) to SRBC. In contrast, lower doses of CY enhanced both DTH and PFC responses. Time course studies showed that CY inhibited the precursors of suppressor cells and had little or no effect on suppressor cells which have already encountered antigens. This was further confirmed by passive transfer studies which showed that suppressor cells were inhibited if CY was administered at the same time or 2 days before SRBC injection, but were not affected if CY was given after antigen stimulation. Direct evidence for the effect of CY on suppressor cells was obtained by cell fractionation with a Ficoll density gradient. The denser suppressor cell population was absent from the spleens of mice treated with 200 mg/kg of CY 2 days before i.v. injection with 1 × 109 SRBC.
Regulation of the mixed leukocyte culture reaction by suppressor cells
Authors: Rode H. N. , Uotila Marjatta , Gordon J. 
Published: February 2007

AbstractRegulation of the mixed leukocyte culture (MLC) reaction by suppressor cells raised and tested in MLC has been evaluated. The experiments described suggest that suppressors are distinct from cytotoxic T lymphocytes (CTL), both in terms of conditions optimal for their activation, as well as through demonstration of efficient suppression in the total absence of cytotoxic activity. Suppressor cells inhibit the activation of the precursors of CTL, and may also prevent the production of the lymphokine blastogenic factor; they do not appear to interfere with the reaction of primed cells. It is suggested that suppressor cells may regulate the MLC reaction by preventing recruitment of fresh competent cells, and by limiting the duration of the reaction of cells already activated.
Studies on the nature of the cell surface antigen reacting with cytolytic T lymphocytes in murine oncornavirusinduced tumors
Authors: Gomard Elisabeth , Levy J. P. , Plata F. , Henin Yvette , Duprez Véronique , Bismuth A. , Reme T. 
Published: February 2007

AbstractThe nature of the target antigen, expressed on murine sarcoma virus (MSV) and related murine tumors which reacts with T killer lymphocytes, remains ill‐defined. The experiments reported here show that: (a) the previously described H‐2 restriction phenomenon is found under all experimental conditions including 3–4 and 16–20‐h chromium release tests. With 16–20 h tests and highly efficient T lymphocytes however, quantitative methods are necessary to demonstrate the H‐2 restriction. These results support the hypothesis that H‐2 molecules may be determinant in the structure and/or in the function of the cytolytic T lymphocyte (CTL) reactive antigen. (b) Under syngeneic conditions (i.e. using H‐2‐identical immune lymphocytes, stimulators and target cells), the pattern of specificities recognized by anti‐MSV or anti‐Friend T killer cells on 20 different lymphomas suggests that the main reactive antigen is an “FMR‐like” substance. Identical conclusions were drawn from competition experiments. (c) Blockings were obtained by pre‐incubation of the target cells with a goat anti‐gp70, suggesting a possible role of the viral gp70 in the antigen recognized. However, this could be due to nonspecific reactions as two other anti‐gp70 sera as well as with antisera directed against the viral components gp45, pr60, p30, p15, p12 and p10 did not block. The CTL/tumor cell interaction was not inhibited by virion‐associated antigens added to the medium. Lysostrip and co‐capping experiments have failed to reveal an association between H‐2 and gp70. The nature of the viral protein bearing the “FMR‐like” substance therefore remains to be established.
Cytofluorometric analysis of macrophages activated in vivo or in vitro
Authors: Stadler Beda M. , De Weck A. L. 
Published: February 2007

AbstractThe relative RNA content of single macrophages was measured by cytofluorometry after differential staining of cellular DNA and RNA with the metachromatic fluorescent dye acridine orange. This method allowed the differentiation of two major groups in the adherent macrophage population differing in their RNA content. After in vivo stimulation of mice (by injection of thioglycollate medium) or guinea pigs (by injection of oil), an increasing percentage of macrophages possessing a high RNA content is recovered. In vitro stimulation of macrophage cultures with lipopolysaccharide had the same enhancing effect on cellular RNA content. Cytofluorometric measurement of RNA content may possibly become an efficient and rapid method of measuring macrophage activation.
Primary in vitro antibody formation in the rat: partial characterization and properties of an inhibitor cell present in normal spleen
Authors: Corvalán J. R. F. , Howard J. C. 
Published: February 2007

AbstractRat spleen cells are shown to be unresponsive to sheep red cells (SRBC) in vitro under conditions in which thoracic duct lymphocytes (TDL) respond very well. By adding unresponsive spleen cells to responsive TDL cultures, the spleen cells are shown to contain an inhibitor capable of preventing the response to SRBC. The inhibitory activity is a property of live cells; it is sensitive to radiation doses as low as 100 R × rays and to mitomycin C. It can be completely removed from spleen cell suspensions by extraction with large amounts of carbonyl iron or by filtration through nylon wool columns. It is less efficiently removed by filtration through Sephadex G‐10 columns, and is completely resistant to the cytotoxic effects of silica. From a practical point of view, extraction of a spleen cell suspension with carbonyl iron is a useful method of obtaining fully responsive lymphocyte populations from rat spleen.
Ontogeny of B lymphocyte function. VI. Ontogeny of thymus cell capacity to facilitate the functional maturation of B lymphocytes
Authors: Szewczuk M. R. , Sherr D. H. , Siskind G. W. 
Published: February 2007

AbstractThe differentiation of the B cell population from fetal mice to produce a normal, adult‐like, heterogeneous response, with respect to antibody affinity, has been shown to require (or to be facilitated by) thymus cells. The maturation of the thymus cell population to be capable of facilitating this differentiation of the B cell population was studied. It was found that the thymus cell population acquires the capacity fo facilitate (or induce) this maturation of the B cell population between seven and ten days after birth. Thus, the normal maturation of the B cell population to give a response which is heterogeneous with respect to affinity, appears to be controlled by the maturation of thymus function.
Acquired heterophile antigens on the surface of human cell lines
Authors: Aguilera S. , Ivanyi J. 
Published: February 2007

AbstractChicken IgM antibodies raised against sheep erythrocytes (SE) reacted with a heterophile carbohydrate antigen designated as “HC”. This antigen was visualized by SE rosette formation with antibody‐sensitized and formaldehydefixed target cells. Cells from eight lymphoblastoid lines and ten lines of diverse histogenetic origin all expressed HC on their surface to a greater or lesser degree when grown in fetal calf serum (FCS). Lymphoblastoid cell lines, HSB2 and Namalva, lost most of their HC antigen after three cell divisions when grown in medium which contained normal human serum (NHS) instead of FCS. The acquired origin of HC was demonstrated by the conversion of HSB2‐HC+ into HSB2‐HC' cells after incubation in the presence of FCS or fetuin for 18 h at 37°C. The acquisition of HC antigen depended on the concentration of fetuin as well as the time and temperature of incubation. The presence of NHS in the culture medium reduced the degree of HC incorporation. The level of HC expressed on the cell surface was reduced by treating HSB2 cells with sodium periodate but not by proteolytic enzymes. Competitive inhibition with hog blood group substance and sheep IgG suggested similar specificity of HC on target cells which had been sensitized with either fetuin or sheep IgM (Eur. J. Immunol. 1977.7:204). The avidity of chicken antibodies t o HC h either of these systems was several orders of magnitude lower than the binding to SE.
Evidence for the endogenous production of T cell receptors bearing idiotypic determinants
Authors: Julius M. H. , Cosenza H. , Augustin A. A. 
Published: February 2007

AbstractUnprimed thymus‐derived (T) cells from spleens of either conventional TEPC 15+ (T15+) BALB/c mice or neonatally suppressed T15− BALB/c mice were used to reconstitute neonatally suppressed T15− BALB/c nude mice and conventional T15+ BALB/c nude mice, respectively. In so doing, the idiotypes produced by phosphorycholine (PC)‐specific bone marrow‐derived (B) cells were dissociated from idiotypes putatively produced by PC‐specific T cells. Subsequent to priming of the reconstituted BALB/c nude mice with either anti‐T15 antisera or PC‐MOPC 315, their splenic T cells were assessed for PC‐specific helper activity and expression of the T15 idiotype.Our results indicate that expression of the T15 idiotype by T cells as determined by (a) the ability to prime PC‐specific helper cells with anti‐T15 antibodies, and (b) the ability to inhibit PC‐specific helper function with anti‐T15 antibodies, depended on the idiotype of the unprimed donor T cell source and not that of the B cells in the reconstituted recipients. We conclude that the idiotype‐bearing T cell receptor specific for PC is not a passively adsorbed B cell product.
Properties of antisera against lymphocytes of nude mice
Authors: Rudnicka Wieslawa , Długońska Henryka , Żelazowski P. , Szewczyk K. , Gościcka Teresa 
Published: February 2007

AbstractThe activity of rabbit antisera against nu/nu BALB/c lymphocytes was estimated in vivo and in vitro.It was found that anti‐lymphocyte serum (ALS) against nu/nu lymph node cells suppressed the alloantigen reaction and the spontaneous rosette‐forming cell (sRFC) or plaque‐forming cell (PFC) formation for T‐dependent (sheep red blood cells) and T‐independent (lipopolysaccharide) antigens. ALS against nu/nu spleen cells affected only the sRFC and PFC for T‐independent antigen. The former serum exhibited a high cytotoxicity for the suspensions enriched or depleted in B cells, while the latter was more cytotoxic for the suspension enriched in B cells. This may indicate that ALS anti‐nu/nu spleen cells is specific for B lymphocytes, and ALS anti nu/nu lymph node cells is directed not only to B cells but also to a subpopulation of T lymphocytes. It may suggest the existence of a subpopulation of T lymphocytes in nu/nu lymph node cells.
Monoclonal xenogeneic antibodies to murine cell surface antigens: identification of novel leukocyte differentiation antigens
Authors: Springer T. , Galfrè G. , Secher D. S. , Milstein C. 
Published: February 2007

AbstractHybrid myeloma cell lines secreting monoclonal antibodies to mouse cell surface antigens have been prepared. Spleen cells from a DA rat immunized with B10 mouse spleen cells that had been enriched for T cells were fused to cells from a nonsecreting mouse myeloma line (NSI). The presence in the culture supernatants of antibodies binding to mouse spleen cells was tested by a binding assay with 125I‐labeled anti‐rat IgG. From a large number of positive cultures, ten independent hybrid clones were purified, each secreting a different antibody. Each antigenic target was analyzed by (a) gel electrophoresis of immunoprecipitated 125I‐labeled cell surface molecules, (b) heat stability, (c) strain and species distribution and (d) cross‐inhibition of binding of different monoclonal antibodies.It was concluded that the ten monoclonal antibodies regognized four types of antigen. One was the heterophile, heat‐stable, Forssman antigen. The second (mol.wt. 210 000) appears to be a major 125I‐labeled lymphoid cell surface protein. The third, a minor component of spleen cells, was precipitated as two polypeptides of mol.wt. 190 000 and 105000. Five IgG‐secreting clones identify the fourth antigen, a heat‐stable, possibly glycolipid component expressed on mouse red blood cells and also on thymocytes. Cross‐inhibition studies suggest that these last monoclonal antibodies bind to overlapping, but not identical, determinants. The class and chain composition of the monoclonal antibodies were studied by gel electrophoresis, isoelectric focusing and ability to lyse red blood cells and thymocytes.
The macrophage, target cell of the synthetic adjuvant muramyl dipeptide
Authors: Fevrier M. , Birrien J. L. , Leclerc C. , Chedid L. , Liacopoulos P. 
Published: February 2007

AbstractThe mechanism of adjuvant activity of the synthetic glycopeptide N‐acetylmuramyl‐L‐alanyl‐D‐isoglutamine or muramyl dipeptide (MDP) was studied using in vitro plaque‐forming cell (PFC) response to sheep erythrocytes (SRBC). Addition of MDP to DBA/2 mouse spleen cell cultures resulted regularly in a 2 to 3‐fold increase of PFC numbers/106 recovered cells (p < 0.01). Supernates (SPN) from MDP‐stimulated cultures added to standard spleen cell + SRBC cultures brought about even more important increases of PFC numbers (p < 0.01 to p < 0.001). SPN from cultures supplemented with MDP alone (without SRBC) were more active than those of cell + MDP + SRBC cultures, and SPN removed on day 3 of culture were more active than those of day 5. This activity of SPN was maintained accross an H‐2 histocompatibility barrier. Although pretreatment of spleen cells with anti‐θ antigen serum entirely suppressed the anti‐SRBC PFC response in spite of the presence of MDP, SPN from these cultures were as active as SPN from normal spleen cell MDP‐stimulated cultures. In contrast, pretreatment of spleen cells with specific rabbit anti‐mouse macrophage serum entirely suppressed both anti‐SRBC response and SPN activity. It was concluded that the target cell for MDP is the macrophage which releases factors ultimately acting on B cells through T cell mediation.
A time study of the requirement for carrier‐specific helper cells in the response of mice to dinitrophenylated keyhole limpet hemocyanin
Authors: Segre Mariangela , Segre D. 
Published: February 2007

AbstractThe anti‐hapten response of spleen cells from mice primed with hapten‐carrier (dinitrophenylated keyhole limpet hemocyanin) was decreased by depletion of T cells during the first four days after secondary antigenic stimulation, but was unaffected when the T cells were depleted on day 5. The response of cultures that were depleted of T cells prior to secondary antigenic stimulation was restored by addition of carrier‐primed cells during the first two days of culture, partially restored on day 3, but not at later times. Thus, T cells were required only at about day 4 of a secondary response to a T‐dependent antigen that peaked on day 8. Autoradiography experiments showed that the frequency of antigen‐binding cells increased with time regardless of the presence of T cells in the cultures. We conclude that helper T cells are not required for B cell proliferation, but are required for the differentiation of B cells to antibody‐secreting cells.
Intrathymic pathogenesis of myasthenia gravis: transient expression of acetylcholine receptors on thymus‐derived myogenic cells
Authors: Wekerle H. , Ketelsen U.‐P. , Zurn Anne D. , Fulpius B. W. 
Published: February 2007

AbstractDifferentiation of myogenic stem cells from undifferentiated thymic stem cells is thought to play a critical role in the pathogenesis of myasthenia gravis. The expression of membrane acetylcholine receptor (AChR) on the membranes of developing muscle clones in cultures of murine thymus reticulum was followed and found to be transient. AChR are first expressed shortly after fusion of myotubes. In subsequent stages of myogenic development, the density of homogenously distributed AChR is strongly increased, and, in addition, concentrated “hot spot” AChR areas appear. During further maturation, membrane AChR are lost. Highly mature myotubes (3 months in culture) lack substantial amounts of homogenous AChR, as well as hot spots.
Rat macrophage‐mediated toxicity to cancer cells: effect of endotoxins and endotoxin inhibitors contained in culture media
Authors: Martin F. , Martin Monique , Jeannin J.‐F. , Lagneau Annick 
Published: February 2007

AbstractThe cytotoxic effect of normal or BCG‐activated rat macrophages on a syngeneic line of cancer cells was compared in media containing rat or bovine sera. Normal macrophages were usually cytotoxic to cancer cells in fetal or newborn bovine serum; however, they enhanced cancer cell growth in normal rat serum. BCG‐activated macrophages were toxic to cancer cells regardless of the serum used in the assay. Many cell culture media or sera obtained commercially were found to be contaminated by bacterial endotoxins. When endotoxin‐free reagents were used in the toxicity assay, different results were observed: normal macrophages were not cytotoxic, but rather, they often enhanced cell growth even in fetal bovine serum; toxicity of activated macrophages was significantly reduced in normal rat serum. These results suggest that endotoxin and endotoxin inhibitors play a role in the modulation of macrophage‐mediated cytotoxicity. These results emphasize the importance of monitoring endotoxin contamination in cell culture reagents used in assays involving macrophages.
The effect of colchicine and colcemid on the mitogeninduced blastogenesis of lymphocytes
Authors: Steen H. B. , Lindmo T. 
Published: February 2007

AbstractThe effect of colchicine and colcemid (1 × 10−6 M) on the blastogenic response of human lymphocytes to concanavalin A was studied in vitro by three different methods. (a) Measurement of [3H]thymidine ([3H]dThd) incorporation which was strongly suppressed by the drugs. (b) Volume spectroscopy showing that the growth of cellular and nuclear volume was only moderately affected by the drugs during the first two days of culture: in drug‐treated cultures, 25% of the cells responded by measureable growth of their nuclear volume as compared to 30% in untreated cultures. After two days, however, growth stagnated in drug‐treated cultures, and cell division never occurred. (c) Flow cytofluorometry, showing that in drug‐treated cultures the number of cells measurably increasing their DNA content, i.e. entering S‐phase, was about 60% of that in untreated cultures. However, the drugs caused a majority of the responding cells to stop DNA synthesis before completing S‐phase. This effect could not fully account for the strong suppression of the [3H]dThd incorporation indicating that colchicine and colcemid caused a malfunction of the [3H]dThd assay. It is concluded that colchicine and colcemid do not significantly inhibit initiation of a blastogenic response indicating that microtubuli, which are known to be affected by these drugs, are not essential for the triggering of blastogenesis.
Expression of Thy‐1 glycoprotein on lectin‐resistant lymphoma cell lines
Authors: Trowbridge I. S. , Hyman R. , Ferson Theresa , Mazauskas Catherine 
Published: February 2007

AbstractLectin‐resistant mutants with specific defects in glycosylation have been selected from the mouse lymphoma cell line, BW5147 (Thy‐1+). The quantitative expression of cell surface glycoproteins on the mutant cells has been studied. The results show that some glycosylation defects that confer resistance to the cytotoxic effects of concanavalin A block the expression of Thy‐1 glycoprotein on the cell surface. However, some changes in the oligosaccharides of Thy‐1 glycoprotein generated by glycosylation defects found in PHAR mutant cells and restricted to the termini of complex‐type oligosaccharides have no effect on the ability of Thy‐1 to reach the cell surface. No glycosylation defects were found that interfered with the expression of either gp 69,71 or H‐2 on the surface of the mutant cells. It is concluded that aberrant biosynthesis of Thy‐1 oligosaccharides can interfere with its expression on the cell surface, but that specific changes in oligosaccharide structure are necessary to block transport to the cell surface and integration into the plasma membrane.
The in vitro immune response to a T‐independent antigen I. The effect of macrophages and 2‐mercaptoethanol
Authors: Nordin A. A. 
Published: February 2007

AbstractThe in vitro immune response of murine spleen cells to the T cell‐independent antigen, 2,4‐dinitrophenyl‐β‐alanyl‐glycyl‐glycyl‐N(2‐aminoethyl)carbamyl‐methylated Ficoll (DAGG‐Ficoll), requires the presence of macrophages, or 24‐h culture supernates from peritoneal cells. Complete reconstitution of the response by supernates, however, is dependent on the addition of 2‐mercaptoethanol. Antigen is required to fully express the in vitro immune response, but is not required in cultures of peritoneal cells in order to obtain active supernates. Active supernates can be obtained from allogeneic or syngeneic peritoneal cell cultures. The enhancing effects of 2‐mercaptoethanol and peritoneal cell supernates appear to be synergistic nonspecific events directed toward lymphocyte activation and differentiation.
Quantitative comparison of K cell potential in human T and null cells
Authors: Caraux J. , Thierry C. , Serrou B. 
Published: February 2007

AbstractUsing a short‐term quantitative assay of the antibody‐dependent cell‐mediated cytotoxicity (ADCC) of human peripheral blood lymphocytes towards 51Cr‐labeled mouse lymphoma cells, it is possible to estimate the relative involvement of various lymphocyte populations in the overall ADCC potential displayed by unfractioned lymphocytes. Lymphocytes were separated by means of an anti‐F(ab')2 column combined with sedimentation of E rosette‐forming cells or EA rosette‐forming cells, and a discontinuous serum albumin gradient, and were characterized by several surface markers. ADCC results were expressed as the cytotoxic capacity of 106 cells of each population (lytic units/106 cells) as well as as the cytotoxic potential of each population by taking into account their relative numerical sizes. Although the null cells had the highest cytotoxic capacity, highly purified T cells also disclosed a cytotoxic capacity which, because of the large numerical excess of T cells over null cells, could account for closely equivalent cytotoxic potentials of these two populations. ADCC was entirely abolished by further removal of Fc receptor‐bearing cells, in all the subsets studied. Our data underline the role that the small proportion of Fc receptor‐carrying T cells might play in ADCC.