bluuebunny/crossref_metadata_2025 huggingface dataset:
Granulocyte‐macrophage colony‐stimulating factor‐cultured bone marrow‐derived macrophages reveal accessory cell function and synthesis of MHC class II determinants in the absence of external stimuli
Authors: Fischer Hans‐Georg , Opel Beate , Reske Konrad , Reske‐Kunz Angelia B.
Published: March 2007

The antigen‐mediated activation of a number of T cell clones by bone marrow (BM) cells cultivated in the presence of various colony‐stimulating factor (CSF) preparations was investigated. BM macrophages (BMMϕ,) grown in L929 cell supernatant as a crude source of macrophage colony‐stimulating factor (M‐CSF) as well as BM cells propagated in the presence of recombinant M‐CSF exhibited transient antigen presentation potential to some T cell clones, being maximal on day 7 and having declined to a low level by day 19 of in vitro culture. Treatment of these long‐term‐cultivated BMMϕ, populations with recombinant interferon‐γ (IFN‐γ) resulted in predominant antigen presentation capacity. In contrast, BM cells differentiated in the presence of recombinant granulocyte (G)M‐CSF developed highly efficient accessory cell function to all T cell clones examined. This function became apparent earlier, was retained during the time period tested (up to day 19 of continuous culture) and did not require prior stimulation by IFN‐γ. The functionally competent cells were shown to belong to the monocyte/macrophage lineage. These findings are consistent with the demonstration of substantial levels of major histocompatibility complex (MHC) class II molecules synthesized by GM‐CSF‐cultured BM cells in the absence of exogenous IFN‐γ. In contrast, M‐CSF grown BM cells synthesized only minute amounts of Ia antigens unless they were stimulated by IFN‐γ. Because GM‐CSF‐cultivated BM cells proved clearly superior to M‐CSF‐grown and IFN‐γ‐activated BM cells with respect to antigen‐presenting capacity but exhibited lower levels of MHC class II molecules, other properties acting in addition to surface Ia antigens might be responsible for their pronounced T cell accessory function.
The role of suppression in immunoregulation: in vivo analysis using a monoclonal antibody to T suppressor factors
Authors: Ferguson Thomas A. , Ptak Wlodzimierz , Michael Iverson G. , Flood Patrick
Published: March 2007

We have used a monoclonal antibody (mAb)‐specific for murine T suppressor (Ts) cells (mAb 14‐12) to study the role of T cells in tolerance and immunoregulation. We demonstrate that mAb 14‐12 can block in vivo T, cell activity in a variety of experimental systems. It prevents the induction of Ts cells induced by i.v. injection of the water‐soluble hapten 2,4,6‐trinitrobenzene sulfonic acid, and the protein antigen bovine serum albumin. When 14‐12 mAb is given prior to the i.v. injection of Tstrinitro phenyl‐conjugated spleen cells (TNP‐SC) it blocks the induction of T, cells and sufficiently overcomes suppression so that TNP‐SC is able to induce immunity. mAb 14‐12 can convert nonresponder mice into responders for the Ir gene‐controlled response to the random terpolymer L‐glutamic acid60‐L‐alanine30‐L‐tyrosine10 (GAT), and can substitute for cyclophosphamide in overcoming a suppressor barrier in the adoptive transfer of contact sensitivity. Administration of 14‐12 mAb just prior to immunization results in the augmentation of contact sensitivity, antibody and plaque‐forming cell responses. These results demonstrate the versatility of this reagent for the study of Ts cell activity.
Frequency analysis of functional Ig Cε gene expression in the presence and absence of interleukin 4 in lipopolysaccharide‐reactive murine B cells from high and low IgE responder strains
Authors: Savelkoul Huub F. J. , Termeulen Jacqueline , Coffman Robbert L. , Van Der Linde‐Preesman Rianne A.
Published: March 2007

Nonresponder SJL mice produce low levels of antigen‐specific IgE after immunization, compared to responder strains. Young athymic BALB/c nude mice are unable to produce antigen‐specific or total IgE in their serum. These mice also have very low numbers of background IgE‐secreting cells in their lymphoid organs. High‐responder BALB/c mice do have substantial numbers of background IgE‐secreting cells while low‐responder AKR mice show intermediate numbers. Similar differences were found when analyzing lipopolysaccharide (LPS)‐reactive B cells in cell suspensions of spleen and bone marrow in limiting dilution cultures. Limiting dilution analysis of T cell‐depleted splenic B cell cultures revealed that the defective IgE production in SJL mice is not due to an intrinsic B cell defect. This defect can be substantially overcome by addition of exogenous interleukin 4 (IL4) to these cultures. Furthermore, it was shown in limiting dilution cultures that SJL thymocyte feeder cells were able to suppress IgE production by LPS‐activated high‐responder BALB/c B cells. The addition of IL4 or neutralizing antibodies against IL4 or interferon‐y to these cultures helped to overcome this suppressive effect to a large extent. We conclude that different IgE responder types are caused, at least in part, by a defective IL4 production or by a defect in the TH2 system that is functionally detectable at the level of thymocytes.
Species conservation of the T cell lymphocyte CD2 cell surface antigen
Authors: Brown Marion H. , Sewell William A. , Mason David Y. , Rothbard Jonathan B. , Crumpton Michael J.
Published: March 2007

A rabbit polyclonal antiserum was raised against a synthetic peptide, termed CD2‐300, comprizing 18 amino acid residues which are conserved among the cytoplasmic domains of the human, rat and mouse CD2 antigens. Cross‐depletion experiments showed that the CD2 monoclonal antibody OKTl1 and purified CD2‐300 antibodies (Ab) precipitated the same molecules from the surface of human T lymphoblasts. The results of immunoprecipitation analyses indicated that the purified CD2‐300 Ab were specific for human and mouse CD2, and that the CD2‐300 peptide competitively and specifically inhibited precipitation by CD2‐300 Ab in both species. When employed to stain murine tissues, the CD2‐300 Ab gave the anticipated pattern of distribution for the CD2 antigen, although there was some nonspecific labeling of non‐T cells.
Aggravation of experimental cutaneous leishmaniasis in mice by administration of interleukin 3
Authors: Feng Zhu Yun , Louis Jacques , Kindler Vincent , Pedrazzini Thierry , Eliason James F. , Behin Reza , Vassalli Pierre
Published: March 2007

Previous studies from our laboratory have shown that some in vitro maintained Leish‐mania major‐specific L3T4+ T cells were capable of exacerbating cutaneous leishmaniasis after adoptive transfer to normal syngeneic mice. Results presented in this report show that these cells released substantial amounts of interleukin 3 (IL 3) and granulocyte‐macrophage colony‐stimulating factors after specific stimulation in vitro. In order to assess the involvement of such lymphokines in the exacerbation of cutaneous leishmaniasis by these L3T4+ T cells, the effect of the administration of important doses of IL 3 on the course of infection with L. major was investigated. The treatment of genetically susceptible B ALB/c mice with IL 3 resulted in an enhancement of the size of lesions and favored the multiplication of parasites at anatomical sites distant from the primary lesion. Although IL 3 did not modify the development of lesions in genetically resistant CBA mice, this lymphokine promoted the growth of Leishmania in lymph node draining the lesion. Finally, the addition of IL3 to macrophages parasitized in vitro enhanced the survival of intracellular Leishmania major.
A map of VH genes located next to the DH region in the Igh locus of two congenic Igh‐recombinant mouse strains
Authors: Lehle Georg , Kolb Cornelia , Kappen Claudia , Schü Ralph , Weiler Eberhardt , Krawinkel Ulrich
Published: March 2007

A new congenic mouse strain (C57BL16‐Igh‐Vb‐Ca) with a recombinant chromosome 12 is described. It carries the Igh‐la allele, but shows the serological characteristics of C57BL/6 when analyzed for idiotype expression with respect to the antigens dextran and (4‐hydroxy‐5‐iodo‐3‐nitrophenyl)acetyl (NIP). We analyzed liver DNA from one animal for restriction fragment length polymorphism by hybridization to probes detecting members of nine VH gene families and DH segments, and compared it to DNA from animals carrying the nonrecombinant haplotypes Igh2 and Ighb, respectively. The breakpoint of recombination maps to the region carrying members of VH gene families VGAM3.8, PC7183 and Q52. The CB8KN strain which according to the serological analysis carries a recombinant Igh locus (Igh‐Va‐Cb) on BALB/c background was also analyzed. In this strain the breakpoint of recombination again maps to the region carrying members of VH gene families VGAM3.8, PC7183 and Q52. Our results show that the VH genes of families PC7183 and Q52 are interspersed and map to the region next to the DH locus. At least one gene from the VGAM3.8 family also maps to this region in the Igha and the Ighb haplotype.
Increased bactericidal macrophage activity induced by immunological stimuli is dependent on interferon (IFN)‐Γ
Authors: Leist Thomas P. , Heuchel Rainer , Zinkernagel Rolf M.
Published: March 2007

During generalized immune responses such as the acute phase of graft‐vs.‐host reaction (GvHR) or many systemic viral infections the macrophage‐monocyte system of mice is activated as demonstrated by their increased bactericidal capacity against Listeria monocytogenes. To study the effect of interferon (IFN)‐γ in maintainance of macrophage activity, lymphocytic choriomeningitis virus (LCMV) primed C57BW6 mice or (C57BL/10 × B10.BR) F1 mice undergoing a GvHR were treated with polyclonal specific sheep anti‐IFN‐γ antiserum. In both cases injection of anti‐IFN‐γ resulted in inhibition of the stimulatory effects on macrophages as detected by reduced bactericidal activity when compared to mice treated with normal serum. Treatment with a polyclonal sheep anti‐IFN‐α, β antiserum on the other hand did not interfere with the activation status of the macrophages. The findings suggest that IFN‐α is produced both early in a GvHR and during the acute phase of an systemic infection with LCMV, and that it is involved in in vivo modulation of the increased activity of mononuclear phagocytes in immunologically stimulated mice.
Infection of B lymphocytes by the human immunodeficiency virus and their susceptibility to cytotoxic cells
Authors: Malkovsk Miroslav , Philpott Karen , Dalgleish Angus G. , Mellor Andy L. , Patterson Steve , Webste A. David B. , Edwards Andrew J. , Maddon Paul J.
Published: March 2007

The T4 molecule (CD4) is an important component of the human immunodeficiency virus (HIV) receptor. As yet, no other component has been demonstrated. We report here that two cell lines, a B lymphoblastoid cell line (Gupta) and a glial cell line (HEB) derived from human embryonal brain tissue, are productively infectable with two distinct isolates of HIV as judged by electron microscopy and immunological and virological studies. These two cell lines do not display detectable surface CD4 glyco‐protein. However, using S1 nuclease analysis, we have found that both cell lines do express low levels of CD4 mRNA. Neither of them produced syncytia formation upon HIV infection, a recognized feature of HIV‐infected cells strongly expressing the CD4 glycoprotein. It is conceivable that the CD4 mRNA is translated, resulting in meager surface expression of CD4 molecules undetectable by conventional techniques. Therefore, infection with HIV may be one of the most sensitive methods of demonstrating low levels of CD4 expression by human cells. Furthermore, HIV‐infected Gupta cells have here been shown to be more susceptible to the lytic activity of natural killer (NK) cells than their uninfected counterparts. These phenomena may be important for pathogenesis of HIV‐associated disorders.
Thymocyte clones from 14‐day mouse embryos II. Transcription of T3γ gene may precede rearrangement of TcRδ and expression of T3δ, T3ε and T11 genes
Authors: Pelkonen Jukka , Tunnacliffe Alan , Palacios Ronald
Published: March 2007

We have studied the state of TcRδ gene and the expression of T3δ, T3ε, T3γ and T11 (CD2) genes in the fetal thymocyte (FT) clones A2, G15, H5, E10, D5, H12, F1 and D11 obtained from a 14‐day B10.BR mouse fetal thymus. The eight FT clones contain the TcRδ gene in the germ‐line configuration as determined by Southern blot analysis. With the exception of clones E10 and D5, the other six FT clones express normal sized transcripts for T3δ gene and none of the eight FT clones produced detectable RNA transcripts for T3δ, T3ε and T11 genes as assessed by Northern blot analysis. Together with our previous work showing that all eight FT clones contain the TcRδ and the TcRβ gene clusters in the germ‐line configuration, the data indicate that the FT clones represent the earliest stage of T cell development identified within the thymus. Our results provide evidence that (a) the T3γ gene is the first of the genes that encode components of a TcR/T3 complex to be expressed in ontogeny within the thymus; (b) the T3 (δ, E, γ) genes are switched on asynchronously and their expression must be differentially regulated, and (c) the T11 gene product may not be involved in early stages of T cell development within the thymus.
Interferon‐alpha can synergize with interleukin 2 for human in vitro antibody response
Authors: Delfraissy Jean‐Fragois , Wallon Christine , Galanaud Pierre
Published: March 2007

We tested the effect of interferon (IFN)‐α on the specific anti‐2,4,6‐trinitrophenyl (TNP) response induced by TNP‐conjugated polyacrylamide beads in cultures of purified human B cells. IFN‐α alone had no effect. Interleukin 2 (IL2) alone had a restorative effect which could be considerably (10 x) enhanced by IFN‐α. This reflected a true synergy most apparent with IL 2 concentrations of 10 U/ml and IFN‐α concentrations of 103‐105 U/ml. The highest concentrations of IFN‐α were not inhibitory. In contrast, IFN‐α did not enhance the effect of an IL2‐free T cell‐derived supernatant able to support the B cell differentiation. Sequential incubations showed that IFN‐α acted earlier than IL2 on B cell response. The effect of IFN‐α was dependent on an efficient interaction between IL2 and its receptor which could be inhibited by a monoclonal antibody toward the CD25 antigen. Thus, IFN‐α can positively interact with a well defined interleukin, IL2, at a pre or post receptor level to potentiate antibody response.
Evidence that protein kinase C differentially regulates the human T lymphocyte CD2 and CD3 surface antigens
Authors: Cantrell Doreen A. , Verbi Winston , Davies Adelina , Parke Peter , Crumpton Michael J.
Published: March 2007

The purpose of the present study was to explore the effects of protein kinase C (PKC) stimulation on two cell surface receptors that regulate T cell growth: the T cell antigen receptor/CD3 complex and the CD2 antigen. The data show that PKC differentially regulates the expression and functions of CD2 and CD3 molecules. Thus, activation of PKC induced a decrease in cell surface levels of CD3 molecules but an increase in the expression of CD2 antigens. Additionally, prolonged stimulation of PKC inhibited subsequent T cell activation via CD3 but promoted activation via CD2 molecules. These results suggest that the CD2 cellular activation pathway would be preferred in T cells which have been exposed to stimulators of PKC. The molecular basis for the regulatory effects of PKC on CD3 and CD2 molecules and its physiological significance are discussed.
The preferential accumulation of helper‐inducer T lymphocytes in inflammatory lesions: evidence for regulation by selective endothelial and homotypic adhesion
Authors: Pitzalis Costantino , Kingsley Gabrielle , Haskard Dorian , Panayi Gabriel
Published: March 2007

The mechanisms which lead to the accumulation of T lymphocytes into inflammatory lesions are not clearly understood. We have previously shown that synovial CD4 T lymphocytes are mostly CDw29UCHL1 (helper‐inducer cells) and very few carry the CD45R antigen which identifies the suppressor‐inducer subset. Synovial CD8 cells are also CDw29UCHL1CD45R−. In the present study, lymphocytes from pleural and peritoneal inflammatory infiltrates were shown to have a similar phenotypic pattern. Furthermore, it was demonstrated that the CDw29UCHL1 subset had a greater ability than CD45R cells to adhere to endothelial cells and to form homotypic clusters. Differential surface expression of LFA‐1 on the two subsets was also shown, but this could not account for the demonstrated adhesion differences. Differences in adhesion between CDw29/UCHL1 and CD45R cells may explain the preferential accumulation of CDw29/UCHL1 cells in inflammatory infiltrates and underlie some of the functional differences between cells taken from sites of chronic inflammation and those from peripheral blood.
Maturation of the delayed‐type hypersensitivity response in SJL mice: absence of effector cell induction
Authors: Matsushima Glenn K. , Stohlman Stephen A.
Published: March 2007

Immunization of young adult SJL mice (6 weeks of age) with a wide variety of particulate and soluble antigens does not elicit a delayed‐type hypersensitivity (DTH) response. Young adult SJL lack a DTM response through 8 weeks of age but attain the mature adult level of responsiveness at 10 weeks of age. Nylon wool‐enriched TDTH effectors and an antigen‐specific T cell clone both elicited DTH responses when transferred into 6‐week‐old SJL. Thus, the cascade of events at the local site appears to be functionally intact in 6‐week‐old SJL. However, T cells from immunized 6‐week‐old SJL fail to transfer DTH responsiveness to naive 6‐week‐old SJL recipients unless macrophages from 12‐week‐old SJL supplemented the immunization. Thus, the unresponsiveness of 6‐week‐old SJL appears to be due to a lack of induction of TDTH effectors. In addition, SJL mice immunized at 6 weeks of age and challenged with antigen at the DTH responsive age of 12 weeks did not mount a DTH response. Immunized 6‐week‐old SJL, supplemented with macrophages from 12‐week‐old SJL, and 1Zweek‐old SJL did respond to a second antigenic challenge when held for an equivalent 6‐week period. Thus, 6‐week‐old SJL fail to induce Tom effectors and to generate memory TDTH cells. Finally, antigen‐pulsed macrophages from 12‐week‐old SJL transferred DTH responsiveness into naive 6‐week and 12‐week‐old SJL recipients, while antigen‐pulsed cells from 6‐week donors were unable to transfer DTH responsiveness. These data indicate that the maturational deficit in the DTH responsiveness of 6‐week‐old SJL resides in the inability of macrophages to induce TDTH effectors.
B cell memory to thymus‐independent antigens type 1 and type 2: the role of lipopolysaccharide in B memory induction
Authors: Zhang Jun , Liu Yong‐Jun , Maclennan Ian C. M. , Gray David , Lane Peter J. L.
Published: March 2007

Several studies have indicated that thymus‐independent (TI) antigens, unlike their thymus‐dependent (TD) counterparts, are poor at generating memory antibody responses (Immunol. Today 1981.3: 217). In contrast to this view, the present report shows that the TI type 1 (TI‐1) antigen, 2,4,6‐trinitrophenyl‐lipopolysaccharide (TNP‐LPS), elicits good secondary responses in rats. These secondary antibody responses are not only greater in magnitude than the primary responses, but display a different pattern of Ig classes with more IgG and IgA antibodies produced. In transfer experiments between congenic strains of rats which differ in their kappa light chain Ig allotype, it is shown that this memory is attributable to persistent B cell clones. The TI‐2 antigen, 2,4‐dinitrophenyl‐hydroxyethyl starch (DNP‐HES), given alone did not elicit B cell memory. However, when DNP‐HES is presented to the immune system in association with LPS, the pattern of the anti‐DNP response is similar to that elicited by TNP‐LPS.

The capacity to generate TI memory is associated with the appearance of hapten‐specific B cells in the marginal zones of the spleen. Hapten‐binding cells were induced in the marginal zones following immunization with TNP‐LPS, but not by DNP‐HES. However, concurrent immunization with DNP‐HES and LPS which were not covalently linked was found to induce DNP‐binding cells in the marginal zone. There is complete correlation between the appearance of hapten‐binding memory B cells in the marginal zone and the capacity of these antigens to induce secondary responses.
Long‐lasting thymus‐independent immune responses to anti‐idiotype lipopolysaccharide conjugates require continuous B cell renewal
Authors: Burlen Odile , Coutinho António , Freitas Antonio A.
Published: March 2007

In the present investigation, we have studied the antibody response of both C57BLJ6 lipopolysaccharide‐responder mice (B6 LPS‐R) and C57BLAOScCr LPS‐nonrespon‐der mice (B10.Cr LPS‐NR) upon immunization with copolymers of LPS and either Ac38 or Ac46 anti‐idiotypes. As both strains of mice studied are of the Ighb allotype the antibody response obtained was quantified by estimating the serum levels of the complementary idiotype, B1–8, in immunized mice. The results show that while the injection of the LPS‐R strain B6 with copolymers of LPS anti‐idiotype resulted in a long‐lasting idiotype response the immunization of the LPS‐NR strain, B10.Cr, resulted in virtually no response. This finding allowed us to perform cell transfer experiments to study the response of isolated cells from B6 mice transferred into LPS‐NR hosts. Using such a cell transfer model, the results obtained suggest that long‐lasting idiotype responses observed in the LPS‐R strain require continuous B cell production in bone marrow. The relevance of this finding to the understanding of the long‐lasting (fluctuating) antibody responses to nondegradable thymus‐independent polysaccharides is discussed.
Phenotypic characteristics of cells involved in induced suppression to murine experimental autoimmune thyroiditis
Authors: Parish Nicole M. , Roitt Ivan M. , Cooke Anne
Published: March 2007

Suppression of induced experimental autoimmune thyroiditis can be consistently transferred with spleen cells to syngeneic recipients, provided they are first treated with 200 rads irradiation. Treatment with anti‐Thy‐1 in vivo immediately prior to transfer abrogates the suppression, while depleting B cells has no effect.The in siru induced tolerance can be prevented by treatment with monoclonal antibodies to the Ly‐1 or L3T4 molecules either prior to or post tolerization. Anti‐Ly‐2 treatment has no effect. In the transfer, again treatment of donors with anti‐L3T4 prior to transfer prevents the demonstration of suppression in the recipients, while anti‐Ly‐2 does not affect suppression. These data suggest that the suppression is being mediated either by a CD4− T suppressor cell or a CD4 suppressor inducer cell. Preliminary experiments do not support the possiblity of a CD8 suppressor cell being activated in the recipient.
A MEMBER OF A NEW VH GENE FAMILY ENCODES ANTI‐BROMELINIZED MOUSE RED BLOOD CELL AUTOANTIBODIES
Authors: Reininger Luc , Kaushik Azad , Izui Shozo , Jaton Jean‐Claude
Published: March 2007

A cDNA clone encoding the variable region of the heavy chain of a BALB/c anti‐bromelinized mouse red blood cell (BrMRBC) monoclonal antibody has been characterized. The nucleic acid sequence indicates that the variable region of the heavy chain is likely encoded by variable‐VCP12, diversity‐DSP 2 (5, 7 or 8) and joining‐JH1 germ‐line genes. An identical combination of V genes was observed for six other CBA/J and NZB anti‐BrMRBC hybridomas. The BALB/c VCP12 nucleotide sequence is less than 80% homologous to members of the 10 known VH families. Moreover, the genomic restriction fragments detected under moderate stringency conditions with the radiolabeled cDNA probe did not correspond to those obtained with probes of the most homologous VH families (7183 and X24).

The results indicate that the VCP12 gene defines a new VH family which we propose to designate vH11. The observation of 1, 2 or 3 enomic restriction fragments at the most, with mice bearing the Igh‐Vd or J, Igh‐Va or bF or Igh‐Vc haplotypes, suggests the existence of a few VCP12‐related genes.
Stable expression of the cDNA encoding the human T lymphocyte‐specific CD2 antigen in murine L cells
Authors: Clipstone Neil A. , Crumpton Michael J.
Published: March 2007

The human CD2 antigen is a T lymphocyte cell surface glycoprotein that has been implicated in both T lymphocyte adhesion and activation. The requirement for a T lymphocyte‐specific factor(s) in the mechanism of signal transduction initiated via the CD2 antigen has been explored using murine L cells transfectants that stably express the human CD2 antigen at the cell surface. Such transfectants express the three CD2 epitopes previously defined on human T lymphocytes. However, combinations of CD2 monoclonal antibodies, that stimulated an increase in the cytoplasmic calcium concentration of the human T cell line Jurkat, failed to induce a similar signal in the transfectants. These results indicate that the transfected CD2 antigen cannot alone transduce intracellular signals in response to stimulatory combinations of CD2 monoclonal antibodies, and suggest that the functional CD2 antigen expressed on human T lymphocytes requires the association of another, as yet undefined factor(s).
T‐immunogenic peptides are constituted of rare sequence patterns. Use in the identification of T epitopes in the human immunodeficiency virus gag protein
Authors: Claverie Jean‐Michel , Kourilsky Philippe , Langlade‐Demoyen Pierre , Chalufour‐Prochnicka Ada , Dadaglio Gilles , Tekaia Fredj , Plata Fernando , Bougueleret Lydie
Published: March 2007

The sequences of a set of 63 peptides of demonstrated T immunogenicity have been analyzed and compared with two different randomly generated sets of sequences. This study indicates a statistically significant tendency of T immunogenic peptides to be constituted of clusters of rare tetrapeptides, as evaluated from the available sequence data banks. This result has been used to locate potential T epitopes in the human immunodeficiency virus (HIV) gag protein. Four peptides corresponding to the best candidate T epitopes (chosen in regions of conserved sequence among different virus isolates) have been synthesized and found to be recognized by a HIV‐1‐specific, HLA‐A2‐restricted human cytotoxic T cell line.
T cell dependence of the “natural” autoreactive B cell activation in the spleen of normal mice
Authors: Huetz Fançois , Sciard‐Larsson Eva‐Lotta , Pereira Pablo , And Denis Portnoi , Coutinho Antönio
Published: March 2007

A high frequency of clonal precursor B cells producing lytic antibodies to syngeneic erythrocytes treated with bromelain (BMRC) is revealed in normal mouse spleen cells by lipopolysaccharide‐driven limiting dilution analysis. All such specificities are recovered as activated blasts after density gradient fractionation, the “small lymphocyte” pool being depleted of anti‐BMRC reactivities. In contrast, the spleens of athymic (nude) mice contain undetectably low frequencies of these specificities in either lymphocyte compartment. Transfer of relatively low numbers of normal syngeneic splenic T lymphocytes to adult nude mice restores the high frequency of anti‐BMRC clonal precursor B cells, again in the activated, but not in the resting spleen cell fractions. Large total T cells are more than tenfold better than resting T cells in reconstitution potential, as are enriched CD4+ as compared to CD8+ cells which are practically devoid of activity in this respect. These results apply exclusively to B cells at a differentiative stage that allows for extensive clonal expansion, since there is a marked difference between the frequency of clonal precursors determined by limiting dilution analysis and the frequency of Ig‐secreting plaque‐forming cells of the same specificity, and induced by the same mitogen in short‐term cultures. The implications of these findings for the physiology of autoreactivity and repertoire selection in the compartment of perinatal B cells are discussed.
Highly efficient action of autocrine mouse interferon‐γ expressed via a retroviral vector
Authors: Watanabe Yoshihiko , Sakata Tsune‐Aki
Published: March 2007

Following infection with a mouse interferon‐γ (IFN‐γ)‐producing retrovirus, various types of mouse cell lines began to constitutively secrete IFN‐γ in the culture medium, but the IFN‐γ production level varied according to cell type. Effects of the IFN‐γ on the IFN‐γ‐producing cell itself (autocrine effects) were examined. In the IFN‐γ‐producing cells, the expression of the major histocompatibility complex class I genes was augmented; this augmentation was remarkable in T cell lines tested in this work, regardless of their poor IFN‐γ production. This autocrine effect was highly efficient and could not easily be abrogated by the exogenous addition of anti‐IFN‐γ antibodies. Such antibody resistance was also observed for the antiviral effect of the autocrine IFN‐γ on an IFN‐γ gene‐transferred fibroblast line. These results suggest that apparently low titers of physiological IFN‐γ might exert strong in vivo autocrine and possibly paracrine effects.
Organization of the human CD3 locus on chromosome 11
Authors: Tunnacliffe Alan , Olsson Carina , Buluwela Lakjaya , Rabbitts Terence H.
Published: March 2007

Three CD3 genes, γ, δ, ϵ map to human chromosome 11 band q23. A 75‐kb region of 11q23 containing all three genes has been characterized by field inversion gel electrophoresis and molecular cloning. The CD3 genes lie within a stretch of 50 kb of DNA, orientated 3′‐CD3γ‐5′:5′‐CD3δ‐3′ :3′‐CD3ϵ‐5′. Only 1.6 kb separate the CD3δ and CD3δ genes, while the CD3δ and CD3ϵ genes are approximately 22 kb apart. CD3 gene expression is one of the first events during the maturation of the thymocyte, and therefore the clustering of CD3 genes may define a chromatin domain which is activated early in T cell development.
Limiting dilution analysis of proliferative responses in human lymphocyte populations defined by the monoclonal antibody UCHL1: implications for differential CD45 expression in T cell memory formation
Authors: Merkenschlager Matthias , Terry Linda , Edwards Robert , Beverley Peter C. L.
Published: March 2007

Using limiting dilution analysis, we investigated proliferative responses of UCHL1+ and UCHL1− T cell populations to compare the precursor cell frequencies following recall and alloantigen stimulation, and the complexity of cellular interactions within UCHL1+ and UCHL1− populations. We find high frequencies of recall antigen responses among UCHL l+, but not UCHL1− T cells. In contrast, both populations contain similar frequencies of alloantigen responsive cells. Our results are consistent with single‐hit kinetics in recall as well as alloantigen responses and show no complex cellular interactions within the responding populations. In conclusion, the difference between the recall antigen response of UCHL 1+ and UCHL1− cells observed in conventional proliferation assays is most probably due to a high frequency of recall antigen‐responsive UCHL1+ cells and not to suppressive phenomena in the UCHL1−population. These data suggest that memory T cells are largely of the UCHL 1+ phenotype. The relation of post‐thymic T cell maturation and differential CD45 expression is briefly discussed.
Regulatory effects of human IgE‐binding factors in the IgE synthesis by human and rat lymphocytes
Authors: Kisaki Tomonari , Leung Donald Y. M. , Jardieu Paula , Geha Raif S. , Ishizaka Kimishige
Published: March 2007

We have previously established human T cell hybridomas which produce IgE‐binding factors. Incubation of one of the T cell hybridomas, 166A2, with human IgE dimer in the presence of 1 μg/ml bradykinin resulted in the formation of IgE‐binding factors having affinity for lentil lectin. The factors selectively enhanced both IgE‐forming cell responses of rat mesenteric lymph node (MLN) cells and spontaneous IgE synthesis by human peripheral blood B cells of atopic patients, without affecting the IgG response. The same factors that enhanced IgE synthesis of B cells from atopic patients also enhanced IgE synthesis induced under bystander conditions by activated alloreactive T cells. Fractionation of the affinity‐purified IgE‐binding factors by gel filtration revealed three molecular mass species, i.e., 60 kDa, 30 kDa and 15 kDa. The 60‐kDa and 15‐kDa IgE‐binding factors selectively enhanced both the spontaneous IgE synthesis by B cells of atopic patients and IgE response of rat MLN cells. In contrast, the 30‐kDa IgE‐binding factors had only marginal enhancing effects on the IgE synthesis by both human B cells and rat MLN cells. When the 166142 hybridoma cells were incubated with IgE dimer in the presence of glycosylation‐inhibiting factor (GIF), essentially all IgE‐binding factors formed by the cells had affinity for peanut agglutinin (PNA) but for neither lentil lectin nor concanavalin A. All of the 60‐kDa, 30‐kDa and 15‐kDa species, having affinity for PNA, selectively suppressed the potentiating factor‐enhanced IgE response of rat MLN cells. The factors also suppressed the IgE synthesis of human B cells from atopic patients when the synthesis was enhanced by IgE‐potentiating factor. The results indicate that human IgE‐binding factors regulate IgE synthesis by both human and rat lymphocytes.
In vitro T cell responses to a candidate Epstein‐Barr virus vaccine: human CD4+ T cell clones specific for the major envelope glycoprotein gp340
Authors: Ulaeto David , Waace Lesley , Morgan Andrew , Morein Bror , Rickinson Alan B.
Published: March 2007

Specific T cell proliferation was observed in short‐term blood mononuclear cell cultures set up from Epstein‐Barr virus (EBV)‐immune individuals and challenged either with UV‐irradiated EB virions or with a candidate subunit vaccine preparation, the purified envelope glycoprotein gp340 incorporated into immune stimulating complexes (gp340 iscoms). Limiting dilution culture of the activated T lymphoblasts in interleukin 2‐containing medium generated stable CD3+CD4+CD8‐ T cell clones. Particular clones showing virus‐specific proliferation in preliminary screening assays were selected for more detailed study. Three gp340 iscoms‐induced clones from EBV‐immune donor CG responded specifically to restimulation either with UV‐EBV or with purified gp340 iscoms in the presence of autologous antigen‐presenting cells (APC). Both T cell‐depleted blood mononuclear cells and the EBV‐transformed B cell line (treated with Acyclovir to block endogenous gp340 production) could be used for presentation, the latter being the more efficient when gp340 iscoms was the source of antigen. Blocking studies with monoclonal antibodies to HLA class II antigens and experiments using HLA‐typed allogeneic APC indicated that all three gp340‐specific CG clones were restricted through the HLA‐DR2 antigen. One gp340 iscoms‐induced clone from another EBV‐immune donor, MR, likewise showed gp340‐specific proliferation, in this case restricted through a HLA‐DR4 antigen. Using HLA‐DR‐homozygous B cell lines representing the five known DR4 subtypes, efficient presentation of gp340 to this T cell clone was observed with both DR4Dw4 and DR4Dw14 antigens. Parallel experiments on one UV‐EBV‐induced T cell clone from donor MR gave a different pattern of results; these cells appeared to be specific for a virus structural component other than gp340 and to be restricted through an HLA‐DP determinant.
Complement activation is not required for IgG‐mediated suppression of the antibody response
Authors: Heyman Birgitta , Wiersma Erik , Nose Masato
Published: March 2007

Feedback suppression of the antibody response by IgG is known to be dependent on intact Fc regions. However, it is not clear which of the Fc‐mediated effector functions is required. In the present report we have studied whether ability or inability of the IgG antibodies to activate the complement system was of consequence for their immunosuppressive effect

First, a monoclonal IgG1‐anti‐2,4,6‐trinitrophenyl (TNP) antibody, unable to activate complement via the classical or alternate pathway, was shown to be able to inhibit more than 90% of the in vivo sheep erythrocyte‐specific antibody response in mice when TNP coupled to sheep erythrocytes was used as antigen

Second, we investigated the immunosuppressive ability of a non‐complement‐activating mutant IgG2a,‐anti‐TNP monoclonal antibody. The mutant differs from the wild type by a single amino acid substitution in the CH2 domain leading to inability to fix complement factor Clq. However, the mutant has the same affinity for antigen and the same Fc receptor‐binding capacity as the wild type antibody. It is demonstratd that the mutant was as efficient as the wild type antibody in inhibiting an in vitro antibody response to TNP‐coupled sheep erythrocytes

These findings confirm the non‐determinant specificity and Fc dependence of IgG‐mediated suppression, and show that the Fc‐mediated effector mechanism is independent of complement activation. The results instead suggest binding to Fc receptors as a necessary step in feedback immunosuppression and favor inactivation of B cells by cross‐linking of Fc and antigen receptors on their surface rather than elimination of antigen by complement‐dependent phagocytosis as the effector mechanism.
Establishment of tumor‐specific immunotherapy model utilizing vaccinia virus‐reactive helper T cell activity
Authors: Shimizu Yoshio , Hasumi Katsuhiko , Masubuchi Kazumasa , Okudaira Yoshio
Published: March 2007

It was previously demonstrated that preimmunization of mice with live vaccinia virus (VV) and subsequent immunization with VV‐infected (modified), syngeneic tumor cells resulted in enhanced induction of tumor‐specific immunity through a cellular collaboration between VV‐reactive helper T (VV‐Th) cells and tumor‐specific effector cell precursors. On the basis of this augmenting system, a tumor‐specific immunotherapy model was established in which a growing tumor regressed.

C3H/HeN mice were pretreated with cyclophosphamide to eliminate nonspecific suppressor T cell activity and subsequently inoculated (primed) s.c. with live VV, leading to augmented induction of VV‐Th cell activities. Four weeks later, the mice were inoculated i.d. with syngeneic X5563 myeloma cells. Six days after the tumor cell inoculation, live VV was injected into the tumor mass three times at 2‐day intervals. Seven of ten mice which had received VV priming and subsequent VV injection into the tumor mass exhibited complete tumor regression. On the contrary, mice which had received mere intratumoral VV injection in the absence of VV priming failed to exhibit appreciable tumor regression. Mice whose tumor had completely regressed (regressor mice) by the above VV immunotherapy were shown to have acquired systemic anti‐tumor immunity, which was confirmed by a challenge with syngeneic tumor cells after the tumor regression. In vitro analysis of these immune mice revealed that potent tumor‐specific cytotoxic T lymphocyte responses were preferentially induced, but with no detectable anti‐tumor antibody responses. Such a potent tumor‐specific immunity was not observed in mice which had received an intratumoral VV injection in the absence of VV priming. Thus the results clearly indicate that the tumor regression was accompanied by concurrent generation of a potent tumor‐specific immunity, suggesting that the cellular collaboration between VV‐Th cells and tumor‐specific effector cell precursors is also functioning in this VV‐immunotherapy protocol, likewise the immunoprophylactic model. Therefore, the present model provides an effective maneuver for tumor‐specific immunotherapy and this system will be theoretically applicable to human cancer treatment.
Age‐associated increase in the expression of T cell antigen receptor γ chain genes in mice
Authors: Matsuzaki Goro , Yoshikai Yasunobu , Kishihara Kenji , Nomoto Koji , Yokokura Teruo , Nomoto Kikuo
Published: March 2007

T cell function generally declines with age. To determine the underlying cause of the age‐related decline, we compared the expression levels of T cell antigen receptor genes encoding γ, β and α chains in the lymphoid tissues of young (8 wk old) vs. aged (40 wk old) mice. An age‐associated increase in γ chain gene transcripts was evident in the thymocytes, spleen cells and mesenteric lymph node cells. Aged mice had a relatively high proportion of CD3+CD4−CD8− cells but a reduced level of CD3+CD4−CD8+ cells in the lymphoid tissues, as compared with young counterparts. The allo‐reactivity in the lymphoid cells, as assessed by mixed lymphocyte reaction (MLR) responses, decreased with advancing age. On the contrary, increased levels of syngeneic MLR and spontaneous cytolytic activity were noted in the lymphoid cells of aged mice, as compared with findings in their young counterparts. A remarkable increase in the number of CD3+CD4−CD8− cells and level of the γ chain gene messages was also detected in the responder cells of day 4 syngeneic MLR culture from aged mice. An increase in the number of T cells bearing γ chain may be related to the alterations in immunological functions in aged mice.
Prostaglandin E2 and the increase of intracellular cAMP inhibit the expression of interleukin 2 receptors in human T cells
Authors: Rincón Mercedes , Tugores Antonio , López‐Rivas Abelardo , Silva Augusto , Alonso Miguel , De Landázuri Manuel O. , López‐Botet Miguel
Published: March 2007

We have analyzed the effect mediated by prostaglandin E2 (PGE2) and different reagents that increase intracellular cAMP on the expression of the p55 subunit (CD25) of interleukin 2 receptors (IL2R), on the levels of CD25‐specific mRNA and on the expression of high affinity IL 2R. In purified T cells, activated either by an anti‐CD3 monoclonal antibody or phytohemagglutinin, the addition of PGE2 (10−6 M), forskolin (5 × 10−5 M), cholera toxin (0.2 μg/ml) or dibutyryl cAMP (dBcAMP) (10−4 M) decreased the cell surface expression of IL 2R by reducing (40%‐78% inhibition) the proportions of CD25+ cells as well as the expression of high affinity IL2R, detectable after 24 h. Furthermore, it was observed that PGE2 reduced the concentration of IL2R‐specific mRNA after a 6‐h period of activation, indicating that its regulatory activity takes place at a pretranslational level. The addition of exogenous recombinant IL2 only partially reversed the inhibition, thus suggesting that PGE2 and increased intracellular concentration of cAMP directly interfered with CD25 expression and that their effect could not be merely attributed to a lack of IL2 dependent positive feedback. Cells cultured under the same conditions in the presence of phorbol myristate acetate, that activates protein kinase C, were refractory to the CAMP‐mediated regulation. Finally, we demonstrate that both PGE2 and dBcAMP inhibit the generation of inositol metabolites after T cell activation, thus indicating that these reagents interfere with early signal transduction mechanisms which precede the synthesis of IL2R.
PB76: a novel surface glycoprotein preferentially expressed on mouse pre‐B cells and plasma cells detected by the monoclonal antibody G‐52
Authors: Strasser Andreas
Published: March 2007

A monoclonal antibody (mAb) G‐5‐2 was isolated which binds to transformed as well as normal cells of the B lineage but not to cells of the T cell, myeloid lineages nor to fibroblasts. mAb G‐5‐2 reacts with pre‐B and plasma cell‐transformed lines, and it preferentially recognizes normal pre‐B cells from fetal liver and bone marrow as well as plasma cells from spleen of mice. G‐5‐2+ fetal liver cells isolated by cell sorter express mRNA for μ heavy chain Ig gene and generate in vitro antibody‐producing cells when co‐cultured with lipopolysaccharide and rat thymocyte filler cells. During development the frequency and staining intensity of G‐5‐2+ cells in fetal liver from normal mice increases from 1% G‐5‐2+ cells at day 14 to∼7% positive cells at day 18 of gestation. Several strains or normal mice contain comparable numbers of G‐5‐2+ cells as well as B‐220+ and BP‐1+ B cell precursors in the fetal liver. Mice carrying the xid mutation have 3‐4‐fold less G‐5‐2+ as well as B‐220+ and BP‐1+ cells in the fetal liver, suggesting that the effects of the xid mutation may be manifested from early stages of B cell development. Fetal liver cells from mice carrying the scid mutation were found to contain normal numbers of G‐5‐2+ as well as B‐220+ and BP‐1+ pre‐B cells. These results indicate that differentiation from progenitors to pre‐B cells in scid mice may occur normally; the scid mutation would thus appear to affect the process of rearrangement and expression of the Ig genes in the developing pre‐B cells. mAb G‐5‐2 precipitates a 76‐kDa glycoprotein from surface‐radiolabeled pre‐B cells and plasma cells. Taken together, these results indicate that G‐5‐2 mAb recognizes a novel B cell lineage‐specific surface molecule called PB76 which is preferentially expressed by pre‐B cells and plasma cells.
T cell responses of normal individuals towards recombinant protein antigens of Mycobacterium tuberculosis
Authors: Munk Martin E. , Schoel Bernd , Kaufmann Stefan H. E.
Published: March 2007

Recombinant β‐galactosidase fusion proteins from Mycobacterium tuberculosis were purified by affinity chromatography and used for stimulation of unselected T lymphocytes freshly isolated from healthy individuals. It was found that the 12kDa, 19‐kDa, 65‐kDa and 71‐kDa recombinant (r) proteins tested stimulated T cells from healthy individuals in an antigen‐specific way. These data demonstrate that it is feasible to screen purified r‐proteins with unselected T cell populations. The existence of T cells with reactivity to these antigens in healthy individuals suggests T cell activation independent from clinical disease and hence that these proteins are not indicative for active tuberculosis.
A VH gene is located within 95 Kb of the human immunoglobulin heavy chain constant region genes
Authors: Buluwela Lakjaya , Rabbitts Terence H.
Published: March 2007

Using cosmids covering about 117 Kb upstream of the human immunoglobulin chain C, gene, we have identified a potentially functional VH gene, belonging to the VHVI subgroup. This VHVI gene is only about 95 Kb from the Cμ gene and is probably the first functional VH segment of the Igh locus. These results illustrate the proximity of the human VH, DH and JH segments involved in creation of the complete heavy chain genes.
Transcription of protooncogenes during stimulation of normal human B lymphocytes
Authors: Smeland Erlend B. , Blomhoff Heidi Kiil , Ohlsson Rolf , Davies Catharina De Lane , Funderud Steinar , Boye Erik
Published: March 2007

Protooncogenes play important roles in the regulation of growth and differentiation of normal cells. In this study we have examined the cell cycle‐dependent regulation of transcription of various protooncogenes after stimulation of human peripheral blood B lymphocytes. The transcriptional rate of various genes was determined by means of a nuclear run‐on assay. We found that several protooncogenes were transcriptionally activated after stimulation (myc, p53, K‐ras, H‐ras, sis and ets), but with different kinetics of induction. In contrast, some oncogenes, especially those encoding membrane‐associated or cytoplasmatic proteins like abl, rel or mil/raf, were transcribed at a relatively constant rate during the cell cycle.
Antigen presentation by liposomes as model system for T‐B cell interaction
Authors: Walden Peter
Published: March 2007

Using the earlier established liposome system for antigen presentation, in which liposomes bearing major histocompatibility complex (MHC)‐class II molecules inserted into and protein antigen covalently linked to the membrane were found to be sufficient for an antigen‐specific and MHC‐restricted activation of T cells, the minimal requirements for T‐B cell interaction were investigated. Liposomes carrying MHC class I1 molecules and antigen‐specific monoclonal antibodies were constructed and tested for their ability to present soluble antigen to T cells. With the antigens lactate dehydrogenase B and pigeon cytochrome c, a specific stimulation of T cell clones and hybridomas could be obtained. These results demonstrate the possibility of a direct involvement of the immunoglobulins on the B cell surface in their interaction with T cells.