bluuebunny/crossref_metadata_2025 huggingface dataset:
The regulation of IgG subclass production in man: low serum IgG4 in inherited deficiencies of the classical pathway of C3 activation
Authors: Bird Prudence , Lachmann Peter J.
Published: March 2007

Human serum IgG subclasses have been measured by a sensitive enzyme‐linked immunoassay in 52 subjects with severe genetic deficiency of a complement component. The mean serum IgG4 in 4 subjects with C3 deficiency was 8.2 γg/ml and in 14 subjects with (C1‐4 deficiency was 27.9 γg/ml. These means are severely depressed compared with the mean normal IgG4 of 292 γg/ml. IgG4 levels in C5‐9 deficiency (175 γg/ml) and ClINH deficiency (179 γg/ml) did not differ significantly from normal. Serum IgG2 was reduced significantly, but far less severely than IgG4, in C3 and in some cases of C1‐4 deficiency. IgGl and IgG3 levels were within the normal range in all complement‐deficient groups. Age differences between the groups do not explain the very low levels of IgG4 in C1‐4 and C3 deficiency. These data suggest that serum IgG4 synthesis is dependent on an intact classical, but not alternative, pathway for activation of C3 and that IgGCcommitted B cells require a complement‐dependent maturation pathway not required by B cells committed to other IgG isotypes. IgG4 antibody responses are associated with secondary responses to T‐dependent antigens. The possibility that IgG4 may be the product of a memory B cell which has been through a stage of differentiation in a germinal centre is discussed.
Expression of CR2/EBV receptors on human thymocytes detected by monoclonal antibodies
Authors: Tsoukas Constantine D. , Lambris John D.
Published: March 2007

The biologic effects of the third component of complement, C3, are mediated via receptors which specifically bind the enzymatic degradation products resulting from the cleavage of C3. One of the products, C3d, has been associated with binding to the second complement receptor CR2 (CD21). This receptor, which is identical to the receptor for Epstein‐Barr virus (EBV), has been primarily found on cells of the B lineage, but not on mature T cells or other cells of erythroid or myeloid lineages. In the present investigation, we report the presence of CR2 on human thymocytes. Indirect immunofluorescence analysis employing monoclonal anti‐CR2 antibodies revealed a range of thymocyte reactivity from 15% to 63% in thirteen experiments using cells of different donors. Reactivity was always greater with the monoclonal anti‐CR2 (CD21) antibody HB‐5 than with two other antibodies which recognize distinct epitopes on the CR2 molecule. Two‐color immunofluorescence analysis indicated that the brightest of the HB‐5‐stained thymocytes also reacted with the monoclonal anti‐CD1 antibody T6 (immature thymocyte marker) while some of the duller HB‐5‐staining cells reacted with the monoclonal anti‐CD3 antibody Leu‐4 (mature thymocyte marker). Immunoprecipitation of CR2 on thymocytes with antibody HB‐5 and polyacrylamide gel electrophoretic analysis revealed a protein of 145 kDa molecular mass which is consistent with the size of CR2 found on B lymphocytes. These findings raise several questions regarding the biologic role of CR2‐EBV receptor on cells of the T lineage.
Low doses of interleukin 2 induce bystander cell lysis by antigen‐specific CD4 inflammatory T cell clones in short‐term assay
Authors: Gromkowski Stanislaw H. , Hepler Kristin M. , Janeway Charles A.
Published: March 2007

The effect of recombinant interleukin 2 (rIL2) and interferon‐γ (IFN‐γ) on the cytolytic activity of a CD4 class I1 major histocompatibility complex‐ovalbumin (OVA)‐specific murine clone called 5.8.6 was examined. Low doses of IL2 (0.1–1.0 U/ml) induce clone 5.8.6 to kill in an antigen‐independent fashion in short‐term 51Cr‐release and 3H‐release assays (6–12 h). Targets killed by 5.8.6 cells include P815, YAC‐1 and B lymphoma cells. IFN‐γ, alone or in combination with IL2, has no effect. 5.8.6 and similar inflammatory CD4 T cell clones have been shown to lyse bystander target cells in the presence of a specific stimulator target. We propose that killing of bystander targets by clone 5.6.8 is due to nonspecific cytolytic activity induced by the clone's own IL2 secreted in response to recognition of the specific target.
Inhibition of interleukin 2‐induced proliferation of cloned murine T cells by glucocorticoids. Possible involvement of an inhibitory protein
Authors: Redondo Juan Miguel , Fresno Manuel , López‐Rivas Abelardo
Published: March 2007

The ability of glucocorticoids to inhibit interleukin 2 (IL2)‐induced T cell proliferation in two cytotoxic T cell (CTL) clones has been studied. A complete inhibition of DNA synthesis by dexamethasone (Dx) could be observed when IL2‐depleted cultures of CTL were either incubated for 6 h with the hormone prior to the addition of IL2 or treated simultaneously with Dx and a low concentration of IL2. No significant reduction in the number and affinity of IL2 receptors was seen after 6 h incubation with Dx. The order of potency observed with the different steroids indicated that this inhibitory effect was mediated through binding to a specific glucocorticoid receptor. The action of these hormones possibly involves the synthesis of an inhibitory protein(s), since the presence of cycloheximide during the incubation with Dx prevented the inhibition of DNA synthesis. Furthermore, supernatant from Dx‐treated CTL contained a nondialyzable factor which inhibited DNA synthesis and cell growth of CTL clones induced by IL2. Blocking of IL2 synthesis and IL2 receptor formation have been proposed as one of the major mechanisms of glucocorticoid‐induced immunosuppression. Our results indicate that these hormones may also affect T cell proliferation by inhibiting IL2 activity.
A predominant idiotype independent of specificity, or Ig and H‐2 allotypes, is found in the primary but not the secondary murine antibody response to lysozyme
Authors: Kaplan Mark A. , Keller Margaret A. , Hsu Di‐Hwei , Ch'Ng Lean‐Kuan , Miller Alexander , Sercarz Eli E.
Published: March 2007

Removal of just the three N‐terminal residues Lys‐Val‐Phe (TIP) on hen egg white lysozyme (HEL), by aminopeptidase cleavage, eliminates an antigenic determinant which is a recurrent and dominant focus of primary but not secondary antibody responses to HEL in a variety of mouse strains. We have generated an anti‐idiotypic rabbit antiserum against such a TIP‐dependent monoclonal antibody (mAb). This antiserum reacts with many different primary anti‐HEL mAb, but fails to react with all of a variety of secondary anti‐HEL mAb. The idiotype defined by this antiserum, termed IdXE, is a common feature of early anti‐HEL antibody responses but does not appear in secondary responses. Although the presence of IdXE and TIP dependence is correlated in primary responses, studies of idiotype expression on mAb and on plaque‐forming cells (PFC) using mixed erythrocyte monolayers clearly show that at the single‐cell level the properties are separable, ie., not all TIP‐recognizing PFC display IdXE and a sizable proportion of cells producing non‐TIP‐dependent antibodies are IdXE+. The restricted idiotypy and specificity of early antibody responses to HEL occur in each of eight diverse mouse strains tested: it is not associated with a particular MHC haplotype, heavy chain allotype or light chain allotype. The finding of such strain‐independent restriction in the early response pattern to a typical protein antigen is novel and suggests the involvement of highly conserved, potent regulatory mechanisms which are manifested as a limitation in the initial expression of the available repertoire.
Interferon‐γ and tumor necrosis factor induce the L‐arginine‐dependent cytotoxic effector mechanism in murine macrophages*
Authors: Drapier Jean‐Claude , Wietzerbin Juana , Hibbs John B.
Published: March 2007

We tested several monokines and muramyl dipeptide (MDP) to determine whether they induce the L‐arginine‐dependent effector mechanism in cultured murine macrophages. Recombinant interferon‐γ (rIFN‐γ) and recombinant tumor necrosis factor (rTNF) synergize to induce nitrite (NO2−) and nitrate (NO3−) synthesis from L‐arginine as well as to cause inhibition of the iron‐dependent enzyme aconitase in macrophages. Unlike rTNF, recombinant interleukin 1 (rIL1) and rIL6/B cell stimulatory factor 2 (rIL 6/BSF‐2) did not act as cofactors when added to macrophages in the presence of rIFN‐γ. rIFN‐γ plus MDP induced the L‐arginine‐dependent effector mechanism in murine macrophages. However, induction by rIFN‐γ plus MDP was inhibited by anti‐rTNF antibodies which suppressed both NO2−/NO3− synthesis and aconitase inhibition. This result indicates that endogenously produced TNF is involved in the induction of the L‐arginine‐dependent effector mechanism when MDP is the co‐stimulant with rIFN‐γ. In contrast, anti‐rTNF antibodies did not fully suppress the effect of combining rIFN‐γ and lipopolysaccharide, suggesting that, in this case, activation of the L‐arginine‐dependent effector pathway may involve more than induction of TNF synthesis by the macrophages. These results provide information, at a biochemical level, on a mechanism through which combination of IFN‐γ and TNF can modulate macrophage functions involved in the control of cell proliferation.
Studies on the release of cell‐associated interleukin 1 by paraformaldehyde‐treated murine macrophages
Authors: Streck Helmut , Günther Christian , Ulrich Beuscher Horst , Röllinghoff Martin
Published: March 2007

Experiments are presented demonstrating the release of interleukin 1 (IL1) by lipopolysaccharide‐stimulated murine macrophages (Mϕ) after treatment of the cells with paraformaldehyde (PFA). The IL 1 activity set free was completely blocked by a rabbit anti‐mouse IL 1α antiserum. Immunoprecipitation studies revealed that the IL 1 released was of Mr 33 kDa, 23 kDa and 17 kDa. Incubation of PFA‐treated Mϕ in the presence of leupeptin reduced the amount of detectable low molecular mass (i.e. 23 kDa and 17 kDa) IL lα. Addition of leupeptin to PFA‐treated Mϕ also reduced the amount of released IL 1 activity, suggesting that proteolytic modification of the IL lα precursor is involved in the generation of biological active IL lα. It is proposed that the cell‐associated 33‐kDa IL 1 is released from the Mϕ by vesiculation of parts of the Mϕ cell membrane, followed by a proteolytic cleavage step.
Clonal analysis of CD4 CD8‐ human thymocytes expressing a T cell receptor γ/δ chain. Direct evidence for the de novo expression of CD8 surface antigen and of cytolytic activity against tumor targets*
Authors: Mingari Maria Cristina , Varese Paola , Bottino Cristina , Melioli Giovanni , Moretta Alessandro , Moretta Lorenzo
Published: March 2007

CD4−CD8− human thymocytes were obtained by treating total thymocyte suspensions with antiCD4 and anti‐CD8 monoclonal antibodies (mAb) and complement. The resulting cell populations contained virtually no CD4+, CD8+ or WT31+ cells and 17–65% CD3+ cells. In addition, analysis of cell reactivity with delta‐TCS‐1 mAb (specific for the Cγ2‐encoded, nondisulfide‐linked form of TcR γ/δ), revealed the presence of a variable proportion of δ‐TCS‐1+ cells (the % of δ‐TCS‐1+ cells were lower than the percentage of CD3+ cells). Upon culture in recombinant interleukin 2 (IL2, in the presence of irradiated mononuclear cells), CD4−CD8− thymocytes underwent extensive proliferation. In addition, a progressive increase of CD8+ cells (but not of CD4+ or WT31+ cells) could be detected. Cells also progressively acquired cytolytic activity against K‐562 or fresh melanoma cells. Fresh CD4−CD8− thymocytes were cloned under limiting dilution conditions. The cloning efficiencies were relatively high (1/3 cells); in addition, virtually all the clonal progenies obtained displayed cytolytic activity and expressed the CD3+WT31−δ‐TCS‐1+ surface phenotype. About half of the clones analyzed were CD8+, whereas none expressed CD4 antigens. We conclude that (a) only δ‐TCS‐l‐reactive, TcRγ/δ+ cells can be isolated from CD4−CD8− thymocytes cultured in IL2, and (b) the expression of CD8 antigen and of cytolytic activity reflects a true in vitro phenotypic change of CDK, noncytolytic precursors (and not the preferential growth of few contaminating cells).
Interferon‐gamma protects human endothelial cells from lymphokine‐activated killer cell‐mediated lysis
Authors: Renkonen Risto , Ristimäki Ari , Häyry Pekka
Published: March 2007

In adoptive immunotherapy the lymphokine‐activated killer (LAK) cells, known to be cytotoxic to many tumor cell lines, are injected i.v. into tumor‐bearing animals or cancer patients. However, in addition to a significant reduction in tumor masses, complications occur in many cases, most severe of which are the vascular leak syndrome and hypotension. In this report we show that LAK cells are also cytotoxic to normal vascular endothelial cells, which may partly contribute to these complications. Incubation of the endothelial cells with interferon‐gamma (IFN‐Γ), but not with inter‐leukin 1 (IL1) or tumor necrosis factor, protects the endothelial cells from LAK‐mediated lysis in a dose‐ and time‐dependent manner. The protective effect is abolished by monoclonal antibody against IFN‐γ. However, the IFN‐γ treatment does not protect LAK‐sensitive tumor cell lines from LAK‐mediated lysis. Concomitantly IFN‐γ also induces both class I and class II antigens on endothelial cells. The induction of these major histocompatibility complex (MHC) antigens does not explain the protective effect: timewise, the protection is complete already within 24 h after addition of IFN‐γ to endothelial cell culture, whereas the induction of MHC antigens peaks at 72 h, and antibodies against these antigens are not able to abolish the protective effect.
Specificity of proliferative response of human CD8 clones to mycobacterial antigens
Authors: Rees Ann , Scoging Anne , Mehlert Angela , Young Douglas B. , Ivanyi Juraj
Published: March 2007

Human CD8 T lymphocyte clones (TLC) were generated from the pleural effusion of patients with tuberculosis using a protocol that required, in addition to antigen, co‐culture of purifed CD8+ T cells, accessory cells, interleukin 2 (IL2) and anti‐CD3‐Sepharose. The TLC obtained were stimulated by mycobacterial soluble extracts in an IL2‐dependent and MHC class I‐restricted manner. When antigen‐responsive TLC were screened with extracts from the recombinant mycobacterial library they were found to respond to either the Y3125 (100‐kDa) or the Y3111 (71‐kDa) λgt11 clones. Polyacrylamide gel immunoblot analysis demonstrated that the CD8 TLC responded to fractions with the molecular mass range 27–45 kDa in the Y3125 lysogen and 60–90 kDa in the mycobacterial soluble extract. The specificity of TLC reactive with the Y3111 clone was confirmed using the 71‐kDa antigen purified from the same lysogen. These TLC recognized sequences common to the 71‐kDa protein derived from mycobacteria, E. coli or a human cell line. Studies of three TLC using antigen‐presenting cells of known genetic haplotype indicated that stimulation with both the Y3125 and the 71‐kDa antigens were restricted by determinants encoded by HLA‐B8.
Class I alloantigen is sufficient for cytolytic T lymphocyte binding and transmembrane signaling
Authors: Kane Kevin P. , Goldstein Steven A. N. , Mescher Matthew F.
Published: March 2007

Based largely on antibody blocking studies, a number of surface “accessory” molecules on effector cytolytic T lymphocytes (CTL) have been implicated as having a role in mediating CTL binding and lysis of target cells, possibly via binding to ligands on the target cell surface. Despite this, cloned allogeneic CTL were able to specifically bind cell‐size, artificial membranes (pseudocytes) bearing only class I alloantigen. This binding triggered CTL degranulation, as measured by serine esterase release. Thus, class I alloantigen alone is both a necessary and sufficient ligand for specific binding and effective transmembrane signaling to occur.
Postnatal B cell development: influence of trinitrobenzenesulfonic acid treatment during pregnancy
Authors: Zöller Margot
Published: March 2007

Prenatal treatment with a reactive hapten may be well suited for analyzing the establishment of self tolerance because the hapten binds ubiquitously to proteins and cells and persists for a long period in the developing organism. Based on this consideration, pregnant BALB/c mice were treated with 2,4,6‐trinitrobenzenesulfonic acid (TNBS), searching for differences in 2,4,6‐trinitrophenyl (TNP) responsiveness in their offspring as compared to litters of untreated mice.

The frequency of TNP‐specific T‐independent B cells of litters from TNBS‐treated mothers was very low at birth and remained below 10% of controls until the age of 42 days. On the contrary, in 8‐day‐old prenatally TNBS‐treated litters, the frequency of TNP‐specific T‐dependent B cells was higher than in controls. Expansion of TNP‐specific B cells after antigenic stimulation of control mice started at the age of 3–4 weeks and expansion rates increased with age, while in prenatally TNBS‐treated mice, significant expansion rates were seen at the age of 2 weeks only. Yet, after restimulation with TNP‐lipopolysaccharide or with a TNP‐anti‐TNP conjugate, but not after restimulation with TNP‐ovalbumin, similar numbers of plaque‐forming cells (PFC) were observed with spleen cells of prenatally untreated and TNBS‐treated mice, the latter revealing an exceptional predominance of IgG PFC.

Thus, TNP‐specific B cells were not deleted, but prenatal TNBS treatment resulted in an altered compositon of TNP‐specific B cell subpopulations, their regulation differing qualitatively from the one observed in prenatally untreated mice.
Concomitant production of different lymphokines in activated T cells
Authors: Andersson Ulf , Sander Birgitta , Andersson Jan , Möller Goran
Published: March 2007

The intracellular accumulation of five different lymphokines in individual cells could be identified by lymphokine‐specific antibodies and an indirect immunofluorescence technique with UV microscopy. When peripheral blood mononuclear cells from one healthy donor were activated in vitro by the T cell mitogen anti‐CD3 monoclonal antibody, the maximal number of cells producing interleukin (IL)2, IL6 or tumor necrosis factor (TNF)−α occurred 6 h after initiation of the cultures, while peak numbers of interferon‐γ, TNF‐β and a second wave of TNF‐α‐synthesizing cells were noted approximately 20 h later. By performing two‐color immunofluorescence studies we observed a variegated production pattern with cells making no, one or several lymphokines simultaneously. All five cytokines accumulated in the Golgi organelle resulting in a very characteristic morphology of the staining with or without additional cytoplasmic immunofluorescence.
Expression and functional role of CD23 on T cells
Authors: Armitage Richard J. , Goff Lindsey K. , Beverley Peter C. L.
Published: March 2007

We have found that approximately 10%–15% of tonsil, but not peripheral blood, T cells express the CD23 antigen following activation with 12‐O‐tetradecanoylphorbol 13‐acetate (TPA), phytohemagglutinin (PHA) or recombinant interleukin 4. The proliferative response of tonsil T cells is significantly increased when CD23 monoclonal antibodies (mAb) are present in the cultures. In contrast, no such proliferative augmentation is seen when peripheral blood T cells are cultured in this way. Supernatant (SN) of Epstein‐Barr Virus‐transformed B lymphoblastoid cell lines (EBVLCL), is found to have a similar co‐stimulatory effect on the proliferation of tonsil T cells to that seen with CD23 mAb. This effect is greatly diminished by preclearing SN with CD23 mAb. Similarly, SN from a CD23 L cell transfectant augments the proliferative response of tonsil T cells to both TPA and PHA. The CD23 molecule expressed by TPA‐driven T cell blasts appears identical in size to the 45‐kDa glycoprotein present on EBVLCL and activated B cells. In constrast, a 42‐kDa molecule is observed when CD23 is precipitated from T cells activated with PHA. The results presented here demonstrate that CD23 is expressed on activated tonsil, but not peripheral blood T cells and plays a role, via the binding of CD23 mAb and CD23 material, present in EBVLCL and CD23 transfectant SN, in the regulation of T cell proliferation in response to mitogens such as PHA and TPA.
Human lamina propria lymphocytes bear homing receptors and bind selectively to mucosal lymphoid high endothelium
Authors: Jalkanen Sirpa , Nash Geoffrey S. , Toyos Juan De Los , Macdermott Richard P. , Butcher Eugene C.
Published: March 2007

It has been hypothesized that the selective recognition of tissue‐specific endothelial cell molecules helps determine the in vivo distribution of lymphoid effector cells by controlling the extravasation of their circulating precursors. Here we report (a) immunofluorescence studies of the cell surface phenotype of human lamina propria lymphocytes (LPL), including staining with monoclonal antibody Hermes‐1, which defines a 90‐kDa lymphocyte surface glycoprotein involved in recognition of high endothelial venules (HEV); and (b) functional analyses of the ability of LPL to bind to HEV in frozen sections of mucosal lymphoid tissues (appendix or Peyer's patch) vs. peripheral lymph nodes. Essentially all LPL bear the Hermes‐1 antigen, over 90% at levels comparable to those of circulating PBL. As a population, LPL display a quantitative preference for adherence to mucosal HEV, binding 0.8–1.5 times as well as PBBL to mucosal HEV, but only 0.1–0.5 times as well to HEV in peripheral lymph nodes. Of particular interest was the behavior of the lymphoblast fraction, which typically constituted 3–7% of LPL. These cells, defined by size, consisted of a mixture of T cells and surface IgA blasts. One hundred percent were Hermes‐1bright, and they bound 4–8 times more efficiently to mucosal HEV than PBL while failing to bind detectably to lymph node HEV. LPL binding to mucosal HEV involves the gp90Hermes, since the monoclonal anti‐gp90 antibody, Hermes‐3, and a polyclonal anti‐gp90 antiserum inhibit the binding of small LPL and of LP blasts. The remarkable efficiency and specificity of binding by LP blasts may reflect retention of homing properties of the blood‐borne precursors of these blasts and is discussed in relation to the capacity of immunoblasts in mesenteric nodes and in thoracic duct lymph to traffic selectively to mucosal lymphoid and extralymphoid sites. The demonstration of organ‐specific endothelial cell recognition by LP lymphoblasts provides considerable support for the concept that selective interactions with endothelium play an important role in directing the distribution of activated lymphocyte subsets in vivo.
T cell interactions generated by synthetic peptides covalently linked to a carrier
Authors: Childerstone Amanda , Haron Jay A. , Lehner Thomas
Published: March 2007

We have attempted to extend the synthetic peptide‐carrier bridge concept of T cell‐B cell interaction to T cell‐T cell interaction. DNA synthesis of human CD4 cells that were sensitized in vivo to a native streptococcal antigen (SA) was stimulated in vitro with synthetic peptides (SP) derived from the sequence of native SA. The SP were linked to tetanus toxoid (TT) as a carrier which was recognized by primed T cells. The uptake of [3H]thymidine was significantly greater when stimulated with covalently linked SP‐TT than that with non‐covalently mixed SP and TT. The TT‐ and SP‐sensitized CD4 cells were then enriched and depleted by panning on TT‐ or SP‐treated monocyte layers. When TT‐enriched CD4 cells were reconstituted with SP‐enriched cells, [3H]thymidine uptake was significantly greater with the linked SP‐TT than with the mixed SP and TT. However, reconstitution of the TT‐enriched with SP‐depleted CD4 cells or the converse failed to increase significantly DNA synthesis by cells stimulated with the linked SP‐TT. The production of interleukin 2 (IL2) and expression of IL2 receptors were then assayed to examine any difference in stimulation between TT and SP. Both IL 2 and IL 2 receptors were diminished and delayed when T cells were stimulated with SP as compared with TT. The results suggest that epitope‐linked clusters of monocytes, TT‐sensitized CD4 and SP‐sensitized CD4 cells enable IL 2 released by the TT‐sensitized CD4 cells to stimulate the SP‐sensitized CD4 cells that produce inadequate amounts of IL 2. Indeed, addition of recombinant IL 2 to T cells stimulated with mixed SP and TT induces an increase in DNA synthesis which becomes similar to that resulting from stimulation with the linked SP‐TT.
Differential secretion of tumor necrosis factor‐α and granulocyte/macrophage colony‐stimulating factors but not interferon‐γ from CD4 compared to CD8 human T cell clones
Authors: Pawelec Graham , Schaudt Kurt , Rehbein Arnika , Busch Friedrich W.
Published: March 2007

Tumor necrosis factor‐alpha (TNF‐α) is a pleiotropic lymphokine which may have important regulatory effects on immune responses. It is shown here that eight alloreactive CD4 T cell clones (TCC) secreted significant amounts of TNF‐α after stimulation with either specific alloantigen or 12‐O‐tetradecanoylphorbol 13‐acetate together with the calcium ionophore ionomycin (up to 50 ng/ml/24 h/106 cells) whereas CD8 TCC failed to do so (max. 2 ng/ml/24 h/106 cells). The CD8 TCC also secreted markedly less granulocyte/macrophage colony‐stimulating factor than the CD4 cells. However, this was not indicative of a general decrease of lymphokine production by CD8 cells because CD4 and CD8 TCC both secreted similar amounts of interferon‐gamma. These results show that regulatory CD4 lymphocytes can produce large amounts of TNF‐α, whereas CD8 effector cells cannot do so.
Bu‐1 antigen expression as a marker for B cell precursors in chicken embryos
Authors: Houssaint Elisabeth , Lassila Olli , Vainio Olli
Published: March 2007

Genetically polymorphic cell surface antigen, Bu‐1, is expressed on B cells as well as on a subset of macrophages. Bu‐1 cells are also present in embryonic spleen and bone marrow, and these could represent prebursal precursors for B cells and Bu‐1 macrophages. To test the repopulation capacity of these cells we sorted 14‐day embryonic spleen cells from Bu‐1a‐homozygous donors into Bu‐la and Bu‐la‐ fractions and transferred them into age‐matched irradiated Bu‐1b‐homozygous recipients. Four to six weeks after hatching, the recipients were analyzed for Bu‐1 chimerism. The results demonstrate that B cell precursors are exclusively present in the Bu‐1 population of 14‐day embryonic spleen, whereas the Bu‐1 macrophage subpopulation can be repopulated by either the Bu‐1 or the Bu‐1‐ fraction of these embryonic cells. Bone marrow cells from young chickens could also repopulate the Bu‐1 macrophage subset but not the B cell compartment, thus confirming previous data that postnatal bone marrow does not contain B cell precursors. These results demonstrate that all B cell precursors in the 14‐day embryonic spleen carry the Bu‐1 antigen, and suggest that there is no lineage relationship between the Bu‐1 B cells and macrophages.
Surface expression of the T cell receptor complex requires charged residues within the α chain transmembrane region
Authors: John Susan , Banting George S. , Goodfellow Peter N. , Owen Michael J.
Published: March 2007

The T cell receptor (TcR) complex is a multi‐subunit glycoprotein comprising at least five transmembrane polypeptides. An unusual characteristic of each of the trans‐bilayer domains is the presence of charged amino acids. To examine the importance of these residues for the association and consequent surface expression of the components of the complex, a TcR α chain containing either charged or neutral residues within its transbilayer segment was introduced into the human T cell line MOLT‐4, and the appearance of the TcR complex at the cell surface was assayed. Surface expression was observed only in MOLT‐4 cells transfected with the α chain containing charged transbilayer residues. Thus, these residues most probably play a crucial role in the assembly process.
Immune status of a μ, χ transgenic mouse line. Deficient response to bacterially related antigens
Authors: Lamers Marinus C. , Vakil Meenal , Kearney John F. , Langhorne Jean , Paige Christopher J. , Julius Michael H. , Mossmann Horst , Carsetti Rita , Köhler Georges
Published: March 2007

We have examined the immune repertoire and immune response of a mouse that carries transgenes for a μ heavy chain and ϰ light chain. The expression of these genes is under the regulation of their own controlling elements. The transgenes are expressed early in ontogeny and are easily detectable from day 13 of gestation onwards. The pre‐B cells seem to function normally as they generate IgM‐secreting colonies at normal frequencies. Colonies show predominantly the transgenic specificity. Expression of the transgenes is not limited to B cells since around 10%–20% of peripheral T cells and 50% of thymocytes express the μ transgene as an intracellular protein. Ectopic expression of ϰ was not seen. The spleen size of the transgenic mouse is decreased by around 20%; this reduction is largely caused by a reduction of the B cell pool. Almost all B cells express the transgenes, only 30% co‐express endogenous heavy chain genes and all co‐express endogenous light chain genes. Serum Ig levels for IgM and IgA were normal, 20% of the IgM consist of the transgenic product. Serum IgG levels were decreased. T cell functions (helper and cytotoxic) were normal. Immune responses to conventional antigens were impaired, especially in the early phases of the immune response, but after boosting they were virtually normal, except for IgG3 which remained low. Primary antibody reponses to T cell‐independent antigens of the class II type (bacterially related antigens) were absent, although precursor frequencies for these antigens were within the expected range. The significance of this finding, as it relates to allelic exclusion of Ig genes, is discussed.
T cell malignancy in Richter's syndrome presenting as hyper IgM. Induction and characterization of a novel CD3, CD4‐, CD8 T cell subset from phytohemagglutinin‐stimulated patient's CD3, CD4, CD8 leukemic T cells
Authors: Raziuddin Syed , Assaf Hasan M. , Teklu Bayu
Published: March 2007

A patient is described, having Richter's syndrome and immunodeficiency with hyper IgM, who developed suppressor T cell lymphoma (CD3, CD4‐, CD8) following untreated helper‐suppressor T cell chronic lymphocytic leukemia (CD3, CD4, CD8). The neoplastic T cells in both malignancies expressed interleukin (IL) 2 receptors but were deficient in typical CD2 and CD5 pan T antigens. Additionally, a large percentage of malignant lymph node T cells expressed HLA‐DR activation antigens. In vitro immunoglobulin‐production experiments demonstrated that the patient's leukemic blood T cells had an excess helper function for IgM synthesis but a suppressor function for IgG and IgA synthesis by normal B and T cells. The leukemic blood T cells demonstrated a poor response to phytohemagglutinin (PHA). A defect in IL 2 receptor expression was evident in PHA‐stimulated leukemic blood T cells. Of interest was the observation that PHA stimulated the induction of a novel CD3, CD4‐, CD8 T cell subset from patient's CD3, CD4, CD8 leukemic blood T cells. These PHA‐induced CD3, CD4‐, CD8 T cell subsets produced an elevated proliferative response to PHA and concanavalin A, had a helper cell function for IgM synthesis and produced highly elevated amounts of IL 2.
Synergy between interleukin 4 and interleukin 2 conveys resistance to cyclosporin A during primary in vitro activation of murine CD8 cytotoxic T cell precursors
Authors: Bubeck Ruth , Miethke Thomas , Heeg Klaus , Wagner Hermann
Published: March 2007

Even though cyclosporin A (CsA) suppresses in vitro production of lymphokines such as interleukin 2 (IL 2) and responsiveness of cytotoxic T cell (CTL) precursors to IL 2, thereby inhibiting the in vitro generation of CTL, in vivo CsA does not affect the induction of alloreactive CTL. This paradox suggests that CsA‐resistant signals are operating in vivo. Using an in vitro model system in which the requirement for antigen‐presenting cells during primary activation of resting murine CD8 T cells is bypassed by immobilized anti‐CD3 monoclonal antibodies, we here describe conditions in which IL 4 conveys CsA resistance to murine CD8 T cells triggered by immobilized anti‐CD3 monoclonal antibodies to respond to IL 2. CsA resistance of IL 4 and IL 2‐responsive CD8 T cell parallels conditions in which signals provided by IL 4 and IL 2 synergize with each other. CsA dissociates in vitro proliferative and differentiative events by suppressing the former while enhancing the latter. In addition to the known pleiotropic effects of IL 4, our results define an IL 4‐dependent, CsA‐resistant signal pathway which allows CTL differentiation in the absence of significant cell proliferation.
Characterization of the subset of immature thymocytes which can undergo rapid in vitro differentiation
Authors: Nikoli¸‐Žugi¸ Janko , Moore Mark W. , Bevan Michael J.
Published: March 2007

Recently, we reported that thymocytes expressing the CD8 molecule on their surface can give rise to CD4+CD8+ double‐positive and CD4+ single‐positive progeny following intrathymic transfer into an irradiated host mouse. Thymcoytes expressing a high density of CD8, referred to as CD8hi, and those expressing a low density of the molecule, CD8lo, were both able to differentiate in vivo. In this study we examined the ability of these CD8+ thymocyte populations and of CD4−CD8− double‐negative thymocytes to change their phenotype during brief in vitro culture. CD8− thymocytes were prepared by anti‐CD4 plus complement lysis followed by positive selection of the survivors on anti‐CD8‐coated plates. After 16 h of culture, > 60% of CD8+ thymocytes became double‐positive. Both CD8hi and CD8lo cells were able to show this in vitro change: about 30% of the former and about 80% of the latter became double‐positive. In contrast to this, double‐negative thymocytes which had been depleted of cells expressing low densities of CD8 did not show such a phenotypic conversion in vitro. Further panning experiments suggested that all of the CD8+ thymocytes actually express a low surface density of the CD4 molecule which is undetectable in our cytofluorometric assays.
Longitudinal study of leukocyte functions in homosexual men seroconverted for HIV: rapid and persistent loss of B cell function after HIV infection
Authors: Terpstra Fokke G. , J. M. Al Bert , Roos Marijke T. H. L. , Wolf Frank De , Goudsmit Jaap , Schellekens Peter T. H. A. , Miedema Frank
Published: March 2007

The early effects of infection with human immunodeficiency virus (HIV) were investigated in homosexual men who had seroconverted for anti‐HIV antibodies. Leukocyte functional activities were determined in longitudinally collected peripheral blood mononuclear cell samples. During the first 10 months following seroconversion, anti‐CD3 monoclonal antibody‐induced T cell proliferation, monocyte accessory function and T helper activity on B cell differentiation in a pokeweed mitogen‐driven system were not affected. In contrast, from the moment of seroconversion on, B cells of seroconverted men failed to produce immunoglobulin in the pokeweed mitogendriven system. This defect was not restored by addition of normal CD4+ T cells. Immunoglobulin synthesis induced by Staphylococcus aureus and interleukin 2 decreased gradually, until it was completely lost 10 months after seroconversion. In addition, proliferation in response to anti‐IgM or Staphylococcus aureus by B cells from HIV seroconverted men was decreased. The lack of inducible in vitro B cell activity was not accompanied by elevated spontaneous Ig synthesis by B cells of the seroconverted men. In the second group of men studied during the 2nd year following seroconversion, T helper activity on normal B cell differentiation significantly decreased, whereas anti‐CD3‐induced T cell proliferation and monocyte accessory function were not significantly affected. Our results demonstrate that in almost all HIV‐infected individuals B cell functional defects are the first leukocyte abnormalities observed preceding defects in T helper activity.
The induction of protective immunity to Leishmania major in the BALB/c mouse by interleukin 4 treatment
Authors: Carter Katherine C. , Gallagher Grant , Baillie Alan J. , Alexander James
Published: March 2007

The ability of interleukin 4 (IL4), administered subcutaneously around the cutaneous lesion in the form of hydrophilic gels, to affect the development of established Leishmania major infections in the BALB/c mouse was studied. IL4 had a therapeutic effect on L. major lesion growth compared with control mice, causing not only resolution of the parasite lesions over a period of 10 weeks but also rendering animals resistant to reinfection. Adoptive transfer of splenic T cells, obtained from IL4‐treated animals, conferred significant resistance to L. major infection in naive BALB/c mice compared with controls. These results demonstrate that IL4 is capable of not only reversing the usual (i.e. non‐curing) course of L. major infection in the BALB/c mouse, but also of promoting the generation of protective immunity. The nature of the gel used to deliver the cytokine was found to be important since the therapeutic activity of IL4 in poloxamer gel was not observed when a hydroxypropylmethyl cellulose (hypromellose) gel was used as the IL4 vehicle.
The methylation state of the T cell antigen receptor β chain gene in subpopulations of mouse thymocytes
Authors: Sakamoto Shigeru , Mathieson Bonnie J. , Komschlies Kristin L. , Bhat Narayan K. , Young Howard A.
Published: March 2007

Previous analyses of T cell receptor β chain (TcR β) genomic DNA from subsets of human peripheral blood leukocytes suggested that the TcR β methylation pattern might reflect distinct differentiation pathways. The studies presented here, using murine thymocyte subsets, have specifically addressed the question of whether methylation of TcR β DNA is related to the cellular maturity and type of TcR β mRNA expressed in the different subsets. We have observed that the DNA isolated from either CD4+ or CD8+ thymocytes, the more mature thymic subsets, is less methylated in the TcR β region than DNA isolated from the CD4−CD8−, double‐negative population containing the more immature thymocytes. In addition, this pattern of DNA methylation is directly related to the ratio of 1.3‐kb to 1.0‐kb TcR β mRNA seen in these different cell types. Although a quantitative difference in the level of TcR β mRNA was noted for the two mature subsets, no qualitative difference in the ratio of 1.3‐kb to 1.0‐kb mRNA was detected. Furthermore, these DNA methylation patterns appear to be lineage related, because the TcR β region of genomic DNA isolated from mouse macrophages is heavily methylated.
Acceleration of the onset of diabetes in NOD mice by thymectomy at weaning
Authors: Dardenne Mireille , Lepault Françoise , Bendelac Albert , Bach Jean‐François
Published: March 2007

The effect of thymectomy performed at weaning (3 weeks) and at 6–7 weeks of age on the incidence of diabetes was examined in the non‐Obese diabetic (NOD) mouse, a spontaneous model of immunologically mediated insulin‐dependent diabetes similar to human type I diabetes. When performed at weaning, thymectomy led to a dramatic increase in the incidence of diabetes in NOD females in comparison to sham‐thymectomized animals. Conversely, no change in the incidence of the disease or the expression of insulitis was noted when thymectomy was performed in NOD males. When delayed beyond 6–7 weeks of age, thymectomy had no effect on NOD males and females. Flow cytometry analysis of spleen cells from intact mice and mice thymectomized at weaning or at 6–7 weeks of age demonstrated a significant depletion of the T cell subsets in both groups of thymectomized animals. These results indicate that the onset of diabetes in NOD mice is submitted to thymic regulation and that the T cell depletion induced by thymectomy at weaning accelerates the disease, an effect possibly due to the loss of some T cell‐dependent suppressor mechanisms.
Interleukin 5 is a differentiation factor for IgA B cells
Authors: Schoenbeck Simone , Mckenzie Douglas T. , Kagnoff Martin F.
Published: March 2007

Interleukin 5 (IL 5) stimulates murine B cells to IgA production in vitro. The present study examined the B cell target of IL 5 activity, and asked whether IL 5 acts as an isotype switch factor, a growth factor, or a differentiation factor on B cells that produce the IgA isotype. Lipopolysaccharide‐activated surface IgM‐positive, surface IgA‐positive or surface IgA‐negative B cell populations from spleen or Peyer's patches were stimulated with IL 5, after which the expression of cell surface IgA, IgA secretion, and numbers of IgA‐secreting cells were determined. IL 5 increased the IgA response by acting on B cells that are already committed to IgA expression. Thus, with regard to the IgA response, IL 5 acts as a differentiation factor, rather than a growth or IgA isotype switch factor.
Pgp‐1hi T lymphocytes accumulate with age in mice and respond poorly to concanavalin A
Authors: Lerner Adam , Yamada Takatsugu , Miller Richard A.
Published: March 2007

Aging is associated with an accumulation of T cells functionally hyporesponsive to the effects of mitogens such as concanavalin A. Recent studies in mice and humans have identified surface markers useful for distinguishing antigen‐stimulated memory T cells from virgin T cells. In mice, memory T cells within the CD8+ cell population have been shown to express relatively high levels of the cell surface glycoprotein Pgp‐1. On the theory that aging might diminish the supply of virgin thymic emigrants without compromising the production of memory T cells, we examined the proportion of Pgp‐1hi CD4+ and CD8+ cells in the spleen, blood and lymph nodes of mice of varying age. We found a dramatic (2.5‐fold) age‐associated increase in the percentage of cells with the Pgp‐1hi phenotype. By limiting dilution methods, the frequency of concanavalin A‐responsive T cells was found to be significantly reduced in the Pgp‐1hi cell pool, whether measured by interleukin 2‐dependent proliferation, interleukin 2 production or generation of cytotoxic effectors. Pgp‐1hi and Pgp‐1lo T cells from young mice proliferate equally well when stimulated by optimal doses of phorbol myristate acetate and ionomycin suggesting that the poor responses to concanavalin A do not simply reflect low viability. Aging leads both to an increase in mitogen‐hyporesponsive Pgp‐1hi T cells, and also to lower responsiveness of cells in the Pgp‐1hi subset.
Molecular mapping of the human T cell receptor gamma (TRG) genes and linkage of the variable and constant regions
Authors: Lefranc Marie‐Paule , Chuchana Paul , Dariavach Piona , Nguyen Catherine , Huck Sylvie , Brockly Frédérique , Jordan Bertrand , Lefranc GÉRard
Published: March 2007

In the human T cell receptor gamma (TRG) locus, fourteen variable (TRGV) genes belonging to four subgroups have been identified upstream of two constant region (TRGC) genes. Three joining segments, JP1, JP and J1, have been localized upstream of TRGC1, and two others, JP2 and J2, upstream of TRGC2. In this report, we demonstrate that a unique Xho I fragment of 120 kilobases (kb) contains the fourteen TRGV genes and that the hybridization of that fragment in pulsed‐field gel electrophoresis (PFGE) allows linkage of the variable region to the constant region locus. We also show that the variable and the constant regions are remarkably close to each other since the distance between V11, the most 3′ V gamma gene, and JP1, the most 5′ J gamma segment, is only 16 kb. With its 14 V gamma genes, spanning 100 kb, the two C gamma genes and 5 joining segments covering less than 40 kb and only 16 kb separating the most 3′ V gene from the most 5′ J segment, the human TRG locus spans 160 kb of genomic DNA and represents a particularly condensed locus compared to the other rearranging gene loci.
Deletion of Mls‐reactive T cells in H‐2‐compatible but Mls‐incompatible bone marrow chimeras
Authors: Yoshikai Yasunobu , Ogimoto Masaro , Matsumoto Koji , Sakumoto Misao , Matsuzaki Goro , Nomoto Kikuo
Published: March 2007

The cellular basis of tolerance induction to Mls‐encoded antigens in radiation bone marrow (BM) chimeras has been investigated in two H‐2‐compatible strain combinations of AKR/J (H‐2k, Thy‐1.1, Mls‐Ia) and C3H/He (H‐2k, Thy‐1.2, Mls‐IIa). Sequential appearance of host‐ and donor‐derived T cell subsets and T cell receptor gene messages occurred in the peripheral lymphoid organs of both irradiated AKR/J mice reconstituted with C3H/He BM cells (C3H/He‐AKR/J chimera) and irradiated C3H/He mice reconstituted with AKR/J BM cells (AKR/J‐C3H/He chimera). A large number of cells expressing T cell receptor γ genes were detected in spleen on day 21 after reconstitution, while the normal level of alloreactivity was first detected in the spleen on day 56 after reconstitution in correlation with the appearance of appreciable levels of Thy‐1high cells and T cell receptor α and β gene transcripts. T cells bearing Vβ6, that is strongly correlated with reactivity to antigens encoded by the Mls‐Ia genetic locus, were virtually abolished in spleen on day 56 in both C3H/He‐AKR/J chimera and AKR/J‐C3H/He chimera. Furthermore, expression of Vβ3 gene transcripts, that are important for recognizing Mls‐IIa, was undetected either in the peripheral lymphoid cells of AKR/J‐C3H/He chimera or in those of C3H/He‐AKR/J chimera. These results suggested that clonal elimination of self‐reactive T cells bearing Vβ3 or Vβ6 was induced by both host‐derived radioresistant cells and donor‐derived repopulating cells in the thymus of radiation BM chimeras.
Regulation by interleukin 2 of CD23 expression of leukemic and normal B cells: comparison with interleukin 4
Authors: Hivroz Claire , Vallé Alain , Brouet Jean Claude , Banchereau Jacques , Grillot‐Courvalin Catherine
Published: March 2007

Recombinant interleukin (IL) 4 has been shown to be able to up‐regulate low‐affinity Fc receptor for IgE (FcεRII)‐CD23 expression on B cells as well as on other human mononuclear cells. We demonstrate here that, in opposition with previous reports, recombinant IL 2 also can up‐regulate CD23 expression on B cells. This was first observed on CLL cells which represent a monoclonal proliferation of B cells arrested at an intermediate stage of activation. Cells of 5 out of 12 B‐CLL studied display such an increase and all 5 proliferated, in vitro, directly in response to IL 2. Similarly, upon triggering with anti‐μ and IL 2, normal tonsillar B lymphocytes also demonstrate an increase of CD23 expression but this was observed only on day 3. Interferon‐γ was able to inhibit this IL 2‐mediated up‐regulation of CD23 on normal B cells but not on CLL‐B cells; on those cells interferon‐γ was similarly unable to inhibit the IL 4‐mediated CD23 up‐regulation. These results suggest that CD23 regulation is complex and related to the stage of activation and the cell type.