bluuebunny/crossref_metadata_2025 huggingface dataset:
Genetic control of nonresponsiveness to hepatitis B virus vaccine by an extended HLA haplotype
Authors: Hatae Ken , Kimura Akinori , Okubo Ryoko , Nishimura Yasuharu , Sasazuki Takehiko , Watanabe Hiroshi , Erlich Henry A. , Ueda Kohji
Published: March 2007

We previously reported evidence for a statistical association between the serologically determined HLA‐Bw54, DR4 and DRw53 alleles and the non‐immune responsiveness to hepatitis B virus surface antigen (HBsAg) in the Japanese population. To identify the locus and allele within the HLA region associated with the nonresponsiveness to HBsAg, serological HLA typing, DNA typing of HLA‐DQ and DP alleles using amplified HLA genes and sequence‐specific oligonucleotide probes, and restriction fragment length polymorphism (RFLP) analysis of the fourth component of complement (C4) genes were performed in healthy unrelated Japanese vaccinees who were immunized subcutaneously three times with plasma‐derived HBsAg vaccine. In nonresponders to HBsAg, the frequencies of HLA‐Bw54 cross‐reactive epitope group (CREG); (Bw54, Bw55, Bw56 and other Bw22), C4 RFLP (6.5 kb + 12.0 kb), DR4, DRw53 and DQw4 (DQA1*0301‐DQB1*0401) were increased and the frequencies of HLA‐DR1, DRw6 and DQw1 were decreased as compared with those in healthy unrelated controls. Further analysis revealed that the coexistence of HLA‐Bw54CREG and DR4‐DRw53‐DQw4 (DQA1*0301‐DQB1*0401) was associated with the nonresponder group, whereas, donors positive for exclusively either Bw54 CREG or DR4‐DRw53‐DQw4 (DQA1*0301‐DQB1*0401) were not associated with the nonresponder group. Because there is a strong linkage disequilibrium between HLA‐Bw54CREG, C4 RFLP (6.5 kb + 12.0 kb) and HLA‐DR4‐DRw53‐DQw4 (DQA1*0301‐DQB1*0401) in the Japanese population, the extended HLA‐Bw54CREG‐C4 RFLP (6.5 kb + 12.0 kb)‐DR4‐DRw53‐DQw4 (DQA1*0301‐DQB1*0401) haplotype may well control nonimmune responsiveness to HBsAg. This extended HLA haplotype controls nonresponsiveness as a dominant genetic trait because all ten heterozygotes and two of three probable homozygotes of this extended HLA haplotype were nonresponders.
Enhanced expression of tumor necrosis factor receptor mRNA and protein in mononuclear cells isolated from rheumatoid arthritis synovial joints
Authors: Brennan Fionula M. , Gibbons Deena L. , Cope Andrew P. , Feldmann Marc , Mitchell Tracey , Maini Ravinder N.
Published: March 2007

We previously proposed the hypothesis that the pro‐inflammatory cytokine tumor necrosis factor‐α (TNF‐α) plays a pivotal role in the pathogenesis of rheumatoid arthritis (RA) based on our observations that it is the dominant inducer of interleukin‐1 (IL‐1) and granulocyte‐macrophage colony‐stimulating factor (GM‐CSF) production in RA synovial joint mononuclear (MNC) cells in culture. Since TNF‐α acts via two membrane receptors, we have extended those studies to investigate the distribution of the p55 and p75 TNF receptors (TNF‐R) in RA tissue. Surface receptor expression was quantitated by flow cytometry using monoclonal antibodies specific to the p55 (HTR‐9) and the p75 (UTR‐1) TNF‐R. Both receptors were significantly increased on MNC isolated from the synovial membrane of RA patients compared to normal or RA peripheral blood MNC. Interestingly, the p75 TNF‐R was increased both on large monocytic/macrophage‐type cells and CD3+ lymphocytes. Furthermore, there was a significant increase in the proportion of CD3+ cells in RA synovial fluid expressing the p75 TNF‐R, compared to matched peripheral blood MNC. In contrast to RA synovial MNC, p75 or p55 TNF‐R expression was not significantly increased in osteoar‐thritis synovial MNC. In addition, Northern blot analysis indicated abundant expression of both p55 and p75 mRNA in RA synovial joint MNC. This was in contrast to normal peripheral blood MNC cells which contained little or no constitutive TNF‐R mRNA; following stimulation with phytohemagglutinin and IL‐2, a rapid and transient expression of both receptor mRNA was induced. These results, therefore, indicate that in RA synovial joint tissue there is up‐regulation of both p55 and p75 TNF‐R mRNA and surface protein expression, and with the presence of TNF‐α in RA tissues, these results provide support to our hypothesis that TNF‐α is of critical importance in the pathogenesis of RA.
The use of a non‐depleting anti‐CD4 monoclonal antibody to re‐establish tolerance to β cells in NOD mice
Authors: Hutchings Patricia , Reilly Lorraine O' , Parish Nicole M. , Waldmann Herman , Cooke Anne
Published: March 2007

The use of immunosuppressive drugs in the management of autoimmunity penalizes a large part of the immune system for the misdemeanors of a small minority of T cells. An ideal form of therapy would be one in which it were possible to render the immune system tolerant of the inciting antigens with minimal effects on other responses. We here show that it is possible to re‐establish self tolerance in an animal model of insulin‐dependent diabetes mellitus without prior deletion of CD4+ T cells using a short course of therapy with a non‐lytic monoclonal antibody to the CD4 adhesion receptor on T cells. This tolerance can be achieved even when diabetogenic cells are already in the pancreas. Primary responses to antigens given after therapy has ceased are normal and secondary responses to antigens seen prior to, but not during, the period of antibody therapy can remain unaffected. This suggests that intervention with selected CD4 antibodies may have significant advantages over and above that provided not only by conventional immunosuppression but also over that provided by a depleting antibody.
In vivo responses of CD4+ and CD8+ cells to bacterial superantigens
Authors: Herrmann Thomas , Lees Rosemary K. , Robson MacDonald H. , Baschieri Selene
Published: March 2007

Staphylococcal enterotoxin B (SEB) is a bacterial superantigen that binds to major histocompatibility complex (MHC) class II molecules and specifically activates T cells bearing Vβ8 T cell receptor domains. We have compared several aspects of the response of CD4+ and CD8+ T cell subsets to SEB in vivo. Vβ8+ cells in both subsets proliferated to a similar extent upon SEB injection. Furthermore, mRNA for interferon‐γ was induced in both subsets with similar kinetics and SEB dose‐response. Finally CD8+ (but not CD4+) T cells from SEB‐injected mice exhibited SEB‐specific lysis of MHC class II‐bearing target cells. Collectively, these data indicate that the CD4:MHC class II interaction confers no detectable selective advantage to CD4+ cells in the in vivo response to SEB. The observed effector functions of both subsets may contribute to SEB‐induced immunopathology.
Bone marrow cells of athymic nude mice express functional T cell receptor α chain transcripts rearranged to Vδ2, 3, 4, 5, 6 genes
Authors: Spieß Sibylle , Kuhröber Andreas , Schirmbeck Reinhold , Reimann Jörg
Published: March 2007

From bone marrow cells (BMC) of athymic nude mice, T cell receptor (TcR) α chain transcripts were selectively amplified by polymerase chain reaction (PCR) using Vδ2−, Vδ3−, Vδ4−, Vδ5−, Vδ6− and Cα‐specific primers. Amplified DNA fragments were cloned, and 32 randomly selected clones from 5 PCR were sequenced. Twenty‐three distinct rearrangement events were detected, of which 87% (20/23) were in‐frame. All five tested Vδ genes (Vδ2, 3, 4, 5, 6) rearranged in‐frame to Jα−Cα. N‐region diversity in Vδ−Jα junctions present in most clones was limited to two to five nucleotides. P‐nucleotide additions in this region were also detected. The Vδ5 gene located 3′ of Cδ in reversed transcriptional orientation was rearranged to Jα by inversion. The Jα usage pattern of the sequenced clones was strongly biased towards rearrangement of the most 5' genes (located nearest to Cδ) of the Jα cluster: the most 5′ Jα (Jα TA1) was used by 30% of all clones, and 78% of all Jα rearranged to Vδ were located in the 5′ 12 kb of the 60‐kb Jα cluster. As distinct Vδ/Cδ and Vα/Cα TcR usage patterns are prevalent in peripheral T cell populations, our data suggest that these TcR usage patterns results from repertoire selections operating in αβ and γδ T cell lineages, but not from preferential Vδ‐Cδ and Vα‐Cα rearrangement patterns.
Regulation of graft‐versus‐host‐reaction by Mlsa‐reactive donor T cells
Authors: Muluk Satish C. , Hakim Frances T. , Shearer Gene M.
Published: March 2007

Injection of A/J splenocytes (H‐2Dd, Mlsc) into unirradiated (A/J x CBA)F1 (BAF1) host mice (H‐2Dd/k, Mlsd) results in an acute suppressive graft‐vs. ‐host reaction (GVHR), characterized by immune dysfunction and appreciable donor cell engraftment; injection of the CBA/J parent (H‐2Dk, Mlsd), which recognizes no Mls disparity in the host, results in little or no GVHR. Furthermore, the Mlsa‐reactive Vβ6 and Vβ8.1 T cell subsets in A/J T cells expand significantly in the GVHR host. Finally, depletion of Vβ6+ and Vβ8.1+ from the A/J population abrogates the proliferative response to BAF1 in vitro and the development of GVHR in vivo. Thus, the response to Mls determinants can contribute to the generation of a GVHR.
Induction of antigen‐specific tolerance by cyclosporin A
Authors: Stitz Lothar
Published: March 2007

Recently, we reported preliminary evidence for the induction of tolerance in vivo by cyclosporin A (CSA) during a persistent virus infection in rats. In the present communication, those observations are verified and the findings extended to the functional level of cell‐mediated immunity. Mice infected intracerebrally with lymphocytic choriomeningitis virus (LCMV) normally die from a fatal immunemediated disease after 6–8 days but they do not succumb if treated intraperitoneally with 50 mg/kg/day of CSA. Immunosuppression initiated one day before infection and continued for at least two consecutive weeks resulted in the absence of immunopathologic disease of the brain and in the survival of mice, which were found to be persistently infected virus carriers. In these animals, no cytotoxic T cell activity could be detected. The effect of CSA was not due to a toxic effect on the immune response since immune reactivity was restored as early as 4 days after discontinuation of the drug in control animals. Neither secondary in vitro nor in vivo restimulation resulted in the generation of a cellular antiviral immune response. Cytotoxic T cell reactivity to third‐party antigen, however, could be detected, although somewhat delayed. Additionally, spleen cells from CSA‐treated mice did not clear the virus from LCMV‐infected recipients upon adoptive transfer, whereas spleen cells from LCMV immune mice completely eliminated virus infection in carrier mice. However, mice immunosuppressed with CSA and infected with vesicular stomatitis virus (VSV) did not generate a primary immune response but were immunologically fully reactive to challenge infection, providing evidence for the absence of tolerance and the presence of antigen‐specific temporal unresponsiveness. Thus, as exemplified by VSV infection in which the virus does not replicate to considerable titers in mice and viral antigens do not persist, the presence of the foreign antigen for prolonged periods of time could be shown to be a conditio sine qua non for CSA‐induced tolerance.
Presentation of superantigen by human T cell clones: A model of T‐T cell interaction
Authors: Nisini Roberto , Matricardi Paolo M. , Fattorossi Andrea , Biselli Roberto , D'amelio Raffaele
Published: March 2007

Superantigens (SAg) interact with T lymphocytes bearing particular Vβ sequences as part of their T cell receptor (TcR). The interaction, however, requires the presence of major histocompatibility complex (MHC) class II molecules on antigen‐presenting cell (APC). In peculiar circumstances, MHC class II+ T cell clones (TCC) have been shown to present peptides and selected antigens interacting with antigen‐specific TCC in the absence of APC. In this report we studied the capacity of SAg to mediate a T‐T cell interaction, investigating the TCC ability to present a panel of staphylococcal enteroxins (SE) independently of the presence of added APC. Upon exposure to a broad range of SE concentrations, MHC class II+ TCC showed an intense proliferative response even in the absence of professional APC. Diverse SE optimally stimulated responder TCC at different concentrations. The proliferation was inhibited by anti‐DR monoclonal antibodies, both in the presence and in the absence of APC. The SE activation of TCC in the absence of APC induced the same series of phenotypic variations as that observed following the TCC stimulation with APC. Irradiated TCC efficiently presented membrane‐bound SE to responder TCC as well as professional APC. These results show that a single cell of a given clone effectively presents the SE to other cells of the same clone, and provide evidence that SAg can efficiently mediate T‐T cell interaction. In addition, the possibility also exists that one cell of the clone can actually undergo an auto‐stimulation via SAg‐mediated interactions between its own TcR and MHC class II molecule. It has recently been suggested that the Vβ‐selective depletion of T cells observed in acquired immunodeficiency syndrome (AIDS) patients might be a consequence of the interaction between a human immunodeficiency virus (HIV)‐encoded SAg and T cells expressing a SAg complementary Vβ. We suggest that the hypothesized HIV‐encoded SAg might mediate T‐T cell interactions that could play a relevant role in the Vβ‐selective depletion of T lymphocytes observed in HIV‐infected patients.
Immunobiological studies on experimental visceral leishmaniasis. II. Adherent cell‐mediated down‐regulation of delayed‐type hypersensitivity response and up‐regulation of B cell activation
Authors: Basak Saroj K. , Saha Bhaskar , Bhattacharya Amal , Roy Syamal
Published: March 2007

Visceral leishmaniasis or kala‐azar is characterized by a variety of immunopathological consequences in man. The most remarkable of these are the depression of cell‐mediated immunity and polyclonal B cell activation. The consequences observed in man could be induced in a murine model by inoculating the causative agent, Leishmania donovani. The cell‐mediated response was studied in this murine model in terms of the delayed‐type hypersensitivity (DTH) response toward leishmania antigen in a progressive infection. BALB/b (H‐2b) mice showed progressive enhancement in the DTH response, whereas BALB/c (H‐2d) mice showed strong DTH at the onset which gradually disappeared (defined as DTH‐negative phase) and reappeared again at the later stage of infection. Adoptive transfer of enriched populations of splenic T cells from infected BALB/c mice together with parasite antigen into the footpad of syngenic normal recipients produced a dramatic enhancement in the DTH response, except at the onset of the DTH‐negative phase. These observations indicate that adherent cells have a role in suppression of the cell‐mediated immune response and also that another mechanism operates at the onset of the DTH‐negative phase. This DTH‐negative phase was not caused by depletion of DTH‐mediating cells from the repertoire, but rather by suppression mediated by a subset of T cell evolved in the course of infection. Characterization on the basis of lymphokine production of the T cells mediating the DTH response and of T cells mediating suppression of the DTH response showed them to be of Th1 and Th2 type, respectively. Studies also indicated that at the onset and the later stages of infection suppression was mediated by adherent cells, but at the onset of DTH‐negative phase, in particular, suppression was mediated by Th2 cells. Furthermore, experiments also showed that adherent cells from infected mice gained another property, that of driving B cells, in a T cell‐dependent manner.
Virus infection blocks the processing and presentation of exogenous antigen with the major histocompatibility complex class II molecules
Authors: Domanico Susan Z. , Pierce Susan K.
Published: March 2007

Helper T cell recognition of antigen requires that antigen be processed and presented by class II‐expressing antigen‐presenting cells (APC). Many antigens presented by the immune system are part of infectious organisms, for example, bacteria and viruses, which themselves may affect APC function. Here we show that infection of B cell lines as APC with viruses of two different families, namely, influenza A or vaccinia, completely block processing and presentation of an exogenous globular protein antigen pigeon cytochrome c. The block appears to be primarily within the processing pathway, as virus infection has little effect on the presentation of an antigenic peptide of pigeon cytochrome c which does not require processing. It is likely that several steps in the processing pathway are affected. Only live infectious virus, not UV‐inactivated virus blocks APC function, indicating that there is no competition of viral particles with cytochrome c for the class II processing machinery. As compared to uninfected cells, virus‐infected cells internalize less antigen bound to surface Ig but degrade a similar portion of that which enters the cell. Virus infection results in reduced protein synthesis in APC which may also be a factor in decreasing APC function. Significantly, we show that the processing of a high affinity evolutionary variant of cytochrome c from Drosophila melanogaster is reduced less by virus infection as compared to c. Such knowledge may guide the selection of antigenic epitopes in vaccine design.
Interleukin‐1 induces c‐fos and c‐jun gene expression in T helper type II cells through different signal transmission pathways
Authors: Muñoz Eduardo , Zubiaga Ana M. , Huber Brigitte T.
Published: March 2007

Interleukin (IL)‐1 induces proliferation and expression of several protooncogenes in the T helper 2 cell line D10A. We have analyzed the signal transmission pathways activated by IL‐1 in these cells, leading to the expression of c‐jun and c‐fos. IL‐1 induced c‐jun gene transcription and mRNA expression by means of a pathway dependent on protein tyrosine kinase activity since tyrphostin, a specific inhibitor of tyrosine kinase, inhibited this induction. This mechanism of transmission signaling was independent of protein kinase C (PKC) and was linked to the 80‐kDa IL‐1 receptor (IL‐1R). In addition, phorbol esters did not induce c‐jun mRNA expression, whereas c‐fos mRNA expression mediated by IL‐1 dependent on PKC; this pathway was linked to a different, still unidentified IL‐1R that was functional in the D10A cell line.

Accumulation of intracellular cAMP generated by IL‐1 through the 80‐kDa IL‐1R negatively regulated c‐fos expression which was induced by IL‐1 through PKC activation. We conclude that IL‐1 modulates the expression of c‐fos in D10A cells by occupying of two independent IL‐1R that are linked to different signal transduction pathways.
Co‐crosslinking FcϵRII/CD23 and B cell surface immunoglobulin modulates B cell activation
Authors: Campbell Kim A. , Lees Andrew , Finkelman Fred D. , Conrad Daniel H.
Published: March 2007

Previous studies have shown that a highly multivalent from of anti‐IgD or anti‐IgM, prepared by conjugating the respective antibodies to dextran, causes extensive B cell proliferation with ng/ml concentrations of the anti‐immunoglobulin (Ig). A modification of this system has been exploited to investigate the effect of co‐crosslinking the FcϵRII and surface Ig by binding DNP to the dextran backbone (DNP‐dextran) and employing a DNP‐specific monoclonal IgE of either rat or mouse origin. Addition of anti‐IgD‐(Hδa/1)[DNP‐dextran] or anti‐IgM‐[DNP‐dextran] to purified, resting murine B cells resulted in B cell proliferation over a broad dose (0.03‐30 μg/ml). Addition of DNP‐specific rat or mouse IgE dramatically modulated the proliferative response. Proliferation in response to doses greater than 0.3 μg/ml Hδa/1‐[DNP‐dextran] was consistently reduced in a dose‐dependent manner in the presence of increasing amounts of IgE while proliferation to lower concentrations of Hδa/1‐[DNP‐dextran] was slightly enhanced or not influenced at all by the IgE anti‐DNP. Interleukin‐4 (IL‐4) significantly increased the IgE effect, in line with its known enhancing effects on FcϵRII levels. Experiments measuring Ig production rather than proliferation demonstrated that in the presence of IgE anti‐DNP, B cells produced lower amounts of immunoglobulin (IgG1 or IgM) in response to an anti‐Ig signal. Control experiments demonstrated that the IgE effect on proliferation was blocked by monoclonal anti‐FcϵRII, but not anti‐FcγRII, thus demonstrating the necessity for IgE/FcϵRII interaction. In addition, the necessity for co‐crosslinking was shown by the inability of IgE anti‐DNP to affect the proliferative response to Hδa/1‐dextran even in the presence of various doses of DNP‐dextran. These results demonstrate that co‐crosslinking of sIg and the FcϵRII results in an altered B cell response to anti‐Ig mediated activation. IL‐4 does not ablate this inhibition, in contrast to the effect of co‐crosslinking FcγRII and surface Ig, suggesting a model whereby IgE can modulate its own production.
A survey of protein‐DNA interaction sites within the murine immunoglobulin heavy chain locus reveals a particularly complex pattern around the DQ52 element
Authors: Kottmann Andreas H. , Brack Christine , Eibel Hermann , Köhler Georges
Published: March 2007

The expression of immunoglobulin (Ig) genes is regulated at two levels: rearrangement of individual gene segments and transcription of continuous genes. To find transacting factors involved in mediating locus‐ and segment specific gene activation and expression, we surveyed a 3600‐bp genomic region of the murine Ig heavy chain locus, spanning from the DQ52 element to the Ig heavy chain intron enhancer. We discovered nine, previously undescribed, protein‐DNA complexes and estimated their individual binding affinity preferences (Kr) by quantitative gel shift measurements. We observed one novel protein DNA interaction at the enhancer, two in the JH1 region and six within a 300‐bp region immediately 5′ to the DQ52 locus. The latter show a complex and specific binding pattern when comparing nuclear extracts derived from pre‐B cells and fibroblasts. Further characterization of the interactions at the DQ52 locus by electron microscopy revealed the preferential formation of a protein complex binding to the DQ52 locus with pre B cell extracts. This behavior and the clustering of interaction sites 5′ to the DQ52 element suggest that this region is involved in the regulation of heavy chain gene assembly.
T and B cell receptors discriminate major histocompatibility complex class II conformations influenced by the invariant chain
Authors: Rath Satyajit , Lin Rong‐Hwa , Rudensky Alexander , Janeway Charles A.
Published: March 2007

Direct recognition of major histocompatibility complex (MHC) molecules may occur when T cells are positively selected in the thymus and also during recognition of non‐self MHC molecules. Since peptide recognition and binding of particular monoclonal antibodies is strongly influenced by the invariant chain (Ii) of the class II molecule, we have asked whether Ii also affects recognition of non‐self MHC molecules by T cells. We find that Ii binding alters MHC class II conformation as detected by a monoclonal antibody, and that this alteration is retained in cell surface MHC class II molecules after Ii dissociates. This altered conformation also affects recognition by allogeneic T cells. Normal T cells and T cell clones preferentially recognize MHC class II molecules that have been associated with Ii, suggesting that thymic selection may be influenced by MHC conformation independently of specific peptide binding.
Human genomic sequences corresponding to murine CD3η‐related transcripts: Lack of conservation or expression of homologous human products
Authors: Lerner Adam , Diener Andrew C. , Reinherz Ellis L. , Clayton Linda K.
Published: March 2007

We have cloned and sequenced human genomic DNA homologous to exons 9 and 10 of the CD3 ζ/η/θ locus. Although there are open reading frames within the human sequences corresponding to the translated portions of murine exons 9 and 10, we find no evidence of conservation of the encoded polypeptide product. Furthermore, using oligonucleotides derived from these homologous sequences, we are unable to detect human CD3η‐ or CD3θ‐like transcripts by polymerase chain reaction amplification of reverse‐transcribed RNA from a variety of human lymphoid tissues. Despite the absence of evidence for conservation of human CD3η and CD3θ, there is a surprising degree of similarity between human and murine nucleotide sequences, not only for exons 9 and 10 (78% and 70%, respectively), but also for the 9/10 intron (71%). A possible mechanism for this conservation is discussed.
Correlation between killing activity towards the murine L929 cell line and expression of membrane‐associated lymphotoxin‐related molecule of human lymphokine‐activated killer cells
Authors: Miyake Masazumi , Horiuchi Atsushi , Kimura Katsuhiko , Abe Yasuhito , Kimura Shigeru , Hitsumoto Yasuo
Published: March 2007

Human lymphokine‐activated killer (LAK) cells expressed a membraneassociated lymphotoxin‐related molecule (mLT) which was detected by flow cytometric analysis with anti‐lymphotoxin antibody. Upon removal of exogenous interleukin‐2 from LAK cell culture medium and another 24 h cultivation, the expression of mLT was decreased. Corresponding to the decrease of mLT expression, the killing activity of LAK cells towards L929 cells was remarkably reduced and killing of MIA PaCa‐2 and U937 cells was moderately reduced, whereas killing of Daudi and K562 cells was fully restored. The supernatant of mLT‐expressing LAK cells had no cytotoxic activity towards L929 cells in the absence of actinomycin D. Moreover, not only the killing of L929 cells but also that of human tumor cell lines (MIA PaCa‐2, U937) by mLT‐expressing LAK cells was partially inhibited in the presence of anti‐lymphotoxin antibody. These results suggest an involvement of mLT in the killing of some tumor target cells by LAK cells.
Restricted α/β receptor gene usage of idiotype‐specific major histocompatibility complex‐restricted T cells: Selection for CDR3‐related sequences
Authors: Snodgrass H. Ralph , Fisher Anne M. , Bruyns Eddy , Bogen Bjarne
Published: March 2007

We have sequenced the T cell receptor (TcR) Vα and Vβ genes of seven independent BALB/c CD4+ T cell clones specific for the immunoglobulin λ2 light chain produced by the MOPC 315 myeloma (λ2315). All the clones recognize a peptide of residues 91–101 of λ2315 and are restricted by the major histocompatibility complex (MHC) molecule I‐Ed. The results indicate that in BALB/c mice, this anti‐idiotypic response uses a very limited number of TcR. The four clones which cross‐react between Phe94 and Tyr94 peptide analogues use very similar receptors (Vα3, Jα1, Vβ6, Jβ1.1). The Vα3 gene used by all of these clones is identical and has not been previously described. Although the four clones differ in nucleotide sequence in the V/J borders, two had identical receptors at the amino acid level. One of the cross‐reactive clones exhibits a heteroclitic response to the Tyr94 peptide variant resulting from a single amino acid exchange in the V/J junction of the α chain. The three remaining clones which recognize only the Phe94 and not the Tyr94 peptide have somewhat more diverse TcR, however, two of these three clones use Vβ6. One of these non‐crossreacting clones is alloreactive, the specificity of which can be attributed to differences in the N‐D‐J sequences. Taken together these data indicate that this T cell response to an immunoglobulin idiotope is very restricted in terms of the TcR used. These data in conjunction with recently published results indicate that, although there can be strong preference for individual Vα or Vβ gene segments, certain Vα/Vβ combinations are preferentially selected for interacting with a given peptide/MHC combination, and that the CDR3‐related regions are crucial for antigen fine specificity and alloreactivity.
Synergistic induction of interleukin‐6 by tumor necrosis factor and lithium chloride in mice: Possible role in the triggering and exacerbation of psoriasis by lithium treatment
Authors: Beyaert Rudi , Schulze‐Osthoff Klaus , Van Roy Frans , Fiers Walter
Published: March 2007

One of the side effects of treatment of manic depressive disease with lithium salts is the triggering or aggravation of psoriasis. In a murine model, subcutaneous (s.c.) injection of a combination of tumor necrosis factor (TNF) and lithium chloride (LiCl) induces a psoriasiform inflammatory reaction. Recent studies suggest that interleukin (IL)−6 and its inducer TNF may play an important role in the pathophysiology of psoriasis. To understand the mechanism involved in the exacerbation of psoriasis by lithium salts, the IL‐1, IL‐6 and granulocyte‐macrophage colony‐stimulating factor (GM‐CSF) levels in murine skin injected with TNF in combination with LiCl were studied. IL‐6 levels in skin extracts of mice treated s.c. with a combination of TNF and LiCl were considerably increased as compared to the levels found in skin extracts from mice treated with TNF or LiCl alone. In contrast, in the same skin extracts IL‐1 levels were not changed and GM‐CSF was even not detectable. Although less pronounced, increased IL‐6 levels could also be found in the sera of mice treated s.c. with TNF and LiCl. Injection with IL‐1, interferon‐γ, lipopolysaccharide, or phorbol 12‐myristate 13‐acetate also induced IL‐6 in murine skin. However, these IL‐6 levels were not enhanced by co‐treatment with LiCl. Likewise, no inflammatory reaction could be seen in mice treated with these agents. These results suggest a role for endogenous TNF and IL‐6 in the triggering or aggravation of psoriasis in lithium‐treated patients.
Commitment to the T cell receptor‐αβ or ‐γδ lineages can occur just prior to the onset of CD4 and CD8 expression among immature thymocytes
Authors: Petri Howard T. , Scollay Roland , Shortman Ken
Published: March 2007

Two types of T lymphocytes, distinguishable by their surface expression of either the γδ or the αβ T cell receptor (TcR) for antigen, populate the periphery in the adult. In addition, immature precursors of both T cell types can be found in the thymus. While it is generally accepted that these two cell types represent distinct lineages, it is not known at which developmental stage these lineages diverge. The most mature thymocyte precursor population not yet expressing T lineage‐specific surface markers (i.e. CD3, CD4, and CD8) is known to be capable of generating TcR‐αβ T cells, and has been thought to be preprogrammed into the TcR‐αβ lineage at an earlier developmental stage. We now show that this late‐stage precursor is capable of giving rise to cells of both the TcR‐αβ and ‐γδ lineages, both in vitro after intrathymic transplantation, and in vitro in simple culture medium or medium with cytokines. Thus it appears that the divergence of TcR‐αβ and ‐γδ cells can occur at a relatively late stage of intrathymic development, just prior to the onset of CD4 and CD8 expression in most cells.
Random entry of circulating lymphocyte subsets into peripheral lymph nodes and Peyer's patches: No evidence in vivo of a tissue‐specific migration of B and T lymphocytes at the level of high endothelial venules
Authors: Westermann Jürgen , Blaschke Volker , Zimmermann Gesine , Hirschfeld Ulrich , Pabst Reinhard
Published: March 2007

Lymphocytes continuously migrate through the body and thus immune competent cells are constantly delivered to most tissues. They interact with high endothelial venules (HEV) via specific homing receptors and vascular addressins, and these molecules seem to be the reason for a preferential homing of B lymphocytes into Peyer's patches and of T lymphocytes into peripheral lymph nodes.

When lymphocytes derived from lymph node cell suspensions were applied in the in vitro lymphocyte/endothelium binding assay, the well‐known preference of mouse lymph node B lymphocytes for Peyer's patch HEV compared to peripheral lymph node HEV was confirmed in the rat (2.8 times). When in the same in vitro assay thoracic duct lymphocytes (TDL) were used this preference was far less obvious (1.4 times). However, by injecting rat TDL intravenously and by tracing them directly in HEV, B, T, CD4+ and CD8+ lymphocytes are seen to enter Peyer's patches and peripheral lymph nodes in vivo without preference.

Thus, in contrast to lymphocytes from lymph node cell suspensions, no evidence was found of a tissue‐specific migration of thoracic duct B, T, CD4+ and CD8+ lymphocytes at the HEV level. This finding demonstrates the importance of considering both experimental conditions and the cell source used when investigating lymphocyte traffic.
Production of 17.2.25 μ transgenic and endogenous immunoglobulin in X‐linked immune deficient mice
Authors: Rabin Evelyn , Yingzi Cong , Imanishi‐Kari Thereza , Wortis Henry H.
Published: March 2007

In M54 mice transgenic for a completely rearranged μa heavy chain there is a decrease in total B cells and the rearrangement of endogenous immunoglobulin genes is partially inhibited. Surprisingly, however, endogenous immunoglobulin gene rearrangement and significant heavy chain polypeptide production does occur. We tested the hypothesis that only CD5+ B cells produce endogenous immunoglobulin by taking advantage of the fact that X‐linked immune deficient (xid) mice normally are deficient in CD5+ B cells. We found that the frequency of CD5+ splenic B cells was similar in XxidY transgenic and non‐transgenic F1 males, and in XxidX transgenic and non‐transgenic F1 females. In both XxidX and XxidY transgenic F1 mice some, but not all, splenic B cells are CD11b+. There was a striking deficit of splenic B cells expressing endogenous immunoglobulin in XxidY transgenic mice, although this was not true for peritoneal cells. Thus, the introduction of the 17.2.25 μ transgene does not prevent the development of CD5− B cells nor does it limit endogenous immunoglobulin gene arrangement and expression solely to CD5+ B cells. However, in mice capable of expressing B cell surface CD5 or CD11 this transgene can lead to expansion of the fraction of B cells positive for these molecules. We conclude that while the introduction of the 17.2.25 μ transgene alters the frequencies of B cell populations maturation is not limited to one subpopulation.
Functional maturation of recent thymic emigrants in the periphery: Development of alloreactivity correlates with the cyclic expression of CD45RC isoforms
Authors: Yang Chun‐Ping , Bell Eric B.
Published: March 2007

The transition from fully developed CD4+CD8− single‐positive (SP) thymocytes into fully mature recirculating peripheral T cells is both poorly understood with regard to the expression of restricted isoforms (CD45R) of the leukocyte common antigen and in terms of T cell function. The present investigation monitored the extrathymic development of CD4+CD8− SP thymocytes in euthymic recipients using allotype‐marked donor cells and monoclonal antibody OX22 which recognizes an epitope on the C exon of rat CD45R. We established that donor‐derived cells in the blood 1 day later bore the phenotype of the injected SP thymocytes (CD4+ Thy‐1+ CD45RC−). T cells with the identical phenotype were also present in the thoracic duct lymph of uninjected rats, suggesting that the Thy‐1+ CD45RC− T cells represent recent thymic emigrants (RTE) which have migrated to the periphery of their own accord. During extrathymic maturation donor‐derived peripheral RTE lost Thy‐1 within 3 days and expressed the CD45RC+ high molecular weight isoform by day 7; between days 8 and 14 a proportion (25%–30%) of the donor cells once again lost the high molecular weight isoform (CD45RC−). The transition of SP (CD45RC−) thymocytes to fully mature CD45RC+ CD4 T cells via intermediate peripheral RTE was accompanied at each stage by an increased ability of the maturing T cells to induce skin allograft rejection. Unexpectedly, the subsequent loss of the high molecular weight isoform, following presumed antigen encounter, was associated with a significant reduction in the ability of this Thy‐1− CD45RC− subpopulation to effect graft rejection. The cyclic expression of CD45RC isoforms on both immature and mature CD4 T cells and the fact that the low molecular weight isoform was found in the periphery on both RTE (unquestionably naive) and antigen‐experienced CD4 T cells, makes it unlikely that this isoform uniquely identifies memory T cells, at least in the rat.
Cytokines inhibit the development of liver schizonts of the malaria parasite plasmodium berghei in vivo
Authors: Vreden Stephen G. S. , Van den Broek Maries F. , Oettinger Maria C. , Verhave Jan Peter , Meuwissen Joep H. E. T. , Sauerwein Robert W.
Published: March 2007

The effect of induction of an acute‐phase response and its mediators on the development of liver schizonts of the rodent malaria parasite Plasmodium berghei was investigated in Brown Norway rats. Subcutaneous injection of turpentine oil 24 h or 5 min before inoculation of sporozoites resulted in 80% and 35% reduction of schizont development, respectively. Turpentine oil induced high plasma levels of interleukin‐6 (IL‐6). Intraperitoneal administration of IL‐1, IL‐6 or both, significantly reduced liver schizont development. This reduction was also present if IL‐6 had been administered 24 h after sporozoite inoculation. Inhibition induced by IL‐1 could be prevented by simultaneous administration of polyclonal anti‐IL‐6. Administration of polyclonal anti‐IL‐6 without IL‐1 resulted in a 40% increase of liver schizonts compared to control animals. We conclude that induction of an acute‐phase response during experimental Plasmodium berghei infections in Brown Norway rats, strongly inhibits liver schizont development and that IL‐6 is a key mediator in this process.
The adjuvant effect of Vibrio cholerae and Escherichia coli heat‐labile enterotoxins is linked to their ADP‐ribosyltransferase activity
Authors: Lycke Nils , Tsuji Takao , Holmgren Jan
Published: March 2007

This study addressed the question of whether the mucosal adjuvant property of cholera toxin (CT) and the structurally closely related Escherichia coli heat‐labile toxin (LT) requires the enterotoxic and adenylate cyclase/cAMP activating property of these molecules. Therefore, we investigated the cytotoxic and adjuvant abilities of the enterotoxins and compared the results with those obtained with the non‐toxic CT and LT derivatives; recombinant CTB (rCTB) and a mutated LT (mLT), which had a single amino acid substitution in position 112 (Glu→Lys) of the A subunit. Detailed functional studies revealed that, in contrast to the enterotoxins, both rCTB and mLT lacked ADP‐ribosylating and cAMP‐stimulating abilities. However, similar membrane ganglioside GM1‐receptor binding ability of all the putative adjuvants was demonstrated. When the probe antigen, keyhole limpet hemocyanin (KLH), was given perorally together with CT or LT strong gut mucosal anti‐KLH immune responses were stimulated, whereas no or very low anti‐KLH responses were seen in the groups which antigen admixed with rCTB or the mLT. Moreover, the specific serum antibody responses to the various immunization protocols closely paralleled the local anti‐KLH response in the gut. From these results it appears that the adjuvant mechanism of LT, and probably also of CT, is linked to the ability to ADP‐ribosylate and to stimulate cAMP formation. However, this study does not unequivocally rule out other possibilities such as interactions by the A1 fragment of CT or LT with other G‐proteins than Gsα or events that parallel or precede the effects on the adenylate cyclase/cAMP system. Thus, the levels of ADP‐ribosylation and cAMP‐induction that are required and the key event or target cell that is responsible for the adjuvant effect of CT and LT remain to be elucidated. Studies are underway to address these issues.
Tyrosine kinase triggering in thymocytes undergoing positive selection
Authors: Carrera Ana C. , Baker Carrie , Robert Thomas M. , Pardoll Drew M.
Published: March 2007

Developing T cells undergo distinct selection processes that determine the T cell receptor (TcR) repertoire. One of these processes is positive selection. Positive selection involves the differentiation to mature T cells of thymocytes bearing TcR capable of recognizing antigens in the context of self‐major histocompatibility complex (MHC) molecules. To study the potential involvement of tyrosine phosphorylation in the mechanism of positive selection, we have analyzed the activities of the tyrosine kinases pp56lck and pp59fyn in thymocytes expressing a unique TcR specific for HY antigen+ H‐2 Db. Thymocytes undergoing positive selection displayed higher kinase specific activities of pp56lck and pp59fyn than nonselecting thymocytes. Furthermore, these increases in kinase activities were found only in the CD4+CD8+ subpopulation of thymocytes, where the selection process is believed to occur. These data suggest that tyrosine phosphorylation is part of the intracellular signals involved in MHC class I‐driven positive selection from CD4+CD8+ immature thymocytes to CD4−CD8+ mature cells.
Discrimination of human CD4 T cell clones based on their reactivity with antigen‐presenting T cells
Authors: Wyss‐Coray Tony , Brander Christian , Frutig Karin , Pichler Werner J.
Published: March 2007

In this report, we describe the discrimination of human T cell clones based on their reactivity with activated T cells as antigen‐presenting cells (APC). CD4+ T cell clones specific for peptide P30 of tetanus toxin (amino acids 947–967) and restricted to the DP4 molecule were established and tested for proliferation to peptide presented either by peripheral blood mononuclear cells (PBMC), Epstein‐Barr virus (EBV)‐transformed B cells or major histocompatibility complex (MHC) class II‐expressing T cells. We found two sets of T cell clones: one set proliferated to peptide presentation by PBMC, EBV‐transformed B cell lines (EBV‐B cells) and MHC class II+ T cells (termed T‐responder clones), while the other set of clones was only stimulated to proliferate, if the peptide was presented by PBMC or EBV‐B cells, but not by T cells (T‐nonresponder clones). Nevertheless, these T‐nonresponder clones recognized P30 also on T cells, as revealed by Ca2+ influx. The discrimination of the clones was not due to different avidities of the T cell receptors (TcR) of individual clones for the MHC‐peptide complex as T‐responder and T‐nonresponder clones had similar dose‐response curves to P30 presented by fixed EBV‐B cell lines. Addition of cytokines [interleukin (IL)‐1, IL‐2, IL‐4 and interferon γ] did not change the proliferative response of the clones, which was consistent throughout an observation period of >4 months. T‐nonresponder clones, exposed to P30 on MHC class II‐expressing T cells, became not anergic, as they could be restimulated by P30 presented on EBV‐B cells. The measurement of a panel of T cell activation markers and adhesion molecules on T‐responder and T‐nonresponder clones revealed a higher expression of the CD28 molecule on the T‐nonresponder clones. The data suggest that freshly cloned T cells can be differentiated by peptide presentation on classical (PBMC, EBV‐B cells) or non‐classical APC (class II+ T cells), and that this discrimination is further underlined by different levels of adhesion molecules.
Kinetics of cytokine mRNA production in the brains of mice with progressive toxoplasmic encephalitis
Authors: Hunter Chris A. , Roberts Craig W. , Alexander James
Published: March 2007

C57BL/10 ScSn (B10) mice infected orally with Toxoplasma gondii were killed on days 5, 10, 15, 20 and 30 post infection and their brains excised. These were either used to count total tissue cyst numbers or divided for RNA purification and histopathological studies. The first signs of inflammation were on day 10 post infection, before the appearance of cysts in the brain, and correlating with the appearance of activated astrocytes. These mice had a mild meningitis with areas of encephalitis. Small numbers of cyst stages were first observed in the brain on day 15 and by day 20 the cyst numbers had increased dramatically but were not always associated with inflammation. After this time point, total cyst numbers did not increase significantly though there developed a marked variation in tissue cyst size with larger cysts becoming more numerous. The use of the polymerase chain reaction to assist in the amplification of brain RNA allowed the characterization of the kinetics of cytokine production within the brains of these animals. Only IL‐1α was found to be expressed constitutively in control mice. Transcripts for other cytokines associated with activated monocytes, microglial cells and astrocytes [tumor necrosis factor (TNF)‐α and interleukin (IL)‐6] were present on day 10, (IL‐6) and day 15 (TNF‐α) post infection. Thereafter, these cytokines were present in all infected animals. Of the T cell‐associated cytokines, IL‐4, a characteristic product of the T helper (Th)2 cell subset, was detected on days 10 and 15, while granulocyte macrophage colony stimulating factor (GM‐CSF) which can be produced not only by this cell type but also by Th1 cells and CD8+ T cells, was also present on day 15 but not thereafter. Transcripts for interferon (IFN)‐γ, present from day 15 post infection, were probably produced by CD8+ T cells, as IL‐2 which would indicate Th1 cell involvement was only detected 30 days after infection. The continual presence of IFN‐γ and TNF‐α, cytokines with reported anti‐toxoplasmic activity, in the CNS of B10 mice throughout the latter half of the experimental period did not diminish the severity of infection. These results indicate that the CD4+ Th2 subset may allow a rapid rise in cyst numbers and so be important in determining susceptibility to toxoplasmic encephalitis.
Analysis of the roles of CD4+ and CD8+ T cells in autoimmune diabetes of NOD mice using transfer to NOD athymic nude mice
Authors: Yagi Hideki , Matsumoto Mitsunobu , Kunimoto Kikuko , Kawaguchi Junko , Makino Susumu , Harada Minoru
Published: March 2007

The NOD mouse, which spontaneously develops insulitis and overt diabetes, is a model of autoimmune type I diabetes mellitus. For the precise analysis of the roles of CD4+ and CD8+ T cells in the pathogenesis of this mouse, these subsets must be transferred into recipients that are completely free of T cells and pathological changes. We used athymic NOD nude mice, which congenitally lack mature T cells and are free of insulitis and hyperglycemia up to the age of 60 weeks, as recipients for this purpose. To the nude recipients we transferred either one of a highly purified CD4+ or CD8+ T cell subset derived from non‐diabetic female NOD mice; any in vivo increase in the contaminating T cell subsets was prevented by injecting the antibody homologous to it. Most of the T cell‐reconstituted recipients were treated with cyclophosphamide to promote the onset of overt diabetes. Transfer of the CD8+ T cell subset alone did not induce insulitis or hyperglycemia. In contrast, transfer of the CD4+ T cell subset alone produced insulitis, but not hyperglycemia, in all the recipients. However, the subsequent transfer of CD8+ T cells into CD4+ T cell‐reconstituted recipients induced severe insulitis and hyperglycemia in almost all the recipients. In these diabetic recipients, we observed severe damage of the pancreatic islets and the infiltration of a large number of CD8+ T cells into the remaining islets; insulin‐secreting β cells were no longer detected. These results suggest that CD4+ T cells play a predominant role in the development of insulitis and that CD8+ T cells migrate into the islets and are subsequently, with the aid of CD4+ T cells, differentiated into killer cells which act against β cells.