bluuebunny/crossref_metadata_2025 huggingface dataset:
Murine monoclonal IgG antibodies: Differences in their IgG isotypes can affect the antibody effector activity when using human cells
Authors: Lobo Peter I , Patel Hirenkumar C
Published: May 2007

The current studies were aimed at investigating why certain murine anti‐CD3 isotypes (e.g. IgG2b) were poor activators of human T cells despite binding to the same epitope as the IgG2a anti‐CD3. Most experiments were conducted with a human T cell line (HuT‐78) and U937 a human histiocytic cell line with FcγRI and FcγRII. HuT‐78 cells lack FcγR. Anti‐CD3‐TCR of IgG2a isotypes and some antibodies of the IgGl isotype, but not lgG2b, activated HuT‐78 to secrete IL‐2 only in the presence of U937. Epitope binding differences could not entirely explain these observations as OKT3E(IgG2a) but not its switch variant IgG2b1 activated HuT‐78 in the presence of U937. Of interest, 0KT3D(lgG1) in its intact form, but not its F(ab)2 activated HuT‐78 to secrete IL‐2 in the absence of U937 suggesting therefore that 0KT3D activates T cells in the absence of macrophages and provided its Fc domain is intact. All three anti‐CD3 with IgG2b isotypes (but none with the IgG2a isotypes) activated HuT‐78 to secrete IL‐2 only when these antibodies were immobilized on to plastic (in the absence of U937). Of considerable importance, anti‐CD3 activation of human T cells with the IgG2b isotype was efficient in the presence of murine macrophages. These observations would suggest that murine anti‐CD3 with lgG2b and certain antibodies of IgG1 isotypes, have inherent human T cell activating potential provided the Fc domain is in some manner activated, as for example, by binding to plastic or to FcγR on murine macrophages. Macrophage cytokines are not essential. Therefore, ineffectual anti‐CD3‐mediated human T cell activation when using murine mAb with the IgG2b isotypes can best be explained on lack of Fc domain activation by human macrophages. This may indeed be the case as IgG2b and certain antibodies of IgG1 isotype, failed to bind to FcγR on macrophages at 37°C. These studies would indicate that murine mAb with the IgG2b isotype may be potentially useful for human use, especially in situations where receptor blockade (without cell activation) is of prime importance.
Antarctic isolation: Immune and viral studies
Authors: Tingate Trevor R , Lugg Desmond J , Muller H Konrad , Stowe Raymond P , Pierson Duane L
Published: May 2007

Stressful environmental conditions are a major determinant of immune reactivity. This effect is pronounced in Australian National Antarctic Research Expedition populations exposed to prolonged periods of isolation in the Antarctic. Alterations of T cell function, including depression of cutaneous delayed‐type hypersensitivity responses and a peak 48.9% reduction of T cell proliferation to the metogen phytohaemagglutinin, were documented during a 9‐month period of isolation. T cell dysfunction was mediated by changes within the peripheral blood mononuclear cell compartment, including a paradoxical atypical monocytosis associated with altered production of inflammatory cytokines. There was a striking reduction in the production by peripheral blood mononuclear cells of the predominant pro‐inflammatory monokine TNF‐α and changes were also detected in the production of IL‐1, IL‐2, IL‐6. IL‐1ra and IL‐10. Prolonged Antarctic isolation is also associated with altered latent herpesvirus homeostasis, including increased herpesvirus shedding and expansion of the polyclonal latent Epstein‐Barr virus‐infected B cell population. These findings have important long‐term health implications.
Interleukin‐5 and eosinophils induce airway damage and bronchial hyperreactivity during allergic airway inflammation in BALB/c mice
Authors: Hogan Simon P , Koskinen Aulikki , Foster Paul S
Published: May 2007

The cytokines IL‐4 and lL‐5 secreted from antigen‐activated CD4+ T cells are thought to play central roles in the clinical expression and pathogenesis of asthma. However, there is conflicting evidence in animal models of allergic airway inflammation as to the relative importance of IL‐5 and eosinophils to the mechanisms underlying the induction of bronchial hyperreactivity and morphological changes to the airways in response to aeroallergen. In a recent investigation, the development of aeroallergen‐induced bronchial hyperreactivity in BALB/c mice was thought to be exclusively regulated by IL‐4, with no role for lL‐5 or eosinophils being demonstrated. In contrast, allergic airway disease could not be induced in IL‐5‐deficient mice of the C57BL/6 strain. A model of allergic airway inflammation, which displays certain phenotypic characteristics of late‐phase asthmatic responses, was used in the present investigation to establish a role for IL‐5 and eosinophils in the initiation of bronchial hyperreactivity and in the pathogenesis of allergic airway disease in BALB/c mice. Sensitization and repetitive aerosolization of mice with ovalbumin resulted in a severe airway inflammatory response which directly correlated with the induction of extensive airway damage and bronchial hyperreactivity to β‐methacholine. Treatment of mice with anti‐IL‐5 mAb before aeroallergen challenge, abolished blood and airway eosinophilia, lung damage and significantly reduced bronchial hyperreactivity. These results show that IL‐5 and eosinophilic inflammation play a substantial role in the pathophysiology of allergic airway disease and, moreover, that aeroallergen‐induced bronchial hyperreactivity is not exclusively regulated by IL‐4. These results also suggest that eosinophils are predominantly responsible for regulating aeroallergen‐induced structural changes to the airways which contribute, in part, to the mechanism underlying the induction of bronchial hyperreactivity. Thus, there are at least two distinct pathophysiological mechanisms for the induction of aeroallergen‐induced airway occlusion.
A recombinant GM‐CSF‐PE40 ligand toxin is functionally active but not cytotoxic to cells
Authors: O'Brien Phillipa , Smythe Anne , Biggs James C , Smith Glenn M
Published: May 2007

A granulocyte/macrophage colony‐stimulating factor (GM‐CSF)‐Pseudomonas exotoxin (PE) 40 fusion protein was constructed for potential use in the treatment of myeloid leukaemias, as a conditioning agent prior to allogeneic bone marrow transplantation or for ex vivo purging of malignant cells prior to autologous bone marrow transplantation. The GM‐CSF‐PE40 fusion protein successfully binds to the GM‐CSF receptor and is capable of initiating a mitogenic signal similar to native GM‐CSF in the GM‐CSF‐dependent TF1 cell line. The toxin component also appears to be fully functional as determined by an in vitro adenosine diphosphate‐ribosylation assay. The GM‐CSF‐PE4n fusion protein, however, was not cytotoxic to a number of myeloid leukaemia cell lines. It is suggested that the mechanism of internalization of the GM‐CSF receptor is not appropriate for the translocation of PE to the cytosol where it can fulfill its cytotoxic potential.
Expression of both Th1 and Th2 cytokines correlates with the histological rejection of MHC‐matched and MHC‐mismatched foetal pancreas allografts in mice
Authors: Kovarik Jiri , Koulmanda Maria , Mandel Thomas E
Published: May 2007

Foetal mouse pancreatic islet grafts were used to investigate differences in the histological appearance and cytokine expression pattern during acute rejection of fully MHC‐mismatched. and MHC‐matched but minor histocompatibility‐mismatched (mH) allografts. Grafts of foetal islet tissue from non‐obese diabetic mice under the kidney capsule of non‐immunosuppressed MHC and mH‐disparate BALB/c mice were rejected by day 9, whereas the rejection of only mH‐disparate C3H tissue into CBA mice occurred between 11 and 15 days. In both situations enhanced expression of transcripts for Th1 (IL‐2, IFN‐γ, TNF‐β) and Th2 cytokines (IL‐4, IL‐6, IL‐10) was demonstrable at the peak of infiltration of immune cells into the graft site, indicating a close association of these cytokines with graft destruction. Besides these kinetic differences no variation in the expression pattern of the tested cytokines could be demonstrated, indicating that the allograft response in either combination leads to enhanced expression of pro inflammatory cytokines which could contribute to graft destruction.
Molecular interaction of growth hormone with two monoclonal antibodies recognizing distinct epitopes
Authors: Wang Bosco Shang , Lumanglas Araceli L , Zhang Ren‐Jie , Tian Zu‐Guang
Published: May 2007

Two monoclonal antibodies (mAb), designated PS‐7.6 and PS‐11.2, were generated against recombinant porcine growth hormone (pGH) and shown to enhance the hormonal activity in promoting the growth of animals. The mAb were compared and their functional relationship investigated. It was demonstrated by radioimmunoassay that PS‐11.2 did not compete, but rather enhanced binding of 125I‐pGH tracer to PS‐7.6, suggesting that both mAb recognized distinct epitopes and also were additive in their antigen bindings. Surface plasmon resonance analysis using optical BIAcore technology (Pharmacia Biosensor, Piscataway, NJ, USA) provided additional data to support this idea because pGH, after being captured by PS‐11.2, remained capable of interacting with PS‐7.6. An anti‐idiotypic mAb was employed and shown to interact with PS‐7.6 but not PS‐11.2, implying that the differences in the Fab variable regions of these two mAb might contribute to their epitope specificity. Binding kinetics were determined by the BIAcore and the individual affinities of PS‐7.6 and PS‐11.2 to pGH were 6.8 × 10−8 and 1.2 × 10−9 mol/L, respectively. When these mAb were sequentially subjected to the BIAcore, however, their affinities decreased by approximately 100‐fold. Therefore, binding of pGH with one mAb significantly impaired a subsequent interaction with another mAb despite the fact that both mAb targeted different epitopes. Hypophysectomized rats were used for functional analysis and pGH was active in promoting growth of these GH‐deficient animals. The hormonal effect was further improved by incubating pGH with either PS‐7.6 or PS‐11.2 prior to administration. However, enhancement by individual mAb was completely abolished when pGH was treated with both mAb together, indicating their unpredictable biological interference with each other. Therefore, the present findings clearly demonstrate that although PS‐7.6 and PS‐l 1.2 recognize separate epitopes, their individual interactions with pGH are closely interrelated both immunologically and biologically.
IFN‐γ inducibility of class II transactivator is specifically lacking in human tumour lines: Relevance to retinoblastoma protein rescue of IFN‐γ inducibility of the HLA class II genes
Authors: Lu Yanmei , Tschickardt Michael E , Schmidt Brian J , Blanck George
Published: May 2007

We have previously reported that HLA class II induction by IFN‐γ is rescuable by reconstitution of functional retinoblastoma protein (RB) in two RB‐defective tumour lines: the breast carcinoma line. MDA‐ 468‐S4 (S4) and the non‐small cell lung carcinoma line. H2009. To determine the range of tumours and tumour types in which RB rescues HLA class II inducibility, we examined another RB‐defective tumour line. the retinoblastoma line. WERI‐Rb1. As in the case of S4 and H2009, HLA‐DRA and ‐DRB were non‐inducible by IFN‐γ in WERI‐Rb1. However, neither inducibility of DRA nor DRB mRNA was restored in an RB‐positive stable transformant of WERI‐Rb1. WLRB‐S, While guanylate‐binding protein (GBP) inducibility indicated that the basic IFN‐7 signal transduction pathway remained intact in WERI‐Rb1, mRNA for class II transactivator (CIITA), a mediator of the IFN‐γ activation of the HLA class II genes and several other genes related to immune function, was not detectable in IFN‐γ‐treated WERI‐Rbl. indicating that the lack of CIITA expression was responsible, at least in pan. for the inability of RB to rescue HLA class Il‐inducibility. The HLA class Il‐associated invariant chain (Ii), the expression of which is also up‐regulated by CIITA. was non‐inducible in WERI‐Rb1. consistent with non‐inducible CIITA. Also. IFN‐γ failed to activate the DRA. DRB and Ii promoters in WERI‐Rb1. However, exogenous CIITA expression in WERI‐Rb1 activated the DRA. DRB and Ii promoter‐chloramphinocol acetyltransferase constructs, confirming that CIITA was not induced in WERI‐Rb1 and indicating that other proteins required for activation of the class II and Ii promoters were functional in this cell lines. Examination of additional cell lines for GBP and CIITA induction revealed that a specific lack of the CIITA IFN‐γ response is common in human tumour lines. The possible role of CIITA defects in tumorigenesis is discussed.
A function for CD2 on murine B cells?
Authors: Keogh Michael‐Christopher , Elliot James , Norton Trisha , Lake Richard A
Published: May 2007

CD2 is expressed on murine B cells, probably as a result of a chromosomal translocation event during speciation. There are no activating antibodies to mouse CD2, but when activated non‐specifically, only T cells up‐regulate their expression of CD2. We investigated the expression and function of CD2 on B cells using mice transgenic for human CD2 under the control of a modified version of the autologous promoter/enhancer that included the immunoglobulin enhancer. This construction directs expression of human CD2 to the B cell compartment as well as to the T cell compartment. In this paper, we confirm that activating pairs of anti‐CD2 monoclonal antibodies are mitogenic for mouse T cells transgenic for human CD2. In contrast, mouse B cells that express similar amounts of human CD2 are not stimulated to proliferate by equivalent doses of these antibodies. We were also unable to show any functional consequence for these B cells as a result of CD2 ligation.
Effects of anti‐endothelial cell antibody in pre‐eclampsia on endothelin‐1 release from cultured endothelial cells
Authors: Yamamoto Tatsuo , Takahashi Yuko , Kuno Souichiro , Geshi Yumi , Sasamori Yukifumi , Mori Hiroyuki
Published: May 2007

In order to investigate the pathophysiological significance of anti‐endothelial cell antibody (AECA) in pre‐eclampsia, the effects of AECA on endothelin‐1 (ET‐I) and prostaglandin I2 (PGI2) release from cultured human umbilical vein endothelial cells (HUVEC) was evaluated. Serum samples were taken from 85 pre‐eclamptic and 20 normal pregnant women. Anti‐endothelial cell antibody was measured by ELISA using HUVEC. The release of ET‐1 and 6‐keto PGF 1‐α, a stable metabolite of PGI2, from HUVEC were evaluated after incubation with IgG‐AECA‐positive sera and IgG isolated from AECA‐positive sera. The incidence of IgG‐and IgM‐AECA was 24.7 and 8.2%, respectively. The release of ET‐I in the medium containing IgG‐AECA‐positive sera was significantly greater than in the medium containing IgG‐AECA‐negative sera. There was significant correlation between the levels of IgG‐AECA and the release of ET‐1 from endothelial cells. The ET‐1 release by IgG isolated from AECA‐positive sera was greater than that from AECA negative sera. However, the release of 6‐keto PGFI‐α by AECA‐positive sera was not significantly different from that of AECA‐negative sera. It is concluded that IgG‐AECA in pre‐eclampsia increases ET‐I release from endothelial cells and that AECA may affect local vascular function in this disorder.
Dexamethasone suppresses release of soluble TNF receptors by human monocytes concurrently with TNF‐α suppression
Authors: Joyce David A , Kloda Anna , Steer James H
Published: May 2007

Glucocorticoids suppress many monocyte functions, including endotoxin‐stimulated release of TNF‐α. Monocytes also release soluble receptors for TNF (sTNF‐R), which can modulate TNF bioactivity. We therefore examined the effects of the glucocorticoid, dexamethasone, on the release of soluble forms of the 55 kDa and 75 kDa receptors for TNF (sTNF‐R55 and sTNF‐R75) by human monocytes and the human monocytic Mono Mac 6 cell line. Peripheral blood mononuclear cells (PBMC) spontaneously released 406 ± 181 pg/106 cells of STNF‐R75 over 18 h in culture and Mono Mac 6 cells released 554 ± 29pg/106 cells. Lipopolysaccharide (LPS) exposure increased release of sTNF‐R75 by 54 and 217%, respectively. Dexamethasone suppressed both spontaneous and LPS‐stimulated release. The effect of dexamethasone was concentration dependent. At 1 μmol/L, dexamethasone suppressed the LPS‐stimulated release of sTNF‐R75 by 86% in PBMC and by 40% in Mono Mac 6 cells. Neither PBMC nor Mono Mac 6 cells released measurable amounts of sTNF‐R55, but spontaneous release of sTNF‐R55 from purified human monocytes (55 ± 2 pg/106 cells over 18 h) was reduced by 45% in the presence of dexamethasone. Dexamethasone reduced bioactive TNF in PBMC cultures, as well as immunoassayable TNF‐a, which indicates that suppression of TNF‐α release was biologically more important than suppressed release of soluble inhibitors. Similar concurrent suppression of IL‐1β and IL‐Ira release occurred in PBMC and Mono Mac 6 cultures exposed to dexamethasone.
The induction of immune responses to murine malignant mesothelioma by IL‐2 gene transfer
Authors: Leong Clement C , Marley Julia V , Loh Suzanne , Robinson Bruce WS , Garlepp Michael J
Published: May 2007

Stable IL‐2 transfectant clones have been derived from two non‐immunogenic murine malignant mesothelioma (MM) cell lines to investigate the induction of protective antitumour immunity to MM. AC29‐IL‐2 transfectant clones grew at a slower rate in vivo than the parental cell line or a transfectant control clone but all inoculated mice developed tumours despite the continued ability of the tumour cells to express IL‐2. Tumour development after inoculation of AB1‐IL 2 transfectants varied, the degree of in vivo inhibition (40–100%) being directly related to the rate of IL‐2 secretion of the transfectants. When mice which had rejected the ABl‐lL‐2 transfectants were challenged with parental AB1 cells, a proportion (16–70%) of mice from each group remained tumour free at least 45 days after challenge (naive mice developed tumours within 26 days). The inhibition of growth of the initial inoculum of ABl‐IL‐2 transfectants was independent of CD4+ and CD8+ cells, consistent with the demonstration of non‐specific cytotoxic activity by splenocytes from mice inoculated with the IL‐2 transfectants. These data suggest that IL‐2 expression by MM cells is capable of generating in vivo immunity to the tumour. This immunity may be relatively weak or may be subject to downregulation so that consistent rejection of unmodified tumour cells is not achieved. Genetic modification with combinations of genes, including lL‐2 and B7‐1.will be necessary for reliable generation of protective immunity to MM.
DNA vaccines for parasitic infections
Authors: Kalinna Bernd H
Published: May 2007

There has been a tremendous explosion in the area of DNA vaccine research over the last 4 years, particularly in relation to antiviral vaccines. This report discusses the development and application of this new technology with regard to parasitic infections. Progress has been made towards the development of a vaccine against malaria, cryptosporidiosis, leishmaniasis, toxoplasmosis and schistosomiasis. In the future, nucleic acid vaccines will be a useful tool to help control these and other parasitic infections.
Toward clinical trials of DNA vaccines against malaria
Authors: Hoffman Stephen L , Doolan Denise L , Sedegah Martha , Wang Ruobing , Scheller Libia F , Kumar Anita , Weiss Walter R , Le Thong P , Klinman Dennis M , Hobart Peter , Norman Jon A , Hedstrom Richard C
Published: May 2007

In mid 1997 the first malaria DNA vaccine will enter clinical trials. This single gene DNA vaccine encoding the Plasmodium falciparum circumsporozoite protein (PfCSP) will be studied for safety and immunogenicity. If these criteria are met, a multi‐gene DNA vaccine designed to induce protective CDS8+ T cell responses against P. falciparum infected hepatocytes will be subsequently assessed for safety, immunogenicity and capacity to protect immunized volunteers against experimental challenge with P. falciparum sporozoites. Our perspectives on malaria vaccine development in general,1 and on a multi‐gene DNA vaccine in particular,2 have been recently reviewed. Herein, we review the rationale and experimental foundation for the anticipated P. falciparum DNA vaccine trials.
DNA vaccination against virus infection and enhancement of antiviral immunity following consecutive immunization with DNA and viral vectors
Authors: Ramsay Alistair J , Leong Kah Hoo , Ramshaw Ian A
Published: May 2007

Recent demonstrations of the immunogenicity of antigens encoded in DNA plasmids following delivery by various routes have heralded a new era in vaccine development. In this article, we review progress in DNA‐based antiviral immunoprophylaxis. Preclinical studies have already established the immunogenicity of DNA plasmids encoding protective antigens from a wide variety of viral pathogens and work published in recent months has raised real prospects of broadly protective DNA vaccination against infections with influenza virus and HIV. We also describe a consecutive immunization protocol consisting of a priming dose of vaccine antigen encoded in DNA plasmids followed by a booster with the same antigen encoded in recombinant fowlpox virus vectors. We have used this strategy to generate protective antiviral cell‐mediated immunity and sustained, high‐level antibody responses both systemically and at mucosae. and to elucidate immunological mechanisms underlying the development of immunity to antigens delivered in DNA vectors.
Cytokines and costimulatory molecules as genetic adjuvants
Authors: Pasquini S , Xiang Z , Wang Y , He Z , Deng H , Blaszczyk‐Thurin M , Ertl HCJ
Published: May 2007

DNA vectors expressing an antigen derived from a pathogen or a cancerous cell have been shown, after inoculation into experimental animals, to trigger de novo synthesis of foreign proteins, which induce an immune response. This immune response can be modulated by coinoculation of vectors encoding either cytokines or costimulatory molecules. A variety of cytokines such as granulocyte/macrophage colony‐stimulating factor (GM‐CSF), lL‐2, IL‐4, IL‐12 and IFN‐γ, as well as the costimulatory molecule B7.I. have been tested to date for their ability to amplify the immune response to genetic vaccines. Although the results obtained thus far clearly show that coadministration of vectors expressing immunomodulatory molecules, such as cytokines, may increase the efficacy of genetic vaccines, this approach is currently considered unsuitable for use in human patients due to the potential side effects of persistent cytokine expression.
The role of CD45 and CD45‐associated molecules in T cell activation
Authors: Altin Joseph G , Sloan Erica K
Published: May 2007

CD45 (lymphocyte common antigen) is a receptor‐linked protein tyrosine phosphatase that is expressed on all leucocytes, and which plays a crucial role in the function of these cells. On T cells the extracellular domain of CD45 is expressed in several different isoforms, and the particular isoform(s) expressed depends on the particular subpopulation of cell, their state of maturation, and whether or not they have previously been exposed to antigen. It has been established that the expression of CD45 is essential for the activation of T cells via the TCR, and that different CD45 isoforms display a different ability to support T cell activation. Although the tyrosine phosphatase activity of the intracellular region of CD45 has been shown to be crucial for supporting signal transduction from the TCR, the nature of the ligands for the different isoforms of CD45 have been elusive. Moreover, the precise mechanism by which potential ligands may regulate CD45 function is unclear. Interestingly, in T cells CD45 has been shown to associate with numerous molecules, both membrane associated and intracellular; these include components of the TCR‐CD3 complex and CD4/CD8. In addition, CD45 is reported to associate with several intracellular protein tyrosine kinases including p56lck and p59fyn of the src family, and ZAP‐70 of the Syk family, and with numerous proteins of 29–34 kDa. These CD45‐associated molecules may play an important role in regulating CD45 tyrosine phosphatase activity and function. However, although the role of some of the CD45‐associated molecules (e.g. CD45‐AP and LPAP) has become better understood in recent years, the role of others still remains obscure. This review aims to summarize recent findings on the role of CD45 and CD45‐associated molecules in T cell activation, and to highlight issues that seem relevant to ongoing research in this area.
B cell life span: A review
Authors: Fulcher DA , Basten A
Published: May 2007

Debate has surrounded the subject of B cell life span since it was first measured in mice in the early 1970s. In the 25 years which have passed since then, it has become increasingly apparent that the methods employed to measure rates of B cell turnover, such as pH]‐thymidine labelling, cell transfer or cell ablation, brought about significant disruptions to normal physiology which in themselves might have affected B cell turnover. More recently the use of bromodeoxyuridine has overcome many of these methodological difficulties and has allowed rates of B cell renewal to be measured within B cell subpopulations defined by multiparameter flow cytometry. Such studies have largely resolved the issue, concluding that about 85% of peripheral B cells are phenotypically mature and display first‐order exponential kinetics defined by a half‐life of 5–6 weeks, whilst the remainder are short‐lived with a life span of several days. This review examines both traditional and recent methods and discusses the influence of age, self‐tolerance and randomness in the overall shaping of a kinetically stable mature B cell population.
Nucleic acid vaccination of sheep: Use in combination with a conventional adjuvanted vaccine against Taenia ovis
Authors: Rothel JS , Waterkeyn JG , Strugnell RA , Wood PR , Seow H‐F , Vadolas J , Lightowlers MW
Published: May 2007

This report describes the use of a nucleic acid vaccine in a large outbred animal species both alone and in combination with a conventionally adjuvanted vaccine. The gene encoding a host‐protective antigen (45W) from the sheep parasite Taenia ovis was cloned into the expression vector pcDNA3 and the resultant plasmid termed pcDNA3‐45W. Eleven of 15 sheep injected either intramuscularly or intradermally with pcDNA3‐45W mounted a serum antibody response to 45W which for both routes of injection was predominantly IgG1. However, the level of antibody elicited by the nucleic acid vaccine was low and repeated vaccinations did not boost the response. Injection of pcDNA3‐45W into animals in which an immune response had previously been generated by vaccination with recombinant 45W using Quil A as adjuvant (rec45W vaccine), did not result in enhanced antibody levels. Initial vaccination with pcDNA3‐45W and subsequently with the rec45W vaccine resulted in antibody levels significantly higher (P < 0.05) than those obtained in sheep which had only received the rec45W vaccine. This enhanced antibody response was predominantly of the IgG1, subclass (IgG1: IgG2 5:1) in animals injected with the nucleic acid vaccine by the i.m. route. Surprisingly, a second rec45W vaccination of these animals led to little or no increase in IgG1 levels and a 10‐fold increase in IgG2 resulting in a predominance of 45W‐specific IgG2. (IgG1:IgG2, 0.25:1). These studies revealed that nucleic acid vaccination has efficacy, albeit limited, in the sheep and supports previous investigations which showed that antibody responses elicited by immunization are determined by both the route and mode of antigen delivery.
DNA cancer vaccines: A gene gun approach
Authors: Mahvi David M , Sheehy Michael J , Yang Ning‐Sun
Published: May 2007

A wide variety of approaches, all using gene transfer, have been tested experimentally as alternative means to vaccinate against cancer, either prophylactically or therapeutically. These include both ex vivo and in vivo gene transfer to tumour and/or non‐tumour cells, using both viral and non‐viral vectors. The transferred DNA has varied widely as well, including genomic or cDNA encoding tumour‐associated or oncofoetal antigens, cytokines, histocompatibility molecules, and costimulatory molecules. Several of these approaches have been applied in human clinical trials. This review summarizes those approaches, then compares and evaluates various methods using cytokine DNA in conjunction with autologous tumour cells, with particular emphasis on particle‐mediated gene transfer via a gene gun. Finally, prospects and needs for further development are discussed.
Characterization of CD4+CD8+ thymocytes observed in SClD‐bg mice
Authors: Shibata S , Asano T , Noguchi A , Kimura H , Hashimoto N , Hayakawa J , Ogura A , Doi K
Published: May 2007

Previously, we reported that a strain of severe combined immunodeficient (SCID) mice, namely SCID‐bg, spontaneously develop CD4+CD8+ double positive (DP) thymocytes despite their scid mutation. In the present study, we intend to further characterize the DP thymocyte population in SCID‐bg mice with Southern hybridization and flow cytometry. Southern hybridization analyses of sorted DP thymocytes in SCID‐β mice showed rearrangement of T cell receptor (TCR) β and TCRγ gene segments, although the expression of TCRβ and γδTCR molecules was absent. The phenotype of the DP thymocytes in SCID‐bg mice was CD44− heat‐stable antigen (HSA)+CD25−, and they did not express CD69. Interestingly, the expression of thymus leukaemia (TL) antigen was observed in the DP thymocytes of SCID‐bg mice but not in their CD4 CDS double negative (DN) fraction. Fas expression was higher and bcl‐2 expression was down‐regulated in the DP thymocytes as compared to the DN thymocytes in SCID‐bg mice, suggesting that they are not immortalized cells having escaped from apoptosis. Taken together, these results show that the phenotype of the DP thymocytes in SCID‐bg mice is similar to that of the earliest phase of the DP thymocytes in normal mice, although the expression of the molecules in the pre‐TCR complex is absent.
Blood group antibodies are made by CD5+ and by CD5− B cells
Authors: Wuttke Natasha J , Macardle Peter J , Zola Heddy
Published: May 2007

The B1 subset of B lymphocytes is associated with the production of low‐affinity, polyspecific antibodies. B1 cells are generally recognized by their expression of CD5, and comprise the majority of neonatal B cells. The neonate responds to a restricted range of antigens, and generally makes low‐affinity IgM antibody. Published data suggest that antibodies against the blood group antigens A and B are found occasionally in cord blood, and develop rapidly in infants as a result of cross‐reactivity with bacterial carbohydrate antigens. This suggests that CD5+ B1 cells may be specialized to make antibodies against such carbohydrate antigens. In this study we evaluated the appearance of antibodies against the blood group (ABO) antigens in human infants, using reagents which specifically distinguish between IgM (made by the infant) and IgG (mainly of maternal origin) and immunofluorescence to detect low levels of antibody. Having established that antibody is always detectable by 8 months of age, and frequently much earlier, we developed a plaque assay to examine the phenotype of cells making antibody against blood group antigens. At 8 months of age, CD5+ and CD5+ cells were both capable of making anti‐blood group antibody.
Cisplatin‐stimulated murine bone marrow‐derived macrophages secrete oncostatin M
Authors: Sodhi Ajit , Shishodia Shishir , Shrivastava Anju
Published: May 2007

Cisplatin (CP), a widely used anticancer drug activates cells of the immune system to a tumoricidal state, and thus functions as a potent biological response modifier. Expression of oncostatin M (OSM), a novel cytokine having a growth regulatory effect, was studied in bone marrow‐derived macrophages treated with cisplatin. Supematants from CP‐stimulated macrophages were found to be cytostatic for OSM‐sensitive A375 melanoma cells. Immunoblot analysis with anti‐OSM antibody revealed that expression of OSM in macrophages upon CP stimulation is a rapid process and within 30 min of CP treatment, a significant amount of OSM is secreted into the culture supernatant. These results therefore indicate that CP can stimulate murine bone marrow‐derived macrophages to produce OSM which can be implicated as one of the cytostatic/cytocidal factors in the antitumour action of cisplatin‐stimulated macrophages.
The immunomodulatory compound 2‐acetyl‐4‐tetrahydroxybutyl imidazole causes sequestration of lymphocytes in non‐lymphoid tissues
Authors: Bradbury MG , Qiu MR , Parish CR
Published: May 2007

2‐Acetyl‐4(5)‐(1,2,3,4‐tetrahydroxybutyl) imidazole (THI) is an immunomodulatory compound which causes a reversible lymphopenia in mice by an unknown mechanism. In this study, we investigated the whereabouts of cells lost from the blood and the spleen during THI treatment. Homing studies following i.v. injection of fluorescently labelled splenocytes into THI‐pretreated recipients showed that THI increased labelled cells in the liver, lungs and kidneys of THI‐treated mice. Furthermore, the sequestration in the liver occurred just 1.5 h after injection of labelled cells with the increase still being present at 24 h after injection. Microscopic examination of liver sections indicated that fluorescent lymphocytes were clustered within the liver sinusoids in THI‐treated mice, possibly associated with endothelial cells. The liver retention of lymphocytes was confirmed by immunohistochemical studies which showed a significant increase of T cells in the liver of THI‐treated mice. To determine the subset of lymphocytes which are lost from the spleen and sequestered in non‐lymphoid organs, lymphocytes remaining in the spleen after THI treatment were characterized. Our results confirmed that THI reduced B cells, CD4+ and CDS+ T cells and cells expressing CD62L, CD44 and IL‐2R in the spleen.
An evolution‐based hypothesis on the origin and mechanisms of autoimmune disease
Authors: Boyd Graham W
Published: May 2007

The pathogenesis of autoimmune disease remains an enigma. Here, the condition is analysed from an evolutionary standpoint, and the thesis developed that viruses, in particular retroviruses, are important to our evolution, and that their inappropriate re‐expression by repetitive (? ischaemic) cell damage in individuals of appropriate major histocompatibility type, leads to autoimmune disease. Such a view requires a slight adjustment to traditional ways of seeing Darwinian evolution, but one which makes real sense of the MHC‐restricted nature of the adaptive immune response.
Mucosal unresponsiveness to aflatoxin B1 is not broken by cholera toxin
Authors: Oliver Alfred R , Silbart Lawrence K , Keren David F , van Kruiningen Herbert J , Miller Bradford F , Rearick Christina
Published: May 2007

Rabbits immunized via chronically isolated ileal loops with aflatoxin B, (AFB) conjugated to porcine thyroglobulin (TG) mixed with the mucosal adjuvant cholera toxin (CT) produced very small mucosal antibody responses to AFB. Strong mucosal and systemic antibody responses to CT and TG were generated by this immunization protocol, suggesting that the observed unresponsiveness was specific to AFB. Parenteral immunization with AFB‐TG produced strong serum IgG anti‐AFB responses, indicating that the conjugate preparation was immunogenic and that the rabbits possess the requisite systemic B and T cell repertoires to recognize and respond to AFB. This mucosal unresponsiveness was distinct from oral tolerance, as animals immunized mucosally with AFB‐TG mixed with CT produced vigorous serum IgG anti‐AFB responses upon subsequent parenteral immunization with AFB‐TG. In vitro mitogen stimulation of lymphocytes isolated from Peyer's patches and mesenteric lymph nodes of unimmunized rabbits revealed the presence of AFB‐specific B cells at levels comparable with those found in the spleen. These observations indicate that unresponsiveness to AFB is hapten‐specific, restricted to the mucosa, and refractory to the adjuvancy of CT.
Activation and signal transduction via mitogen‐activated protein (MAP) kinases in T lymphocytes
Authors: Hardy Kristine , Chaudhri Geeta
Published: May 2007

The various mitogen‐activated protein (MAP) kinases have central roles in the signalling pathways of T lymphocytes. Their activation is uniquely dependent on dual phosphorylation of a serine/threonine and a tyrosine residue and is regulated by several levels of kinases in parallel cascades. In addition, both the MAP kinases and their upstream, activating kinases are regulated by several phosphatases. Although each of the MAP kinases have many cytoplasmic substrates, their ability to translocate to the nucleus means that they can transmit signals from the cytoplasm directly to transcription factors, which are sometimes nuclear bound. The MAP kinase cascades are activated in T lymphocytes by a variety of different external stimuli. They play an important role in transducing both the signal from T cell receptor and costimulatory molecules, on the T cell surface, and are able to regulate several of the transcription factors controlling the expression of critical genes, including that for IL‐2. This review examines how the activation of several MAP kinases is regulated, their role in signal transduction initiated by a variety of stimuli, and how this may lead to different cellular responses.
Cytokines and cross‐linking of sIgM augment PMA‐induced activation of human leukaemic CD5+ B cells
Authors: Tangye Stuart G , Weston Kathryn M , Raison Robert L
Published: May 2007

Purified leukaemic CD5+ B cells obtained from patients with B cell chronic lymphocytic leukaemia (B‐CLL) undergo activation and differentiation following in vitro stimulation with optimal concentrations of the phorbol ester PMA. This paper examines the ability of exogenous cytokines, anti‐Ig antibodies, or combinations of these, to enhance or replace the activation signal provided by PMA to different populations of leukaemic B cells. Proliferation induced by PMA was enhanced 2–20‐fold when the cells were co‐cultured with either anti‐Ig, IL‐2, IL‐4. IL‐I3. IFN‐γ or TNF‐α. Moreover, the combination of anti‐Ig. PMA and any one of the above cytokines further enhanced proliferation. Anti‐Ig and exogenous cytokines were also capable of inducing proliferation in leukaemic B cells cultured with a non‐mitogenic concentration of PMA. When taken together with the finding that IL‐2, IL‐4, IL‐13, IFN‐γ and TNF‐a prevent in vitro apoptosis of leukaemic CD5+ B cells, the results presented here suggest that these cytokines, in conjunction with signals delivered via sig, may play a role in the proliferation of leukaemic B cells in vivo and. consequently, the pathogenesis of B‐CLL.
Infusion of soluble myelin basic protein protects long term against induction of experimental autoimmune encephalomyelitis
Authors: Staykova Maria A , Simmons Rex D , Willenborg David O
Published: May 2007

Protection against experimental autoimmune encephalomyelitis (EAE) induced by s.c. infusion of myelin basic protein (MBP) alone is dose dependent and long lived. Protection is not effective against passively induced disease nor is it transferable with lymphoid cells. The proliferative response of lymph node cells to MBP following encephalitogenic challenge is decreased in the EAE‐protected animals as is the production of IL‐2 and IFN‐γ by these cells. Treatment with soluble MBP primed rats for antibody production is evidenced by the early appearance of anti‐MBP antibody following encephalitogenic challenge. Determination of antibody isotype following challenge revealed a change in the ratio of IgG1 to IgG2a with a significant increase in the amount of IgG1 produced. These data suggest that infusion of high dose soluble neuroantigen primes the immune response such that subsequent challenge with an encephalitogenic inoculum pushes the response down a non‐destructive Th2 autoimmune pathway.
A method of estimating the numbers of human and mouse T cell receptors for antigen α and β chain V‐genes
Authors: Johnson George , Wu Tai T
Published: May 2007

T cell receptors for antigen (TCR) V‐genes are under a very restrictive evolutionary pressure in order to maintain their biological activities of interacting with MHC class I or II molecules and processed peptides at the protein level. This is in contrast to immunoglobulin V‐genes which can mutate more freely. As we have discussed before, 17 or less nucleotide differences between any two mouse γ light chain V‐genes can be due to somatic mutations induced by antigens, allelic variations, and the combination of these two mechanisms. Thus, a cut‐off of 17 nucleotide differences has been used to estimate the numbers of the other human and mouse immunoglobulin chain V‐genes. Except for mouse heavy chains where experimental study is not yet available, our estimated numbers are in good agreement with experimental findings. For TCR V‐genes, however, this cut‐off value should be modified as illustrated in the present analysis. Our estimation of the number of human TCR β chain V‐genes is also in good agreement with the recent experimental study of sequencing 685 kb of that gene locus. Estimations for the numbers of human α mouse a and α chain V‐genes will wait for future experimental verification.
Awakening the global conscience: Who will benefit from new vaccines in the 21st century?
Authors: Nossal GJV
Published: May 2007

The World Health Organization's (WHO) Global Programme for Vaccines and Immunization has three linked aims. The first is to give the so‐called Expanded Programme on Immunization (EPI) vaccines to as many of the 125 million children who are born into the world each year as possible. The second is to ensure for the world an adequate supply of vaccines, and to safeguard vaccine quality. The third is in the field of vaccine research and development, not only coordinating the worldwide effort for new and improved vaccines but also preparing the way for their introduction into the EPI and continually to seek ways to simplify vaccination schedules. Enormous effort has gone into the polio eradication campaign. Following brilliant progress in both India and Africa, the goal of eradication by the year 2000 or shortly thereafter now seems achievable. Although a decision has not yet been taken, an attempt at measles eradication may well be the next huge challenge. The Global Programme for Vaccines and Immunization (GPV) is closely tied up with the Children's Vaccine Initiative (CVI) which is the name given to an umbrella organization which seeks to unite all the forces in the world promoting widespread use of vaccines. The chief functions of CVI are to be a strategic think tank, particularly as regards priorities; and to be a strong, consistent and effective advocacy group. Previously there had been some misunderstanding of the respective roles of WHO and CVI. These have now been cleared up by a dual stratagem — one single person, Dr JW Lee, as the administrative head of both Programmes; and one single Scientific Advisory Group of Experts or SAGE to guide the scientific aspects of both Programmes, The author has the honour of being Chairman of SAGE, It is apparent, however, that resource constraints are looming large in the affairs of both GPV and CVI. Clearly, the newer vaccines will be more expensive than the traditional ones, and the world must grope for new mechanisms to bring the fruits of the current upsurge of interest in vaccine development to all the countries of the world, not just the affluent ones.
DNA vaccines against tuberculosis
Authors: Lowrie Douglas B , Silva Celio L , Tascon Ricardo E
Published: May 2007

This edited transcript of a presentation at the‘Vaccines Beyond 2000’conference series of investigations by the authors throwing light on the mechanisms of protective immunity against tuberculosis in mice and raising hope for a new kind of vaccine to replace bacille Calmette‐Guérin (BCG), DNA encoding only one or a few protein antigens was found capable of conferring persistent protection equal to the effect of BCG. The essential features seem to be an endogenous origin of the antigen within transfected mouse cells which favours the development of CD8+/CD44hi/IFN‐γ‐producing T cells with antigen‐specific cytotoxicity. Such cells were the most efficient in adoptive transfer of protection from infected or DNA‐vaccinated mice to naive mice.
Immunological requirements for a subunit vaccine against tuberculosis
Authors: Elhay Martin J , Andersen Peter
Published: May 2007

Tuberculosis remains one of the most important threats to world health. Current vaccination and prevention strategies are inadequate and there is an urgent need for a new vaccine. The current vaccine bacille Calmette‐Guérin (BCG), is unable to protect against re‐activation of disease in later life and its efficacy varies tremendously in different human populations. An ideal replacement would be a non‐living subunit vaccine that could impart protective efficacy greater than BCG but without its drawbacks. Before such a goal is achieved, however, there are many parameters that need to be examined in experimental systems. Such studies have revealed that apart from the selection of immunologically relevant antigens, dosage of antigen and type of adjuvant need to be chosen carefully. These parameters need to be examined in the context of the complex biology of the disease and, despite recent progress in defining host/pathogen interactions, experimental vaccines tested so far have fallen short of the protective efficacy of BCG. A coordinated approach, stimulating the various facets of cell‐mediated immunity will probably be essential for development of protective immunity through subunit vaccination.
An antigen valence theory to explain the evolution and organization of the humoral immune response
Authors: Hodgkin Philip D
Published: May 2007

The three modes of antibody production, natural, T independent (TI) and T dependent (TD) are conserved among vertebrate species suggesting an important role for each in protection against pathogens. Here, I use an artificial ‘universe’ to argue that the three modes of antibody production represent layers that evolved to deal optimally with antigens of different valence. Thus, the apparently more sophisticated TD response has not superseded the natural and TI components of the humoral immune response. Furthermore, the characteristic differences in isotype, somatic mutation and memory displayed by each antibody layer are appropriate for their targeted range of surface structures. It is also suggested that the TD and TI activation arms are at the extremes of a continuum, with signal integration of antigen and T cell‐derived signals contributing to B cell decisions about isotype selection, proliferation and secretion that minimize the time to protection.