bluuebunny/crossref_metadata_2025 huggingface dataset:
Mechanisms of induction of primary virus‐specific cytotoxic T lymphocyte responses
Authors: De Bruijn Marloes L. H. , Nieland John D. , Schumacher Ton N. M. , Ploegh Hidde L. , Martin Kast W. , Melief Cornelis J. M.
Published: March 2007

We have investigated the ability of various antigen‐presenting cell (APC) types to induce primary anti‐viral cytotoxic T lymphocyte (CTL) responses by single in vitro stimulation. Of these APC types, only dendritic cells (DC) and RMA‐S lymphoma cells could induce primary CTL responses, but by divergent mechanisms. DC were capable of generating primary virus‐specific CTL, either by presenting viral peptide or processed infectious virus. In contrast, RMA‐S cells could not present endogenous antigen, e. g. after virus infection, but this cell line very efficiently presented exogenous viral peptides to induce primary virus‐specific CTL in vitro. Spleen cells, lipopolysaccharide‐induced B cell blasts or the non‐mutated RMA cells did not have the ability to trigger unprimed T cells by single in vitro stimulation. We have investigated several characteristics important for primary CTL response induction by DC and RMA‐S cells (summarized in Fig. 6). Primary CTL response induction by DC or RMA‐S cells was blocked by anti‐LFA‐1 or anti‐CD8 monoclonal antibodies (mAb). DC rapidly aggregated with unprimed T cells, which was independent of LFA‐1 and CD8 molecules. RMA‐S cells did not form conjugates with unprimed T cells. Despite their abundant major histocompatibility complex (MHC) class I cell‐surface expression, DC did not bind much exogenously added viral peptide. In contrast, the MHC class I molecules on RMA‐S cells bound a large quantity of exogenously administered peptide. Powerful adhesion by DC and high expression of relevant MHC/peptide complexes on RMA‐S cells are important features in the initial contact with unprimed T lymphocytes. In a later stage of contact, both DC and RMA‐S cells activate LFA‐1 (and CD8) molecules at the T cell surface to strengthen and maintain the contact between T cell and APC.
Human neutrophils release their major membrane sialoprotein, leukosialin (CD43), during cell activation
Authors: Rieu Philippe , Porteu Françoise , Bessou Gilles , Lesavre Philippe , Halbwachs‐Mecarelli Lise
Published: March 2007

Leukosialin (CD43) is a sialic acid‐rich molecule with a relative molecular mass (Mr) of 140 000 highly represented on polymorphonuclear neutrophils (PMN) and on most leukocytes. One of its functions may be to prevent nonspecific cell‐to‐cell interactions through negative charge repulsions. As tested by immunofluorescence, neutrophil CD43 membrane expression was shown to decrease by up to 80% upon cell activation by phorbol myristate acetate (10 ng/ml) or by N‐formyl‐L‐methionyl‐L‐leucyl‐L‐phenylalanine (FMLP; 10−6 M) in the presence of cytochalasin B. The kinetic of this decrease paralleled that of CD11b up‐regulation. FMLP alone, tumor necrosis factor (TNF‐α), lipopolysaccharide and granulocyte macrophage colony‐stimulating factor had moderate or insignificant effects, while inducing striking CD11b up‐regulation. Cell priming with TNF‐α followed by FMLP stimulation resulted in up to 40% decrease of CD43 expression. Anti‐CD43 mAb immunoprecipitated three fragments of Mr 130 000, 49000 and 34000 from the cell‐free supernatant of activated neutrophils, suggesting that CD43 is released from the membrane by proteolysis. Indeed, the decrease in CD43 expression was inhibited by phenylmethanesulfonylfluoride (PMSF). Homotypic aggregation of activated PMN was also inhibited by PMSF and could result, at least in part, from the shedding of CD43. The shedding of such a strongly anionic and major membrane protein should drastically modify PMN surface charge and may allow previously hindered interactions by exposing new adhesion molecules.
CD45RA −RO+ subset is the major population of dividing thymocytes in the human
Authors: Okumura Meinoshin , Fujii Yoshitaka , Inada Keiji , Nakahara Kazuya , Matsuda Hikaru
Published: March 2007

CD45, or leukocyte common antigen, is expressed in different isoforms on different subsets of thymocytes, suggesting its involvement in the process of T cell development in the thymus. We report studies on CD45 isoform expression on human thymocytes at various stages of development using three‐color flow cytometric analysis and cell cycle analysis. Among CD45RO+ cells 18.4% were in S+G2/M phase and represented more than 80% of the dividing cells in the thymus. Among the CD45RO− cells 10.9% were also in cell cycle. Because the CD45RO+ population is almost exclusively CD45RA−, the CD45RA−RO+ subset constitutes the major portion of dividing cells in the thymus. Both the CD1high and the CD3− populations were actively cycling. However, the former was almost 100% and the latter only 50% CD45RA−RO+. Dividing CD45RA−RO+ cells contain, therefore, many cells that have not yet expressed the CD3/T cell receptor complex and presumably have not yet undergone selective procedures. These results are hard to reconcile with the previously presented hypothesis that CD45RO represents a marker for cells that are destined to die in the thymus. Instead, these results suggest an alternative possibility that CD45RO+ cells may contain cells that can mature and, thus, also constitute the thymic generative lineage.
Afferent lymph veiled cells prime CD4+ T cell responses in vivo
Authors: McKeever Declan J. , Awino Elias , Morrison W. Ivan
Published: March 2007

The interdigitating cell (IDC) population of the lymph node paracortex is believed to be responsible for the induction of CD4+ T cell responses to soluble antigens. We have examined the role of afferent lymph veiled cells (ALVC), the putative precursors of IDC, in the induction of primary bovine CD4+ T cell responses in vivo. ALVC prepared from lymph draining an antigen inoculation site stimulated maximal responses in antigen‐specific T cell clones as soon as 30 min after inoculation. In addition, antigen‐pulsed ALVC were shown to induce primary antigen‐specific T cell responses when administered in vivo. Observed influences of fixation and the addition of chloroquine or class II major histocompatibility complex‐specific monoclonal antibodies on presenting function confirmed that ALVC process and present antigens using the endosomal pathway. We conclude that ALVC rapidly internalize antigens deposited in the periphery, and process them for presentation to naive T cells in the draining lymph node. Their function is, therefore, likely to be an important factor in the induction of primary T cell responses to soluble antigens in vivo.
Functional characterization of a novel anti‐B7 monoclonal antibody
Authors: de Boer Mark , Parren Paul , Dove Jeffrey , Ossendorp Ferry , van der Horst Gerda , Reeder John
Published: March 2007

For optimal activation of T cells, binding of their T cell receptor to antigenic peptides in the context of major histocompatibility complex molecules on antigen‐presenting cells (APC) is not sufficient. Accessory signals, provided by accessory cells, are needed to induce proliferation and clonal expansion of normal T cells. It has been shown previously that the B7 molecule, present on the cell surface of activated APC, can provide the second signal by binding to the CD28 molecule on T cells. Here we describe a novel anti‐B7 (mAb), B7‐24. This mAb binds to a functionally important epitope of the B7 molecule. Fab fragments of B7‐24 can almost completely block anti‐CD3‐induced, B7‐dependent T cell proliferation when tested in a model system where purified T cells are co‐cultured with 3T6 cells expressing the human FcγRII and human B7, in the presence of anti‐CD3 mAb. In contrast, mAb B7‐24 is not able to inhibit T cell proliferation in primary mixed lymphocyte reactions where purified T cells are co‐cultured with Epstein‐Barr virus‐transformed B cells. These findings suggest that other cell surface molecules allow for maximal proliferation of T cells in mixed lymphocyte reactions, even when the interaction between B7 and CD28 is blocked by B7‐24.
Rescue from anti‐IgM‐induced programmed cell death by the B cell surface proteins CD20 and CD40
Authors: Valentine Mary A. , Licciardi Karen A.
Published: March 2007

Programmed cell death (PCD), or apoptosis, is characterized by several morphologic alterations and eventual cleavage of nuclear DNA into oligonucleosome‐length fragments. We defined a human B cell line, Ramos, that responds with PCD following ligation of surface IgM. Of the DNA in Ramos cells 3%–10% was fragmented as early as 4 h after IgM ligation. Propidium iodide staining demonstrated that 20%–40% of Ramos cells became apoptotic by 18 h and further established that cells transiting into the S phase of the cell cycle were susceptible to PCD. Addition of several agents to the Ramos cells abrogated anti‐IgM‐induced PCD, including the phorbol 12‐myristate 13‐acetate (PMA). In contrast to the effect of PMA, the 4αPMA isomer of PMA neither activated protein kinase C (PKC) nor rescued the cells from anti‐IgM‐induced PCD, confirming a role for PKC in negating apoptosis. To explore the effect of physiologic signals on anti‐IgM‐induced PCD, antibodies against the CD20 or CD40 molecules were added in concert with anti‐IgM. Both CD20 and CD40 synergize with anti‐IgM to augment proliferation but neither molecule activates PKC in Ramos cells. Both anti‐CD20 and anti‐CD40 reduced the number of cells undergoing anti‐IgM‐induced PCD. Unlike the effect of anti‐CD40, addition of anti‐CD20 to anti‐IgM‐stimulated cells negated PCD only in a subset of cells. Maximal rescue occurred following the addition of anti‐CD40 and occurred by 4 h and at least up to 20 h of culture. These data show that (a) PCD can be initiated in B cells entering the S phase of the cell cycle, (b) PCD can be triggered by engagement of surface IgM in the absence of ancillary signals or PKC activation, and (c) rescue from PCD can occur by several mechanisms, either PKC dependent or PKC independent.
Immunoglobulin x light chain germ‐line transcripts in human precursor B lymphocytes
Authors: Thompson Allan , Timmers Erik , Kenter Marcel J. H. , Kraakman Margriet E. M. , Hendriks Rudolf W. , Schuurman Ruud K. B.
Published: March 2007

B lymphoblastoid cell lines (BLCL), established from bone marrow and peripheral blood mononuclear cells from two severe combined immunodeficiency (SCID) patients, manifested a complete absence of genomic rearrangements of the immunoglobulin (Ig) heavy (H) and light (L) chain loci. The BLCL contained germ‐line transcripts of the Ig x region locus of approximately 1.2 kilobases (kb). By cDNA cloning and sequence analysis the transcripts were shown to consist of a Cx segment, a Jx1 gene segment, 160 base pairs (bp) of Jx1 5′ intervening sequence, containing the heptamer/nonamer recombination recognition sequences and at the 5′ end a 523‐bp segment designated human x°, The first 206 bp of this 5′ segment were homologous to the reported murine x° region. Genomic restriction mapping and DNA sequence analysis demonstrated that the human x° segment is located approximately 4 kb upstream of Jx1. The x° segment contains a putative promoter region with an OCT2 binding site, and has a splice donor site to accomplish splicing to an acceptor site 160 bp upstream of Jx1. Expression of the x° gene segment was found in BLCL derived from normal fetal bone marrow, in which both Ig x loci were in the germ‐line configuration. These findings indicate that the described transcripts are not only present in SCID, but also in normal developing pre‐B lymphocytes. The expression of germ‐line Ig x L chain transcripts may be associated with the locus becoming accessible to gene rearrangement.
Peritoneal exudate lymphocyte and mixed lymphocyte culture hybridomas are cytolytic in the absence of cytotoxic cell proteinases and perforin
Authors: Helgason Cheryl D. , Prendergast John A. , Berke Gideon , Bleackley R. Chris
Published: March 2007

We have utilized the sensitive polymerase chain reaction (PCR) to determine whether cytotoxic T lymphocyte (CTL) hybridomas generated from peritoneal exudate lymphocytes (PEL) and mixed lymphocyte cultures (MLC) express transcripts for perforin and the cytotoxic cell proteinases CCP1 to CCP5. We could readily detect less than one transcript per cell using this methodology. Cytolytic activity could be induced to varying levels in four of the five hybridoma clones tested. With the exception of low level CCP2 expression in the MLC hybridoma MD45 following antigen stimulation, all of the hybridomas could be stimulated to function as potent cytolytic cells in the complete absence of perforin or CCP transcripts. PCR analysis utilizing actin primers indicated that all samples contained material which could be reverse transcribed and PCR‐amplified. These results support the argument that populations of lymphocytes do exist that are capable of target cell lysis by an alternative mechanism not involving perforin and CCP.
Development of human Th1 and Th2 cytokine responses: The cytokine production profile of T cells is dictated by the primary in vitro stimulus
Authors: van der Pouw‐Kraan Tineke , de Jong Rolien , Aarden Lucien
Published: March 2007

Regulation of interleukin (IL)‐4 production, but not IL‐2 production, was found to be quite different in either freshly isolated T cells or T cell clones. Both fresh T cells and T helper 2‐like clones produced IL‐4 when stimulated with anti‐CD2 in combination with anti‐CD28. However, whereas T cell clones showed enhanced IL‐4 production when phorbol 12‐myristate 13‐acetate (PMA) was used in addition to anti‐CD2 and anti‐CD28, IL‐4 production by fresh T cells was inhibited by the presence of PMA. Prestimulation of fresh T cells led to the following observations: (a) activation in the absence of PMA led to a reversal of the PMA effect and (b) within 2 days these cells resembled T cell clones in that IL‐4 production was no longer inhibited by PMA. When prestimulation was carried out in the presence of PMA, the inhibition of IL‐4 production seemed irreversible. Removal of PMA after 3 days did not lead to renewed capability of IL‐4 production, whereas IL‐2 production was unimpaired. Our data show that the capacity of cultured T cells to produce IL‐4 is determined and fixed during the first 2‐3 days of stimulation.
Localization of self antigen: implications for antigen presentation and induction of tolerance
Authors: Stockinger Brigitta , Gran Catriona F. , Hausmann Barbara
Published: March 2007

The fifth component of complement (C5) is a self antigen expressed in serum of normal mice at a concentration of about 50 μg/ml. We have previously shown that C5 is constitutively processed and presented by antigen‐presenting cells (APC) in normal mice to induce and maintain complete tolerance in major histocompatibility complex (MHC) class II‐restricted T cells. This report addresses the question of whether C5 presentation involves exogenous antigen which has been internalized for processing or whether intracellular, biosynthesized C5 is being presented with MHC class II. Macrophages were found to synthesize, but not secrete C5 in bone marrow chimeras made from irradiated C5‐deficient [C5(−)] hosts reconstituted with C5‐sufficient [C5(+)] bone marrow [C5(+) ← C5(−)]. In these mice, macrophages are the only source of C5. [C5(+) ← C5(−)] chimeras are not tolerant of C5 and generate C5‐specific T and B cell responses upon immunization indistinguishable from those of C5(‐) mice. Macrophages from [C5(+) ← C5(‐)] chimeras are unable to activate C5‐specific T cell hybrids in vitro unlike macrophages from a C5(−) strain that has matured in a C5‐expressing environment [C5(−) ← C5(+) chimeras]. This shows that under physiological conditions in vivo intracellular C5 does not get access to the class II presentation pathway and thus, does not induce tolerance in class II‐restricted T cells.
Kinetics of peritoneal B‐1a cells (CD5 B cells) in young adult mice
Authors: Deenen Gerrit Jan , Kroese Frans G. M.
Published: March 2007

In the mouse, conventional B cells are continuously generated from precursor cells located in the bone marrow (BM), whereas the small subset of B‐1 cells (formerly called Ly‐1 B cells) constitute a self‐replenishing population of cells. Here we studied the kinetics of murine peritoneal B‐1a cells (i.e. B‐1 cells expressing CD5). The actual number of B‐1a cells in the peritoneal cavity that are proliferating, as detected by metaphase arrest and S‐phase index, was below detection level, indicating that these cells do not divide significantly at this anatomical location. To establish the life‐span of B‐1a cells we used long‐term administration of 5‐bromo‐2′‐deoxyuridine in combination with three‐color immunocytology on cytospin preparations. The renewal rate of peritoneal B‐1a cells was 1.3% per day representing a 50% renewal time of 38 days. Splenic B cells and popliteal lymph node B cells (predominantly conventional B cells) showed an almost identical renewal rate of 1.1% per day. The data show that peripheral B cells from various lymphoid tissues and locations do not differ significantly in their renewal capacity, even though there are differences in their developmental origin.
T suppressor hybridomas and interleukin‐2‐dependent lines induced by copolymer 1 or by spinal cord homogenate down‐regulate experimental allergic encephalomyelitis
Authors: Aharoni Rina , Teitelbaum Dvora , Arnon Ruth
Published: March 2007

Suppressor T (Ts) hybridomas and interleukin‐2‐dependent T cell lines were established from spleens of mice, which had been rendered unresponsive to experimental allergic encephalomyelitis (EAE) either by mouse spinal cord homogenate or by the synthetic suppressant copolymer 1 (Cop 1). The Ts hybridoma supernatants and the Ts line cells specifically suppressed the in vitro response to the encephalitogenic myelin basic protein (BP), as indicated by inhibition of both the proliferation and interleukin‐2‐secretion responses of a BP‐specific T cell line. Moreover, these Ts cells prevented the development of actively induced EAE in vivo. All hybridomas and lines were most effective when injected at the time of disease induction, thus suggesting that they operate as effector suppressor cells, and functionally inhibit encephalitogenic responses. The data presented here suggest that the suppressor cells are stimulated by the protective epitopes included in the BP as well as in the Cop 1 molecules and that they play an active role in the regulation of EAE. The generation of Ts lines and hybridomas, which have been induced by Cop 1, establish the specific stimulation of suppressor cells to EAE as a mechanism underlying the therapeutic activity of Cop l.
Split tolerance of Thl and Th2 cells in tolerance to Theiler's murine encephalomyelitis virus
Authors: Peterson Jeffrey D. , Karpus William J. , Clatch Richard J. , Miller Stephen D.
Published: March 2007

Theiler's murine encephalomyelitis virus (TMEV) produces a chronic, inflammatory demyelinating disease in susceptible mouse strains that is used as a model for multiple sclerosis. Because disease susceptibility correlates temporally with the development of virus‐specific delayed‐type hypersensitivity (DTH) responses, we studied methods and mechanisms by which virus‐specific DTH could be specifically inhibited. The intravenous injection of UV‐inactivated TMEV coupled to syngeneic splenocytes via a carbodiimide linkage (TMEV‐SP), prior to immunization, induced a significant degree of tolerance in virus‐specific helper (Th) cells as determined by decreased DTH and T cell proliferative responses, and decreased interleukin (IL)‐2 and interferon (IFN)‐Y protein and mRNA levels. In contrast to the reduced levels of Thl‐specific lymphokine mRNA levels, IL‐4‐specific mRNA levels in response to virus stimulation were not affected in tolerant mice. Surprisingly, the total anti‐TMEV antibody response in DTH tolerant mice was enhanced 20‐100‐fold over sham‐tolerized controls and was composed of reduced levels of anti‐virus IgG2a, but dramatically increased levels of anti‐virus IgGl. The “split‐tolerance” was antigen specific, dependent on the concentrations of TMEV and carbodiimide used in the coupling procedure, and varied with the number of coupled syngeneic splenocy tes administered. The fixative effects of carbodiimide on antigen‐presenting function were necessary for the induction of DTH tolerance with TMEV‐SP, since intravenous administration of virus coupled to splenocytes via a biotin‐avidin linkage led to enhanced virus‐specific antibody responses, but was unable to inhibit DTH unless concomitantly fixed with carbodiimide. Collectively, the data indicate that Thl cells (mediating DTH, IL‐2 and IFN‐γ production, and helper function for IgG2a production) were specifically anergized, with concomitant stimulation of Th2 cells (producing IL‐4 and mediating helper function for IgGl antibody production).
Mechanisms that generate human immunoglobulin diversity operate from the 8th week of gestation in fetal liver
Authors: Cuisinier Anne‐Marie , Gauthier Laurent , Boubli Léon , Fougereau Michel , Tonnelle Cécile
Published: March 2007

The repertoire of immunoglobulin expressed very early in human development was approached by cloning and sequencing 55 rearranged and 11 germ‐line VH transcripts, after amplification by polymerase chain reaction of cDNA libraries derived from two fetal livers at 8 and 13 weeks of gestation. All families with the exception of VH2, were expressed as soon as 8 weeks, with preferential usage of certain germ‐line genes. Very few somatic mutations, randomly localized, were identified. By contrast, in a series of clones derived from the same VDJ rearrangement using the VH6 family, extensive mutations had taken place, mostly accumulated in the third complementarity‐determining region (CDR3) suggesting that the specialized enzymatic machinery was at hand very early during human development.

Some other characteristics of the fetal repertoire also emerged, namely increased usage of JH3 and JH2, as compared to the adult pattern, where JH4 is dominant and reduced length of the D/CDR3 regions. All D gene families were identified, and their usage frequently involved D‐D fusions. N diversity was present very early, and increased with age.

Identification of germ‐line transcripts pertaining to all six VH families including pseudogenes, in the E55 library, revealed a population very different as compared to rearranged gene transcripts. This suggests that a large portion of VH locus is accessible for transcription, bringing no evidence of correlation between preferential rearrangement of a given VH gene and its localization in the locus.
Alterations of CD2 association with T cell receptor signaling molecules in “CD2 unresponsive” human T lymphocytes
Authors: Schraven Burkhart , Wild Martin , Kirchgessner Henning , Siebert Brigitte , Wallich Rainer , Henning Stefan , Samstag Yvonne , Meuer Stefan C.
Published: March 2007

CD2‐associated molecules were identified by means of in vitro kinase assays of CD2 immunoprecipitates obtained from nontransformed human T lymphocytes lysed in the detergent brij 58. Under these conditions CD2 was found to be associated with the protein tyrosine kinases p56lck and p59fyn as well as two low molecular weight phosphoproteins. The latter were identified as the ζ and ϵ chains, the major signaling components of the CD/7 TcR complex. Importantly, induction of T cell unresponsiveness towards CD2‐mediated stimuli by means of CD3/Tcell receptor (TcR) modulation results in uncoupling of ζ and ϵ from the CD2 molecule, while its associations with p56lck and p59fyn remain unaffected. Moreover, despite the incapacity of T lymphocytes to undergo DNA synthesis in the CD3/TcR‐modulated state, CD2 triggering still results in tyrosine phosphorylation of some unknown protein substrates. Thus, the same ζ and ϵ chains which are components of a functional TcR complex appear to also couple to the CD2 molecular complex. Moreover, dissociation of TcR and CD2 complexes in intact cells seems to block CD2‐mediated Tcell growth but does not result in complete abolishment of the signal transducing capacity of the CD2 receptor.
Fine specificity and VJ usage of light chains in antibodies to the phosphorylcholine hapten
Authors: Lötscher Marcel , Heusser Christoph H. , Amstutz Hanspeter , Blaser Kurt
Published: March 2007

In the memory response to the phosphorylcholine hapten (PC) two major groups of anti‐PC antibodies with different fine specificities are elicited. Group I antibodies are mainly PC specific, whereas Group II antibodies are comprised of two specificities directed against the phenyl‐PC and the phenyl moiety of the PC hapten. The VL gene usage of 17 monoclonal memory anti‐PC antibodies were investigated by Southern blot analysis and nucleotide sequencing. Six out of eight Group I memory PC‐specific antibodies used the same VK22‐JK5 rearrangement as the major T15 primary response idiotype. One expressed a mutated JKI and one employed another VK22 gene family member. A shift in specificity from PC (Group I) towards phenyl‐PC (Group II) was accompanied with the usage of either VK1C‐JK1 or VK1A‐JK5 rearrangements. The phenyl‐specific Group II antibodies expressed the Vλl‐Jλ L chain rearrangement in combination with VH M141 expressing H chains. In this specific segment of Group II antibodies most mutations were found. Thus four different VL genes were found to contribute to the fine specificity of memory response antibodies to the PC hapten in a clear structure‐function relationship. The diversified fine specificity in the memory response derives mainly from the usage of different L chains with particular VJ rearrangements in combination with VH of the dominant initial response clonotype and is not primarily due to mutational events.
Correlation between cell‐mediated immunity and degree of infection in subjects living in an endemic area of schistosomiasis
Authors: de Jesus Amelia M. Ribeiro , Almeida Roque P. , Bacellar Olivia , Araujo Maria Ilma , Demeure Christian , Bina Jose Carlos , Dessein Alain J. , Carvalho Edgar M.
Published: March 2007

Cell‐mediated immunity to Schistosoma mansoni antigens, unrelated antigens and mitogens was evaluated in 50 subjects with the same degree of exposure to infection living in an endemic area of schistosomiasis. The degree of infection, assessed by the number of eggs/g of stool, was variable in this population (0‐5604), suggesting differences in susceptibility to infection. Absence of lymphoproliferative response was observed in 56% of this group, despite having a response to purified protein derivative of tuberculin (PPD) and tetanus toxoid (TT) antigens and to pokeweed mitogen. The 50 subjects were divided into two groups, according to their degree of infection. The lymphoproliferative responses to schistosomula and adult worm antigens in the group with a low degree of infection (≤400 eggs/g of stool) were higher than the ones documented in patients with a high degree of infection (>400 eggs/g of stool), and these differences were statistically significant (p ≤0.001). An inverse correlation between the lymphocyte proliferation in response to S. mansoni antigens and the degree of infection was also observed (p = 0.02), indicating that subjects with a lower degree of infection have a higher lymphoproliferative response to schistosomula and adult worm antigens. No differences in the lymphocyte reactivity to other antigens (PPD and TT) were detected in these groups. An impairment of interferon‐γ in vitro production was observed when the lymphocytes from these subjects were stimulated with S. mansoni adult worm antigen, although they produced gamma interferon in response to phytohemag‐glutinin.
Characterization of four novel ϵ chain mRNA and a comparative analysis of genes for immunoglobulin E in rodents and man
Authors: Hellman Lars
Published: March 2007

The nucleotide sequence of the 3′ region of the E chain gene for human IgE is presented. A comparison of the entire region from 5′ of exon C1 to the M2 exon of the mouse, rat and human ϵ chain genes shows that the overall structure of the ϵ chain gene have changed only minimally during the 60‐70 million years of evolutionary separation between rodents and man.

We have previously shown that a number of rearrangements larger than 10 bp have relatively recently occurred in the C4/M1 intron of the rat or the mouse E chain genes. A majority of these rearrangements were found within or in close proximity to repetitive sequences of Z‐DNA‐forming potential (CA dinucleotide repeats). The C4/M1 intron has evolved very rapidly, to such an extent that no apparent homology can be detected between rodents and man. Only remnants of the repetitive sequences are present in man, supporting the theory that repetitive sequences having Z‐DNA‐forming properties may play a role in the evolution of the eucaryote genome by promoting recombinations, leading to a rapid evolutionary drift of sequences in close proximity to these repeats.

We report here the characterization of the membrane domains of human IgE and four novel mRNA transcribed from the human E chain locus. The primary structures have been determined by polymerase chain reaction cloning and nucleotide sequence analysis. All five mRNA contain the C3 domain and the membrane exon 2 (M2). Due to frame shifts caused by novel splice sites or novel splice‐site combinations, the proteins encoded by three out of these four novel mRNA differ in their carboxy‐terminal end from the classical secreted or membrane‐bound immunoglobulins. Northern blot analysis shows significant levels of at least three out of these four novel mRNA in an IgE‐producing human cell line.

One of the mRNA encodes a transmembrane‐like structure which has characters in common with the transmembrane region of the CD3 components of the T cell receptor complex (CD3 γ,δ and ϵ). This indicates that IgE‐producing B cells possibly have two separate signal‐transducing systems.

A comparison of the classical membrane anchoring domain of the human ϵ chain with a panel of immunoglobulin membrane domains from fish to higher mammals is presented. A tyrosine and a glutamine residue is found to be conserved between all cytoplasmic domains of all post‐switch immunoglobulin classes indicating a functional conservation of these amino acid residues. Suggested functions for these residues are their participation in signal transduction or in linkage to the cytoskeleton for internalization of antibody‐antigen complexes.
Inhibition of human immunodeficiency virus infection by the lectin jacalin and by a derived peptide showing a sequence similarity with gp120
Authors: Favero Jean , Corbeau Pierre , Nicolas Michel , Benkirane Monsef , Travé Gilles , Dixon James F. P. , Aucouturier Pierre , Rasheed Surayia , Parker John W. , Liautard Jean Pierre , Devaux Christian , Dornand Jacques
Published: March 2007

Jacalin is a plant lectin known to specifically induce the proliferation of CD4+ T lymphocytes in human. We demonstrate here that jacalin completely blocks human immunodeficiency virus type 1 (HIV‐1) in vitro infection of lymphoid cells. Jacalin does not bind the viral envelope glycoprotein gp120. Besides other T cell surface molecules, it interacts with CD4, the high‐affinity receptor to HIV. Binding of jacalin to CD4 does not prevent gp120‐CD4 interaction and does not inhibit virus binding and syncytia formation. The anti‐HIV effect of the native lectin can be reproduced by its separated a‐subunits. More importantly, we have defined in the a‐chain of jacalin a 14‐amino acid sequence which shows high similarities with a peptide of the second conserved domain of gpl20. A synthetic peptide corresponding to this similar stretch also exerts a potent anti‐HIV effect. This peptide is not mitogenic for peripheral blood mononuclear cells and does not inhibit anti‐CD3‐induced lymphocyte proliferation. These results make jacalin a chain‐derived peptide a potentially valuable therapeutic agent for acquired immunodeficiency syndrome.
Development of T cell receptor αβ‐bearing T cells in the submersion organ culture of murine fetal thymus at high oxygen concentration
Authors: Watanabe Yoshihiro , Katsura Yoshimoto
Published: March 2007

Organ culture (OC) of murine fetal thymuses on a membrane filter floating on the medium has been used as an important strategy in studies of the mechanism of T cell development. On the other hand, the submersion organ culture (S‐OC) system, in which fetal thymus lobes are submerged in the culture medium, is not popularly used because the growth of T cells is much lower than that in OC at the air‐medium border (AMB‐OC). In the present work, we tried to culture the fetal thymuses in the S‐OC system at 5% CO2 and various concentrations of O2. We found that in the environment containing 5% O2, γδ cells were selectively generated, though the cell recovery was less than one‐tenth of that seen in AMB‐OC. Generation of γδ T cells was hardly affected by increasing the O2 concentration. In marked contrast, the development of αβ T cells was highly dependent upon the O2 concentration. In the S‐OC at more than 60% O2, differentiation and growth of T cells, as determined in terms of recovered cell number, CD4 vs. CD8 profile and predominance of αβ lineage, were comparable to those observed in AMB‐OC. It was further shown that clonal deletion of Vβ6+ T cells occurred in high O2 S‐OC of CBA/J (Mls‐1a) but not C3H/HeJ (Mls‐1b) mice, the extent of the deletion being low but comparable with that seen in AMB‐OC. These results indicated that the fetal thymus microenvironment was potentially capable of supporting the development of both γδ and αβ T cells, and that skewing to one of these lineages was determined by an additional factor(s) such as the concentration of O2 dissolved in the medium.
Optimization of primers for cloning libraries of mouse immunoglobulin genes using the polymerase chain reaction
Authors: Kettleborough Catherine A. , Saldanha José , Ansell Keith H. , Bendig Mary M.
Published: March 2007

We have optimized primers for cloning libraries of murine heavy and light chain variable regions using the polymerase chain reaction. Since we are interested in cloning murine Fab fragments for expression in bacterial cells, the heavy chain primers were designed to clone Fd fragments comprising the heavy chain variable domain and the first domain of the IgG constant region. The light chain primers were designed to clone the entire murine kappa chain. Using ten degenerate 5′ primers and a degenerate 3′ primer to amplify murine Fd and seven degenerate 5′ primers with a single 3′ primer to amplify kappa chains, a diverse repertoire of mouse variable regions was cloned from mouse spleens.
Association of tumor necrosis factor (TNF) and class II major histocompatibility complex alleles with the secretion of TNF‐a and TNF‐0 by human mononuclear cells: a possible link to insulin‐dependent diabetes mellitus
Authors: Pociot Flemming , Briant Laurence , Jongeneel C. Victor , Mölvig Jens , Worsaae Helle , Abbal Michel , Thomsen Mogens , Nerup Jørn , Cambon‐Thomsen Anne
Published: March 2007

We have investigated the correlation between different tumor necrosis factor (TNF) and class II major histocompatibility complex alleles in the lipopolysaccharide‐ or phytohemagglutinin‐induced secretion of TNF‐α and TNF‐β by human monocytes and peripheral blood mononuclear cells in 87 unrelated Danish male individuals. Significant differences in TNF‐α secretory capacity between TNF Ncol restriction fragment length polymorphisms, TNFa and TNFc micro‐satellite alleles and DR alleles were identified. No correlation with TNF‐β secretory capacity was found for any of the markers studied. TNF genotyping allowed us to define four extended HLA haplotypes which correlate with TNF‐α secretory capacity. Two of these are DR4 positive: DQw8, DR4, TNFB*1, TNFa6, B44, A2 and DQw8, DR4, TNFB*2, TNFa2, B15, A2. Individuals carrying the TNFB*2, TNFa2 haplotype had a higher TNF‐α secretory capacity than those carrying the TNFB*1, TNFa6 haplotype. In a group of DR3/DR4 heterozygous patients with insulin‐dependent diabetes mellitus (IDDM), the frequency of the TNFa2 allele was higher than in HLA‐DR matched controls, whereas theTNFa6 allele was more frequent in control individuals. In the DR3/DR4 heterozygous diabetic group 12/26 had the alleles combination DQw8, DR4 (Dw4), C4A3, TNFB*2, TNFa2, B15, whereas only 1/18 controls had this haplotype. This diabetogenic haplotype is identical to the DR4 haplotype which correlates with a higher TNF‐α response. These observations suggest a direct role for the TNF locus in the pathogenesis of IDDM.
Functional double‐negative T cells in the periphery express T cell receptor Vβ gene products that cause deletion of single‐positive T cells
Authors: Martínez‐a Carlos , Marcos Miguel A. R. , de Alboran Ignacio M. , Alonso José María , de Cid Rafael , Kroemer Guido , Coutinho Antonio
Published: March 2007

A proportion of peripheral T cells lack surface expression of the CD4 or CD8 coreceptor molecules and hence are designated as “double negative” (DN). Most DN T lymphocytes express the Γ/β T cell receptor (TcR), but a minor fraction of them, in both humans and mice, express the α/β TcR. Whereas α/β+ DN T lymphocytes are infrequent (< 1%) in conventional lymphoid organs (spleen, blood, lymph node), they account for two‐thirds of the T cells residing in adult bone marrow. Analysis of the TcR Vβ repertoire expressed by peripheral DN T cells revealed a high frequency of cells bearing autoreactive TcR that cause deletion of “single‐positive” (SP) (CD4+CD8− or CD4−CD8+) T cells. Peripheral DN cells thus represent a cell type that is relatively resistant to clonal deletion. Furthermore, such cells have not been inactivated (anergized) in vivo since they proliferate and secrete interleukins in response to cross‐linking by monoclonal antibodies specific for these Vβ gene products that are deleted in SP T cells. These results might help to understand the association of peripheral expansion of DN cells and development of autoimmune diseases.
Role of flanking variable sequences in antigenicity of consensus regions of HIV gp120 for recognition by specific human T helper clones
Authors: Manca Fabrizio , Habeshaw John A. , Dalgleish Angus G. , Fenoglio Daniela , Pira Giuseppina Li , Sercarz Eli E.
Published: March 2007

Human T helper cells can discriminate among strain variants of HIV gp120 because of T cell clones recognizing non‐conserved regions, as demonstrated with T cells from HIV‐infected individuals and vaccinated volunteers and with primary T cell lines and clones obtained by in vitro immunization.

To obtain a better definition of cross‐reactions among T cell determinants within HIVgp120 variants, we used a panel of analog peptides within residues 236‐251 from the BRU, MN, SF2 and RF strain sequences to induce primary human T cell lines and clones. Different patterns of response were obtaind using each of the analog peptides, although they all share the consensus sequence 246‐251. Clones recognizing this sequence were generated by priming with the BRU and RF analog peptides, but not with the SF2 analog peptide. SF2 did not induce any 242‐245‐specific clones, but only T cells recognizing the 236‐240 sequence. A preferential response to residues 236‐240 was obtained by priming with the BRU and SF2 peptides, but not with the MN and RF peptides.

These results suggest that although the analog peptides exhibit a high degee of homology and share a consensus of the C‐terminal sequence (246‐251), the T cell response to the conserved sequence 246‐251 is controlled by flanking sequences. Therefore the presence of a shared sequence per se does not imply in vitro expansion of clones with that fine specificity, even though such clones are available within the naive repertoire and can be triggered by an analog peptide.
Charge‐dependent binding of granzyme A (MTSP‐1) to basement membranes
Authors: Vettel Ulrike , Brunner Georg , Bar‐Shavit Rachel , Vlodavsky Israel , Kramer Michael D.
Published: March 2007

The murine T cell‐associated serine proteinase granzyme A [also termed Murine Tcell‐associated serine proteinase‐1 (MTSP‐1), or SE‐1] expresses optimal enzymatic activity under extracellular milieu conditions. It degrades a variety of proteins that are constituents of basement membranes. Granzyme A is harbored within intracellular storage granules from which its release can be induced by appropriate ligand binding to extracellular matrix receptors of Tcells. Secreted granzyme A has, therefore, been implicated in the degradation of extracellular matrix barriers during T cell migration. Here we show that granzyme A binds to natural basement membranes in a charge‐dependent manner. Binding of granzyme A to charged surfaces protects it from inhibition by natural high molecular weight inhibitors. The interaction of granzyme A with in vitro‐produced extracellular matrices liberates basic fibroblast growth factor, which is bound to negatively charged heparan sulfate glycosaminoglycans of the extracellular matrix. We propose that the charge‐dependent interaction of granzyme A with basement membranes has multiple, biologically relevant consequences.
Co‐selection of the rare T cell receptor‐γ B haplotype in mouse lines selected for low responsiveness to red blood cell antigens
Authors: Roger Thierry , Pépin Louis‐Ferdinand , Couderc Jacques , de Franco Marcelo , Seman Michel
Published: March 2007

Tcell receptor (TcR)‐γ haplotype was investigated in seven pairs of murine Biozzi lines selected for low and high antibody (Ab) response to different antigens (Ag). High‐responder lines (H) express γA or γC haplotypes irrespective of the selecting Ag. In contrast, the γB haplotype, which is rare in laboratory mouse strains, is found in all Iow‐responder lines (L) to sheep erythrocyte Ag (SE). However, the TcR‐γB locus might only have a low penetrance in the control of the SE response. Moreover, investigations using LIVA mice, which were selected for low SE response from homozygous γA founder parents, indicate that the γB haplotype is neither necessary nor sufficient to achieve a low‐responder phenotype. The γB haplotype might, thus, be co‐selected to confer to L mice an improved resistance to bacterial infections mediated by γδ5 T cells compensating the profound and nonspecific immune perturbation associated with the low Ab response.
B7/BB1, the ligand for CD28, is expressed on repeatedly activated human T cells in vitro
Authors: Sansom David M. , Hall Nicolas D.
Published: March 2007

The activation of T cells is now thought to require at least two distinct signals. One signal is delivered through the interaction of the antigen‐specific T cell receptor with major histocompatibility complex (MHC) molecules and peptide, while the other is received from interactions with less precisely defined accessory or costimulatory molecules. In the absence of this second costimulatory signal, some T cells subsequently become unresponsive to antigenic stimulation. One of the major candidates for providing such a second signal to T cells is the molecule B7 interacting with the T cell glycoprotein CD28. In the present study we have investigated whether B7 is expressed on human T cell lines and clones, since these cells have the capacity to present antigen to each other by expressing MHC class II molecules. Our results demonstrate that B7 can be detected on T cell clones and on repeatedly activated but not freshly isolated peripheral blood T cells. The expression of B7 is dependent on the state of activation of the cells, being maximally expressed shortly after restimulation and becoming undetectable as the cells quiesce. Together, these results suggest that B7 expression may be of importance to T cells, perhaps in the avoidance of anergy.
Improved survival from potentially lethal graft‐vs.‐host disease by donor pretreatment with a recipient‐specific blood transfusion. II. Evidence for a principal role of the CD4+ T cell subset
Authors: Knulst Andre C. , Tibbe G. John M. , Bril‐Bazuin Clara , Benner Robbert
Published: March 2007

Pretreatment of prospective donors of hemopoietic cells with a single recipient‐specific blood transfusion can significantly decrease the morbidity and mortality of potentially lethal graft‐vs.‐host disease (GVHD) in lethally irradiated, allogeneically reconstituted mice. In a previous report we described the requirements for induction of this blood transfusion effect. In the present study we addressed in particular the mechanism underlying this effect. The beneficial effect of blood transfusion appeared to be due to the white blood cell population in the transfused blood. X‐irradiation (20 Gy) of the blood prior to transfusion did not abrogate the effect, which makes a veto cell mechanism unlikely. The blood transfusion effect in this model appeared to be mediated by the CD4+ T cell subset, since purified CD4+ spleen cells from transfused donors caused considerably less morbidity and mortality than naive CD4+ spleen cells. Apparently CD8+ cells were not involved, because their absence did not affect the beneficial effect. This observation was further confirmed by the finding that treatment of recipient mice that were reconstituted with spleen cells from transfused donors with anti‐CD8 monoclonal antibody (mAb) did not abrogate the blood transfusion effect. Interestingly, the blood transfusion effect was enhanced by administration of anti‐CD4 mAb to the recipients. The anti‐CD4 mAb might impair the interaction between T cells and antigen‐presenting cells, resulting in functional inactivation.
NK1.1+ CD4+ CD8‐ thymocytes with specific lymphokine secretion
Authors: Arase Hisashi , Arase Noriko , Nakagawa Ken‐Ichi , Good Robert A. , Onoé Kazunori
Published: March 2007

CD4+8− or CD4−8+ thymocytes have been regarded as direct progenitors of peripheral T cells. However, recently, we have found a novel NK1.1+ subpopulation with skewed T cell antigen receptor (TcR) Vβ family among heat‐stable antigen negative (HSA−) CD4+8− thymocytes. In the present study, we show that these NK1.1+ CD4+8− thymocytes, which represent a different lineage from the major NK1.1− CD4+8− thymocytes or CD4+ lymph node T cells, vigorously secrete interleukin (IL)‐4 and interfron (IFN)‐γ upon stimulation with immobilized anti‐TcR‐αβ antibody. On the other hand, neither NK1.1− CD4+8−thymocytes nor CD4+ lymph node T cells produced substantial amounts of these lymphokines. A similar pattern of lymphokine secretion was observed with the NK1.1+ CD4+ T cells obtained from bone marrow. The present findings elucidate the recent observations that HSA− CD4+8− thymocytes secrete a variety of lymphokines including IFN‐γ, IL‐4, IL‐5 and IL‐10 before the CD4+8− thymocytes are exported from thymus. Our evidence indicates that NK1.1+ CD4+8− thymocytes are totally responsible for the specific lymphokine secretions observed in the HSA‐ CD4+8− thymocytes.
Intestinal T lymphocytes in the chicken express an integrin‐like antigen
Authors: Haury Matthias , Kasahara Yoshihito , Schaal Stefan , Bucy R. Pat , Cooper Max D.
Published: March 2007

We report the characterization of a molecule recognized on chicken T cells by the murine A19 monoclonal antibody that was generated by immunization with intestinal intraepithelial lymphocytes. Immunofluorescence analysis indicated that both αβ and γδ T cell subpopulations in the intestine express the A19 antigen, but natural killer cells and B cells do not. The A19‐marked T cells were preferentially localized in the intestinal epithelium and less frequently in the underlying lamina proprial, T cells appearing in the intestine during embryonic life were A19 negative but acquired the antigen within the first few days after hatching. Although rarely found on cells in non‐intestinal tissues at any age, very late expression of the A19 antigen could be induced by concanavalin A stimulation of splenic and circulating T cells. Transforming growth factor β1 enhanced this induction of A19 expression. The A19 molecules expressed by intestinal T cells and activated splenic T cells were biochemically identical, consisting of a multi‐molecular complex of proteins with approximate Mr of 205, 145 and 75 kDa under nonreducing conditions and 120, 90 and 28 kDa under reducing conditions. The characteristics of this multimolecular complex and its differential expression suggest that the A19 antigen is a member of the integrin family which may function in the retention of intestinal lymphocytes.