bluuebunny/crossref_metadata_2025 huggingface dataset:
Cross‐protection in mice infected with influenza A virus by the respiratory route is correlated with local IgA antibody rather than serum antibody or cytotoxic T cell reactivity
Authors: Liew Foo Y. , Russell Stuart M. , Appleyard Geoffrey , Brand Colin M. , Beale John
Published: February 2007

Mice previously infected with an aerosol of A/Rec 31 influenza virus were strongly protected against an aerosol challenge with A/Vic influenza as judged by lung virus titers recovered 2 days after the challenge infection. Such complete homotypic immunity was not achieved by priming with live Rec 31 virus injected i.v. or UV‐inactivated Rec 31 virus administered s.c. together with Al(OH)3 and saponin. The reason for the superior protective effect of the natural infection was investigated. The protection induced by respiratory infection with Rec 31 virus was specific for influenza A viruses. It was not correlated with specific serum hemagglutination inhibition antibody titer or cross‐reactive cytotoxic T (Tc) cell reactivity. Moreover, the transfer of splenic and lymphoid T cell populations with strong secondary Tc activity did not significantly reduce lung virus titers in recipient mice 3 days after infection. The protection however occurred in parallel with the presence of cross‐reactive IgA antibody in the lung washings. It thus appears that local secretory IgA plays a causal role in the prevention of cross‐infection by influenza A virus. Serum antibody and Tc cells, on the other hand, may be crucial for recovery from such infection. All mice primed with live Rec 31 virus, administered i.v. or by aerosol and expressing equally high levels of Tc reactivity, survived a lethal challenge with A/PR8 virus. The same challenge, however, killed half of the mice immunized s.c. with inactivated Rec 31 virus which induced only a low level of Tc reactivity.
Autoregulation of autoantibody synthesis in mercuric chloride nephritis in the Brown Norway rat I. A role for T suppressor cells
Authors: Bowman Christine , Mason Donald W. , Pusey Charles D. , Lockwood Christopher M.
Published: February 2007

Mercuric chloride injections in the Brown Norway rat induce the transient formation of anti‐glomerular basement membrane (GBM) autoantibodies. Transfer of spleen cells from convalescent animals, after circulating anti‐GBM autoantibodies are no longer detectable, inhibits reinduction of the disease by HgCl2 in naive recipients. This inhibition is significantly less when the T suppressor cell population is depleted by the monoclonal antibody, MRCOX8, before transfer. Our studies suggest a role for T suppressor cells in autoregulation in this animal model of autoimmune nephritis and may form a basis for the design of specific therapy for anti‐GBM disease in man.
Frequency of λ light chain subtypes in mouse antibodies to the 2,4‐dinitrophenyl (DNP) group
Authors: Liu Theresa , Reilly Edward B. , Chengbo Zhang , Eisen Herman N.
Published: February 2007

Of the three λ chain subtypes made by inbred mice, chains of the λ1 subtype are much more frequent than those of the other subtypes (λ2,λ3) in antibodies (Ab) to those few antigenic structures that are known to elicit responses, in which λ chains are the predominant type of light chain [(4‐hydroxy‐3‐nitrophenyl)acetyl (NP) and dextran]. The reasons for the frequency differences are not understood, and the large difference between the λ1 and λ3 frequencies is particularly puzzling, because in nearly all (about 95%) chains of these subtypes the N‐terminal 97 or 98 amino acids are endoded by the same Vλ‐gene segment. In an effort to identify an Ab response that has different λ subtype frequencies, we analyzed the light chains of the Ab made by BALB/c and B6 mice in response to 2,4‐dinitrophenylated chicken gamma globulin (DNP‐CGG). We found that approximately 40% of the elicited anti‐DNP molecules had λ chains and of these approximately 40% were of the λ2 or λ3 subtype. Polyacrylamide gel electrophoresis indicated that the λ2 and λ3 chains were about equally abundant. Similar λ subtype frequencies were found in the anti‐DNP Ab produced by the hybridomas made with spleen cells from the same immunized mice. In the anti‐DNP Ab elicited by DNP‐CGG and in the anti‐NP Ab elicited by NP‐CGG the different λ subtype frequencies (λ1/λ2 + λ3 = ca. 1.0‐1.5 in anti‐DNP and ca. 30 in anti‐NP) were unaffected by immunizing mice with each of these antigens alone or with a mixture of the two. This finding, though preliminary, suggests that isotype‐specific regulatory T cells are not responsible for the markedly different λ subtype frequencies in anti‐DNP and anti‐NP Ab.
Isotypes and specificities of immunoglobulins produced by germ‐free mice fed chemically defined ultrafiltered “antigen‐free” diet
Authors: Hooijkaas Herbert , Benner Robbert , Pleasants Julian R. , Wostmann Bernard S.
Published: February 2007

The regulation of the “spontaneously” occurring (“background”) Ig synthesis of mice has been studied by determining the numbers of IgM‐, IgG‐ and IgA‐secreting cells and a part of the IgM antibody‐specificity repertoire in spleen, bone marrow (BM) and mesenteric lymph nodes (MLN) of conventional and “antigen‐free” mice. These antigen‐free mice were germ‐free raised and fed an ultrafiltered solution of chemically defined low molecular weight nutrients, and thus devoid of exogenous antigenic stimulation. The secretion of IgM, IgG and IgA by spleen, BM and MLN cells was assessed in the protein A plaque assay, while specific IgM antibody‐secreting cells were detected by plaque assays specific for differently haptenated sheep red blood cells.

In general, antigen‐free and conventional mice were found to have roughly equal numbers of IgM‐secreting cells in spleen and BM. The number of IgG‐secreting cells in the spleen of antigen‐free mice was the same as in the spleen of conventional mice, but in the BM their number was 3–5‐fold decreased. About one half of the antigen‐free mice did not have MLN, and in the half which did, 5 times less IgM‐ and more than 100‐fold less IgG‐secreting cells were found as compared with conventional mice. The number of IgA‐secreting cells in antigen‐free mice was drastically decreased in all three organs tested.

The antibody‐specificity repertoire of the “background” IgM‐secreting cells in the spleen and BM of the antigen‐free and conventional mice was much alike. This indicates that in antigen‐free mice the available antibody repertoires are established independently of exogenous and/or mitogenic stimulation.
HLA‐DR‐4‐associated alloreactivity of an HLA‐DR‐3‐ restricted human tetanus toxoid‐specific T cell clone: inhibition of both reactivities by an alloantiserum
Authors: Umetsu Dale T. , Yunis Edmond J. , Matsui Yoshiki , Jabara Haita H. , Geha Raif S.
Published: February 2007

We present here the first report of a human helper/nducer T cell clone (F6) that specifically recognizes tetanus toxoid (IT) in the context of self‐major histocompati‐ bility complex (MHC) determinant(s) (HLA‐DR3), and in addition recognizes a specific but unrelated MHC determinant(s) in the absence of conventional antigen. Extensive subcloning insured that the cells were progeny of a single cell. Furthermore, removal of the cells proliferating to the alloantigen with bromodeoxyuridine and light removed cells responding to both TT plus self‐MHC and to the stimulating alloantigen, again indicating that F6 was the progeny of a single cell.

The alloantigen recognized by this TT‐specific clone appears to be closely linked to HLA‐DR4 since cells from 13 of 14 HLA‐DR4+ donors stimulated F6. An antiserum which recognizes HLA‐DR4, when added to cultures, blocked the alloreactivity of F6, and in addition blocked its proliferation to 'IT plus HLA‐DR3. Absorption of this antiserum with HLA‐DR4+ cells or with IT‐pulsed HLA‐DR3+ cells removed its capacity to inhibit the proliferation of F6. These results suggest that the antigen recognition unit on F6 is stimulated both by allodeterminants expressed on HLA‐DR4 cells and by TT plus HLA‐DR3. These moieties cross‐react at the T cell recogni‐ tion level as well as at the antibody level.
A central anti‐DNA idiotype in human and murine systemic lupus erythematosus
Authors: Eilat Dan , Fischel Ruth , Zlotnick Avinoam
Published: February 2007

The monoclonal anti‐DNA autoantibody A52 (IgG2b) was obtained from a (NZB × NZW)F1 (B/W) hybridoma. Two rabbits were immunized with the pure monoclonal antibody and produced anti‐idiotypic (Id) antibodies. The purified anti‐Id reacted with three different B/W monoclonal anti‐DNA antibodies at or close to their DNA binding sites. Moreover, the rabbit antibodies had a profound inhibitory effect on the polyclonal anti‐DNA activity in the majority of sera derived from B/W mice and human systemic lupus erythematosus (SLE) patients. The A52 IgG must, therefore, represent a major cross‐reactive Id of anti‐DNA immunoglobulins. In addition, the rabbit anti‐Id antibodies may act as the “internal image” of antigen and should prove useful in modulation of the autoimmune response to DNA in SLE.
Antibody‐mediated suppression of the immune response is determinant specific
Authors: Möller Göran
Published: February 2007

It was studied whether antibody‐mediated suppression of the immune response was determinant specific. Fluorescein isothiocyanate (FITC)‐conjugated sheep red cells were used as the immunogen and antibodies were raised both against the carrier sheep red cells and the hapten FITC. When these antibodies were injected 1‐3 h after the immunogen they only suppressed the immune response to the corresponding determinant. Anti‐carrier antibodies usually enhanced the response to the hapten. Therefore, antibody‐mediated suppression of the immune response is determinant specific and cannot be mediated in vivo to a detectable extent by the Fc part of the antibodies.
Suppressor T cell induction by soluble OKT3 antibody does not require cross‐linking of the T3 molecule
Authors: Delfraissy Jean‐François , Wallon Christine , Boué François , Vazquez Aimé , Galanaud Pierre
Published: February 2007

The monoclonal antibody OKT3 can induce T suppressor cells of the in vitro antibody response when used at concentrations as low as 10 ng/ml and in cultures containing as few as 4% OKT3‐pretreated T cells. These suppressor cells are radioresistant, cyclosporin sensitive and belong to the T4 as well as the T8 subpopulations. In contrast with the mitogenic effect of OKT3 the suppressor activity can be induced and expressed in highly monocyte‐depleted cultures. Moreover F(ab')z fragments of OKT3, although not mitogenic, are able to induce suppressor cells. Thus cross‐linking of the T3 molecule (such as that realized when intact OKT3 IgG and monocytes are present) is not required to induce suppressor cells among resting normal T cells.
Immune responses of thymusf/ymphocyte embryonic chimeras: studies on tolerance and major histocompatibility complex restriction in Xenopus
Authors: Flajnik Martin F. , Du Pasquier Louis , Cohen Nicholas
Published: February 2007

A new model has been developed to address the question of whether T cells that traverse an allogeneic thymus during early and late life become restricted to interact, in vivo, with other leukocytes and target cells that display the major histocompatibility complex (MHC) antigens of the thymus haplotype. Chimeras were made microsur‐ gically with pairs of 24‐h‐old Xenopus embryos such that the anterior region of an embryonic chimera contained the thymus anlagen and was of one MHC genotype, whereas the posterior region contained the anlagen of all hemopoietic cells and was of another genotype. Assays to determine the MHC haplotype restriction specificity of T cells in chimeras that had been reared through metamorphosis involved: specific antibody responses (IgM and IgG) to dinitrophenylated keyhole limpet hemocyanin; rejection of minor H locus disparate skin grafts that expressed the MHC antigens of either the thymus donor or the lymphocyte donor; and mixed leukocyte culture. MHC‐mismatched chimeras displayed split tolerance since they accepted skin grafts of the thymus haplotype but had lymphocytes that proliferated in response to MHC antigens of the thymus donor strain as well as to MHC antigens of third‐party donors. IgM responses of MHC‐matched and MHC‐mismatched chimeras and of nonchimeric controls did not differ. However, the IgG responses of MHC‐mismatched thymus/ lymphocyte chimeras peaked later than those of MHC‐matched chimeras and normal controls. Data from skin grafting protocols were consistent with the proposition that there may be in vivo selection of T cells reactive to minor H antigens presented in association with the MHC antigens of the thymus rather than the MHC antigens of the lymphocytes themselves. These data suggest that although it is not absolute, there is thymic selection of the T cell repertoire in Xenopus.
In vivo suppression of T‐dependent antibody responses by treatment with a monoclonal anti‐L3T4 antibody
Authors: Coulie Pierre G. , Coutelier Jean‐Paul , Uyttenhove Catherine , Lambotte Paul , Van Snick Jacques
Published: February 2007

Minute amounts of the anti‐L3T4 antibody designated GK1.5 were found to deeply suppress in vivo antibody responses to T‐dependent antigens. Primary responses to sheep erythrocytes were completely inhibited even when GK1.5 was administered up to 6 days before or 4 days after the antigen. Secondary responses to potent immunogens like sheep erythrocytes or keyhole limpet hemocyanin were also completely abolished by a single injection of GK1.5 just before the boost. This treatment had no effect on T‐independent reactions such a s the polyclonal activation of B lymphocytes with lipopolysaccharide or the anti‐2, 4,6‐ trinitrophenyl (TNP) response elicited by injection of TNP‐Ficoll.
T cell triggering by lectins I. Requirements for interleukin 2 production;er lectin concentration determines the accessory cell dependency
Authors: Roosnek Eddy E. , Brouwer Mieke C. , Aarden Lucien A.
Published: February 2007

The requirements for lectin‐induced interleukin 2 (IL2) production by human T cells have been investigated. With two different types of T cells, the Jurkat T cell lymphoma and highly purified HLA class II− peripheral T cells, the amount of IL2 produced was strongly dependent on the lectin concentration used. Addition of accessory cells caused a shift in the dose‐response curve, resulting in strongly enhanced IL 2 production at low concentrations. Thus, the (absolute) accessory cell dependency for T cells to produce IL2 is defined by experimental conditions. Only at lectin concentrations that were found to be optimal in the presence of accessory cells, removal of these cells abrogates IL2 production. Furthermore, after depletion of monocytes IL2 production by peripheral T cells became almost completely dependent on the presence of thiols in the culture medium.

In contrast, the IL2 production by the Jurkat line was not influenced by addition of thiols. The Jurkat model was used to study the nature of accessory cell because this cell line does not show any reactivity to allogeneic cells. Various myeloid and B lymphoid cell lines were tested as accessory cells. The capacity to function as accessory cell was not related to the monocytic origin of the cell. B cell lines were far more effective than monocytes, as two HLA class II− monocytic cell lines were not active. Even after HLA class II determinants were induced on these cells by incubation with an interferon‐γ‐containing conditioned medium, they failed to act as accessory cells. These experiments question the importance of HLA class II molecules and monokines, such as IL1, for lectin‐induced IL2 production.
Receptors for immunoglobulin isotypes (FcR) on murine T cells: I. Multiple FcR expression on T lymphocytes and hybridoma T cell clones
Authors: Daëron Marc , Yodoi Junji , Néauport‐Sautès Catherine , Moncuit Janine , Fridman Wolf H.
Published: February 2007

T cell receptors for the Fc portion of the various isotypes of mouse immunoglobulins (FcR) were examined by rosette formation, using as indicator cells erythrocytes coated with monoclonal antibodies of all known isotypes of serum immunoglobulins. Three populations of mouse T cells were studied: normal thymocytes, activated T cells (ATC), generated by educating thymocytes in lethally irradiated allogeneic hosts, and hybridoma T cells, derived from somatic hybridization of ATC with the FcR‐negative thymoma BW.5147. We found that (a) many different FcR could be distinguished by their specificity for a single isotype or for a combination of several isotypes; (b) ATC and hybridoma T cells expressed several such receptors that, at least in cloned cells, could be demonstrated to be borne by individual cells; (c) hybridoma T cells of independent origin bore indistinguishable receptors whereas ATC expressed markedly different FcR and (d) upon overnight incubation at 37°C, immunoglobulins were found to bind onto the cell surface, even though no corresponding constitutive FcR was detected. The same was observed with hybridoma T cells and with thymocytes.

It follows that a single T cell can express several FcR. Altogether, these FcR are capable of binding all known isotypes of serum immunoglobulins. They differ from one T cell to another.
Age‐dependent isotype variation during secondary immune response in MRL/lpr mice producing autoanti‐γ‐globulin antibodies
Authors: Manheimer Audrey , Bona Constantin
Published: February 2007

A profound inability to produce IgG anti‐2,4,6‐trinitrophenyl (TNP) antibodies during the secondary immune response elicited by a T‐dependent antigen was observed in aged MLR/lpr mice. This unresponsiveness is associated with a significantly low indirect anti‐TNP plaque‐forming cell response and a weak in vitro anti‐TNP response upon the culture of keyhole limpet hemocyanin‐primed T cells and TNP‐primed B cells in the presence of TNP. The markedly low IgG anti‐TNP response observed in aged MLR/lpr mice cannot be related to the presence of rheumatoid factors which are observed during the secondary response, since MRL +/+ and 129/J mice, (non‐ autoimmune disease strains), also produce significant amounts of anti‐γ‐globulin antibodies yet mount a strong IgG anti‐TNP response.
Fine specificity analysis of lactate dehydrogenase B‐specific proliferating T cell clones: implications for the mechanism of alloreactivity
Authors: Nagy Zoltan A. , Servis Catherine , Walden Peter , Klein Jan , Goldbergn Erwin
Published: February 2007

T cell clones of C57BL/6 origin which recognize porcine lactate dehydrogenase B (LDH‐BP) together with the Ab molecule were characterized in terms of fine specificity for both LDH‐B and self‐major histocompatibility complex determinants. Using antigen‐presenting cells from the Ab‐mutant strain B6.C‐H‐2bm12 (bm12), three clonotypes could be distinguished: the first responds to LDH‐BP + bm12, the second fails to respond and the third is alloreactive to bm12. The last clone exhibits additional alloreactivities to A molecules expressed in strains of H‐2 haplotypes f, r, s, u, w6, w7, w16, w17 and w23. All three clonotypes give identical response patterns to a panel of 17 different dehydrogenase enzymes, and react to the same tryptic peptide of LDH‐BP. Thus, these clones appear to recognize the same LDH‐B epitope together with at least 3 different determinants of the Ab molecule. The data suggest that alloreactivity is more closely related to T cell specificity for self‐major histocompatibility complex than to specificity for foreign antigen.
A third polypeptide associated with heavy and light chain subunits of class I HLA antigens in immune interferon‐treated human melanoma cells
Authors: Giacomini Patrizio , Aguzzi Adriano , Tecce Raffaele , Fisher Paul B. , Ferrone Soldano
Published: February 2007

Recombinant immune interferon (IFN‐γ) increases the synthesis, expression and shedding of class I HLA antigens by the cultured human melanoma cell line Colo 38. The magnitude of the IFN‐γ‐induced changes in class I HLA antigens is dependent on both the dose and the time of exposure to IFN‐γ and is more pronounced on the heavy chain subunit than on β2‐microglobulin (β2m). In addition, a third, distinct polypeptide with a molecular mass of 14 kDa is present as a major component of the class I HLA molecular pool in IFN‐γ‐treated melanoma cells. As IFN‐γ preferentially increases the synthesis of the heavy chain over that of β2m, the newly induced 14‐kDa component appears to quantitatively replace β2m. The stoichiometric relationship between the three molecules suggests that the IFN‐γ‐induced 14‐kDa component may be involved in the insertion of the heavy chain subunit into the plasma membrane.
Human lymphocytes induce a differential release of prostaglandin E2 and interleukin 1‐like mononuclear cell factor from normal blood monocytes
Authors: Roth Arnaud , Kaufmann Marie‐Thérèse , Cruchaud André , Dayer Jean‐Michel
Published: February 2007

Lymphocytes influence the production of both prostaglandin E2 (PGE2) and interleukin 1 (IL1) by monocytes. We have examined whether these two products are released concomitantly or not under identical culture conditions using monocyte‐ and lymphocyte‐enriched populations obtained on Percoll gradient. IL1 was measured as mononuclear cell factor (IL1/MCF). When incubated with concanavalin A, the monocyte‐enriched fraction (MF; 80–91% monocytes), but not the lymphocyte‐enriched fraction (LF; 95% lymphocytes) produced increasing amounts of PGE2 and MCF. However, when LF cells were added to MF cells in culture, a 40% to 60% decrease of PGE2 secretion was observed whereas the MCF production remained unchanged or increased up to 26‐fold. Such a dissociation between IL1 and PGE2 production by monocytes indicates independent regulation mechanisms in controlling the immune response under the influence of lymphocytes.
Human monoclonal anti‐DNA antibodies react as lymphocytotoxic antibodies
Authors: Shoenfeld Yehuda , Zamir Rina , Joshua Henri , Lavie Gad , Pinkhas Jacob
Published: February 2007

Two out of 25 monoclonal anti‐DNA autoantibodies that were produced by human‐human hybridoma were found to have lymphocytotoxic activity. The antibodies reacted with normal B and T lymphocytes at cold (4°C) as well as at warm (37°C) temperatures. The lymphocytotoxic activity of the monoclonal anti‐DNA antibodies could be inhibited by prior incubation of the antibodies with either polynucleotides, e.g. poly (I), poly(dT) or anti‐idiotypic antibodies, that had been raised against a dominant anti‐DNA antibody. The cross‐reactivity between nuclear material and lymphocyte membrane raises the question whether these apparently diverse materials have a shared epitope. The cross‐reactivity between anti‐DNA antibodies and lymphocyte membrane may account in part for the lymphopenia observed in systemic lupus erythematosus patients.
Lysis of hybridoma cells bearing anti‐clonotypic surface immunoglobulin by clonotype‐expressing alloreactive cytotoxic T cells
Authors: Hua Christine , Buferne Michel , Schmitt‐Verhulst Anne‐Marie
Published: February 2007

A B cell hybridoma (Désiré‐1) was derived which secreted and expressed at its cell surface immunoglobulin (Ig) specific for the antigen‐specific T cell receptor (Ti) of an H‐2Kb‐specific alloreactive cytotoxic T lymphocyte (CTL) clone (KB5‐C20). It was found that the CTL clone could lyse hybridoma Désiré‐1, whereas it could not lyse hybridoma which expressed surface Ig (sIg) binding to other cell surface structures of clone KB5‐C20 such as the H‐2Kk molecule. Blocking of CTL‐target cell interactions using monoclonal antibodies (mAb) indicated that the CTL‐target cell interaction was inhibited with appropriate anti‐H‐2 mAb and by anti‐Lyt‐2 mAb when CTL‐H‐2Kbinteraction was involved but not when CTL‐sIg interaction was involved. The two types of interactions were inhibited by anti‐LFA‐1 mAb. The involvement of the CTL‐Ti structure was necessary to obtain a lytic interaction between CTL and target cells, but a major histocompatibility complex product on the target cells did not need to be involved. Comparison of CTL‐target cell inhibition with cold target cells or with anti‐clonotypic mAb indicated that the Ti‐slg cellular interaction was of much higher apparent affinity than the Ti‐H‐2Kb cellular interaction. These results further suggest potential regulatory effects of CTL‐B cell cross‐idiotypic interactions.
Dominant suppressive effect of the silent E allele on an in vivo T helper cell response under E E region‐linked immune response gene control
Authors: Bogen Bjarne
Published: February 2007

Previous adoptive spleen cell transfer experiments have demonstrated that an immune response (Ir) gene linked to the E E region allows BALB/c T helper lymphocytes (Th) to respond to an idiotope on the Vλ2315 fragment of isologous myeloma protein M315. BALB.K (H‐2k) and BALB.B (H‐2b) do not respond to Vλ2315. While (H‐2d × H‐2k)F1 hybrids have been shown to be responders, it is now demonstrated that (H‐2d × H‐2b)F1 hybrids are low responders. By crossing BALB/c with various H‐2 recombinants on B10 background and probing Th responsiveness to Vλ2315 in these F1 hybrids, the dominant suppressive gene of the H‐2b haplotype is mapped to E Sb. It is argued that the suppressive gene is E, which is a silent allele. A likely explanation for the suppressive effect of the E allele is that reduced amounts of E: E restriction elements are present on antigen‐presenting cells of (H‐2d × H‐2b)F1hybrids because only one Ea gene is functional in such mice. The present report extends previous in vitro findings from other laboratories to the in vivo situation and suggests that silent alleles for class II molecule chains may profoundly affect certain immune responses of individuals heterozygous for the silent allele.
Mapping the functional topography of Fcγ with monoclonal antibodies: localization of epitopes interacting with the binding sites of Fc receptor on human K cells
Authors: Sármay Gabriella , Jefferis Roy , Klein Eva , Benczur Miklós , Gergely Janos
Published: February 2007

A panel of monoclonal antibodies (mAb) specific for the Cγ2, Cγ3 or inter Cγ2/Cγ3 domain epitopes was tested for inhibition of antibody‐dependent cellular cytotoxicity (ADCC) specific for anti‐D IgG‐coated erythrocytes. Significant inhibition of ADCC was demonstrable for some antibodies having specificity for Cγ2 or Cγ3 domain epitopes, while others gave no inhibition. Fab fragments of a representative Cγ2‐specific antibody (A55) and Cγ3‐specific antibody (x3a8) retained their inhibitory capacity in lymphocyte‐mediated ADCC, but only A55 Fab inhibited monocyte‐mediated lysis. Furthermore, the Fab portion of A55 completely abolished the complement‐dependent enhancement of ADCC mediated by concanavalin A‐stimulated cells, while x3a8 Fab had no effect in this system. On the other hand, x3a8 Fab inhibited the binding of anti‐D IgG‐sensitized erythrocytes to lymphocytes while A55 Fab did not influence this latter interaction. The results suggest that Cγ2 domain‐FcR interaction is essential for the triggering of lytic process both in lymphocyte and in monocyte‐mediated ADCC, while Cγ3 domain has no role in the latter but is responsible for the appropriate contact between effector lymphocytes and target cells. A site in the region of Lys274 appears to be critical for triggering of both lymphocyte and monocyte‐mediated ADCC.
Partial purification and biological properties of an eosinophil‐activating factor
Authors: Thorne Kareen J. I. , Richardson Brian A. , Veith Monica C. , Tai Po‐Chun , Spry Christopher J. F. , Butterworth Anthony E.
Published: February 2007

A protein (eosinophil‐activating factor, EAF), which enhances the capacity of human peripheral blood eosinophils to kill antibody‐coated schistosomula of Schistosoma mansoni, has been partially purified from supernatants of cultured peripheral blood mononuclear cells by sequential chromatography on Sephacryl S200 and DEAE‐cellulose. This protein is acidic with a molecular mass on gel filtration of 40 ± 7 kDa. It not only enhances the activity of eosinophils against schistosomula but also increases their ability to lyse antibody‐coated, herpes simplex virus‐infected Chang liver cells. It enhances the production of superoxide and hydrogen peroxide by eosinophils that occurs both spontaneously and in response to opsonized zymosan. However, increased respiratory burst activity does not appear to be responsible for the enhancement of eosinophil‐mediated killing of schistosomula, since a comparable or greater increase in hydrogen peroxide production is induced by column fractions that have little or no effect on schistosomulum killing. EAF enhances eosinophil degranulation, both spontaneously and after incubation with opsonized zymosan. Enhanced degranulation is associated with release of eosinophil peroxidase and eosinophil cationic protein. These findings suggest that EAF enhances the capacity of eosinophils to kill parasites by increasing the extent of eosinophil degranulation and the amount of toxic granule proteins that are secreted.
T cell recognition of ragweed allergen Ra3: Localization of the full T cell recognition profile by synthetic overlapping peptides representing the entire protein chain
Authors: Kurisaki Jun‐Ichi , Atassi Hammad , Atassi M. Zouhair
Published: February 2007

In the preceding report, we described the systematic localization of the full profile of the continuous antigenic sites on ragweed allergen, Ra3, with antibodies from three different host species using a comprehensive strategy, previously introduced by this laboratory. The strategy consists of studying the immunochemical activity of a series of consecutive synthetic overlapping peptides, of uniform size and overlaps, which encompass the entire protein chain. This study reports the localization of the continuous regions on Ra3 that are recognized by T cells from mice immunized with Ra3. The 10 overlapping peptides encompassing the entire Ra3 molecule were examined in vitro for their ability to stimulate lymph node cells from Ra3‐primed BALB/c (H‐2d), C3H/He (H‐2k) SWR (H‐2q) and SJL (H‐2s) mice. Several regions of the molecule (T sites) were found to stimulate Ra3‐primed lymph node cells. This strategy has enabled the localization of the full submolecular profile of T cell recognition of the Ra3 molecule by these mouse strains. Three of the regions recognized by T cells coincided with regions recognized by antibodies (i.e. B cells). It is noteworthy that in addition to sites recognized by both T and B cells the protein has at least one site which is recognized exclusively by T cells and to which no detectable antibody response is directed.
The commitment of secretory cells to the selective expression of immunoglobulin CH genes is determined by the available concentrations of the triggering ligand
Authors: Primi Daniele , Viale Giovanna , Cazenave Pierre‐André
Published: February 2007

The property of lipopolysaccharide to induce B cells to both proliferate and differentiate to IgM, IgG3 and IgG2b expression can be ascribed either to a precommitted sequence of molecular events in the activated B cells or, alternatively, to separate activities which independently modulate the two events. To discriminate between these two possibilities we have investigated the relationship between the doses of the polyclonal stimulus and the commitment of the activated cells to proliferate and to produce various isotypes.

Low doses of ligand supported proliferation as well as IgM but not IgG2b secretion. On the contrary, high doses of the same ligand were less efficient in supporting proliferation but strongly induced heavy chain class switch. The effect of lipopolysaccharide concentrations on CH genes expression decayed with the distance from μ to the respective Cγ gene.

Although we could define different B cell subsets on the basis of their proliferative response to various doses of the ligand, all these B subpopulations were found to be multipotential in terms of their switching capacity.

Taken together our data show that in lipopolysaccharide cultures B cell proliferation and heavy chain switch are two events completely dissociable on the basis of their inducing requirements.
Selective elimination through a cytolytic mechanism of bovine serum albumin‐specific T helper lymphocytes by T suppressor cells with the same antigen specificity
Authors: Heuer Joachim , Kölsch Eckehart
Published: February 2007

An antigen‐specific T suppressor cell clone isolated from a CBA/J mouse tolerized to low doses of bovine serum albumin (BSA) has previously been analyzed with regard to its effector functions. The T suppressor cell clone HF1 specifically inhibits T helper cell responses to the antigen. It also has characteristic cytolytic activity which can neither be classified as cytotoxic T cell nor as natural killer cell activity. Since this lytic capacity might be of relevance in immunoregulation, it has now been studied in more detail. For that purpose BSA‐specific T cell lines have been isolated from immune CBA/J mice in order to test them in 51Cr‐release assays as possible targets for HF1 T suppressor cells. Two T cell lines, both BSA specific and restricted to recognition of I‐Ek major histocompatibility complex determinants, have been selected for the studies because one is a helper cell (83/1), the other a suppressor cell type (83/2). HF1 T cells are able to lyse cells of line 83/1 but not those of line 83/2. Control experiments show that 83/1 cells are not a natural killer cell target and that on the other hand 83/2 cells are susceptible to lysis in an alloreactive BALB/c anti‐CBA/J cytotoxic T cell response. The extent of lysis of 83/1 T cells by HF1 T cells changes with time after antigenic stimulation. The lysis is based on direct effector: target cell interaction and not caused by soluble mediators. The data are discussed with regard to the effector function of a type of T suppressor cells which expresses I‐A and I‐E molecules and whose proliferation is restricted to the recognition of I‐A or I‐E determinants.
Effects of pyocyanine, a blue pigment from Pseudomonas aeruginosa, on separate steps of T cell activation: Interleukin 2 (IL 2) production, IL 2 receptor formation, proliferation and induction of cytolytic activity
Authors: Mühlradt Peter F. , Tsai Hsin , Conradt Peter
Published: February 2007

Pyocyanine was isolated by chloroform extraction of cultures of Pseudomonas aeruginosa, and purified by thin layer chromatography. The effects of pyocyanine on the various stages of T cell activation were studied with concanavalin A‐stimulated CBA/J mouse splenocyres. At 12.5 μM concentration pyocyanine totally inhibited Con A‐dependent prolifzration and development of cytotoxic effector cells. Protein and RNA synthesis was only 50% inhibited at this concentration. Inhibitory doses of pyocyanine were nontoxic, in that cell viability was maintained, and the inhibitory effects were reversible after removal of the drug. Pyocyanine did not interfere with interleukin 2 synthesis, nor did it affect the lytic stage of cytotoxic effector T cells. However, T blasts generated by Con A in the presence of pyocyanine did not grow in response to IL2 even in the absence of pyocyanine, and IL2 receptors, detected by indirect immunofluorescence with the receptor‐specific monoclonal antibody AMT‐13, were diminished in pyocyanine‐treated cells. Pyocyanine also inhibited IL2‐dependent proliferation of T blasts with fully developed IL2 receptors. The substance thus interferes with several discrete stages of T cell activation.
Influence of carriers on the development and localization of anti‐2,4,6‐trinitrophenyl (TNP) antibody‐forming cells in the murine spleen: II. Suppressed antibody response to TNP‐Ficoll after elimination of marginal zone cells
Authors: Claassen Eric , Kors Nel , Van Rooijen Nico
Published: February 2007

The macrophages in the marginal zones in mice spleens were eliminated by i.v. injection of dichloromethylene diphosphonate encapsulated in liposomes. After immunization with a thymus‐dependent (trinitrophenylated keyhole limpet hemocyanin; TNP‐KLH) or thymus‐independent type 1 (TNP‐lipopolysaccharide) antigen, no differences in antibody responses in treated and untreated mice were observed. However, immunization with a thymus‐independent type 2 (TI‐2) antigen (TNP‐Ficoll) resulted in a strong decrease of the antibody response in macrophage‐depleted animals. Anti‐TNP serum levels dropped 10‐fold and the number of antibody‐forming cells in the spleen 30‐60‐fold. These results confirm the special role of the marginal zone macrophages in the processing of TI‐2 antigens, as earlier suggested in splenectomy studies.
Presentation of alloantigens by host cells
Authors: Sherwood Rosemary A. , Brent Leslie , Rayfield Lee S.
Published: February 2007

Presentation of alloantigens by host cells has been examined in vivo by means of a murine cell transfer system. Primary (1°) hosts were activated by the i.p. administration of allogeneic spleen cells and their spleen or peritoneal cells were transferred into syngeneic secondary (2°) hosts 3 days later. Sensitization of 2° hosts was assessed by their ability to reject donor strain skin grafts prematurely. The transferred cells were routinely depleted of T lymphocytes. We show that (a) 5 × 107 spleen and 3 × 106 peritoneal cells consistently caused marked accelerated graft rejection; (b) this effect was antigen specific and observable in all strain combinations studied; (c) it was caused by the active sensitization of 2° hosts, but not by contaminating donor strain cells; (d) the cells involved were plastic adherent and viability was not a requirement; and (e) both class I and II, but not minor, histocompatibility antigens played a role in this model. We conclude that presentation of alloantigens by host antigen‐presenting cells can be a potent route of allosensitization.
IgE antibody and resistance to infection II. Effect of IgE suppression on the early and late skin reaction and resistance of rats to Schistosoma mansoni infection
Authors: Kigoni Emmanuel P. , Elsas Pedro P. X. , Lenzi Henrique L. , Dessein Alain J.
Published: February 2007

Most helminth parasites induce a strong IgE antibody and elevated eosinophil response in their mammalian hosts and a number of in vitro studies have suggested that IgE, possibly in association with eosinophils, may be an essential element of the host protective immunity against helminth infections. To assess the role of IgE in protective immunity, we examined the effect of suppressing the IgE antibody response on rat immunity to Schistosoma mansoni. Suppression was achieved in neonates by injections of rabbit anti‐ϵ chain γ‐globulins, control rats received injections of unspecific γ‐globulins. IgE suppression caused a marked reduction of the inflammatory reaction that developed in the skin of immune rats at the site of a cercarial challenge: the early (30 to 60 min) wheal and flare reaction was abolished, and the late cutaneous reaction (6 to 18 h) associated with intense pruritus, edema and local eosinophilia was greatly reduced. This shows that IgE was critical to the recruitment of effector cells and molecules in the skin during the first 24 h following parasite invasion.

Worms were recovered 18 to 30 days after a primary infection and 18 days after a challenge infection from IgE‐suppressed and control rats. IgE‐suppressed rats cured a first infection as rapidly as the control rats; however, they were two to three times less efficient than the controls at eliminating a second or a third challenge. These observations demonstrate that IgE antibodies are essential for the full development of rat acquired protective immunity against Schistosoma mansoni.
T lymphocytes activated by interleukin 2 alone acquire permissiveness for replication of herpes simplex virus
Authors: Braun Rudiger W. , Kirchner Holger
Published: February 2007

Not only mitogen stimulation or mitogen stimulation in combination with interleukin 2 (IL 2) was capable of causing susceptibility of human T lymphocytes to herpes simples virus (HSV) infection, but also selective stimulation with recombinant IL 2‐induced permissiveness of T lymphocytes to HSV infection. Replication of HSV in such IL 2‐stimulated T cell cultures was shown to be restricted to a T cell subset not exceeding 5% of the total population. Furthermore, IL2 stimulation was sufficient to obtain virus replication in T cells previously infected by HSV and cultivated for several days. This could not be achieved by stimulation with mitogens such as phytohemagglutinin. The level at which virus replication was restricted in nonpermissive T cells was determined to be before immediate early gene expression as assessed by indirect immunofluorescence with monoclonal antibodies against viral proteins expressed at different stages of the viral replicative cycle.
Differentiation antigens on rhesus monkey lymphocytes II. Characterization of RhT3, a CD3‐like antigen on T cells
Authors: Nooij Frans J. M. , Jonker Margreet , Balner Hans
Published: February 2007

A monoclonal antibody FN18 is described, which is specific for mature rhesus monkey T lymphocytes. It defines a cell surface antigen, composed of two polypeptide chains with a molecular mass of 22 and 27 kDa. In view of these and other similarities with the human T3 or CD3 antigen, it was designated as RhT3. Expression, distribution and certain functions of RhT3 were compared with those of its human counterpart. Analogous to anti‐CD3 antibodies in man, FN18 is able to modulate its target antigen, has mitogenic properties and is able to block the pokeweed mitogen and concanavalin A‐driven cell proliferation, but not that caused by phytohemagglutinin. In spite of such minor dissimilarities the available data strongly suggest that the RhT3 antigen is the rhesus monkey's homologue of the human CD3 antigen.
Characterization of human T cell‐derived IgE‐potentiating factor
Authors: Young Michael , Geha Raif S. , Maksad Kurt N. , Leung Donald Y. M.
Published: February 2007

We have previously shown that Fcε receptor‐positive (FcεR+) T cell lines from patients with the hyper IgE syndrome secrete IgE‐binding factors which selectively enhance IgE but not IgG synthesis in cultures of B cells obtained from patients with allergic rhinitis but not from nonatopic subject. In the present study we have tested the effect of supernatants from FcεR+ T cell lines on a large panel of B cells from atopic patients (n = 20). We found that IgE synthesis was selectively enhanced only in B cell cultures in which there was ongoing spontaneous synthesis of IgE. The target of IgE‐potentiating factor(s) was a large low‐density B cell present in the circulation of responding atopic donors. In addition, we further characterized IgE‐potentiating factors derived from FcεR+ T cell lines. The factor(s) fractionated into 2 peaks on Sephadex G‐75 with approximate molecular masses of 15000 and 60000 kDa, and had affinity for lentil lectin but not for peanut agglutinin. Release of IgE‐potentiating factor(s) was enhanced by the addition of exogenous human IgE to FcεR+ T cell cultures and was inhibited by tunicamycin, an inhibitor of N‐glycosylation. These studies suggest a close homology between the physicochemical characteristics of human and rodent IgE‐potentiating factors and the immune signals which modulate production of these IgE regulatory factors.
Idiotope‐specific T cell clones that recognize syngeneic immunoglobulin fragments in the context of class II molecules
Authors: Bogen Bjarne , Malissen Bernhard , Haas Werner
Published: February 2007

We have established idiotope (Id)‐specific T cell lines and clones derived from at least 4 different BALB/c mice immunized with the light chain (λ2315) of the BALB/c myeloma protein M315 (α,λ2). Independently derived clones were indistinguishable in that they reacted to Vλ2315, one or more of the amino acids corresponding to somatically mutated codons 94, 95 and 96 of the third hypervariable region being essential for expression of the Id. While the Id was efficiently expressed on Vλ2315, Fv315 and λ2315 fragments, about a 100–1000‐fold higher molar concentration of Fab315and M315 was needed to induce equivalent responses. Thus, Ig quaternary structure heavily influenced the availability of the Id for T cells. The Vλ2315‐specific T cells were Thy‐1.2+, L3T4+, Ly‐2.2− and I‐Ed restricted. Some of the T cell clones produced interleukin 2 (IL2), IL3 and B cell growth and differentiation factors upon activation. In addition, T cells were cytotoxic in long‐term assays for EE, but not EE‐transfected L cells in the presence of Id. The cytotoxic effect was the basis for an L cell growth inhibition assay for T cell activation that was at least 10‐fold more sensitive than ordinary proliferation assays.
Stable expression of Lyt‐2 homodimers on L3T4+T cell clones
Authors: Gallagher Pauline F. , de St. Groth Barbara Fazekas , Miller Jacques F. A. P.
Published: February 2007

The murine T lymphocyte antigen Lyt‐2 is considered to act as an accessory molecule to the class I‐restricted T cell receptor during antigen recognition. We have previously described two unusual Lyt‐2+L3T4+ class II‐restricted T cell clones whose activation by antigen is inhibited by antibodies to L3T4 but not to Lyt‐2 (B. Fazekas de St. Groth et al., Proc. Natl. Acad. Sci. USA 1986. 83: 2594). The Lyt‐2 immuno‐precipitated from one of these clones was indistinguishable from the molecule found on splenic T cells, as analyzed under reducing conditions on polyacrylamide gels, in two‐dimensional charge/size separations and in peptide mapping. The molecule from the second clone showed slightly more extensive glycosylation but was within the range described for functional Lyt‐2 on cytotoxic T cell lines. Lyt‐2 mRNA from both clones showed no abnormalities on Northern analysis. Lyt‐2 is normally expressed on thymocytes and peripheral T cells as a heterodimer disulfide bonded to the Lyt‐3 glycopeptide, yet Lyt‐3 could not be detected on the cell membranes of our clones; Lyt‐2 existed as stable homodimers without Lyt‐3. Thus Lyt‐3 is not required structurally for the spontaneous expression of Lyt‐2 on lymphoid cells.
A 93‐kDa glycoprotein expressed on human cultured monocytes and dendritic reticulum cells defined by an anti‐K562 monoclonal antibody
Authors: Farace Franjoise , Kieffer Nelly , Caillou Bernard , Vainchenker William , Tursz Thomas , Dokhelar Marie Christine
Published: February 2007

An IgG2a monoclonal antibody, referred to as 12B1 and raised against the K562 cell line, reacted with adherent monocytes maintained in culture for several days but not with bone marrow or peripheral blood cells including freshly isolated monocytes. Among human leukemic cell lines, 12B1 reacted essentially with the promyelocytic HL60 cell line. 12‐O‐Tetradecanoylphorbol 13‐acetate treatment, but no other differentiation inducer, strongly enhanced its reactivity on K562, HL60 and the histiocytic U937 cell line. Immunoperoxidase staining of sections of normal human tissues showed that 12B1 specifically recognized dendritic reticulum cells in germinal centers of lymph nodes, spleen and tonsils. The 12Bl‐detected antigen is a highly glycosylated polypeptide of an apparent molecular mass of 93–86 kDa. The 12B1 antigen appears to be a new glycoprotein marker shared by adherent monocytes and dendritic reticulum cells. The association of the 12B1 epitope with cells which present antigen and/or exert accessory function suggests that this molecule could play a role in these activities.