bluuebunny/crossref_metadata_2025_split huggingface dataset:
The isolation and functional characterization of autoimmune clones expressing inappropriate Ia.
Authors: Cronin P S , Sing A P , Glimcher L H , Kelley V E , Reinisch C L 
Published: December 2022

Abstract
The MRL/lpr mouse is an inbred strain widely accepted as a model for autoimmune disease both in murine and human systems. Developed from a series of crosses involving four strains of mice, the MRL/lpr (H-2k) genome is a composite estimated to contain approximately 75% of its parental LG/J (H-2d) genome. To explore the cellular mechanism underlying lymphoproliferation in the MRL/lpr mouse, we have isolated a series of clones from the lymph nodes of MRL/lpr mice with autoimmune disease. Extensive immunofluorescent analyses of these clones, designated the PAC series, reveal expression of IAk and IEk (beta-chain) cell surface antigens, as well as inappropriate expression of IAd, IEd (beta-chain), and H-2d. PAC cells also express MAC-1, MAC-2, RA3-2C2, and RA3-6B2 and contain esterase-positive cytoplasmic granules. The capacity of PAC cells to present antigen was investigated by co-culturing PAC with IA-restricted, antigen-specific T cell hybridomas +/- antigen. These assays demonstrated the PAC inability to present antigen to IAk-restricted T cell hybridomas, as well as their capacity to present antigen to IAd-restricted T cell hybridomas. In addition, activation of MRL/lpr peritoneal macrophages using gamma-interferon resulted in increased fluorescent staining for IAd and IEd concomitant with decreased fluorescent staining for IAk. Based on these findings, we propose a model of lymphoproliferation in which Ly-1+, H-2K+ T cells proliferate to inappropriate d haplotype antigens expressed by a small subset of monocytes in the MRL/lpr lymph node. The major genomic contribution of the LG/J (H-2d) mouse may be in part responsible for inappropriate antigen expression either by age-dependent expansion of d haplotype cells or by age-regulated expression of Iad and H-2d genes.
Complement activation by heat-killed human kidney cells: formation, activity, and stabilization of cell-bound C3 convertases.
Authors: Baker P J , Adler S , Yang Y , Couser W G 
Published: December 2022

Abstract
Heat-killed kidney cells (HKKC) incubated with serum or purified C3 and factors B and D stain intensely for C3 by immunofluorescence. Binding of complement (C) did not occur if ethylenediaminetetraacetic acid (EDTA) was added to the C source or if factor B or D was omitted from the mixture of alternative pathway components. When the C-treated cells were washed, then incubated in purified C3 containing 10 mM EDTA, C3 conversion ensued, confirming the presence of a cell-bound C3 convertase. C3-reactive cells were not generated if EDTA was present during formation of the convertase. The addition of C3 nephritic factor (C3NeF) during formation of the C3 convertase from alternative pathway components greatly enhanced subsequent C3 cleavage, presumably by stabilizing labile C3bBb sites; however, binding of C3NeF did not appear to extend the half-life of the convertase, which was 35 min at 37 degrees C in each case. In contrast, little or no effect on C3 conversion could be detected after the addition of equivalent C3NeF to serum and HKKC. Thus, C activation by HKKC involves formation and activity of a cell-bound C3 convertase, which under certain circumstances can be stabilized by C3NeF.
Monoclonal antibodies to Salmonella lipopolysaccharide: anti-O-polysaccharide antibodies protect C3H mice against challenge with virulent Salmonella typhimurium.
Authors: Colwell D E , Michalek S M , Briles D E , Jirillo E , McGhee J R 
Published: December 2022

Abstract
The present investigation reports the production of monoclonal antibodies to antigenic determinants of the O-polysaccharide of Salmonella typhimurium lipopolysaccharide (LPS), and assesses the effectiveness of these antibodies in protecting C3H mice against the lethal effects of Salmonella infection. Hybridomas were generated by fusing spleen cells from (BALB/c X A/J)F1 (CAF1) mice hyperimmunized by i.v. injection with acetone-killed S. typhimurium SR-11 with X63-Ag8.653 murine myeloma cells. Hybridomas producing antibodies reactive with S. typhimurium SR-11 whole cells were subcloned, and seven of the resulting clones as well as one previously described clone were selected for use in the studies reported here. Monoclonal antibodies from these eight clones were of the IgG1 (1), IgG3 (6), or IgM (1) isotype and were specific for the O-polysaccharide region of Salmonella LPS, reacting with LPS from smooth S. typhimurium SR-11 and LT-2, but not with LPS from rough S. minnesota R60 (Ra), R345 (Rb), or R595 (Re). The effectiveness of each monoclonal antibody in protecting C3H/HeN and C3H/HeJ mice against the lethal effects of Salmonella infection was evaluated by comparing the median length of survival of groups of mice given antibody by i.p. injection before i.p. challenge with virulent S. typhimurium SR-11 to that of animals that received no antibody. Three out of eight monoclonal anti-O-polysaccharide antibodies, ST-1 (IgM), 10-5-47 (IgG3), and 10-5-6 (IgG3), provided significant (p less than 0.01) protection to C3H/HeN mice challenged with approximately 10(4) LD100 of Salmonella. Only antibodies ST-1 and 10-5-6, however, extended the median length of survival of C3H/HeJ mice beyond that of infected controls. Mouse antiserum prepared against S. typhimurium SR-11 was equally protective in C3H/HeJ mice. In an attempt to understand the contribution of antibody specificity to the relative differences in the protective capacities of the monoclonal antibodies, their reactivities with several Salmonella reference strains of different classical serotypes were examined. Although some differences in reactivity against the different strains were apparent, this approach was not adequate for defining the fine specificity of these monoclonal antibodies. The results of this study provide evidence that monoclonal antibodies with specificity to the O-polysaccharide region of Salmonella LPS can protect C3H mice against challenge with the homologous bacterial strain.
Purification and some properties of streptococcal protein G, a novel IgG-binding reagent.
Authors: Björck L , Kronvall G 
Published: December 2022

Abstract
Protein G, a bacterial cell wall protein with affinity for immunoglobulin G (IgG), has been isolated from a human group G streptococcal strain (G148). Bacterial surface proteins were solubilized by enzymatic digestion with papain. Protein G was isolated by sequential use of ion-exchange chromatography on DEAE-cellulose, gel filtration on Sephadex G-100, and affinity chromatography on Sepharose 4B-coupled IgG. The presence of protein G in various pools and fractions during the isolation was followed by their ability to inhibit the binding of radio-labeled IgG to G148 bacteria. A highly purified protein G was obtained. On polyacrylamide gel electrophoresis in sodium dodecyl sulfate, the apparent m.w. was 30,000, and on agarose gel electrophoresis the purified protein gave rise to a single band in the alpha 1-region. Protein G was found to bind all human IgG subclasses and also rabbit, mouse, and goat IgG. On the IgG molecule, the Fc part appears mainly responsible for the interaction with protein G, although a low degree interaction was also recorded for Fab fragments. IgM, IgA, and IgD, however, showed no binding to protein G. This novel IgG-binding reagent promises to be of theoretical and practical interest in immunologic research.
Surface molecules involved in self-recognition and T cell activation in the autologous mixed lymphocyte reaction.
Authors: Romain P L , Schlossman S F , Reinherz E L 
Published: December 2022

Abstract
Although the importance of T cell lineage-specific surface glycoproteins and MHC gene products in soluble-, viral-, and alloantigen-stimulated immune responses has been well characterized, those involved in autoreactivity are less defined. To address this issue, we examined the ability of monoclonal antibodies to influence the autologous mixed lymphocyte reaction (AMLR). Here we show that both monoclonal anti-T3 and several monoclonal anti-T4 antibodies profoundly inhibited the autoreactivity of unseparated T cells, isolated T4+ cells, and isolated T8+ cells (cultured in the presence of irradiated T4 cells). Furthermore, monoclonal anti-T8 antibodies markedly inhibited the reactivity of the T8 cells co-cultured with irradiated T4 cells, only partially inhibited the proliferative response of unseparated T cells, and had no effect on the T4 cell AMLR responsiveness. Monoclonal antibodies against class II MHC (Ia) antigenic determinants blocked the AMLR between non-T cells and any of the above responder populations; in contrast, monoclonal anti-class I (HLA-A, B, C) antibodies inhibited the response of T8+ cells but not of isolated T4+ cells. These data support the notion that T4 and T8 antigens serve, respectively, as associative recognition elements for class II and class I MHC antigens during the AMLR, and further suggest that interactions involving non-T cell determinants and the T3-Ti- T cell antigen receptor complex are important in autologous reactivity.
Immunoregulation of T-dependent responses by a cloned dendritic cell.
Authors: Clayberger C , DeKruyff R H , Fay R , Pavlakis M , Cantor H 
Published: December 2022

Abstract
We have described a cloned dendritic cell, Clone Den-1, which is a potent accessory cell for some T-dependent immune responses. Clone Den-1 activates T cells in both autologous and allogeneic mixed lymphocyte reactions, but cannot present soluble antigen to T cells that co-recognize nominal antigen plus I-Ab gene products. In addition, Clone Den-1 or factors produced by it can reconstitute plaque-forming cell responses by accessory cell-depleted B plus T cells to the T-dependent antigen sheep red blood cells. The relationship of this clone to heterogeneous populations of dendritic cells and other accessory cells is discussed.
Fc receptors for mouse IgG1 on human monocytes: polymorphism and role in antibody-induced T cell proliferation.
Authors: Tax W J , Hermes F F , Willems R W , Capel P J , Koene R A 
Published: December 2022

Abstract
In previous studies, it was shown that there is polymorphism in the mitogenic effect of mouse IgG1 monoclonal antibodies against the T3 antigen of human T cells. This polymorphism implies that IgG1 anti-T3 antibodies are not mitogenic for T cells from 30% of healthy individuals. The present results demonstrate that this polymorphism is caused by polymorphism of an Fc receptor for mouse IgG1, present on human monocytes. The Fc receptor for murine IgG1 could be detected by a newly developed rosetting assay on monocytes from all individuals responsive to the mitogenic effect of IgG1 anti-T3 antibodies. This Fc receptor was not detectable on monocytes from those individuals exhibiting no mitogenic responses to IgG1 anti-T3 monoclonal antibodies. Cross-linking of T3 antigens appears to be essential for antibody-induced mitosis of T cells, because mononuclear cells that did not proliferate in response to WT 31 (an IgG1 antibody against T3 antigen) showed a proliferative response to Sepharose beads coated with WT 31. The Fc receptor--if functionally present--may be involved in the cross-linking of T3 antigens through anti-T3 antibodies. Further evidence for the involvement of this Fc receptor in antibody-induced T cell proliferation was provided by inhibition studies. Immune complexes containing IgG1 antibodies were able to inhibit the proliferative response to IgG1 anti-T3 antibodies. This inhibition by immune complexes appears to be mediated through the monocyte Fc receptor for mouse IgG1. These findings are important for the interpretation of previously described inhibitory effects of anti-T cell monoclonal antibodies on T cell proliferation, and show that such inhibitory effects may be monocyte-mediated (via immune complexes) rather than caused by a direct involvement of the respective T cell antigens in T cell mitosis. The Fc receptor for mouse IgG1 plays a role in antibody-induced T cell proliferation. Its polymorphism may have important implications for the therapeutic use of IgG1 monoclonal antibodies.
Ta1, a novel 105 KD human T cell activation antigen defined by a monoclonal antibody.
Authors: Fox D A , Hussey R E , Fitzgerald K A , Acuto O , Poole C , Palley L , Daley J F , Schlossman S F , Reinherz E L 
Published: December 2022

Abstract
By using a murine monoclonal antibody produced against an IL 2-dependent human T cell line, we defined a T lineage-specific molecule, termed Ta1, that is expressed strongly on activated T lymphocytes of both the T4 and T8 subsets, as well as on T cell lines and clones, but only weakly on a fraction of resting T cells. SDS-PAGE analysis of immunoprecipitates from 125I-labeled, activated T cells demonstrates a single major band of apparent m.w. 105 KD under both reducing and nonreducing conditions. Unlike anti-IL 2 receptor antibodies, anti-Ta1 does not inhibit T cell proliferative responses to mitogen, antigen, or IL 2-containing medium. Moreover, anti-Ta1 has no effect on T cell-mediated cytotoxicity. Ta1 appears to be a novel human T cell-specific activation antigen that may serve as a useful marker of T cell activation in human disease.
Further characterization of IgM antibodies against maternal alloreactive T cells produced by cloned Epstein Barr virus-transformed cord B cells.
Authors: Miyagawa Y 
Published: December 2022

Abstract
The mother obviously recognizes the fetus as an antigen, and the fetus is protected from the maternal immunologic attacks by eliciting anti-alloreactive T cell antibodies (T lymphocytotoxic human fetal antibody; TLFA). TLFA contains several antibodies against the maternal cells. It is thus necessary for further understanding of TLFA to obtain a single antibody from EBV-transformed cord B cells. EBV-transformations were performed in 28 cord B cell samples, and 16 cell lines were established. Antibody-binding assays of the cloned fetal IgM antibodies were performed by the respective maternal T cells grown in secondary mixed lymphocyte culture (MLC) stimulated by the paternal non-T cells and the maternal long-term culture killer T cells (LCT) in three different families. There were two types of cloned antibodies as identified by their binding to the respective maternal MLC responding T cells and the LCT. Their functions were further analyzed by the maternal MLC and lymphocytotoxic assays by using maternal-paternal cell combinations from the three families. One type of antibody inhibited the maternal MLC T cell proliferation (% inhibition: up to 28.2%, p less than 0.01), and the other inhibited the killer activity of the maternal LCT (% inhibition: up to 45.2%, p less than 0.001). Such a fetomaternal interaction bears perhaps on the fundamental mechanism whereby the mother does not reject the fetus.
Interleukin 1 induces proliferation in two distinct B cell subpopulations responsive to two different murine B cell growth factors.
Authors: Booth R J , Watson J D 
Published: December 2022

Abstract
Two distinct classes of B cell growth factor (BCGF) have been described. BCGF I induces proliferation of anti-IgM-activated B cells, whereas BCGF II acts on a subpopulation activated by dextran sulfate. We examined the effect on both these B cell subsets of a B cell growth and differentiation factor that copurifies with interleukin 1 (BGDF/IL 1) produced by the WEHI-3 cell line. Proliferation was induced by BGDF/IL 1 in cultures of normal spleen cells depleted of T cells and adherent cells and activated by anti-IgM or dextran sulfate. Little effect was observed in cultures of spleen cells from B cell-deficient CBA/N mice. In cultures of normal B cells activated with anti-IgM and dextran sulfate together, BGDF/IL 1 induced a proliferative response comparable with the sum of the responses to the factor and either stimulus alone. These results suggest that anti-IgM and dextran sulfate activate distinct and independent B cell subpopulations, both of which are responsive to BGDF/IL 1.
Binding of C-reactive protein to the pneumococcal capsule or cell wall results in differential localization of C3 and stimulation of phagocytosis.
Authors: Holzer T J , Edwards K M , Gewurz H , Mold C 
Published: December 2022

Abstract
C-reactive protein (CRP) is a serum protein that shows rapid increases of as much as 1000-fold in concentration in response to infection, traumatic injury, or inflammation. CRP reacts with the phosphocholine moiety of pneumococcal cell wall C-polysaccharide, and this reaction can lead to complement activation in vitro and protection against pneumococcal infection in vivo. We have previously studied the chemiluminescence response of human neutrophils to Streptococcus pneumoniae as a measure of in vitro opsonophagocytosis by CRP and complement. CRP in the presence of complement was an effective opsonin for S. pneumoniae serotype 27 (Pn27), but not for serotypes 3 or 6. Because Pn27 differs from most serotypes of S. pneumoniae in containing phosphocholine in its capsular polysaccharide, we have determined the sites of CRP and C3 fixation to Pn27 and S. pneumoniae serotype 4 (Pn4), and related these to the ability of CRP and complement to opsonize these serotypes in vitro. By using a chemiluminescence (CL) assay to measure opsonophagocytosis, CRP was shown to enhance the response of human neutrophils and monocytes to Pn27 in the presence of normal human serum. The CL response of neutrophils and monocytes to Pn4 was not affected by the addition of CRP to serum. The addition of anti-capsular antibody to Pn4 and Pn27 enhanced the CL responses of both neutrophils and monocytes to both bacteria. The localization of bound CRP and C3 on Pn4 and Pn27 was determined by immunoelectron microscopy. CRP bound to Pn4 only in the cell wall region and C3 was located in this area whether or not CRP was present. Anti-capsular antibody deposited C3 in the capsule of Pn4. In contrast, Pn27 bound CRP throughout the capsule and cell wall areas. C3 was deposited in the cell wall region of Pn27 by serum alone and in the cell wall region and capsule when CRP or anti-capsular antibody was present. Because C3 fixation to the capsule was consistently associated with enhanced responses by phagocytic cells, it appears that the site of CRP binding and subsequent complement activation may be critical in the opsonophagocytosis of S. pneumoniae. These findings extend the correlation between capsular C3 and opsonization to a nonimmune system. By using CRP and different pneumococcal serotypes we have shown that the same molecules that are effective in the stimulation of phagocytic cells when bound to the capsule are not effective when bound to the cell wall.
Membrane receptors on Xenopus macrophages for two classes of immunoglobulins (IgM and IgY) and the third complement component (C3).
Authors: Sekizawa A , Fujii T , Tochinai S 
Published: December 2022

Abstract
Using two classes of immunoglobulins (IgM and IgY) and a complement component (C3) purified from Xenopus serum and plasma, we examined the presence of receptors on Xenopus peritoneal macrophages for each ligand. Xenopus macrophages, ultrastructurally quite similar to those in higher vertebrates, were found to have different membrane receptors for both immunoglobulins as well as for C3. Whereas all of these receptors mediated the binding of the SRBC which were coated with each ligand, only the RBC coated with IgY were ingested by the macrophages. We discuss the origin and functional differentiation of phagocyte membrane receptors from the phylogenetic viewpoint, in relation to the serum factors interacting with the receptors.
Defective vaccine-induced immunity to Schistosoma mansoni in P strain mice. I. Analysis of antibody responses.
Authors: Correa-Oliveira R , Sher A , James S L 
Published: December 2022

Abstract
Inbred P4 strain mice have previously been shown to be uniquely defective in their resistance to challenge infection induced by irradiated cercariae of Schistosoma mansoni. To assess whether the low levels of resistance developed by vaccinated P mice could be due to a defective antibody response, we compared the anti-schistosomulum antibody responses in vaccinated P animals with those occurring in vaccinated C57BL/6J (B6) mice, a strain that consistently develops high levels of resistance to challenge infection. Our results indicate that vaccinated P mice develop levels of total anti-schistosomulum antibodies that are significantly lower than those occurring in B6 mice for at least 15 wk after immunization, with the exception of the fifth week, at which time the responses are indistinguishable. Further analysis revealed that the defect in P strain antibody response occurs specifically in the IgM isotype and that specific IgM levels in P mice are less than one-half the levels in B6 mice at every time point examined. In contrast, no differences in total IgM immunoglobulins were evident when sera from normal (nonvaccinated) P and B6 mice were compared. P mouse anti-schistosomulum IgG antibody responses reached the same levels as those observed in B6 mice by 5 wk after vaccination. However, a much faster decay in IgG antibody levels occurred after this time point in P animals. No differences were observed when the levels of anti-schistosomulum antibodies occurring in each of the major IgG isotypes (IgG1, IgG2a, IgG2b, IgG3) were compared in sera from P and B6 mice vaccinated 4 wk previously. Similarly, vaccinated P and B6 mice were found to mount indistinguishable IgG anamnestic responses after challenge infection. Finally, no differences between vaccinated P and B6 mice were observed when immediate (30 min) skin test and mast cell degranulation responses to a soluble schistosome antigenic preparation were compared. The above findings suggest that P strain mice have a specific defect in their ability to mount IgM antibody responses after immunization with irradiated cercariae. The possible contribution of this defect in IgM response to the decreased resistance of vaccinated P mice to challenge infection is discussed.