bluuebunny/crossref_metadata_2025 huggingface dataset:
Monoclonal Antibodies against Leucoagglutinin‐Reactive Human T‐Lymphocyte Surface Components
Authors: BERZINS T. , VARGAS‐CORTES M. , HAMMARSTRÖM M.‐L. , LARSSON Å. , AGUILAR‐SANTELISES M. , ANDERSSON G. , HAMMARSTRÖM S. , PERLMANN P.
Published: June 2006

A monoclonal antibody, K46M (IgM x), obtained after immunization with leucoagglutinin (La)‐reactive T‐cell surface components, stimulated human lymphocytes to proliferate. It induced maximal proliferation at >20μg IgM/ml after 3–4 days of culture. Cells stimulated by K46M produced interleukin 2 (IL‐2) and gamma interfeton (IFN‐γ) and expressed receptors for IL‐2 and transferrin. The majority of the activated cells were phenotypically T cells as defined by monoclonal antibodies against CD3 and CD2, and an increase in the K46M‐positive cells was also observed during the activation period. K4GM‐activated cells display major histocompatibility complex (MHC)‐unrestricted cytotoxicity against several cultured target cells. The frequencies of the cytotoxic and of the proliferative precursor cells were determined using a limiting dilution assay. K46M seems to activate a larger fraction of cytotoxic precursor cells aganit Molt 4 than against K562, but the statistical significance of these observations requires further exploration. Both K46M or La activated 40% of PBL to proliferate, whereas 70% of PBL were induced by OKT3. However, the frequency of K46M‐ativated cells was 40% only when the lymphocytes were plated at low cell densities, i.e. <0.5 cells per well. At higher densities an inhibition of proliferation was seen that resulted in a biphasic response curve, indicating that the activation of PBL by K46M was not a single hit event. This was not found with either La or 0KT3. Whether K46M, in contrast to OKT3 and La, activates a subpopulation with suppressor activity remains to be established.
Phenotypical and Functional Characterization of the Idiotype‐Positive Blood B Cells in Multiple Myeloma
Authors: BLOEM A. C. , CHAND M. A. , VAN CAMP B. , BAST E. J. E. G. , BALLIEUX R. E.
Published: June 2006

In this study the idiotype‐positive B cells of one patient with smouldering multiple mycloma (IgGx) and of one patient with multiple myeloma (IgGλ) were analysed phenotypically and functionally. As regards the expression of B cell‐associated differentiation antigen and size distribution, the idiotype‐positive B ells resembled normal IgG‐bearing blood B Cells. In functional studies the lymphocytes were cultured in vitro with Staphylococcus aureus. pokeweed mitogen, T‐cell factors, or combinations of those. After culture, proliferation and differentiation of the idiotype‐positive B cells were measured by autoradiography, an idiotype‐specific ELISA, and B spot ELISA. The results show that idiotype‐positive B Cell of both patients are able to proliferate after simulation in vitro. In contrast to their normal counterparts, however, almost no increase in the amount of secreted idiotypic IgG could be induced. This suggests that the idiotype‐positive blood B cells have lost some of their ability to respond to exogenous stimuli.
Bone Marrow Derived Cells Express Human T‐Cell Lymphotropic Virus Type I (HTLV‐I)‐Related Antigens in Patients with Multiple Sclerosis
Authors: SANDBERG‐WOLLHEIM M. , ALUMETS J. , BIÖRKLUND A. , GAY R. , GAY S.
Published: June 2006

Mononuclear cells in peripheral blood (PB) and cerebrospinal fluid (CSF) of seven patients and lymph nodes of three patients with clinically definite multiple sclerosis (MS) expressed antigens that reacted with monoclonal antibodies (MoAb) specific for HTLV‐I p19 and p24 gag proteins. The labelled cells were visualized with immunoperoxidase staining and indirect immunofluorescence and identified at the ultrastructural level with immunogold technique. The frequency of these cells was low, ranging from 0.1% to less than 0.01 % in blood. In CSF it was approximately 10 times lower. Cells reacting with anti‐p19 Ab were found in all MS samples, whereas cells reacting with anti‐p24 Ab were found in 3 out of 6 blood samples and in 3 out of 7 CSF samples. All lymph nodes (3/3) obtained from MS patients contained cells that reacted with anti‐HTLV‐I. p19 and p24 Ab. Cells reacting with the same AB were detected in blood of one out of 12 healthy controls. Stained cells were irregular, distinctly larger than lymphocytes, and had abundant cytoplasm, suggesting that they may be monocytes/macrophages. Immunogold particles were located in vacuole‐like structures in the cytoplasm. The presence in MS patients of cells that react with HTLV‐I Ab indicates that a human retroviral genome is being expressed, and suggests that a virus may be present. Our data support a role for a human retrovirus in multiple sclerosis.
Properties of Serine Proteases of Schistosoma mansoni Schistosomula Involved in the Regulation of IgE Synthesis
Authors: VERWAERDE C. , AURIAULT C. , NEYRINCK J. L. , CAPRON A.
Published: June 2006

The regulation of IgE synthesis in vitro and in vivo by schistosomula‐released products (SRP) has been shown to be dependent on the presence of serine proteases. The present paper concerns the characterization of the enzymes involved. The labelling of SRP with [3H]di‐isopropyl phosphofluoridate revealed two molecules, one major with an MW of 27,500 and one minor with an MW of 29,000. The same pattern was obtained by labelling of schistosomula or cercariac surfaces as well as of the total schistosomulum homogenate. The properties of these enzymes were studied by means of various specific substrates or inhibitors of serine proteases. The specificity was relatively narrow, but had some similarity with trypsin. When added to lymphoid rat cells in culture, SRI induced an increased expression of receptors for the Fc fragment of IgE (FcεRII). This suggests that the IgE‐enhancing property of SRP was due to serine protease activity which may act by enhancing the lymphocyte FcεRII.
Limiting Dilution Analysis of Interleukin 2‐Producing Mature T Cells
Authors: ROCHA B. , BANDEIRA A.
Published: June 2006

Evaluation of lymphokine production by individual activated T cells is necessary to characterize their growth requirements. We have studied interleukin 2 (IL‐2) secretion by mature T lymphocytes using a high resolution assay system with the following characteristics: (a) a threshold of IL‐2 detection 25 times lower than classic IL‐2 titration: (b) the ability to discriminate between IL‐2 and IL‐4 activities: (c) absence of ‘in situ’ IL‐2 absorption; (d) IL‐2 production revealed al the single cell level By this method an average of 10% of spleen cells, and 75% of L3T4 cells were detected as producers in a concanavalin A (Con A)‐dependent T cell activation system. Our results also suggest the complete restriction of II ‐2 secretion to cells with this phenotype. Therefore, factors other than IL‐2 must play a major role in Lyt 2+ mitogen‐driven, helper‐independent T cell proliferation.
Lymph‐Borne Dendritic Leucocytes do Not Recirculate, but Enter the Lymph Node Paracortex to Become Interdigitating Cells
Authors: FOSSUM S.
Published: June 2006

Peripheral lymph contains constitutively major histocompatibility complex (MHC) class II‐positive, dendritic leucocytes (DL) with a veiled (VC) or dendritic (DC) shape. On the basis of phenotypic similarities to the interdigitating cells (IDC) T‐dependent areas of lymphoid tissues, they are believed, but not yet proven, to be IDC precursors that develop into mature IDC within the draining lymph nodes. In order to determine the relationship between VC/DC and IDC, highly purified radiolabelled peripheral lymph DL (collected by thoracic duct cannulation of mesenteric lymphadenectomized congenitally athymic, nude rats) were reinjected into the veins or footpads of syngeneic recipients. Later, host blood and lymph were collected and the tissues were biopsied and processed for scintillation counting or for light microscopic autoradiography combined with electron microscopy of neighbouring sections. The intravenously injected VC/DC did not enter lymph nodes or Peyer's patches directly from blood, and did not re‐enter the lamina propria of the gut, but became localized largely in the liver and the spleen. From the liver some of the cells proceeded via afferent lymphatics to the coeliac lymph nodes. Similarly, some of the locally injected cells were curried with peripheral lymph to the draining popliteal lymph nodes, although most were retained in the footpads. In the spleen the VC/DC entered the periarteriolar lymphoid sheaths and in the coeliac and popliteal lymph nodes they became localized in the paracortex, where they acquired the morphology of mature IDC.
Detection of Tumour Necrosis Factor from Lipopolysaccharide‐Stimulated Human Mononuclear Cells by Enzyme‐Linked Immunosorbent Assay and Cytotoxicity Bioassay
Authors: FOMSGAARD A. , WORSAAE H. , BENDTZEN K.
Published: June 2006

Tumour necrosis factor (TNF) or cachectin it an important mediator of endotoxic activity. To investigate the production of TNF from human mononuclear cells (MNC) in response to lipopolysaccharide (LPS), we developed a sensitive and specific enzyme immunoassay (ELISA) and a cytotoxicity bioassay for TNF. The ELISA utilizes the biotin/avidin system and includes four incubation steps. The detection limit was 25 pg recombinant TNF(rTNF)/100μl. There was no interference of medium, serum, plasma, spinal Fluid, or urine and no cross‐reaction with natural or recombinants IL‐1‐α, IL‐1‐β, IL‐2, IFN‐γ, or lymphotoxin (TNF‐β). Recovery of TNF added to the media was 83 123% (n=22). The relative standard deviation within and between assays were 7% and 8% respectively. TNF‐induced cytotoxicity was measured on actinomycin‐D‐treated L‐M mouse fibroblasts. The detection limit in this bioassay was 0.5 U/30μl or 12.5 pg/30μl of rTNF, IL‐1‐α and IL‐1‐β slightly inhibited the cytotoxic activity of rTNF. In this bioassay, cytotoxic activity (50–300 U/ml) was detected only when MNC were stimulated with high concentrations of LPS (100–1000 ng/ml). In contrast, using 0.01–100 ng/ml of LPS, the ELISA detected TNF in a dose‐dependent manner (0.25 ng/ml to 40 ng/ml). It is concluded that TNF is liberated from human blood MNC if stimulated with minute amounts of LPS. It is suggested that human TNF may be secreted in a relatively inactive form or that inhibitors of TNF are generated along with the monokine Because of this, and because commonly used bioassays for TNF fail to distinguish between TNF and lymphotoxin, specific ELISA are recommended to supplement TNF bioassays.
A Critical Consideration of the Rat Epididymis as an Immunologically Privileged Site
Authors: KAZEEM A. A.
Published: June 2006

A literature search reveals a lack of any previous attempt to Implant foreign tissue into the epididymis. Instead, related studies have been carried out within the adjacent testis. Theoretically, there are peculiar immunobiological factors that can require separate consideration of the two adjacent sites. With this background, we designed the present work by removing the adjacent testis and subsequently used biochemical, histological, and electron microscopic methods to assess the fate of parathyroid allografts buried within the epididymis. Since the concept of immunological privilege is usually explained on the basis of the nature of lymphatic drainage, we also studied the pattern of lymphatic drainage at each allograft bed. In the analysis of our results, the animals were grouped according to the nature of lymph pattern from each transplant bed. We observed that prolonged survival of the tissue allograft occurred only when the lymphatic trunk draining the graft bed bypassed all retroperitoneal nodes and opened directly into the blood stream via the cisterna chyli. This anomalous survival is favoured by pretransplant splenectomy. These results demonstrate that the rat epididymis can sometimes be immunologically privileged.
Aging‐Associated Changes in Murine Intestinal Immunoglobulin A and M Secretions
Authors: SENDA S. , CHENG E. , KAWANISHI H.
Published: June 2006

The aging effect on the quantity of intestinal IgA and IgM class‐specific immunoglobulins secreted and the quality of intraluminal intestinal IgA was studied in 5‐to 6‐month old and 24‐to 28‐month‐old male BALB/c mice. The level of IgA increased in the intestinal juice from the aged mice, while the IgM level remained unchanged. These alterations were similar to those found in serum, but the effect of age on serum IgA was profound, almost a threefold increase, in found in serum, but the effect of age on serum IgA was profound, almost a threefold increase, in contrast, to an increase of just under 35% in intestinal secretions. The ratio of the dimeric to total IgA in the small intestine decreased in the older mice, though that of serum was unchanged. In contrast, the total amounts of dimeric IgA in the small intestinal lavage fluid did not change between the two age groups, while the dimeric IgA in serum in older mice were 4.5 times as high as those of young mice. The binding of purified intestinal dimeric IgA to antigens from normal habitant enteric bacteria (γ streptococci and Enterobacter agglomerans) declined in the old mice. In the immunochemical studies, using SDS‐PAGE and isoelectric focusing, the purified intestinal IgA from the young and old mice showed no major difference. Thus, the findings in aged small intestinal perfusates that the increased content of intestinal IgA is due to an increased monomeric IgA, but not to a reduced dimeric IgA, which remains unchanged, and that the binding capacity of the dimeric IgA to the bacterial antigens is diminished, suggest that the level of the matural secretory IgA antibody is decreased. These altered quantitative and functional features of intraluminal intestinal IgA observed in the aged mice appear to be due to the complex heterogeneous effects of senescence on gut‐associated lymphoid tissues, and may contribute to age‐related impairment in gut humoral immune function.
Determination of Herpes Simplex Virus‐Induced Alpha Interferon‐Secreting Human Blood Leucocytes by a Filter Immuno‐Plaque Assay
Authors: RÖNNBLOM L. , CEDERBLAD B. , SANDBERG K. , ALM G. V.
Published: June 2006

A filter immuno‐plaque assay was developed which detects alpha interferon (IFN‐α) secreting human peripheral blood leucocytes (PBL) Polyclonal anti‐IFN‐α antibodies were fixed to the nitrocellulose membrane bottoms of 96‐well Millititer plates, which also contained monolayers of glutaraldehyde fixed human WISH amnion cells infected by Herpes simplex virus type 1 (HSV). Such cell are potent IFN inducers and during a 16 h cocultivation with PBL, IFN‐α was absorbed by the membrane‐bound polyclonal antibodies around IFN‐α‐secreting cells. This IFN‐α was detected with murine monoclonal antibodies against IFN‐α and peroxidase labelled antibodies against murine immunoglobulin, using diaminobenzidine as substrate Distinctly stained plaques were seen, the frequency of which gave a minimal estimate of approximately 10 IFN‐α‐producing cells in 104 PBL (range in 12 blood donors 2.95–25.1). Fewer plaques than expected were seen at low PBL numbers per culture, one explanation being that cell interactions then limit the IFN‐α response. The immuno‐plaque assay should be useful in further studies of the cellular basis of the IFN‐α response.
Morphology of Rat Cardiac Allografts with Permanent Survival Induced by Antithymocyte Globulin
Authors: CLAESSON K. , MJÖRNSTEDT L. , KLARESKOG L. , LARSSON E. , OLAUSSON M. , SÖDERSTRÖM T.
Published: June 2006

In a rat heart transplantation model, permanent graft survival was achieved by anti‐thymocyte globulin (ATG) treatment of Wistar Kyoto (WKy) recipients before grafting with PVG/c hearts. Nine hearts with palpable and electrocardiographic (ECG) function 8–20 months after transplantation were studied with histological and immunohistochemical methods. The dominating findings were fibrosis, intimal thickening, thrombosis of vessels, cellular infiltrates, and a high number of cells expressing class II antigens. These findings suggest that reactions compatible with a chronic rejection can be found in long‐term surviving rat heart allografts. This rat model may thus be used in further studies of a chronic rejection process.
The Complete Amino Acid Sequence of Rat β2‐Microglobulin
Authors: SUNDELIN J. , BJÖRCK L. , LÖGDBERG L.
Published: June 2006

The primary structure of rat β2‐microglobulin (β2m) was determined. It is a polypeptide of 99 amino acids with the following sequence: IQKTPQIQVY SRHPPENGKP NFLNCYVSQF HPPQIEIELL KNGKKIPNIE MSDLSFSKDW SFYILAHTEF TPTETDVYAC RVKHVTLKEP KTVTWDRDM. The primary structure was determined by NH2‐terminal sequence analysis together with sequence determination of one cyanogen bromide fragment and one tryptic peptide. Of other known β2m sequences, rat β2m is most homologous to mouse β2m (83% identity). The rabbit, human, and guinea pig sequences are more distant, with 24,27, and 31% differences, respectively.
Self‐Reactive Delayed Type Hypersensitivity Induced in Mice by Syngeneic Lymphoblasts
Authors: KLEIN I. , KLEIN B. Y. , NAOR D.
Published: June 2006

X‐irradiated (250 rad) or normal A mice injected with syngeneic concanavalin A‐induced lymphoblasts (syn‐Con A blasts) developed an inflammatory response in their footpads 24 to 72 h after injection of syngeneic lipopolysaccharide induced lymphoblasts (syn‐LPS blasts) into these tissues. This immunological activity was designated syngeneic delayed type hypersensitivity (syn‐DTH), because T cells transferred the response to naive recipient. Analysis on Ultrogel or Sephedex G‐50 columns revealed that a Con A‐blast extract contains two syn‐DTH‐stimulating antigens: a small antigen (6000–7000) and a large antigen (apparent MW of 160,000–175,000). This conclusion held true even when protease inhibitors were included in the fractionation procedure. The approximate molecular weights of these antigens estimated by that gel filtrations were confirmed by sodium dodecyl sulphate‐polyacrylamide gel electrophoresis (SDS‐PAGE). The large lymphoblast syn‐DTH‐stimulating antigen contains carbohydrate residues but not products of the H‐2 genetic region. The small antigen does not contain sugar moieties, but it expresses affinity to anti‐H‐2Dd monoclonal antibody. The immune response to the small antigen but not to the large antigen is genetically restricted at body the induction and the elicitation in phases of the DTH. A strain of mice immunized with the small antigen generated syn‐DTH after challenge with lymphoblasts of B10.T (6R) mice, which share the H‐2Dd subregion with A mice but not the H‐2K or the H‐2I subregions. Fast protein liquid chromatography of the small antigen yielded a purified material which appeared as a single band after Coomassie staining of its gel electrophoresis.
The Antigens of Mycobacterium tuberculosis, H37Rv, Studied by Crossed Immunoelectrophoresis. Comparison with a Reference System for Mycobacterium bovis, BCG
Authors: WIKER H. G. , HARBOE M. , BENNEDSEN J. , CLOSS O.
Published: June 2006

On the basis of a previously developed reference system for Mycobacterium bovis, BCG, in crossed immunoelectrophoresis (CIE), antigens of Mycobacterium tuberculosis were identified in an analogous system. A majority of the numbered lines in the BCG system were also present and identified in the M. tuberculosis system. The corresponding antigens in the two systems were identified by dual dilution in CIE, and using monospecific antisera and monoclonal antibodies. Some of the antigens were specifically identified by the demonstration of enzyme activity and by means of hydroxyapatite, concanavalin A (Con A), EDTA, and blue–Sepharose. Three antigens (nos 10, 78, and 81), which were found in high concentrations in M. tuberculosis culture fluid, were not identified or were present in low concentrations in BCG culture fluid. The high percentage of corresponding antigens confirms that there is a very close taxonomic relationship between BCG and M. tuberculosis. Corresponding antigens in BCG and M. tuberculosis did not differ in electrophoretic mobility in the antigenic preparations studied.
The Serum Antibody Response Distributed in Subclasses and Isotypes after Intranasal and Subcutaneous Immunization with Influenza Virus Immunostimulating Complexes
Authors: LÖVGREN K.
Published: June 2006

Immunostimulating complexes (iscoms) were prepared from influenza virus glycoproteins (A/PR8(H1N1)). Mice were inoculated with iscoms by local (oral or intranasal) as well ashy subcutaneous administration. It was shown that one subcutaneous or intranasal inoculation induced serum antibody responses of similar magnitude. The intranasal administration, however, induced somewhat higher IgA and IgM titres than that induced subcutaneous. After a second intranasal or subcutaneous inoculation a prominent increase of the IgG isotypes was found. The secondary IgA and IgM responses were of similar magnitude as those induced alter the primary inoculation. The antibody responses induced were evenly distributed within the IgG isotypes, although the highest titres recorded were of the IgG1 and IgG2 isotypes.
Effects of Culture Substrates and Normal Hepatic Sinusoidal Cells on in Vitro Hepatocyte Synthesis of Apo‐SAA
Authors: SUBRAHMANYAN L. , KISILEVSKY R.
Published: June 2006

Primary hepatocyte cultures synthesize apo‐SAA upon stimulation with supernatant from lipopolysaccharide (LPS)‐treated macrophages. The matrices on which the hepatocytes were grown influence their basal apo‐SAA synthetic capability. Fibronectin was superior. Coculturing hepatocytes with hepatic sinusoidal cells did not adversely affect the ability of hepatocytes to synthesize and secrete apo‐SAA into the culture medium. In 72 h, clear islands of endothelial cells nestled in layers of hepatocytes. Both apo‐SAA, and apo‐SAA, were made in considerable quantities but no evidence could be obtained that the apo‐SAA were free of apo‐A‐1. The coculturing of hepatocytes with liver sinusoidal cells, the site of ultimate AA deposition, is a first step in establishing an in vitro system for AA amyloidogenesis.
Features of the in Vitro Established Rat Large Granular Lymphocyte Leukaemia RNK‐16
Authors: AXBERG I. , NOSE M. , REYNOLDS C. W. , WIGZELL H.
Published: June 2006

A large granular lymphocyte (LGL) leukaemia cell line from the Fisher/F344 rat strain called RNK‐16 has been established in vitro, maintaining the same surface markers as the tumour cell growing in vivo. The tumour has also maintained its specificity pattern and cytotoxic reactivity and serves as a suitable source of natural killer (NK)‐like effector cells in vitro. The cells show no evidence of dependency on, or production of, interleukin 2 or interferons, not is the cytotoxic capacity influenced by treatment with mitogens. The in vitro line does not produce natural killer cytotoxic factor (NKCF) in a constitutive manner, hut can be induced to do so via coculture with tumour target cells. When the fine specificity patterns were analysed, the RNK‐16 cells express species‐preferential lysis of susceptible target cells and a highly discriminatory power to kill only 1 out of 5 rat erythroleukaemia cell lines. When testing normal target susceptibility patterns. RNK‐16 kills lymphoblasts of B type better than T blasts, which is well in line with previous findings on normal NK cell specificity patterns.
Immunization with Nanogram Quantities of Nitrocellulose‐Bound Antigen, Electroblotted from Sodium Dodecyl Sulphate–Polyacrylamide Gels
Authors: LARSSON A. , NILSSON B. O.
Published: June 2006

Intrasplenic immunization with antigen immobilized on nitrocellulose (NC) paper results in an immune response with nanogram amounts of antigen without the use of Freund's adjuvant. Comparing the sensitivity of the intrasplenic immunization with intraperitoneal or subcutaneous administration, we found that the intrasplenic method resulted in more positive animals with higher titres than did the other techniques with the smallest amount of antigen (70 ng of bovine serum albumin). With larger amounts of albumin the intraperitoneal method yielded the highest titres. No loss of antigenicity was observed when we immunized with equal amounts of protein separated by sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS–PAGE), immunoblotted and stained with either Coomassie brilliant blue R 250 or Amido black 10 B.
Responsiveness of T Cells to Mutant Major Histocompatibility Complex Class I Antigen
Authors: FUJIWARA M. , WATANABE H.
Published: June 2006

Proliferative response of splenic T cells of C57BL/6 mice to mutant major histocompatibility complex (MHC) class I antigen (H‐2Kbm1) was examined with regard to the role of accessory cells. T cell proliferation in mixed lymphocyte culture (MLC) was not induced when accessory cells were removed from stimulator spleen cells by passage through Sephadex G‐10 or nylon‐wool column. Anti‐Iab antibodies did not inhibit the proliferative response to class I antigen, whereas the same antibodies completely blocked the response to class II antigen (Iabm12). Accessory cells may not be mere presenters of MHC class I antigen because stimulator cells fixed with 0.05% paraformaldehyde lost the stimulating function. The proliferative response was partially recovered by the addition of recombinant interleukin 1 (IL‐1) and/or IL‐2 to MLC devoid of stimulator type accessory cells. It is concluded that stimulatory type accessory cells were obligatorily involved in the T cell proliferation, and the production of IL‐1 by accessory cells is thought to play a critical role in this process
The Killing of Tumour Cell Targets Coupled to Tuberculin (PPD) by Human and Murine PPD‐Reactive T Helper Clones
Authors: VYAKARNAM A. , LACHMANN P. J. , SIA D. Y.
Published: June 2006

This paper reports on the characteristics of killing by a human and a murine tuberculin (PPD)‐Specific T helper clone of targets to which PPD was attached via the lectin concanavalin A (Con A). The killing was specific for PPD from M. tuberculosis; and targets coupled to Con A alone or to PPD from M. paratuberculosis were not killed. Target cells carrying Con A–PPD wore more effectively lysed than PPD‐pulsed cells. This form of lymphocyte killing, though highly significant, was inefficient. Maximum killing of PPD carrying targets was 30–40% at effector to target ratios of 20:1 and at 16 h. Cells carrying 2×106 molecules of PPD and less than 1.5×106 molecules Con A per cell were killed most efficiently. A major distinction between this helper T cell killing and that mediated by cytotoxic T cells was that both TH clones displayed bystander lysis and killed PPD uncoupled targets when these were cultured with syngeneic PPD‐bound targets. This suggests that the mechanism of cytotoxicity may involve soluble mediators
The Killing of Tumour Cell Targets Coupled to Tuberculin (PPD) by Human and Murine PPD‐Reactive T Helper Clones
Authors: VYAKARNAM A. , LACHMANN P. J.
Published: June 2006

This paper takes up the major histocompatibility complex (MHC) restriction of killing by a murine and a human tuberculin (PPD)‐specific T helper clone of PPD Con A bound targets. In the previous paper we demonstrated that the specificity of killing of such targets was directed against PPD and not the lectin. This paper provides further evidence to suggest that the PPD‐specific clones recognize PPD on PPD–Con A‐bound cells though the T cell antigen receptor complex, since the killing was restricted by MHC class H products. Using a range of syngeneic, allogeneic, and semi‐syngeneic targets we have shown the fine specificity of the restricting element to be one of the two allelles of the DR region (DR 2) for the human clone, and to be the I‐A subregion for the murine clone. Binding studies with radiolabelled class II antibodies were performed to see whether killing efficiency was dependent on the number of class II products expressed. The findings showed that the human B‐EBV targets express 2–3×106 molecules per cell, while the susceptible murine tumours, the Abelson line and the 6A tumour, only expressed 600–800 binding sites per cell. Target cell Susceptibility appeared to be linked to the number of class II molecules expressed; thus the syngeneic murine MBL‐2 tumour expressing 200–300 binding sites per cell was not killed and the lysis of the 6A and Abelson tumours could be enhanced by doubling the number of class II binding sites by incubating cells with Con A‐conditioned medium. However, maximum lysis did not exceed 30–40%, suggesting that class II expression alone did not govern killing.
Non‐Determinant Specificity of Feedback Immunosuppression by IgG Antibodies Injected after the Antigen
Authors: HEYMAN B.
Published: June 2006

The determinant specificity of the IgG‐mediated suppression of the humoral immune response in mice was studied. One hour before or 2.5, 6, 12, or 24 h after the injection of sheep erythrocytes (SRBC) or SRBC‐TNP, CBA/Ca mice received SRBC‐specific monoclonal IgG antibodies. The antibodies did not cross‐react with TNP or gout erythrocytes, the latter an antigen which shows 30% cross‐reactivity with SRBC. Five days later the determinant‐specific plaque‐forming cell response against SRBC and the non‐determinant‐specific response against goat erythrocytes and TNP were determined. Regardless of whether the antibodies were injected before or after the antigen, they suppressed not only the response to the antigenic determinant they bound to, but also the response to other epitopes on the same antigen. This shows that Fc parts of the IgG molecules play a crucial part in suppression of the in vivo antibody response even when, as in a natural situation, the antigen is presented to the immune system before the antibody.
Self‐Reactive Delayed Type Hypersensitivity Induced in Mice by Syngeneic Lymphoblasts
Authors: KLEIN I. , NAOR D.
Published: June 2006

X‐irradiated or normal A mice injected with syngeneic concanavalin A‐induced lymphoblasts (syn‐Con A blasts) developed inflammatory responses in their footpads 24 to 72 h after the injection of syngeneic lipopolysaccharide‐induced lymphoblasts (syn‐LPS blasts) into these tissues. This response was designated syngeneic delayed type hypersensitivity (syn‐DTH). The Con A blast extracts contain small (apparent MW of 6000–7000) and large (apparent MW of 160,000–175,000) syn‐DTH‐stimulating antigens, which are found in the total volume (low molecular weight fraction) and the void volume (high molecular weight fraction), respectively, of AcA 44 gel filtrations of this extract. The small and large antigens exhibit different immunological properties. The small antigen of A mouse lymphoblasts induced syn‐DTH in X‐irradiated (250 rad) mice but not in normal mice, and this immunological activity was elicited with syngeneic but not allogeneic lymphoblasts. The syn‐DTH induced with the small antigen was inhibited by Lyt‐1+2−, I‐Jk+ suppressor T cells or a factor extracted from these cells. In contrast to the small antigen, the large antigen of A mouse lymphoblasts induced syn‐DTH in both normal and X‐irradiated mice, and this immunological activity was elicited by both syngeneic and allogeneic LPS lymphoblasts. The small and large antigens do not immunologically cross‐react, but their immunogenicity is not affected by ultraviolet irradiation, indicating that the immune response against both of them is relatively class II‐independent. The possibility that the cellular autoanti‐lymphoblast response observed in our studies is in fact a mechanism that down‐regulates the lymphoblast activity and thus suppresses the immune response is discussed.
Activation of Monocytes—More than One Process
Authors: CARLSEN E. , PRYDZ H.
Published: June 2006

Monocytes and macrophages respond to a number of exogenous agents by alterations in metabolism and gene expression in a process loosely called ‘activation’. The question arises whether these alterations in cellular activity are the pleiotropic effects of one programmed activation process or result from separately programmed activation pathways. We report that certain cytokines (interleukin 1 (IL‐1α, IL‐1β) and interleukin 2 (IL‐2)) which all activate monocytes, induce the synthesis of thromboplastin (TPL) and (IL‐1β only) factor VII. Interferon‐γ (IFN‐γ) and tumour necrosis factor α (TNFα) do not induce monocyte procoagulant activity, although they both activate monocytes in several respects. Our data thus show that different states of activation are induced. Similar observations have been made by others using different systems.
Antigen–Antibody Complex‐Induced Immunosuppression
Authors: DAI S. , MÖLLER G.
Published: June 2006

The addition of immune complexes (anti‐horse red blood cell (HRC) antibodies plus HRC) to spleen cell cultures activated by lipopolysaccharide (LPS) selectively suppressed the anti‐HRC plaque‐forming cell (PFC) response, but did not affect the PFC response to sheep red Mood cells (SRC). The degree of suppression was directly related to the concentration of immune complexes. F(ab')2 preparations suppressed as efficiently as intact IgG, although the ability of the F(ab')2 preparation to lyse the red cells was abolished. The addition of protein A to the immune complexes (using intact antibodies) did not affect the degree of suppression. The findings suggest that immune complex‐induced suppression of polyclonal B cell activation is caused by constant pans of the light or heavy chains of the antibodies other than the Fc part.
Antibody Response and Acquired Tolerance of A/J Mice: Age‐ and Immunogen‐Related Isotype Differences
Authors: PONNAPPAN U. , CINADER B. , GERBER V. , BLASER K.
Published: June 2006

In earlier work we have observed strain‐ and age‐related diversity of immunological ageing in inbred mice pretreated with tolerogen or left without pretreatment and then immunized. Different isotype show different age‐ and strain‐related changes. Here, we extend this isotype analysis from C57BL/6 and SJL to A/J. By comparison with the first two of these, animals of strain A/J show very little age‐related change, as judged by indirect plaque‐forming response. We have found that in A/J, as in SJL and CS7BL/6 mice, age‐related changes are isotype‐dependent. The age‐related changes in isotype predominance and magnitude differ for different determinants. They depend on the structural relation between the tolerance‐inducing or ‐sensitizing macromolecule and the immunogen.
The Effect of Bearing Tumours on the Ability of Mice to Reject Bone Marrow Transplants
Authors: MILLER S. C. , NGUYEN D. , BIRD I. A.
Published: June 2006

To examine the possible relationship between the cells mediating resistance to tumour cells and those mediating rejection of foreign bone marrow transplants (BMT), the effect of tumour‐bearing on BMT rejection has been measured by means of the spleen colony assay. Moderate doses (<5.0 × 106) of bone marrow cells from DBA/2 strain mice, which normally produce few haemopoietic spleen colonies in γ‐irradiated (950R) CBA/J strain mice, gave numerous (confluent) colonies when given soon after injection of Ehrlich ascites tumour (EAT) cells. Transfusion of [3H]UdR‐labelled DBA/2 bone marrow cells demonstrated that the increased spleen colony formation in tumour‐bearing mice was not due simply to changes in the total number of injected cells homing to the spleen. Injection of EAT ascites fluid alone, given to CBA/J mice before 950R+BMT, transiently reduced spleen colony development, the effect being more marked when fluid from older tumours was used. Supernatant fluid from EAT cells grown in vitro also depressed growth of BMT in vivo. The results reveal two processes in progress in mice bearing an ascites tumour: (1) an early reduction in the natural resistance to BMT allowing successful grafting and spleen colony formation, and (2) a progressive production by the tumour cells of short‐acting soluble factors tending to suppress the proliferation of colony forming bone marrow cells in the transplant. The effect of the tumour‐bearing state in weakening the natural resistance to foreign BMT strongly suggests that both tumour and foreign marrow graft resistance are mediated by the same or closely related effector cells.
Generation and Metabolism of Leukotrienes and Release of Histamine from Human Dispersed Tonsillar Cells
Authors: SCHLÜTER B. , SCHÖNFELD W. , KÖNIG W.
Published: June 2006

We studied the generation and metabolism of leukotrienes (LT) and the release of histamine by human tonsillar cell suspensions. Human tonsils were dissected and mechanically dispersed. This procedure yielded a single cell suspension with 1.6±0.5×108 cells/g tissue consisting of 97.3±0.4% lymphocytes, 1.4±0.3% granulocytes, 1.3±0.3% macrophages/monocytes, and 0.03±0.02% mast cells/basophils. The cells were stimulated either with Ca‐ionophore A 23187, melittin, or anti‐human IgE. Determination of the 5‐Lipoxygenase products LTB4 and LTC4 was performed with specific radioimmunoassays (RIA), and histamine release was measured by the fluorophotometric technique. A time‐and dose‐dependent release of the mediators was monitored LTB4 exceeded the amount of LTC4 in the supernatants. The concentration of leukotrienes ranged between 0.8 and 5.4 ng LTB4/1×108 cells or 0.5 and 1.5 ng LTC4/1×108 cells, depending on the stimulus. Histamine release after stimulation ranged between 25 and 35% of the total histamine content, whereas buffer controls amounted to 17%. The incubation of the cells (1×108) with exogenously added LTB4 resulted in the formation of ω‐oxidated products (20‐OH and 20‐COOH‐LTB4) and a novel unpolar metabolite, as identified by thin layer chromatography. This metabolite was not immunoreactive in the LTB4‐RIA used. LTC4 and LTD4 were converted into LTE4 when added either to sonicated cells or to the cell‐free supernatants of prestimulated tonsillar cells, indicating the release of γ‐glutamytranspeptidase and dipeptidase, respectively. Our data clearly demonstrate the generation and metabolism of the 54‐lipoxygenase products LTB4 and LTC4 as well as the release of histamine from human dispersed tonsillar cells, suggesting that they have a modulatory function with respect to the inflammatory potential at local sites.
Expression of the T Cell Gamma Gene by a Functionally Defined Human T Cell Clone Characterization at DNA, RNA, and Cell Membrane Level
Authors: DAVID V. , LECA G. , VILMER E. , GUGLIELMI P. , CHOUAIB S. , KANELLOPOULOS J. , SIGAUX F. , BENSUSSAN A.
Published: June 2006

In the present study we describe one CD2+CD3+ clone termed DS6 which expressed neither CD4 nor CD8 differentiation antigens and failed to react with WT31, a monoclonal antibody directed against the T cell antigen receptor α/β helerodimer. This clone was isolated from peripheral blood T lymphocytes of a patient with a prolonged immunodeficiency after allogencic bone marrow transplantation. Normal ‐sized T cell γ gene transcripts were detected in DS6 by northern analysis, whereas no mature β or α chain mRNA were found The rearrangement of TCRβ chain genes and T cell γ genes was analysed. While in DS6, TCRβ chain genes remain in germinal configuration, and a unique pattern of monoalleic T cell γ gene rearrangement was observed. The rearrangement involves the recently described Vγ5 segment and the Jγ1 joining segment, which is located upstream of the Cγ1 constant region. To determine the molecular structure present on DS6, an immunoprecipitation was performed with monoclonal anti‐CD3 antibody and a rabbit antiserum raised against γ protein. We have observed, in association with the CD3 complex, a 90 kDa structure which under reducing conditions resolves into three subunits of 45, 40 and 37 kDa. We demonstrated that the rabbit anti‐γ serum only immunoprecipitates the two lower bands. The upper band corresponds to a presently undefined T cell receptor chain. Next, we showed the non major histocompatibility complex (MHC)‐restricted cytolytic activity exhibited by these CTJ3+ CD4‐ CD8‐ cloned T cells and inhibition of the natural killer (NK)‐like activity by the anti‐CD3 monoclonal antibody. The triggering of CD2 or CD3 molecules increased IL‐2 receptor expression on DS6 but failed to induce cell proliferation. This contrasts with recent results obtained with γ‐expressing T cell clones and illustrates the functional heterogeneity of the cells bearing the second T cell receptor.
Peripheral T Cell Lymphomas: An Immunological Study of Seven Unusual Cases
Authors: RAZIUDDIN S. , LATIF A. B. A. , ARIF S. , AHAD A. , ZAIDI A. Z.
Published: June 2006

A multiparameter study of malignant lymph node cells and peripheral blood lymphocytes of seven patients with peripheral T cell lymphoma is presented. The results of monoclonal marker studies showed three cases of helper‐suppressor T cell lymphoma (OKT4+, OKT8+), one case of suppressor T cell lymphoma (OKT8+), and three cases of helper T cell lymphoma (OKT4+). Immunophenotypic heterogeneity of neoplastic T cells with expression of pan‐T antigens, OKT3+, and OKT11+ (erythrocyte rosetting+) was observed in most patients. Six of the seven cases tested showed la and DR antigens. No relationship was detected between patterns of reactivity with T cell reagents and histological types. When tested, the in‐vitro malignant T cells of five patients proliferated in response to concanavalin A (Con A), but had poor response to phytohaemagglutinin. The interleukin 2 receptors showed maximum expression on Con A‐activated T cells of five patients, and phytohaemagglutinin‐activated T cells of one patient. The neoplastic T cells (OKT4+, OKT8+) of one patient studied had suppressor activity for IgG and IgA, and helper activity for IgM synthesis on pokeweed mitogen‐induced normal B cell differentiations.
Cellular, Humoral, and Gamma Interferon Responses toMycobacterium lepraeand BCG Antigens in Healthy Individuals Exposed to Leprosy
Authors: CONVERSE P. J. , OTTENHOFF T. H. M. , GEBRE NEGUSSIE , EHRENBERG J. P. , KIESSLING R.
Published: June 2006

Protective immunity against mycobacteria is dependent on antigen‐specific T cells. The antibodies induced upon immunization with mycobacteria have no apparent role in host protection. Serological techniques have detected some antigens that are also recognized by human T cells but may fail to recognize others. Potentially, there may he differences in the epitopes seen by the T and B cell anti‐mycobacterial antigen repertoires‐ We have screened the different components of sonicated BCG orMycobacterium lepraethat were separated according to their molecular weight (MW) by SDS‐PAGEI and then electroblotted on nitrocellulose paper. The blots were cut into squares and tested directly in a T cell proliferation assay. Our results indicate that peripheral T cells of healthy leprosy patient contacts respond preferentially to the tower MW (<70,000) and not the higher MW fractions ofM. lepraeand BCG, in contrast to the humoral response of these same individuals. The most important fractions in inducing a lymphoproliferative response were in the regions of 11–16kDa of BCG andM. lepraeand to the 22–26kDa region ofM. leprae.These fractions appeared to represent molecular weight regions that were in some instances clearly distinct from previously defined antigens. It was further shown that lymphoproliferation in response to mycobacterial fractions correlated with the production of gamma interferon, a lymphokine required for macrophage activation and elimination of mycobacteria. These studies allow the direct assessment of antigens involved in protective T cell‐mediated immunity, and should be helpful in selecting relevant antigens for skin testing and immunization.
Different Susceptibilities of Normal T Cells and T Cell Lines to Immunotoxins
Authors: PREIJERS F. W. M. B. , TAX W. J. M. , WESSELS J. M. C. , CAPEL P. J. A. , DE WITTE T. , HAANEN C.
Published: June 2006

In the context of ex vivo T cell elimination from bone marrow, the anti‐T cell cytotoxic potential of immunotoxins (IT) prepared by conjugation of die monoclonal antibodies (MOAb) WT32 (CD3), T101 (CD5), and WT1 (CD7) to ricin A chaw was evaluated. The cytotoxicity of IT was based on protein synthesis inhibition in human T cell lines: GHI, CEM, HPB‐ALL, and Jurkat, and appeared closely related to the antigen density and internalization rate of the IT. Normal unstimulated T cells appeared to he rather insensitive to IT not due to a low antigen density or decreased internalization. The cytotoxicity of IT to T cells could he enhanced considerably by NH4Cl. Treatment of T cells with a cocktail of IT (10−8m) and 20 mm NH4Cl resulted in a 5000‐fold cytoreduction as measured by clonogenic assays of limiting T cell dilutions, whereas the haematopoietic progenitor cells remained unaltered. Stimulation of T cells with phytobaemag‐glutinin (PHA) prior to incubation with IT considerably increased the sensitivity to IT treatment. Thus, normal T cells are less sensitive to anti‐T cell IT than T cell lines and activated T cells. This suggests that a low protein synthesis is responsible for the resistance to IT. However, a high specific cytotoxicity of IT to normal T cells can be achieved in the presence of 20 mm ammonium chloride.
Correlation between Specific Immunosuppression and Polyclonal B Cell Activation Induced by a Protein Secreted by Streptococcus mutans
Authors: FERREIRA P. , SOARES R. , RIBEIRO A. , ARALA‐CHAVES M.
Published: June 2006

The relationship between polyclonal B cell activation and immunosuppressor effects induced by F5'EP‐Sm, a non‐cytotoxic protein secreted by Streptococcus mutans, was studied in C57BL/6 mice. Mice created with F5'EP‐Sm exhibited a considerable increase in splenic nonspecific Ig plaque‐forming cells (PFC) compared with untreated mice. The isotypic pattern of non‐specific PFC responses favours IgG2a∼IgG2b>IgG3>IgG1∼IgM, when taken as a ratio between treated and untreated animals. When F5'EP‐Sm was administered 2 days before immunization with sheep red blood cells (SRBC), the non‐specific PFC production was accompanied by an ephemeral increase in specific PFC against SRBC 1 day after immunization, which was quickly replaced by a strong immunosuppression. In contrast, when F5'EP‐Sm was injected after priming, there was little or no demonstrable suppression of specific PFC, and the increase of non‐specific PFC was much less evident. The kinetic curves representing increase or decrease in relation to controls of specific and non‐specific PFC are almost mirror images in each of the isotypes. The in vivo suppressor effect was abrogated in thymectomized mice, although the involvement of the T cell compartment is probably secondary to the B cell mitogen effect, since T‐depleted spleen cells proliferate and synthesize non‐specific Ig when stimulated in vitro with F5'EP‐Sm.
Requirements for Phytohaemagglutinin Activation of Resting Pure CD4+ and CD8+ T Cells
Authors: LEIVESTAD T. , HALVORSEN R. , GAUDERNACK G. , THORSBY E.
Published: June 2006

We have utilized a new method for obtaining highly purified cells using positive selection by immunomagnetic separation to study the conditions required for phytohaemagglutinin (PHA) activation of pure T4 and T8 cells. In the presence of accessory cells (AC), a comparable proliferative response was obtained in the two subsets. In the absence of AC, PHA induced low levels of interleukin 2 (IL‐2) receptor expression as well as responsiveness to IL‐2 in both T4 and T8 cells. If AC or 12‐O‐tetradecanoyl‐phorbol‐13‐acctate (TPA) were also present, IL‐2 production and DNA synthesis were seen in both subsets. A short preincubation with PHA primed' T fells for subsequent responsiveness to IL‐2 or TPA, while preincubation with TPA did not induce response to PHA. Thus, PHA alone is sufficient for the first step of T cell activation lending to IL‐2 receptor expression. The second step leading to IL‐2 production, is dependent on direct interaction with AC in the presence of PHA. While T8 cells are dependent on help by T4 cells for proliferation to occur during stimulation with antigen, in PHA stimulation the requirements for activation and proliferation seem to he identical for T4 and T8 cells.