bluuebunny/crossref_metadata_2025 huggingface dataset:
T and B cells that recognize the same antigen do not transcribe similar heavy chain variable region gene segments.
Authors: Kraig E , Kronenberg M , Kapp J A , Pierce C W , Abruzzini A F , Sorensen C M , Samelson L E , Schwartz R H , Hood L E
Published: June 2004

We have attempted to determine whether T cells and B cells that have the same antigenic specificity and whose receptors share idiotypic determinants in fact express similar VH gene segments. To do this, we have obtained and characterized a cDNA clone containing the entire coding sequence for the VH gene from a glutamic acid60/alanine30/tyrosine10 (GAT)-binding immunoglobulin that carries the CGAT idiotype. The GAT-VH clone was hybridized to Northern blots of GAT-specific T cell RNAs; there was no evidence of a T cell transcript that hybridized to the GAT-VH probe. The T cells analyzed included: (a) 10 GAT-binding suppressor T cell hybridomas, 6 of which secreted factors with CGAT idiotypic determinants, (b) one GAT-specific helper T cell hybridoma, and (c) two GAT-specific helper T cell lines grown in the absence of feeder cells. The detection limit of the Northern blot analysis was 1-2 copies of a particular mRNA species per cell for the hybridomas and 5-10 copies per cell for the T cell lines. Therefore, we conclude that T and B lymphocytes responding to GAT do not utilize similar VH gene segments. Furthermore, the presence of idiotypic determinants on T lymphocytes does not necessarily imply close structural similarity between T and B cell antigen receptors.
Mechanism of unresponsiveness to the alpha 1-6 epitope of dextran B512 in a C57BL substrain.
Authors: Fernandez C , Möller G
Published: June 2004

C57BL/10ScCr mice are low responders to the alpha 1-6 epitope of dextran B512, although other C57BL mice are high responders. Both thymus-independent and thymus-dependent forms of dextran failed to induce an immune response in C57BL/10ScCr mice, but dextran functioned as a good carrier for antihapten responses in this strain. Dextran is a potent polyclonal B cell activator for cells from C57BL/10ScCr mice, although such cells are not activated by LPS. The C57BL/10ScCr mice possess the Igh-V gene coding for antibodies against dextran and the antidextran antibodies induced in (A X C57BL/10ScCr)F1 hybrids share an idiotype with antidextran antibodies produced in C57BL/10 mice. Bone marrow cells from C57BL/10ScCr mice do not respond to dextran when transferred into lethally irradiated C57BL/10 mice and C57BL/10 cells transferred into C57BL/10ScCr mice give a strong antidextran response. Thus, B cells having both the Igh-V gene coding for antibodies against dextran and activation receptors for dextran cannot be activated into antibody synthesis against any form of this immunogen. This determinant specific immunodeficiency suggests the existence of as yet unknown regulatory influences on Igh-V gene expression or B cell activation.
Protection against Mycobacterium tuberculosis infection by adoptive immunotherapy. Requirement for T cell-deficient recipients.
Authors: Orme I M , Collins F M
Published: June 2004

The results of this study demonstrate that spleen cells taken from mice at the height of the primary immune response to intravenous infection with Mycobacterium tuberculosis possess the capacity to transfer adoptive protection to M. tuberculosis-infected recipients, but only if these recipients are first rendered T cell-deficient, either by thymectomy and gamma irradiation, or by sublethal irradiation. A similar requirement was necessary to demonstrate the adoptive protection of the lungs after exposure to an acute aerosol-delivered M. tuberculosis infection. In both infectious models successful adoptive immunotherapy was shown to be mediated by T lymphocytes, which were acquired in the donor animals in response to the immunizing infection. It is proposed that the results of this study may serve as a basic model for the subsequent analysis of the nature of the T cell-mediated immune response to both systemic and aerogenic infections with M. tuberculosis.
Antigen recognition by H-2-restricted T cells. I. Cell-free antigen processing.
Authors: Shimonkevitz R , Kappler J , Marrack P , Grey H
Published: June 2004

We examined the ability of a set of cloned chicken ovalbumin (cOVA)-specific, Id-restricted, T cell hybridomas to produce interleukin-2 in response to cOVA presented by the Ia+ B cell lymphoma line, A20-2J. Although viable A20-2J cells presented native, denatured, and fragmented cOVA more or less equally well, A20-2J cells that were glutaraldehyde-fixed could present only enzymatically or chemically fragmented cOVA. These results suggest that antigen fragmentation may be both necessary and sufficient to define accessory cell processing of soluble antigens so that they may be recognized in association with I-region molecules by T cells.
T cell tolerance to non-H-2-encoded stimulatory alloantigens is induced intrathymically but not prethymically.
Authors: Morrissey P J , Bradley D , Sharrow S O , Singer A
Published: June 2004

The present report has evaluated the differentiation compartment in which T cells are tolerized to non-major histocompatibility complex (MHC)-encoded minor lymphocyte-stimulating locus (MLS) alloantigens. It was observed that T cell precursors are not tolerized prethymically to MLS alloantigens but are tolerized intrathymically and postthymically to MLS alloantigens. The failure of prethymic T cells to be tolerized indicates either that T cell precursors are unable to be tolerized to MLS alloantigens or that cells in the prethymic compartment are unable to induce MLS-specific tolerance. In either case, these results demonstrate that the thymus is the initial site in which T cell tolerance to MLS alloantigen is induced. The present results also demonstrate a striking disparity in the reactivity of thymocytes to MHC and MLS alloantigens expressed in the extrathymic host through which their precursors had migrated. In the experimental mice constructed for these studies, intrathymic T cells were tolerant to the MHC alloantigens but were reactive to the MLS alloantigens expressed by the extrathymic host. This observation is consistent with the concept that T cell precursors may be tolerized to MHC alloantigens at an earlier point in their differentiation than they are tolerized to non-MHC-encoded MLS alloantigens.
Antiidiotype stimulation of antigen-specific antigen-independent antibody responses in vitro. I. Evidence for stimulation of helper T lymphocyte function.
Authors: Weissberger H Z , Shenk R R , Dickler H B
Published: June 2004

Antibodies specific for the idiotypes of B10 anti-(T,G)-A-L antibodies (anti-Id) induced in vivo (T,G)-A-L-primed lymphocytes to secrete anti-(T,G)-A-L antibodies in vitro in the absence of antigen. Responses to anti-Id were quantitatively and qualitatively similar to responses to antigen. Responses were specific in that: (a) only lymphocytes primed in vivo with (T,G)-A-L (but not other antigens or unprimed cells) were inducible; (b) only anti-Id (but not a variety of control antibodies) induced responses; and (c) only anti-(T,G)-A-L antibodies were secreted. Antigen-primed T lymphocytes mixed with unprimed B plus accessory cells also responded to anti-Id and the phenotype of the responding T cells was Lyt-1+, Lyt-2-. Supernatants obtained from antigen-primed T cells incubated for 3 d with anti-Id (but not when incubated with controls) provided help to unprimed B plus accessory cells in the presence of anti-Id, thus providing direct evidence for induction of T lymphocyte helper function by anti-Id. In contrast to responses to (T,G)-A-L, responses to anti-Id did not appear to be regulated by H-2-linked Ir genes. The system described is a powerful tool for delineation of the mechanisms whereby antiidiotype antibodies affect lymphocyte function.
Induction of rheumatoid antibodies in the mouse. Regulated production of autoantibody in the secondary humoral response.
Authors: Nemazee D A , Sato V L
Published: June 2004

A/J mice were found to produce autoreactive IgM anti-IgG1 in response to secondary immunization with a number of protein antigens. No anti-IgG1 was produced after a single such immunization, indicating that antigen: IgG1 antibody complexes were responsible for inducing the autoreactive response. The size of the anti-IgG1 response was in some cases massive and of the same order of magnitude as the response to the foreign immunizing material. No significant anti-IgG2a, anti-IgG2b, or anti-IgG3 response was found in mice producing anti-IgG1. Virtually all of the anti-IgG1 material produced was of the IgM class and bound to the Fc region of autologous IgG1. A component of the anti-IgG1 was shown to be able to distinguish between the two mouse IgG1 allotypes. These results suggest that self-reactive anti-IgG is a common component of the secondary immune response of mice that may have powerful physiological and immunoregulatory effects.
Allosuppressor- and allohelper-T cells in acute and chronic graft-vs.-host (GVH) disease. III. Different Lyt subsets of donor T cells induce different pathological syndromes.
Authors: Rolink A G , Gleichmann E
Published: June 2004

Previous work from this laboratory has led to the hypothesis that the stimulatory pathological symptoms of chronic graft-vs.-host disease (GVHD) are caused by alloreactive donor T helper (TH) cells, whereas the suppressive pathological symptoms of acute GVHD are caused by alloreactive T suppressor (TS) cells of the donor. In the present paper we analyzed the Lyt phenotypes of B10 donor T cells required for the induction of either acute or chronic GVHD in H-2-different (B10 X DBA/2)F1 recipients. First, nonirradiated F1 mice were used as the recipients. We found that unseparated B10 T cells induced only a moderate formation of systemic lupus erythematosus (SLE)-like autoantibodies, but a high percentage of lethal GVHD (LGVHD). In contrast, Lyt-1+2- donor T cells were unable to induce LGVHD in these recipients; these cells were capable, however, of inducing a vigorous formation of SLE-like autoantibodies and the formation of severe immune-complex glomerulonephritis. Lyt-1-2+ T cells were incapable of inducing either acute or chronic GVHD. In another experiment, the sensitivity and accuracy of the GVH system were increased by using irradiated F1 mice as recipients and by comparing donor-cell inocula that contained similar numbers of T lymphocytes. In addition, donor-cell inocula were used that had been tested for their allohelper and allosuppressor effects on F1 B cells in vitro. In the irradiated F1 recipients, too, unseparated donor T cells were superior to T cell subsets in inducing LGVHD; Lyt-1-2+ donor cells were completely and Lyt-1+2- donor cells were almost incapable of doing so. In contrast, Lyt-1+2- T cells, but neither unseparated T cells nor Lyt-1-2+ T cells, were capable of inducing a vigorous formation of SLE-like auto-antibodies. We conclude that the stimulatory pathological symptoms of chronic GVHD are caused by Lyt-1+2- allohelper T cells. In contrast, the development of the suppressive pathological symptoms of acute GVHD appears to involve alloreactive Lyt-1+2+ T suppressor cells.
Idiotype-like molecules on cells of a human T cell leukemia.
Authors: Bigler R D , Fisher D E , Wang C Y , Rinnooy Kan E A , Kunkel H G
Published: June 2004

Two monoclonal antibodies were obtained that showed unique specificities for the leukemic T cells used for immunization. One antibody, S160, was totally specific for the antigen. The other antibody, S511, also reacted with a small population of normal T cells. This was made especially evident by concentrating these normal T cells with the antibody. Considerable evidence was obtained that both antibodies reacted with the same membrane molecules. In the unreduced state a major component of approximately 80 kdaltons was observed; after reduction this split into two components of approximately 43 and approximately 38 kdaltons. The reaction of the two antibodies with different antigenic sites on the same molecule, one representing a private site and the other a more cross-reactive site, strongly suggests an antibodylike molecule, but composed of polypeptide chains differing from immunoglobulins.
Protection of mice from experimental infection with type III group B Streptococcus using monoclonal antibodies.
Authors: Egan M L , Pritchard D G , Dillon H C , Gray B M
Published: June 2004

Mouse hybridoma antibodies of several major classes against group B streptococcus type III have been produced. Mice were immunized with either whole heat-killed or acid-treated organisms to obtain antibodies against both the complete (sialated) or incomplete (nonsialated) forms of the type III polysaccharide. Resulting monoclonal antibodies showed exclusive specificity for either the complete or incomplete antigen. The ability of these antibodies to protect mice from a lethal challenge of live type III organisms was tested with a mucin model that permitted use of very small inocula given intraperitoneally with antibody and mucin. Antibodies specific for the nonsialated antigen were not protective, whether of IgM, IgG2a, or IgG3 isotypes. Antibodies specific for the complete antigen were, however, highly protective, including monoclonals of IgM, IgG2a, and IgA isotypes. These mouse monoclonal antibodies against group B streptococci that are directed against either complete or incomplete antigenic determinants, and include isotypes other than IgM, should be particularly useful for studying the mechanism of protection against experimental infection.
Expression of the thymus leukemia antigen by activated peripheral T lymphocytes.
Authors: Cook R G , Landolfi N F
Published: June 2004

Peripheral T lymphocytes activated in vitro with concanavalin A (Con A) or alloantigens express the thymus leukemia (TL) alloantigen as assessed by staining with the monoclonal antibody TL.m3 and flow cytometric analysis. The determinants detected by TL.m3 on activated cells are encoded within the Tla region and are detected as early as 48 h after activation with Con A. Several long-term cloned cytotoxic T lymphocyte lines were also examined and each expressed TL. By two-dimensional analysis, the TL isolated from activated peripheral cells was indistinguishable from that found on thymocytes and the leukemia cell line ASL-1.
Regulatory mechanisms in cell-mediated immune responses. Role of I-J and I-C determinants in the activation of H-2I and H-2K/D alloantigen-specific suppressor T cells.
Authors: Rich S
Published: June 2004

The role of individual H-2I subregion determinants in the activation of H-2I alloantigen-primed mixed leukocyte response suppressor T cells (MLR Ts), as well as their possible expression on stimulator cells required to trigger primed H-2K- or D-specific MLR Ts, was addressed in these studies. Both genetic and serologic studies demonstrated that MLR Ts potentially primed to alloantigens encoded by the entire H-2I region were triggered to MLR Ts factor production only by stimulator cells bearing the priming I-J and/or I-C, but not I-A or I-E alloantigens. The relevant I-J and I-C determinants were demonstrated on a single antigen-presenting cell population that is used in common by independent I-J-specific and I-C-specific MLR Ts. Unexpectedly, the stimulator cell population necessary to trigger MLR Ts primed to class I H-2K or D alloantigens expressed not only the priming class I determinant, but in addition, I-C alloantigens syngeneic with the MLR Ts haplotype. Stimulator populations bearing the appropriate H-2K or D alloantigen but serologically depleted of I-C+ cells or genetically constructed to display MLR Ts-disparate I-C determinants were ineffective stimulators of class I antigen-primed MLR Ts. Thus these data suggest that as allogeneic determinants, I-J- and I-C-encoded molecules are together the major triggering elements for MLR Ts primed to disparate H-2I region determinants. In addition, self-I-C molecule recognition appears to constitute an important feature of the triggering, and by implication, priming process of H-2 class I antigen-specific Ts cells.
Modulation of fibrin clot formation by human serum amyloid P component (SAP) and heparin.
Authors: Ku C S , Fiedel B A
Published: June 2004

Serum amyloid P-component (SAP) is a normal plasma constituent in man with a circulating concentration of approximately 40 micrograms/ml. Supraphysiological amounts of SAP (150-300 micrograms/ml) have been reported to affect coagulation. We have investigated this further by studying the effect of SAP upon clot times in both the absence and presence of heparin, a suggested ligand for SAP and itself a modulator of coagulation processes. In the absence of heparin, SAP (5-125 micrograms/ml) had no effect on clot times generated by Activated Thrombofax Reagent, brain thromboplastin, Russell's Viper Venom or thrombin when assessed in normal citrated plasma. However, in the presence of amounts of heparin that had only a minor effect upon clot times, SAP (5-40 micrograms/ml) greatly prolonged clot formation, with the thrombin time the most sensitive to SAP. This suggested that the primary effect of SAP was at this distal level of the coagulation pathway. Evaluation by radioimmunoassay revealed that supraphysiological concentrations of SAP (150-300 micrograms/ml) alone reduced by approximately 25% the release of fibrinopeptide A (FPA) from fibrinogen. In the presence of heparin, substantial synergism was observed with maximal reductions of approximately 70% in FPA production requiring only 25-50 micrograms/ml SAP. This inhibition correlated with increased thrombin clot time but was unrelated to any direct modulation in either the activities of anti-thrombin III or activated Factor XIII, and was independent of an alteration in the rate of fibrinolysis. Further, while SAP itself did not interfere with the process of spontaneous fibrin polymerization, in the presence of heparin a prolonged polymerization time (greater than 145%) was observed. We believe that these data reflect the primary mechanisms by which serum amyloid P component influences blood coagulation.
Factor-dependent in vitro growth of human normal bone marrow-derived basophil-like cells.
Authors: Tadokoro K , Stadler B M , De Weck A L
Published: June 2004

A factor(s) present in supernatants from lectin-stimulated peripheral blood mononuclear cells promoted the production of basophil-like cells in liquid cultures of normal human bone marrow cells. The cultured basophil-like cells had lobulated or round nuclei, and the cytoplasmic granules stained metachromatically with toluidine blue and azurophilic with Giemsa. 20% of the metachromatically staining cells were peroxidase positive but not positive for nonspecific esterase. The histamine content was 0.5-2 pg/cell. The basophil-like cells released histamine upon challenge with calcium ionophore A23187 but not with compound 48/80. They also released histamine with anti-IgE when passively sensitized with human myeloma IgE. The development of basophil-like cells was promoted in a dose-dependent fashion by a factor(s) in the conditioned medium. Blocking of cell proliferation with hydroxyurea or X irradiation inhibited the development of basophil-like cells. The production of the factor was dependent on the presence of T cells. The factor was different from interleukin 2 and its molecular weight was estimated to be 25,000-40,000 by gel filtration on a Sephacryl S-200 column. Thus, human basophil-like cells derived from normal bone marrow cells can grow and differentiate in vitro under the regulation of T cells.
Monoclonal IgM rheumatoid factors derived from arthritic MRL/Mp-lpr/lpr mice.
Authors: Theofilopoulos A N , Balderas R S , Hang L , Dixon F J
Published: June 2004

MRL/lpr/lpr (MRL/l) mice develop a lupus-like syndrome and a disease histologically and serologically similar to human rheumatoid arthritis. Their sera contain polyclonal IgM rheumatoid factors (RF) reactive with all murine IgG subclasses (frequently strongest with IgG2a) and several heterologous IgG. To examine the repertoire and epitopic specificities of these RF, we fused splenocytes from 3.5-mo-old seropositive MRL/l mice with appropriate myeloma partners and derived 1,723 hybridomas of which 23 secreted IgMRF. These monoclonal IgMRF bound to murine IgG only, not to other murine isotypes. Eight murine IgG subclass-specific clonotypes were identified. Most clones reacted with either multiple IgG subclasses or with IgG2a alone. A few clones reacted solely with IgG2b but none reacted exclusively with IgG1 or IgG3. Monoclonal IgMRF with exclusively anti-IgG2a activity exhibited allotypic specificity, reacting, with few exceptions, with a, c, and e, but not b, d, or j IgG2a allotypes. Four clonotypes could be distinguished by cross-reactivity with IgG from species other than mice. Monoclonals possessing activity against several murine subclasses cross-reacted extensively with heterologous IgG, including all human IgG subclasses without allotypic restrictions. Monoclonal IgMRF specific for murine IgG2a or 2b did not cross-react with heterologous IgG. Based on the absence of cross-reactions by IgG2a-specific monoclonal autoantibodies, certain peptides of the IgG CH2 and CH3 domains appear to generate the antigenic determinants of the anti-IgG2a RF in MRL/l mice. All of the monoclonal RF bound to Fc and, with one exception, not to Fab fragments of murine IgG. Binding of the monoclonal RF to substrate IgG was not inhibited by Clq, thus excluding the Clq-binding site at the CH2 domain as one of the responsible epitopes in the induction of MRL/l RF. mIgMRF could be categorized as strongly, weakly, or noninhibitable by protein A, which interacts with IgG molecules at or near the CH2-CH3 junction. Inhibition appears to be caused by conformational changes and/or steric shielding of certain IgG areas distant from this junction and not by identical binding sites between protein A and RF. Certain of the mIgMRF that were weakly or not at all inhibitable by protein A were found to cross-react equally well with human Fc (CH2-CH3 domains) and pFc' (CH3 domain) fragments, indicating that the binding site for these monoclonals is at the CH3 domain. Monoclonal RF were devoid of anti-double-strand DNA, anticollagen, or antipeptidoglycan pentapeptide cross-reactivity, but one of the monoclonals cross-reacted with histones, four with single-strand DNA, and one with both histones and single-strand DNA.
Antiadhesive properties of a quaternary structure-specific hybridoma antibody against type 1 fimbriae of Escherichia coli.
Authors: Abraham S N , Hasty D L , Simpson W A , Beachey E H
Published: June 2004

The relationship between the structure and biological function of type 1 fimbriae of Escherichia coli was investigated using a set of monoclonal antibodies directed against conformation-specific antigenic determinants. Of three monoclonal antibodies tested, only one (clone CD3) prevented adhesion of the vaccine strain to epithelial cells or guinea pig erythrocytes. The antibody produced by CD3, but not that produced by the other two hybridoma clones (AA8 and GG1), precipitated isolated fimbriae by double diffusion in agar gel and was shown to bind in a highly discrete, periodic manner along the length of each of the fimbriae by immunoelectron microscopy. Immunoelectroblots of type 1 fimbrial subunits and polymers electrophoresed in SDS-gels indicated that the antibodies in AA8 and GG1 reacted only with fimbrial monomers (mol wt 17,000), whereas the antibody in CD3 reacted only with polymers of mol wt 102,000 (hexamers) or higher. ELISA inhibition assays demonstrated that dissociated fimbrial subunits lost their reactivity with antibody CD3 but gained reactivity with antibodies AA8 and GG1. Conversely, when allowed to reassemble in vitro in the presence of 5 mM MgCl2, the reassembled fimbriae lost their reactivity with antibodies AA8 and GG1 but regained reactivity with antibody CD3. These results demonstrated that certain antigenic epitopes are dependent on quaternary structural determinants, whereas others are independent of quaternary fimbrial structure and also are inaccessible for antibody binding in fimbriae once they have been assembled. These monoclonal antibodies should prove useful in studies of the structural determinants of the biological function of type 1 fimbriae as well as in studies of fimbrial synthesis, transport, and assembly.
The cutaneous infiltrates of leprosy. A transmission electron microscopy study.
Authors: Kaplan G , Van Voorhis W C , Sarno E N , Nogueira N , Cohn Z A
Published: June 2004

The dermal lesions of 18 patients with leprosy have been examined by transmission electron microscopy. The patients exhibited a spectrum of disease from polar lepromatous to polar tuberculoid with intermediate stages in various states of therapy and relapse. The nature and quantities of inflammatory cells and bacteria have been determined by electron microscopy to supplement previous light and fluorescence microscopy studies. Lepromatous leprosy was characterized by many parasitized foam cells containing large, multibacillary vacuoles with intact, osmiophilic Mycobacterium leprae: Bacteria were embedded in an electron-lucent matrix. No extracellular bacteria were evident. Only small numbers of scattered lymphocytes were found. As one approached the borderline state, smaller numbers of bacilli were present as singlets and doublets in small vacuoles of macrophages. The more reactive forms showed increasing bacillary fragmentation, larger numbers of lymphoid cells, and an occasional epithelioid cell. At the tuberculoid end of the spectrum, clear evidence of an exuberant lymphocyte response was evident. Large numbers of T cells with extremely long and complex filipodia were closely associated with epithelioid and multinucleated giant cells. Many of the mononuclear phagocytes appeared nonviable, and areas of necrosis were evident. Bacillary remnants were scarce and the cytoplasm of the epithelioid cells contained occasional dense bodies and many stacks of endoplasmic reticulum and mitochondria. These results suggest that Leu 3a/OKT4 helper cells may be capable of driving the effector function of mononuclear phagocytes. This would lead to a significant microbicidal effect on M. leprae, perhaps through the production of toxic oxygen intermediates.
Immune cell populations in cutaneous delayed-type hypersensitivity.
Authors: Platt J L , Grant B W , Eddy A A , Michael A F
Published: June 2004

Delayed-type hypersensitivity (DTH) is a prototypic T lymphocyte-mediated response to antigenic challenge. In this study, mononuclear cells infiltrating the skin during cutaneous response to tuberculin in presensitized human subjects (responders) and nonimmune controls were identified using monoclonal antibodies by indirect immunofluorescence. In both responders and controls the infiltrate consisted mainly of T lymphocytes (T11+ and OKT3+) and monocytes (OKM1+, 63D3+, Mo2+) which initially accumulated in proximity to small blood vessels and later infiltrated the interstitial dermis and epidermis. More T lymphocytes reacted with OKT4 than with OKT8. 6 h after tuberculin the ratio of OKT4/OKT8 in tissue from responders exceeded that in blood, whereas in tissues studied at 15-48 h and in all control tissues those ratios in blood and tissue were similar. Evidence of T lymphocyte activation was sought using monoclonal antibodies anti-Tac, OKT9, and OKT10. In responders but not in controls the proportion of infiltrating cells reactive with these antibodies increased during the course of DTH. The presence of activated T lymphocytes in tissue was not associated with a comparable increase in peripheral blood cell populations identified by anti-Tac and OKT10. Studies using anti-B1, Leu-7, and anti-IgD/IgM revealed comparatively few reactive cells. Dual-labeling studies demonstrated that most Leu-7--reactive cells also bound T11 while fewer bound OKM1 or OKT8 and that cells reactive with OKIa1 and T11 constituted largely nonoverlapping populations. Specific patterns of reactivity were not observed when tissues were stained with anti-human C3, or poly C9-MA, a monoclonal antibody reactive with a neoantigen on polymerized C9 of the membrane attack complex of complement. The number of epidermal Langerhans cells identified by OKT6 was similar in responders and controls. Thus, the cutaneous response to tuberculin in sensitized individuals is characterized by early enrichment of the OKT4 subpopulation of T lymphocytes in tissue infiltrates and subsequent (15-48 h) evidence of T lymphocyte activation.
Apoprotein E is synthesized and secreted by resident and thioglycollate-elicited macrophages but not by pyran copolymer- or bacillus Calmette-Guerin-activated macrophages.
Authors: Werb Z , Chin J R
Published: June 2004

Macrophages are active secretory cells that display functionally distinct phenotypes that are regulated by inflammation. We have found that apoprotein E (ApoE), a component of plasma lipoproteins, was synthesized and secreted by resident and nonspecifically stimulated macrophages elicited with thioglycollate broth, but not by activated macrophages obtained from mice treated with bacillus Calmette-Guerin, pyran copolymer, whole Corynebacterium parvum, or bacterial endotoxin. ApoE represented approximately 1% of the newly synthesized protein and approximately 10% of secreted protein of resident and thioglycollate-elicited macrophages. ApoE from thioglycollate-elicited macrophages was indistinguishable from ApoE in mouse plasma lipoproteins, as determined by immunoreactivity, peptide mapping, and molecular weight. When specific antibodies were used to localize cell-associated ApoE, strong immunofluorescence was seen in the Golgi region of resident and thioglycollate-elicited macrophages immediately after removal from the peritoneal cavity, as well as after culture for up to 7 d. In contrast, activated macrophages did not synthesize or secrete ApoE to an appreciable extent and had no immunocytochemically detectable intracellular ApoE. When activated macrophages were cultured in medium containing serum, their activated state, as judged by production of H2O2, declined within 48-72 h in parallel with the induction of synthesis and secretion of ApoE and detection of intracellular ApoE by immunofluorescence. During prolonged culture the rate of synthesis and secretion of ApoE increased in both resident and activated macrophages. Therefore, the synthesis and secretion of ApoE may serve as markers for the functional state of macrophages.
Direct demonstration of the identity of T cell growth factor binding protein and the Tac antigen.
Authors: Robb R J , Greene W C
Published: June 2004

Radiolabeled molecules from detergent-solubilized human T cell blasts were fractionated on affinity supports coupled with T cell growth factor (TCGF) and anti-Tac antibody. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis indicated that a glycoprotein of approximately 58,000 mol wt was bound in both cases. Sequential binding to the two affinity supports demonstrated that the molecules recognized in each instance were identical. Thus, the Tac antigen contains the cellular binding site for TCGF. Note added in proof: Preliminary binding experiments using high concentrations of [3H]leucine, lysine TCGF with a low specific radioactivity indicate the existence of a sizeable pool of receptor sites with an affinity 2,000-10,000 times lower than that of the high affinity receptors measured in Fig. 1. Such sites may explain the numerical discrepancy between early TCGF binding experiments (5) and the binding of the anti-Tac antibody. The hypothesis that the anti-Tac antibody apparently reacts with both classes of receptor would explain its effect on the physiological response (high affinity binding) and the high level of Tac antigen on the cell surface.
Establishment of an inbred line of mice that express a synergistic immune defect precluding in vitro responses to type 1 and type 2 antigens, B cell mitogens, and a number of T cell-derived helper factors.
Authors: Mond J J , Norton G , Paul W E , Scher I , Finkelman F D , House S , Schaefer M , Mongini P K , Hansen C , Bona C
Published: June 2004

Introduction of the CBA/N X-linked gene into C3H mice has resulted in the establishment of a new strain of mice that has profound immunologic defects. B cells from these mice show significantly impaired in vitro immune responses to the T cell-independent type 1 antigen trinitrophenyl-Brucella abortus (TNP-BA) as well as markedly reduced proliferative responses to a number of B cell mitogens when compared with the responses of the parental control mice. The in vivo response of such mice to TNP-BA is, however, comparable to that of CBA/N mice. Furthermore, B cells from C3.CBA/N mice are unresponsive to the plaque-forming cell enhancing effects induced by EL4-derived supernatant in the presence of TNP-BA, unlike B cells obtained from CBA/N or C3H/Hen mice whose responsiveness to TNP-BA can be significantly enhanced in the presence of EL4-derived supernatant. The model we have presented to best explain these results suggests that B cells from C3.CBA/N mice can be stimulated only under conditions in which they can interact with carrier-specific T cell help and not under conditions where factor-dependent responses are dominant.
The role of I-J and Igh determinants on F1-derived suppressor factor in controlling restriction specificity.
Authors: Minami M , Aoki I , Honji N , Waltenbaugh C R , Dorf M E
Published: June 2004

In the 4-hydroxy-3-nitrophenyl acetyl (NP) contact sensitivity system, the activity of third-order suppressor cells and their factors is restricted by H-2(I-J) and Igh linked genes. The present report analyzes the specificity of NP-specific Ts3 cells and factors derived from H-2 and Igh heterozygous (B6 X C3H)F1 mice. Two approaches were used. First, heterogeneous populations of F1 Ts3 cells were activated in vitro and then assayed in Ts3-depleted recipients which carried different combinations of H-2 and Igh alleles. The second approach was to hybridize the Ts3 cells and analyze the specificity of the F1-derived TsF3. The combined data demonstrated four functionally distinct populations of Ts3 cells. The activity of each population was restricted by a particular combination of H-2 and Igh haplotypes. Thus, Ts3 cells derived from F1 donors can demonstrate an apparent scrambling of H-2 and Igh restriction specificities. There was functional allelic exclusion of the H-2(I-J) and Igh determinants expressed on (B6 X C3H)F1 hybridoma-derived TsF3. Thus, TsF3 from each cloned hybridoma line expressed only one set of I-J and Igh determinants. Furthermore, there was a complete correlation between the I-J and Igh linked determinants expressed on TsF3 and the restriction specificity. In view of the recent findings on the molecular biology of the I-J region, an alternative interpretation of the role of I-J determinants on suppressor cells and factors is offered.
Immune response to bacterial dextrans. II. T cell control of antibody isotypes.
Authors: Ivars F , Nyberg G , Holmberg D , Coutinho A
Published: June 2004

The isotype distribution of Dextran B 512 (Dex)-specific plaque-forming cells (PFC) and serum antibodies was studied after in vivo immunization in C57BL/6 mice. Although IgG2b and IgG3 could also be detected in most individuals, the majority of non-IgM PFC were of the IgA isotype. All classes other than IgM were T cell-dependent, as shown by their complete absence in athymic "nude" mice. This unusual isotype pattern was further investigated by studying the antibody responses to the same Dex epitope coupled to a protein carrier, and to a different hapten coupled to the carrier Dex or to a protein. The results show that IgA responses are epitope-related and selectively associated with anti-Dex antibodies: no IgA PFC are detected against a hapten coupled to Dex or proteins, while the enhanced levels of helper cell reactivity provided by protein carrier to Dex result in the appearance of IgG1 antibodies in addition to IgA. These results indicate that T cells that modulate isotype patterns in these responses can discriminate between Dex- and DNP-specific B cells in the response to the same carrier. Since the same idiotype is detected on a large fraction of the IgM and IgA anti-Dex response and antiidiotypic helper cells have previously been detected in normal C57BL/6 mice, we suggest that idiotype-specific T cells control the production of IgA antibodies upon immunization with Dex.
Cytotoxic T lymphocyte nonresponsiveness to the male antigen H-Y in the H-2Db mutants bm13 and bm14. Complementation of the response in F1 crosses with the I-Ab mutant bm12 nonresponder and failure of B6 or Db mutant mice tolerant of each other to respond to allogeneic male cells.
Authors: De Waal L P , Melvold R W , Melief C J
Published: June 2004

The cytotoxic T-lymphocyte (CTL) response against the male-specific antigen H-Y in C57BL/6 (B6, H-2b) mice is regulated by the I-Ab and Db molecules. From previous studies, we concluded that the bm12 I-Ab mutant does not respond to H-Y, because of a deletion in its T-helper-cell repertoire. We now demonstrate that two Db mutants, bm13 and bm14, also fail to generate a CTL response to H-Y. The bm12 class-II mutant on one hand and the bm13 and bm14 class-I mutants on the other complemented each other for the H-Y-specific CTL response in (bm12 X bm13)F1 and (bm 12 X bm 14)F1 hybrids. This indicates that the need for tolerance of the mutant class II and class I molecules in these hybrids does not create deletions in the I-Ab-restricted T helper cell and Db-restricted CTL repertoire for H-Y. This study constitutes the first demonstration with H-2 mutants that a CTL response controlled by class I and class II MHC molecules is complemented in an F1 cross between a class I and a class II nonresponder. (B6 X bm 13)F1 and (B6 X bm 14)F1 hybrids only responded to H-Y when the antigen was presented on F1 or B6 antigen-presenting cells (apc) but not on Db mutant apc. B6 or Db mutant responders rendered neonatally tolerant of each other failed to respond to the H-Y antigen presented on the tolerogenic allogeneic cell. In the tolerized animals, a response was only seen with responder (B6) type T cells and responder type (B6) apc, indicating that both the T cell source and the MHC type of the apc have to be taken into account in this system. Thus, Ir genes may act at the level of both the T cell repertoire and antigen presentation.
Nondissociating cationic immune complexes can deposit in glomerular basement membrane.
Authors: Caulin-Glaser T , Gallo G R , Lamm M E
Published: June 2004

The mechanisms by which immune complexes deposit in the glomerular basement membrane have been the subject of much debate, with the relative importance of direct deposition of circulating immune complexes (IC) vs. formation of IC in situ from the binding of circulating antibody to structural or exogenous planted antigen being at issue. In order to determine whether intact IC can deposit as such, covalently linked IC were prepared by a two-step reaction involving the bifunctional reagent toluene-2,4-diisocyanate (TDI), the antigen bovine gamma globulin (BGG), and rabbit anti-BGG antibody. Antigen and antibody were covalently cross-linked, with little self-linkage of antigen or antibody, and IC were purified by gel filtration. The net charge of the complexes was varied by chemical means, either before or after IC formation. When cationic IC were injected intravenously into mice, there was codeposition of antigen and antibody diffusely in the glomerular basement membrane (GBM), and deposits were observed ultrastructurally in the laminae rarae, interna and externa, and the lamina densa. Thus, under conditions of restricted appropriate charge, intact IC can cross the glomerular basement membrane and deposit in subepithelial sites without being excluded by size alone.
Differentiation from precursors in athymic nude mouse bone marrow of unusual spontaneously cytolytic cells showing anti-self-H-2 specificity and bearing T cell markers.
Authors: Reimann J , Miller R G
Published: June 2004

We describe an in vitro limiting dilution culture system that supports growth and differentiation of nylon wool nonadherent bone marrow cells from athymic nude mice. Cells were seeded at low cell numbers (5-120 cells per 20-microliter microculture well) in the absence of added filler or feeder cells but in the presence of conditioned medium. Microwells positive for growth appeared to contain a single clone of cells that adhered together to form a tight cluster referred to here as a colony. A fraction of colonies contained cells that expressed an unusual spontaneous cytolytic activity. They lysed syngeneic or semisyngeneic Con A blast or tumor cell targets but seldom lysed H-2-incompatible Con A blast or tumor target cells, even in a lectin-facilitated assay. A large fraction of colonies contained lymphoid cells that expressed the T cell markers Thy-1 and Lyt-1. Colonies expressing spontaneous cytolytic activity and also containing cells with Thy-1+ and/or Lyt-1+ markers could be grown from nylon wool nonadherent nude marrow cells depleted rigorously by cell sorting of cells expressing either of these markers. Expression of Thy-1 and spontaneous cytolytic activity in a particular colony was significantly correlated. Short-term lines established from cytolytic colonies with T cell markers maintained both characteristics. The cytolytic effector cells observed in these cultures may represent an early stage in the development of the T cell repertoire.
Purine salvage networks in Giardia lamblia.
Authors: Wang C C , Aldritt S
Published: June 2004

Purine metabolism in Giardia lamblia was investigated by monitoring incorporation of radiolabeled precursors into purine nucleotides in the log-phase trophozoites cultivated in vitro in axenic media and incubated in buffered saline glucose. The lack of incorporation of formate, glycine, hypoxanthine, inosine, and xanthine into the nucleotide pool suggests the absence of de novo purine nucleotide synthesis and the inability to form IMP as the precursor of AMP and GMP in G. lamblia. Only adenine, adenosine, guanine, and guanosine were incorporated. Further analysis of the labeled nucleotides by HPLC indicated that adenine and adenosine are converted only to adenine nucleotides whereas guanine and guanosine are only incorporated into guanine nucleotides. There is no competition of incorporation between adenine/adenosine and guanine/guanosine, and there is no interconversion between adenine and guanine nucleotides. Results from analyzing [5'-3H]guanosine incorporation indicate that the ribose moiety is not incorporated with the guanine base. Assays of purine salvage enzymic activities in the crude extracts of G. lamblia revealed the presence of only four major enzymes; adenosine and guanosine hydrolases and adenine and guanine phosphoribosyl transferases. Apparently, G. lamblia has an exceedingly simple purine salvage system; it converts adenosine and guanosine to corresponding purine bases and then forms AMP and GMP by the actions of corresponding purine phosphoribosyl transferases. The guanine phosphoribosyl transferase in G. lamblia is interesting because it does not recognize either hypoxanthine or xanthine as substrate. It thus must have a unique substrate specificity and may be regarded as a potential target to attack as a rational approach to chemotherapeutic control of giardiasis.
Mouse spleen dendritic cells present soluble antigens to antigen-specific T cell hybridomas.
Authors: Sunshine G H , Gold D P , Wortis H H , Marrack P , Kappler J W
Published: June 2004

In the presence of the soluble polypeptide antigens ovalbumin and keyhole limpet hemocyanin, purified mouse spleen dendritic cells induce the secretion of IL-2 by antigen-specific T cell hybridomas. This response is H-2 restricted and can be specifically inhibited by monoclonal anti-I-A. These data indicate that dendritic cells can present soluble antigen to H-2-compatible T cells.
Hapten reactive inducer T cells. II. Evidence that a secreted form of the T cell receptor induces antibody production.
Authors: Dekruyff R H , Clayberger C , Cantor H
Published: June 2004

The biologic activity of molecules synthesized and secreted by hapten-specific inducer T cells was examined. After activation, a single inducer clone secretes both antigen-specific inducer peptides as well as nonspecific factors. The nonspecific factors augment the in vitro response of B cells to sheep erythrocytes (SRBC) and Type 2 T-independent antigens. The antigen-specific molecules (ABM) induce plaque-forming cell (PFC) responses in cultures containing ABM, B cells, and antigen that links the epitope recognized by ABM with the B cell epitope. Induction of B cells by ABM is limited to B cells expressing the same I-A allele as the source of the ABM and this reflects binding by ABM to I-A products on B lymphocytes. The data reported here strongly support the view that inducer cells can activate at least some B cells by secretion of a modified form of the T cell surface receptor.
Acceptor-suppressor T cell hybridoma with a receptor recognizing antigen-specific suppressor factor.
Authors: Takei I , Sumida T , Taniguchi M
Published: June 2004

An acceptor hybridoma with a receptor that recognizes the keyhole limpet hemocyanin (KLH)-specific suppressor T cell factor (KLH-TsF) was established after the fusion of C57BL/6 splenic T cells enriched with KLH-coated petri dishes. The cloned hybridoma (34S-281) could be specifically activated by stimulation with the conventional KLH-TsF or monoclonal KLH-TsF from three different hybridomas in the absence of the relevant antigen (KLH) and it started to produce another factor that suppresses the antibody response against DNP-KLH in a KLH-specific fashion. The KLH specificity of the TsF was required for activation. The new factor was found not to bind the KLH but to be absorbed with the KLH-TsF-producing hybridoma. It is thus strongly suggested that the acceptor site has a complementary structure (antiidiotype) for the KLH-TsF. Moreover, the idiotypic determinant on KLH-TsF was found to have a structure similar to that on some of the anti-KLH antibodies, since the acceptor hybridoma was specifically killed by the conventional anti-KLH antibodies and complement. Drawing on the above results, the idiotype-antiidiotype network in the conventional antigen system is discussed.
Igh variable region-restricted T cell interactions. Genetic restriction of an antigen-specific suppressor inducer factor is imparted by an I-J+ antigen-nonspecific molecule.
Authors: Flood P M , Lowy A , Tominaga A , Chue B , Greene M I , Gershon R K
Published: June 2004

Immunized Ly-1 T cells secrete an antigen-specific molecule that will induce Ly-2+ T cells to express suppressive activity. In two separate systems, factors that suppress the primary anti-sheep erythrocyte (SE) plaque-forming cell response of spleen cells in vitro (Ly-1 TsiF) or the contact sensitivity of azobenzenearsonate (ABA)-TsF1 consist of two macromolecules, one which binds antigen and is IJ-, the other which is I-J+ and does not bind antigen. Both of these chains are required for the factor's biological activity. These factors show a genetic restriction in their ability to induce suppression that is linked to the variable region of the Ig heavy chain gene complex (Igh-V). The I-J+ chain from the ABA-specific TsF1 could replace the I-J+ chain needed by the SE-specific Ly-1 TsiF for biological activity. Mixtures of ABA-binding chain with I-J+ material obtained from the SE-specific Ly-1 TsiF had no effect on the primary anti-SE response in vitro. In mixtures of SE antigen-binding chain from Ly-1 TsiF and I-J+ material from the ABA-specific TsF1, it is the I-J+ molecule that determined the factor's Igh-V restriction. Thus, the antigen-combining site of the factor determined the antigen specificity of this factor but is irrelevant to its Igh-V-linked genetic restrictions. The implications of these results for the idiotype network hypothesis are discussed.