bluuebunny/crossref_metadata_2025 huggingface dataset:
Macrophage Fcγ2b receptor expression and receptor‐ mediated phospholipase activity: regulation by endogenous eicosanoids
Authors: Rhodes John , Salmon John , Wood John
Published: February 2007

The expression of Fcγ2b receptors and receptor‐mediated arachidonic acid metabolism by murine peritoneal macrophages was examined in vitro. The expression of Fcγ2b receptors was found to increase progressively with time in culture and this increase was dependent on protein synthesis and glycosylation. The increase in Fcγ2b receptor expression was inhibited by hydrocortisone and by BW755C, an inhibitor of both the lipoxygenase and cyclo‐oxygenase pathways of arachidonic acid metabolism. Inhibition by BW755C was found to be reversed in the presence of exogenous leukotriene D4. In contrast, selective inhibition of the cyclo‐oxygenase pathway by indomethacin enhanced the increase in receptor expression. This enhancement was only partially reversed by exogenous prostaglandin (PG)E2. Interaction of the FCγ2b receptor with ligand in the form of erythrocytes specifically sensitized with IgGzb resulted in the release and subsequent metabolism of arachidonic acid. PGE2 was found to be the principal product. Occupation of the Fcγ2a receptor did not result in arachidonic acid release. Down regulation of Fcγ2b receptor expression produced a commensurate reduction in receptor‐mediated phospholipase activity measured by arachidonic acid release. Macrophages cultured for 24 h in the presence of fetal calf serum without additional stimuli produced substantial amounts of eicosanoids. PGI2 was the principal product. Taken together these data demonstrate a potential feedback regulation of receptor‐triggered arachidonic acid metabolism by eicosanoids acting at the level of Fcγ2b receptor expression.
T helper cell recognition of idiotopes on λ2 light chains of M315 and T952: evidence for dependence on somatic mutations in the third hypervariable region
Authors: Bogen Bjarne , Jørgensen Trond , Hannestad Kristian
Published: February 2007

Previous work has indicated that BALB/c T helper cells (Th) recognize an idiotope expressed on a 88‐114/117 fragment of Vλ2 of BALB/c myeloma protein 315. In the present study the antigenic structure of this idiotope was further analyzed. Conventional carrier‐specific Th elicited by immunization of BALB/c mice with free λ2315 did not cross‐react with the free λ2 chain of the BALB/c myeloma protein T952 which differs from λ3″ in five amino acid positions (38,94, 95,96, 99). Similarly, Th primed with free λ2T95 did not respond to a boost with free λ2315. Thus, BALB/c h2315‐specific Th recognize an idiotope that depends on some or all of the residues at positions 94, 95, 96 and 99. Furthermore, free λ2T952 contains an idiotope immunogenic to Th that depends on some or all of residues 38, 94, 95, 96 and 99. Th recognition of the free λ2T952 idiotope was quenched upon H + L chain assembly because Th elicited by free λ2T952 did not respond to a boost with the complete T952 myeloma protein. In contrast to the lack of Th cell cross‐reactivity, some of the antisera from BALB/c mice immunized with free λ2T952 cross‐reacted with free λ315, free λJ558 and free λ3CBPC49 but not with free ϰw3129 or polyclonal L chains. The H chain of T952 (α,ϰ2) myeloma protein was abnormally short (Mr = 48 000) and T952 existed as a halfmere probably due to this H chain deletion. Furthermore, H and L chains were disulfide bonded to each other.
Structural in variance of T4 molecules from T cell clone Of different antigen and major histocompatibility complex specificities
Authors: Sayre Peter H. , Reinherz Ellis L.
Published: February 2007

Recent studies have suggested that the T4 molecule may bind to class I1 major histocompatibility complex (MHC) gene products on target cells. Such an interaction could be with either a polymorphic or monomorphic determinant on class II MHC genes. The first would imply that T4 is structurally variable and represents a compo‐ nent of a dual receptor, whereas the latter would suggest that T4 is structurally invariant and serves as an accessory binding molecule. To resolve this question we studied the structural variability of T4 molecules isolated from four clones of differing antigen/MHC specificities. By one‐ and two‐dimensional electrophoretic analysis and by peptide mapping, we detected no differences among the 55‐kDa T4 molecules from these clones. We conclude that T4 serves as an invariant accessory binding structure and that T4 does not confer MHC specificity on T cells.
Human monocyte cytotoxin is not identical with lymphoblastoid lymphotoxin
Authors: Matthews Nicholas
Published: February 2007

Mononuclear phagocytes and lymphocytes can both synthesize cytotoxins which kill certain tumor cell lines and recent evidence suggests that these cytotoxins may be identical. In this study, human monocyte cytotoxin and lymphoblastoid lymphotoxin have been critically compared in terms of specificity, physicochemical characteristics and antigenicity. Despite their similar pattern of reactivity with a panel of cell lines, lymphotoxin was less readily adsorbed than monocyte cytotoxin by tumor cells. The cytotoxins could also be distinguished by their behavior on high performance liquid chromatography and by the failure of antibody to monocyte cytotoxin to react with lymphotoxin.
Mice varying in resistance to African trypanosomiasis respond differently to treatments with variant surface glycoprotein
Authors: Diffley Peter
Published: February 2007

A comparative analysis of responses between resistant and susceptible hosts revealed that DBN/2 mice, after treatment with variant surface coat glycoprotein (VSG) from virulent or avirulent African trypanosomes, developed splenomegaly as the result of a near‐doubling of the splenic cell population, had less polyclonal activation of B cells and were protected upon challenge with homologous trypanosomes. The susceptible C3H/Anf and C3W/HeJ mice on the other hand increased their splenic cell population by only 12%, had about twice the production of unelicited antibodies and were not immunized by the VSG treatments. This indicated that (a) proliferation of spleen cells during African trypanosomiasis may reflect an attempt to generate a specific and protective immune response and is not merely the result of polyclonal activation of lymphocytes; (b) production of unelicited antibodies is not merely a “bystander reaction” to the generation of antigen‐specific responses; and (c) polyclonal antibody production in response to VSG is not linked to the LPS gene. Nonspecific immunosuppression as measured in mitogen assays was not elicited by VSG in either resistant or susceptible mice, indicating that polyclonal lymphocyte activation and nonspecific immunosuppression are unlinked phenomena.

Mice injected with VSG from either virulent or avirulent isolates at levels normally encountered by hosts during severe, acute infection developed the same degree of splenomegaly and production of unelicited (polyclonal) antibodies. Therefore, any differences in polyclonal activation of lymphocytes measured between mice with acute vs. chronic African trypanosomiasis can be attributed to quantitative and not qualitative differences in VSG.
Immunosuppression by cell‐free translation products from monoclonal antigen‐specific suppressor T cell mRNA
Authors: Ricciardi‐Castagnoli Paola , Robbiati Federico , Barbanti Eiena , Colizzi Vittorio , Pini Carlo , De Santis Rita , Doria Gino , Adorini Luciano
Published: February 2007

Polypeptides synthesized in a rabbit reticulocyte lysate system directed by mRNA from the T cell line LH8‐105, obtained by radiation leukemia virus‐induced transformation of hen egg‐white lysozyme (HEL)‐specific suppressor T lymphocytes, are able, when injected into mice, to specifically suppress the antibody response and delayed‐type hypersensitivity to HEL. The suppressive activity exerted by in vitro translated proteins appears to be independent from post‐translational modifications. These in vitro translated polypeptides display fine antigenic specificity in immunosup‐ pression and bind to HEL but not to the closely related ring‐necked pheasant egg‐ white lysozyme immunosorbents. Suppressive molecules obtained by cell‐free translation of LH8‐105 mRNA or by culture supernatant of LH8‐105 cells display, by gel filtration, a similar molecular mass of about 82–90 kDa.
Syngeneic mixed lymphocyte reactions to murine Fc receptor‐bearing, nonadherent low density lymph node cells and epidermal Langerhans cells
Authors: Bienenstock Arielle N. , Belsito Donald V. , Baer Rudolf L. , Rosen Judy , Fossick Lisa E. , Thorbecke G. Jeanette
Published: February 2007

Both Langerhans cells from BALB/c mouse epidermis and nonadherent, low density (LD) cells, obtained from collagenase‐treated minced lymph node, are stimulatory for isolated T cells in syngeneic mixed lymphocyte reaction (SMLR). The method of preparation of LD cells influences whether Fc receptor (FcR) can be detected on them. Fc receptors on nonadherent LD lymph node cells can be detected only if the same procedure is employed as that for Langerhans cell isolation, i.e., Ig‐free bovine albumin must be used during gradient centrifugation and EA resetting must be done overnight at 4°C. Thus, both FcR+ and FcR− LD lymph node cells, as well as FcR+ Langerhans cells, stimulate SMLR. Although Ig+ cells in the LD fraction a lso stimu late the SMLR, their removal does not affect the stimulating capacity of the LD lymph node fraction.
Clonal specificity of concanavalin A‐induced cytotoxic T lymphocytes
Authors: Larsson Eva‐Lotta , Beretta Alberto , Ermonval Myriam
Published: February 2007

The specificity of polyclonally induced cytotoxic T lymphocyte (CTL) precursors has been analyzed under clonal conditions. Primary clones of concanavalin A‐inducible CTL, if tested on different targets, revealed that they could distinguish between (a) two different allogeneic tumor targets; (b) allogeneic and syngeneic tumor targets, and (c) syngeneic B blasts and tumor targets. No “nonspecific” CTL clones were generated under these culture conditions, and all clones were found to display classical immunological specificity.
Lack of inhibition of mitogen‐induced lymphoproliferation by interferon gamma
Authors: Pischedda Franca , Landolfo Santo , Kirchner Holger
Published: February 2007

Interferon (IFN) gamma has been shown to have enhancing effects on immunocompetent cells, as for example induction of the expression of I‐A antigens. In this report the effect of purified mouse IFN‐γ on mitogen‐induced proliferation was studied. In contrast to the situation observed with IFN‐a or IFN‐β, treatment by IFN‐γ had no suppressive effect on mitogenesis. Enhancing effects on DNA synthesis induced by phytohemagglutinin were observed at low concentrations of IFN‐γ in the early stage of lymphocyte activation. The effects on T cell proliferation, however, were not consistent under all experimental conditions.
The large sialoglycoprotein of human lymphocytes. II. Biochemical features
Authors: Axelsson Bernt , Hammarström Sten , Finne Jukka , Perlmann Peter
Published: February 2007

Large sialoglycoprotein of human lymphocytes (L‐LSGP) from thymocytes and from peripheral blood lymphocytes (PBL) of normal donor and of B chronic lymphocytic leukemia (CLL) patients was purified by affinity chromatography to Mucluru pornifera agglutinin (MPA)‐Sepharose followed by preparative sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE). L‐LSGP from the three different sources was very similar in amino acid composition. It contained a high proportion of acidic and hydroxy amino acids and also significant amounts of cystein. No reduction in mobility in SDS‐PAGE was noted for unreduced L‐LSGP. The molecule may already in its native form have an extended conformation containing either free sulfhydryl groups or small S‐S loops not affecting mobility in SDS‐PAGE. L‐LSGP was found to be highly glycosylated, the thymocyte glycoprotein containing somewhat less carbohydrate by weight (44%) than that of PBL (normal PBL 53% and B CLL 52%). This was due primarily to a lower content of sialic acid. The molecules contained mannose, galactose, N‐acetyl galactosamine, N‐acetylglucosamine and sialic acid in molar ratios 1.0:3.0:1.1:1.2:1.3 (thymocyte L‐LSGP), 1.0:3.8:1.2:1.0:1.7 (PBL L‐LSGP) and 1.0:3.5:2.2:1.3:2.8 (B CLL L‐LSGP). The weak interaction of L‐LSGP with lentil lectin, concanavalin A (Con A) and leucoagglutinin (La), its unchanged mobility in SDS‐PAGE after tunicamycin treatment and its high amount of hydroxy amino acids suggest that most carbohydrate chains are O‐glycosidically linked to the peptide chain. Native as well as Nase‐treated L‐LSGP show size microheterogeneity. This is probably due to small chemical differences in the L‐LSGP molecules from different lymphocyte subsets.
Expression of interleukin 2 receptor on murine fetal thymocytes
Authors: Habu Sonoko , Okumura Ko , Diamantstein Tibor , Shevach Eathan M.
Published: February 2007

Rat monoclonal antibodies AMT‐13, 3C7 and 7D4 which react to the mouse interleukin 2 (IL2) receptors were used to define cell populations with the putative IL2 receptors in the mouse thymus as a part of series of investigations to elucidate the mechanism of intrathymic cell proliferation and differentiation. With freshly dissociated cells from the thymus of 15 gestational days, the anti‐IL2 receptor monoclonal antibodies (anti‐IL 2 receptor) reacted with about half of them. The proportion of the reactive cells decreased rapidly thereafter till birth as the numbers of thymus cells expanded. The antibodies reacted with only two to three percent of thymic cells from newborn mice and less than one percent of cells from adult thymus. Through the gestational period, the fetal liver cells did not react with the antibodies. When the thymus cells at early gestational days were subjected to a two‐color analysis, one for the anti‐IL2 receptor and the other for anti‐Thy‐1 or anti‐asialo GM1, by a fluorescence‐activated cell sorter, it was found that the majority (up to 80%) of anti‐IL2 receptor‐reactive cells (IL2 receptor‐positive cells) was also reactive with anti‐Thy‐1. Some of the IL2 receptor‐positive cells but Thy‐1‐negative cells reacted with anti‐asialo GM1, a marker of the immature thymocytes. Immunohistochemically, the IL2 receptor‐positive cells were found mainly in the subcapsular area and in the border region of cortex and medulla. Collectively, these results suggest that the pre‐T lymphocytes are stimulated immediately after their arrival to the thymus from the stem cell source such as fetal liver and bone marrow and are driven into the proliferation via the IL2 receptor system.
The mitogenic lectin from Phaseolus vulgaris does not recognize the T3 antigen of human T lymphocytes
Authors: Kanellopoulos Jean M. , De Petris Stefanello , Leca Gerald , Crumpton Michael J.
Published: February 2007

Human peripheral blood T lymphocytes are stimulated to grow and divide by lectins such as concanavalin A (Con A) and Phaseolus vulgaris phytohemagglutinin (PHA), as well as a few anti‐T cell monoclonal antibodies. The latter antibodies recognize the T3 antigen. It has been suggested previously that PHA and Con A mediate T cell growth by interacting with T3. However, as reported in this study, affinity chromatog‐raphy on immobilized lectins, and immunoprecipitation by lectin plus anti‐lectin antibodies showed that T3 binds Con A but not PHA. Fab fragments of a monoclonal antibody against T3 (namely Leu‐4) inhibited T lymphocyte proliferation induced by T3 antibodies and Con A, but not by PHA. Nevertheless, co‐capping experiments performed with fluorescein‐labeled lectins and rhodamine‐labeled T3 antibodies showed that T3 co‐caps with Con A and PHA receptors, although the co‐capping with PHA was incomplete. Since the T cell receptor for antigen (Ti) has been shown to co‐cap with T3 on the cell surface, we reasoned that PHA induced capping of the T3 antigen by interacting with Ti. A disulfide‐linked heterodimer comprising subunits of about 49 000 and 41 000 mol. wt. that resembled the Ti molecule was detected in PHA‐anti‐PHA immunoprecipitates of various surface‐ and biosynthetically‐labeled T cells, by two‐dimensional (nonreduced vs. reduced) sodium dodecyl sulfate‐poly‐acrylamide gel electrophoretic analysis. The results suggest that PHA triggers T lymphocytes by interacting with the carbohydrate moieties of Ti and imply that T lymphocytes can be stimulated by mitogens via at least two different cell surface molecules (Ti and T3).
VLA‐1: a T cell surface antigen which defines a novel late stage of human T cell activation
Authors: Hemler Martin E. , Jacobson Jennie G. , Brenner Michael B. , Mann Dean , Strominger Jack L.
Published: February 2007

The VLA‐1 protein complex defines a previously undescribed very late stage of activated T cell differentiation, following either alloantigen or mitogen activation. This protein appears after 2–3 weeks of activation, considerably later than the early T cell activation antigens such as the interleukin 2 (IL2) receptor, transferrin receptor, 4F2 antigen, T10 and HLA‐DR, and has therefore been termed very late antigen‐1 (VLA‐1). Unlike the IL2 receptor, VLA‐1 expression does not require restimulation with antigen, and in fact, VLA‐1 expression was high on T cells that had lost their IL2 receptors. Expression of VLA‐1 was found on all or nearly all long‐term‐activated T cells including T4+ and T8+ clones, bulk cultures, long‐term T cells from adults and newborns and long‐term T cells maintained in pure or crude IL2 preparations. VLA‐1 was also found on HTLV‐1 infected T cell populations. Immunoprecipitation experiments confirmed that the VLA‐1 protein complex (210000/130000 Mr) can be co‐expressed with another protein complex called VLA‐2 (165 000/130 000 Mr) on the same T cell clones. However, co‐expression was not obligatory because in some long‐term cultures little or no VLA‐2 was present relative to VLA‐1. Because VLA‐1 defines a novel late stage of T cell activation, being present on all or most all types of long‐term activated T cells, and not on any other cell types in peripheral blood, it has unique potential as a marker for activated T cells in vivo and may provide a clue towards elucidating novel long‐term T cell functions or growth requirements of this late stage of T cell differentiation.
Splenic dependence of the antibody response to thymus‐independent (TI‐2) antigens
Authors: Amlot Peter L. , Grennan Deirdre , Humphrey John H.
Published: February 2007

The murine antibody response to T‐independent (TI)‐2 antigens [2,4‐dinitrophenyl‐Lys‐Ficoll (DNP‐FIC) and DNP‐hydroxyethyl starch (HES)] was impaired long after splenectomy, while responses to TI‐1 [trinitrophenylated lipopolysaccharide (TNP‐LPS)] and thymus‐dependent [TNP‐keyhole limpet hemocyanin (KLH)] antigens were largely unaffected. The antibody response to these TI‐2 antigens was exclusively against the conjugated epitopes [DNP‐, fluorescein isothiocyanate (FITC)‐ or tetramethylrhodamine isothiocyanate (TRITC)‐Ficoll or ‐HES].

Fluorescent conjugates of Ficoll and HES localize selectively to the splenic marginal zone macrophages. This localization was not affected by 750 cGy of X‐irradiation, but the antibody response to the TI‐2 antigens was abrogated for 14 days. Administration of spleen cells restored the antibody response to these TI‐2 antigens in otherwise intact irradiated mice but not if they had been splenectomized.

Our findings indicate that the antibody response to TI‐2 antigens depends upon stimulation of B cells in a splenic environment. This probably involves antigen presentation by marginal zone macrophages.
Structure of primary anti‐(4‐hydroxy‐3‐nitro‐phenyl)acetyl (NP) antibodies in normal and idiotypically suppressed C57BL/6 mice
Authors: Cumano Ana , Rajewsky Klaus
Published: February 2007

Eight monoclonal antibodies from the primary response of C57BLJ6 mice against the hapten (4‐hydroxy‐3‐nitrophenyl)acetyl (NP) were isolated. The antibodies carry λ1 light chains and have similar affinities for the immunizing hapten. Sequence analysis at the level of mRNA reveals that all antibodies express the VH gene 186.2 and all but one the DF116.1 gene segment. The J segment of the heavy chain is JH2 in six cases and JH4 in two. Somatic point mutations are scarcely detectable in the antibodies, but there is extensive sequence variability at the boundaries of the D gene segment, mainly at its 5′ end. However, seven of eight antibodies express tyrosine in position 99 of the heavy chain, encoded either by the 5′ codon of DF116.1 or by presumed N sequences. In the former case, the tyrosine is the first of a stretch of three (positions 99–101). In the latter, a similar stretch (positions 99, 101, 102) is interrupted by aspartic acid, asparagine or cysteine in position 100. These variations profoundly affect idiotypic specificity.

Six of the eight monoclonal antibodies came from mice neonatally suppressed by an anti‐idiotope antibody whose target idiotope is regularly expressed in primary anti‐NP responses and depends upon a non‐germ‐line‐encoded aspartic acid in position 100 of the heavy chain. The sequence data show that the mice circumvent suppression by expressing antibodies which lack this aspartic acid but are otherwise structurally very similar to anti‐NP antibodies from normal animals. Since suppression in the animals is partly controlled by regulatory T cells, we conclude that these T cells are highly restricted in their specificity in that they preferentially see a determinant which also depends upon the aspartic acid in position 100. The data suggest that the VH to D boundary serves as a target of idiotypic selection.
Abrogation and reconstitution of nonresponsiveness: a correlation with high network connectivity
Authors: Singhai Rakesh , Hoffmann Geoffrey W. , Levy Julia G.
Published: February 2007

A monoclonal antibody (Fd‐B2) to ferredoxin, which bears an idiotype scarcely expressed in any of a wide variety of mouse strains, is able to markedly enhance the response to ferredoxin of both high‐responder and intermediate‐responder strains. A rabbit anti‐idiotype serum to Fd‐B2 also specifically enhances the response to ferredoxin in such mice. Most remarkably, the treatment of nonresponder T cells by either the idiotype (Fd‐B2) plus complement or anti‐idiotype antiserum plus complement causes them to be responsive in adoptive transfer experiments. The two responding populations (idiotype‐treated and anti‐idiotype‐treated) can then be combined to reconstitute the nonresponsive state. When the nonresponders are treated with either Fd‐B2 idiotype plus complement or anti‐idiotype plus complement and subsequently respond, the idiotype of the anti‐ferredoxin antibody produced does not bear the Fd‐B2 idiotype. We interpret the results as being consistent with a model in which the unresponsive state for ferredoxin is a state of high network connectivity of the fer‐redoxin‐specific T cells.
Thymus‐independent induction of idiotype suppression in newborn mice by syngeneic anti‐idiotype antisera
Authors: Lehle Georg , Weiler Eberhardt
Published: February 2007

BALB/c and BALB/c nu/nu mice were shown to express to a variable extent in their response against dextran B1355S (Dex), an idiotype which is present on the Dex‐reactive BALB/c myeloma protein MOPC104E. Injection of minute amounts of syngeneic anti‐MOPC 104E idiotype antisera into neonatal euthymic or athymic BALB/c mice suppressed this idiotype in the Dex‐specific response of the adult animals. When spleen cells from suppressed BALB/c mice were transferred into irradi‐ ated BALB Ighb mice the state of suppression persisted. Data are discussed with respect to possible mechanisms regulating expression of this idiotype.
Antibodies against the transferrin receptor block the induction of cytotoxic T lymphocytes. A new method for antigen‐specific negative selection in vitro
Authors: Rammensee Hans‐Georg , Lesley Jayne , Trowbridge Ian S. , Bevan Michael J.
Published: February 2007

The induction of cytotoxic T lymphocytes (CTL) specific for alloantigen in a primary mixed lymphocyte culture (MLC) was used as a model system to study the potential usefulness of monoclonal antibodies directed against the murine transferrin receptor in eliminating antigen‐activated T cells. Two monoclonal antibodies were used which are able to block the transferrin‐mediated uptake of iron by growing cells. One of these antibodies is cytotoxic in the presence of complement (C). Treatment of MLC cells from control, uninhibited cultures with the cytotoxic anti‐transferrin receptor antibody plus C completely knocked out all CTL effector activity showing that all of the effector cells expressed the receptor. However, surviving cells from such antibody‐plus C‐treated populations were not depleted of precursors since they were able to mount a strong CTL response to the original alloantigen upon restimulation. Blocking antibody against the transferrin receptor, in the absence of C, when present during the course of a primary MLC, completely inhibited the generation of effector CTL. Conditions were optimized such that antibody present during the course of the MLC could completely and specifically eliminate all antigen‐activated T cells including precursors as assessed by secondary restimulation with the original, plus third‐ party antigens, in the absence of blocking antibody. This method for producing specifically unreactive T cell populations appears to be superior to previously described techniques.
Inhibition of [3H]thymidine incorporation by Mycoplasma arginini‐infected cells due to enzymatic cleavage of the nucleoside
Authors: Sinigaglia Francesco , Talmadge Kenneth W.
Published: February 2007

Culture supernatants contaminated by Mycoplasma arginini inhibit the incorporation of [3H]thymidine ([3H]dThd) by cytotoxic T lymphocyte cell lines. This study presents evidence that the inhibition of uptake of the nucleoside is due to the rapid cleavage of the exogenous [3H]dThd into thymine. Undine and cytidine as well as dThd are degraded by the mycoplasma‐contaminated supernatants, while no cleavage was observed with uninfected supernatants. Cells contaminated by mycoplasma apparently release a pyrimidine‐specific nucleosidase, possibly a dThd phosphorylase, which is responsible for the inhibition.
Isolation and characterization of an Fc receptor from neonatal rat small intestine
Authors: Simister Neil E. , Rees Anthony R.
Published: February 2007

Receptors for the Fc region of IgG from neonatal rat intestinal brush borders were solubilized using 3‐[(3‐cholamidopropyl)dimethyl‐ammonio]‐l‐propane sulfonate and purified by affinity chromatography. Analysis of IgG‐binding material by sodium dodecyl sulfate‐polyacrylamide gel electrophoresis under reducing conditions reveals two components with apparent Mr of 41 000‐50 000 and 15 000. The larger component is glycosylated and may dimerize, giving a 100‐110‐kDa band on nonreduced gels. Both proteins are localized in the proximal small intestine, where IgG is specifically taken up during the first three weeks of neonatal life, and disappear when specific transport stops after weaning. Electron irradiation of brush borders shows that the functional unit for IgG binding has a molecular weight in sifu of 110 kDa. These data suggest that a dimer of the 41‐50‐kDa protein together with the 15 kDa and other proteins may mediate intestinal transport of maternal IgG.
Cytolytic T cell hybridomas I. Interleukin 2‐independent noncytolytic variants
Authors: Haas Werner , Kisielow Pawel
Published: February 2007

Fluorescein‐specific cytolytic hybrids were obtained by fusion of an interleukin 2 (IL2)dependent murine cytotoxic T lymphocyte clone with the thymoma BW5147. The hybrid cells grow and retain cytolytic activity in medium with recombinant IL2. In medium without IL2 rare variants can be selected which grow in the absence of exogenous IL 2; these variants are not cytolytic. Anti‐IL2 receptor antibodies bind to and inhibit the growth of the cytolytic hybrids while they do not bind to and do not inhibit the growth of the variants. The cytolytic hybrids as well as the non‐cytolytic variants produce interferon gamma in response to antigen. These findings indicate that the noncytolytic IL2‐dependent variants lost IL2 receptors but not antigen receptors.
Cytolytic T cell hybridomas II. Interleukin 2‐independent cytolytic variants
Authors: Haas Werner , Kisielow Pawel
Published: February 2007

Interleukin 2 (IL 2)‐dependent cytolytic hybrids usually loose IL 2 dependence and cytolytic activity concomittantly. Here we describe an exceptional IL 2‐independent variant which lost IL2 receptor but retained cytolytic activity. When the IL 2‐independent cytolytic hybrid cells were fused with IL 2‐dependent cytolytic clones which express IL2 receptors constitutively, IL 2‐dependent hybrids were obtained. This suggests that the expression of IL 2 receptors can interfere with IL 2‐independent growth mechanisms.
Antigen‐nonspecific T cell‐derived factors in B cell activation: differences in the requirements for interleukin 2 in responses of unprimed and primed B cells
Authors: Kuhara Takatoshi , Haughton Geoffrey , Corley Ronald B.
Published: February 2007

The requirements for interleukin 2 (IL 2) and other T cell‐derived helper factors in the responses of unprimed and antigen‐primed B cells to sheep erythrocytes were investigated. Unprimed B cells required both IL 2 and additional factor(s), hereafter referred to as T cell‐replacing factor (TRF), in addition to specific antigen, for antibody production. IL2 was required only during the early stages (⋍24 h) of culture while TRF was necessary only after this time and was then required throughout the remaining culture period. IL2 stimulated the appearance of Thy‐1+ cells in unprimed “B cell” populations which could substitute for the function of IL2, implicating an indirect role, at least in part, for IL2 in the TRF assay. Furthermore, in contrast to the results with unprimed B cells, primed B cells required only late‐acting TRF for optimal antibody responses. We suggest that IL2 activates residual T cells or precursors of T cells in B cell populations which then function, in the presence of specific antigen, to render B cells receptive to T cell‐derived factors which promote B cell growth and differentiation.
Response of glioma cells to interferon‐gamma: increase in class II RNA, protein and mixed lymphocyte reaction‐stimulating ability
Authors: Takiguchi Masafumi , Tingco Jenny P.‐Y. , Buessow Scot C. , Boyer Cinda , Gillespien Yancey , Frelinger Jeffrey A.
Published: February 2007

Previous results by ourselves and others demonstrated that brain cells and cell lines express major histocompatibility complex class II antigens. We examined interferongamma (IFN‐γ)‐mediated induction of human class II antigen expression on the glioma cells. Purified IFN‐γ induced the expression of HLA‐DR antigens on the surface of the glioma cell lines U‐373 MG and U‐105 MG. Concomitant increase of HLA‐DRα‐and HLA‐DCβ‐specific RNA in the cytoplasm was also observed after treatment with IFN‐γ. Increases of class II antigen paralleled the increased level of class II‐specific RNA. The effect of IFN‐γ on the induction of human class II antigen expression was dose and time dependent. A marked induction of human class II antigen expression was observed when glioma cells were cultured with more than 100 U/ml of IFN‐γ. Little or no induction was observed with less than 50 U/ml of IFN‐γ. Compared to human blood monocytes, glioma cells needed higher concentrations of IFN‐γ for the induction of class II antigen expression.

In allogenic mixed lymphocyte cultures, the glioma cell line U‐373 MG stimulated a mixed lymphocyte response (MLR). MLR‐stimulating capacity was augmented by IFN‐γ. The concomitant augmentation of class II antigen levels and MLR‐stimulating capacity suggests that the most relevant factor for MLR stimulation may be antigen density. This is the first report of MLR stimulation by a glioma cell line.
Production and characterization of antibody probes directed at constant regions of the α and β subunit of the human T cell receptor
Authors: Fabbi Marina , Acuto Oreste , Bensussan Armand , Poole Catherine B. , Reinherz Ellis L.
Published: February 2007

To generate antibodies directed at constant regions of the human T cell receptor, purified α and β subunits of a human T cell antigen/major histocompatibility complex receptor from the REX tumor (Ti‐REX) were isolated by preparative sodium dodecyl sulfate‐polyacrylamide gel electrophoresis and utilized to immunize rabbits. H36 (anti‐α subunit) and H38 (anti‐β subunit) antisera were strongly reactive with the denatured subunits and also immunoprecipitated the Ti heterodimer from 125I surface‐labeled lysates of REX, inducer, suppressor and cytotoxic T cell clones, peripheral T lymphocytes and thymocytes. Moreover, immunodepletion experiments showed that such antisera recognized antigenic determinant(s) shared by all Ti molecules expressed in the thymus. Several observations were made with these anticonstant region antibodies. First, peptide map analysis showed that the T cell receptor molecules recognized by the anti‐clonotype and the anti‐constant region heteroantisera on a given T cell clone are identical, thus supporting the view that the T cell receptor undergoes allelic exclusion. Second, since the individual antisera were weakly cross‐reactive with the other denatured subunit, such subunits probably share conserved sequences. Third, the absence of antisera reactivity with intact cells implies that most of these constant region epitopes must be obscured by associated molecules, perhaps including one or more of the 20–25‐kDa T3 subunits. Fourth, the extensive difference in two‐dimensional peptide maps of Ti α subunits from clones of differing specificities makes it likely that the subunit contributes in a major way to antigen/major histocompatibility complex binding.
Isotypes of antibodies induced by plain dextran or a dextran‐protein conjugate
Authors: Seppälä Ilkka , Pelkonen Jukka , Mäkelä Olli
Published: February 2007

Mice were immunized with a(1→6) dextran or its protein conjugate with monthly intervals, and their antibodies were quantitated with an isotype‐resolved radioimmunoassay. Plain dextran (molecular weight = 5–40 million) induced antibody concentrations varying from 20 to 80 μg/ml (primary response). The resposse to a booster injection was weaker than the response to the first injection. More than 90% of anti‐dextran antibodies were IgM but IgG and IgA responses could be unequivocally demonstrated. IgG1 and IgG3 were the predominant subclasses of IgG. Dextran antibody responses to a conjugate of dextran (molecular weight ≈ 10 000) and chicken serum albumin (CSA) were stronger (80–300 μg/ml) than responses to plain dextran, and anti‐CSA responses to the conjugate were even stronger (up to 900 μg/ml).

Three distinctly different isotype patterns were observed. A pattern IgM ≫ IgG1 = IgG3 > IgG2a prevailed in responses to the plain dextran and in primary anti‐dextran responses to dextran‐CSA. Another pattern IgG1 > IgG3 > IgM > IgG2a was observed in late anti‐dextran responses to dextran‐CSA. The third pattern IgG1 ≫ IgG2a > IgG3 ≈ IgM was characteristic of anti‐CSA antibodies. Little IgG2b or IgA antibodies were found. Different isotype patterns can best be explained on the basis of secondary factors such as T cell help.
Effects of soluble aggregates of IgG on the binding, uptake and degradation of the Clq subcomponent of complement by adherent guinea pig peritoneal macrophages
Authors: Veerhuis Robert , van Es Leendert A. , Daha Mohamed R.
Published: February 2007

Earlier studies have indicated that Clq, the first subcomponent of complement component C1, is bound to lymphocytes via specific Clq receptor sites. We have recently shown that adherent guinea pig peritoneal exudate macrophages express specific receptors for Clq (Veerhuis, R. et al., Immunology 1985. 54: 801). The present studies were performed to determine whether binding of 125I‐labeled human Clq (125I‐Clqhu) to adherent guinea pig peritoneal exudate macrophages would also result in ingestion and subsequent degradation of 125I‐Clqhu. The binding of 125I‐Clqhu to adherent peritoneal macrophages at 4°C is inhibited fully not only by Clqhu and guinea pig Clq (Clqgp) but also by pepsin fragments of Clqhu. The amount of trichlo‐roacetic acid nonprecipitable radioactivity that appeared in the supernatant was used as a measure for the degradation of 125I‐Clqhu. 125I‐Clqhu is degraded initially into fragments of 25 kDa, after which it is degraded further into small molecular weight peptides. Ingestion of 125I‐Clq by the macrophages occurs before the 125I‐Clq is degraded.

In the presence of limited amounts of soluble aggregates of guinea pig IgG2 (AIgG), a known activator of C1, part of the Clq is bound to the AIgG and all of the AIgG in turn is bound to the cellular Fc receptors leading to an enhanced binding of 125I ‐Clq to the cells, a binding that was maximal at near equimolar concentrations of 125I‐Clqhuand 131I‐AIgG. In the presence of a 30‐fold excess of AIgG, however, only a small percentage of the AIgG binds to cellular Fc receptors and the interaction of Clq with its receptor is decreased due to competitive inhibition. The results presented in this report thus suggest that free Clq may be eliminated by specific interaction with Clq receptors present on circulating and tissue phagocytoses and, in addition, that in the presence of immune complexes modulation of elimination of Clq may be encountered.
The defect in delayed‐type hypersensitivity of young adult SJL mice is due to a lack of functional antigen‐presenting cells
Authors: Stohlman Stephen A. , Matsushima Glenn K. , Casteel Nancy , Frelinger Jeffrey A.
Published: February 2007

SJL mice exhibit a strain‐specific age‐dependent delay in the maturation of delayed‐type hypersensitivity (DTH) responsiveness. They do not attain “adult” levels of DTH responsiveness until the 10th week of age, which is 4 to 6 weeks later than the other strains of mice tested. In this report we demonstrate that spleen cells, resident peritoneal cells and thioglycollate‐elicited peritoneal exudate cells are all able to transfer DTH responsiveness from naive 12‐week‐old DTH responders to 6‐week‐old nonresponders. Transfer prior to immunization was more efficient at eliciting a response than transfer after immunization. As few as 5 ± 104 cells from 12‐week‐old SJL mice can adoptively transfer responsiveness to unresponsive 6‐week‐old animals. The active cell was found to be adherent, radiation (2000 rds) resistant, I‐A+, Thy‐1− and Mac‐l+. I‐A compatibility between the adoptively transferred population and the nonresponder mice is required. These data suggest that young adult SJL mice lack a functional population of antigen‐presenting cells specific for DTH and that the appearance of these cells is under maturational control.
Antigen presentation of myoglobin: profiles of T cell proliferative responses following priming with synthetic overlapping peptides encompassing the entire molecule
Authors: Bider Garvin S. , Atassi M. Zouhair
Published: February 2007

Recently, the regions of myoglobin, which are recognized by T cells (T sites), were localized by a comprehensive synthetic strategy in which uniform synthetic overlapping peptides encompassing the entire protein chain were examined for stimulation of T cell proliferative activity. In this study, we report about the proliferative response to these peptides, as well as to the native protein, of lymph node cells from mice primed with the overlapping peptides either individually or in a mixture. Some, but not all, of the T site‐containing peptides were effective in priming for an anti‐myoglobin T cell response. Further, several peptides, which were highly immunogenic as free synthetic peptides, were not associated with any of the known T sites in this protein. Thus, the pattern of T cell recognition following priming with the overlapping peptides differs from the pattern observed when the native protein is the priming antigen. If antigen processing proceeds via fragmentation, then only those regions containing T sites would be expected to be effective in priming for a T cell response to the intact protein and, conversely, highly immunogenic peptides would correspond to T sites of the protein. Therefore, these findings indicate that the current concept of antigen fragmentation as a prerequisite for its presentation must be reappraised. We suggest that, in the presentation of a protein antigen, the protein is recognized predominantly intact and that the crucial aspects of presentation are determined by interaction with the cell membrane which trigger cellular activating events.
Analysis of the Thy‐1 pathway of T cell hybridoma activation using 17 rat monoclonal antibodies reactive with distinct Thy‐1 epitopes
Authors: Pont Suzanne , Regnier‐Vigouroux Anne , Naquet Philippe , Blanc Dominique , Pierres Anne , Marchetto Sylvie , Pierres Michel
Published: February 2007

Seventeen monoclonal anti‐Thy‐1 antibodies (mAb) derived from LOU/M rats immunized with mouse T cell clones were used to study the role of Thy‐1 in antigen‐independent T cell activation. These mAb identified Thy‐1.2 or monomorphic determinants and immunoprecipitated a molecule of 25–28 kDa from detergent‐sol‐ ubilized, 125I‐labeled T cell surface proteins. Competitive cross‐inhibition binding assays demonstrated that these reagents defined 3 epitope groups including either Thy‐1.2 (group A) or Thy‐1 monomorphic (groups B and C) determinants. Experiments using high titered culture supernatants revealed that all 6 IgG mAb defining the epitope group C, and one IgG2c mAb directed at a determinant in group A were capable of stimulating the terpolymer‐L‐glutamic acid60‐L‐alanine33‐Ltyrosine10(GAT) plus I‐Ad‐reactive BALB/c T cell hybridoma T14–117.9 to produce inter‐leukin 2 (IL2) in the absence of accessory cells. Cross‐linking of cell‐bound rat mAb by a BALB/c anti‐rat kappa chain mAb, or the presence of B cell lymphomas in the culture resulted in an increase of the Thy‐1‐mediated IL2 responses of this hybridoma. Some mAb from group B required antibody doses exceeding 80 üg/ml in order to activate T cells, while others remained nonstimulatory at any dose tested. Striking synergy in rnAb‐mediated T cell activation was observed when nonmitogenic doses of mAb group groups A and C were mixed in the same culture. Analysis of a panel of GAT plus I‐Ad‐specific T cell hybridomas revealed that these cells markedly differed in the magnitude of their IL2 responses induced by a given amount of stimulating anti‐Thy‐1 mAb. Such reagents also stimulated normal thymocytes to express IL2 receptor on their surface. These studies show that the epitopic specificity and the amount of anti‐Thy‐1 mAb, and the susceptibility of the T cell examined represent important parameters for the triggering of the Thy‐1 pathway of T cell activation.
T cells specific for different antigens express different HLA‐D region products
Authors: Schendel Dolores J. , Johnson Judith P.
Published: February 2007

T cell lines and clones were analyzed for surface expression of la antigens using monoclonal antibodies (mAb) that detect monomorphic and polymorphic epitopes on la molecules encoded by the HLA‐DR and HLA‐DQ gene clusters. All mAb bound to B lymphocytes or lymphoblastoid cell lines of the same individuals from whom the T cells were derived. Three mAb detecting monomorphic epitopes, primarily associated with HLA‐DR, bound to all T cells showing that each clone or line expressed some type of la. Three other mAb defining polymorphic epitopes associated with HLA‐DR products showed differential binding patterns. Two reagents, R3 and E15/4 recognizing the supertypic specificity DRw52 (formerly MT2), bound to every alloreactive clone, whereas the 16.23 mAb, detecting a private DR3‐associated epitope, failed to bind to any clone. In contrast, the 16.23 epitope was detected on high percentages of T cells specific for purified protein derivative of tuberculin (PPD) or tetanus toxoid (TT). Biochemical studies showed that the 16.23 and DRw52‐like epitopes can be present on distinct DR molecules on B cell lines and this may also be the case for T cells.

Three other mAb, detecting epitopes associated with HLA‐DQ, also revealed differential binding patterns when tested on various T cells. Two failed to bind to any alloreactive clone and to only low numbers of PPD‐ or TT‐specific T cell lines, whereas the third bound distinctly to a CD4+/CD8+ alloreactive clone. Biochemical analyses have shown that these DQ epitopes can be present on different molecules. Combined, these observations indicate that differential expression of la molecules encoded by both HLA‐DR and DQ occurs between B and activated T cells as well as among T cell populations of the same individual. Whether these differences reflect quantitative variations in expression of given DR or DQ molecules or, alternatively, are due to differential class II gene expression in activated T cells remains to be determined.
Eosinophil activation by lymphokines and T cell clone products in the rat
Authors: Veith Monica , Pestel Jöel , Loiseau Sylvie , Capron Monique , Capron André
Published: February 2007

T cell lines and T cell clones derived from inbred Fischer rats and specific for Schistosoma mansoni antigens were established. Cell‐free supernatants from the T cell lines demonstrated a marked capacity to enhance IgE‐ and IgGa‐dependent eosinophil mediated killing of S. mansoni larvae in vitro. In addition, supernatants from cloned T cells stimulated with concanavalin A or specific antigen, or unstimulated, enhanced IgE‐dependent eosinophil‐mediated helminthotoxicity. The enhancing activity in both cases was very heat‐stable (100°C, 10 min). We also found that clone‐derived supernatants enhance eosinophil peroxidase release upon stimulation with homologous IgE and anti‐IgE as well as inducing a more delayed spontaneous release of peroxidase. In view of the established thymus dependency for the development of immunity to schistosomiasis in the rat, the availability of these s. mansoni‐specific cloned T cells has enabled the relationship between eosinophils, lymphocytes and anaphylactic antibodies to be examined more closely.
Analysis of lysozyme‐specific immune responses by synthetic peptides. I. Characterization of antibody and T cell‐mediated responses to the N‐terminal peptide of hen egg‐white lysozyme
Authors: Sette Alessandro , Colizzi Vittorio , Appella Ettore , Doria Gino , Adorini Luciano
Published: February 2007

The immunological reactivity against the N‐terminal region of hen egg‐white lysozyme (HEL) has been investigated by a synthetic peptide (PHEL) comprising residue 1–18 of HEL and by an analogue peptide (PREL) in which phenylalanine at position 3 is substituted by tyrosine. Both peptides are immunogenic in (C57BL/10 × DBA/2)F1 mice genetically responder to HEL. In C57BL/6 mice, genetically nonresponder to HEL, PREL induces anti‐peptide antibodies that also bind to PHEL whereas PHEL is not immunogenic.

Thus, a single amino acid substitution in a synthetic peptide converts a nonresponder mouse strain into a responder one. Anti‐PHEL antibodies demonstrate a higher binding to HEL than anti‐PREL antibodies, indicating that phenylalanine at position 3 is important for induction of anti‐peptide antibodies able to recognize native HEL. At the T cell level the two peptides show very high bidirectional cross‐reactivity between themselves and with HEL for interleukin 2 production, antigen‐specific proliferation and delayed‐type hypersensitivity response, whereas conservation of phenylalanine at position 3 is required for induction of suppressor cells cross‐reactive with HEL. This indicates that the N‐terminal region of HEL contains epitope(s) able to induce the same level of helper T cell activity as the native HEL molecule. However, helper T cells do not discriminate between PHEL and PREL whereas phenylalanine at position 3 is critical for HEL‐specific suppressor T cell induction.