bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thymic-independent T cell regeneration occurs via antigen-driven expansion of peripheral T cells resulting in a repertoire that is limited in diversity and prone to skewing.
Authors: Mackall C L , Bare C V , Granger L A , Sharrow S O , Titus J A , Gress R E 
Published: December 2022

Abstract
Thymic regenerative capacity in humans decreases with age, suggesting that thymic-independent pathways of T cell regeneration may predominate during adulthood. Using a murine bone marrow transplantation model, we present evidence that thymic-independent T cell regeneration occurs primarily via expansion of peripheral T cells and is Ag driven since significant expansion of CD4+ or CD8+ transgenic (Tg+)/TCR-bearing cells occurs only in the presence of Ag specific for the TCR. Such expansion resulted in skewing of the regenerated repertoire with 40 to 65% of the regenerated CD4+ or CD8+ T cells expressing the Tg+/TCR in thymectomized hosts after bone marrow transplantation. In experiments in which nontransgenic population are used as T cell inocula, we noted decreased CD4 expansion when Class II MHC was blocked by mAb treatment in vivo, an CD8 expansion failed to occur in Class I MHC-deficient hosts providing evidence that T cell regeneration in thymic-deficient hosts largely occurs via TCR-MHC-mediated selection of peripheral T cell populations. This process results in a T cell repertoire comprised exclusively of T cells recently activated by the antigenic milieu of the host, with negligible numbers of residual "naive" cells bearing TCRs for Ags absent at the time of expansion. These findings have important implications for approached to enhance T cell regeneration in humans and provide evidence that vaccine strategies could skew the T cell repertoire toward a specific antigenic target if administered to thymic-deficient hosts during immune reconstitution.
CD95 engagement releases calcium from intracellular stores of long term activated, apoptosis-prone gammadelta T cells.
Authors: Rovere P , Clementi E , Ferrarini M , Heltai S , Sciorati C , Sabbadini M G , Rugarli C , Manfredi A A 
Published: December 2022

Abstract
Engagement of the CD95 (Apo-1, Fas) membrane receptor is known to induce apoptosis in a variety of sensitive cells, even in the absence of extracellular Ca2+. The signal transduction events implicated in this pathway are poorly understood. We have recently characterized normal human Vgamma9/Vdelta2+ T cell clones that maintain similar levels of CD95 membrane expression throughout the culture. Here we show that 3 wk of culture after in vitro restimulation are necessary for the cells both to die and to acquire the ability to mobilize intracellular Ca2+ upon CD95 ligation. Buffering of intracellular Ca2+ by accumulation of the chelator 1,2-bis(2-amino phenoxy)ethane-N,N,N1,N-tetraacetic acid protects from CD95-triggered apoptosis, suggesting that the two phenomena are causally related. As intracellular Ca2+ release by inhibition of endoplasmic reticulum ATPases induces apoptosis in both recently and long term activated gamma delta cells, the molecular regulation of activation-dependent apoptosis is likely to involve events upstream of CD95-dependent Ca2+ release. The CD95-triggered increase in the intracellular Ca2+ concentration depends on depletion of the same intracellular Ca2+ stores mobilized by ligation of the TCR, and Ca2+ release does not depend on inositol 1,4,5-trisphosphate generation.
The MHC class I genes of the rhesus monkey. Different evolutionary histories of MHC class I and II genes in primates.
Authors: Boyson J E , Shufflebotham C , Cadavid L F , Urvater J A , Knapp L A , Hughes A L , Watkins D I 
Published: December 2022

Abstract
Homologues of the human HLA-A and -B MHC class I loci have been found in great apes and Old World primates suggesting that these two loci have existed for at least 30 million years. The C locus, however, shows some sequence similarity to the B locus and has been found only in gorillas, chimpanzees, and humans. To determine the age of the MHC class I C locus and to examine the evolution of the A and B loci we have cloned, sequenced, and in vitro translated 16 MHC class I cDNAs from two unrelated rhesus monkeys (Macaca mulatta) using both cDNA library screening and PCR amplification. Analyses of these sequences suggest that the C locus is not present in the rhesus monkey, indicating that this locus may be of recent origin in gorillas, chimpanzees, and humans. The rhesus monkey's complement of MHC class I genes includes the products of at least one expressed A locus and at least two expressed B loci, indicating that a duplication of the B locus has taken place in the lineage leading to these Old World primates. Comparison of rhesus monkey MHC class I cDNAs to their primate counterparts reveals fundamental differences between MHC class I and class II evolution in primates. Although MHC class II allelic lineages are shared between humans and Old World primates, no such trans-species sharing of allelic lineages is seen at the MHC class I loci.
Analysis of the CDR3 region of the rearranged IgH chain genes in patients with severe combined immunodeficiency and severe lymphopenia.
Authors: Minegishi Y , Akagi K , Nishikawa K , Okawa H , Yata J 
Published: December 2022

Abstract
Human B cell-negative severe combined immunodeficiency (B-SCID) is a primary immunodeficiency disease characterized by both T and B lymphocytopenia and agammaglobulinemia. Although lymphocytes of B-SCID patients express defective recombinase activity and rarely succeed in making Ag receptors, the molecular defect of the human B-SCID remains to be identified. To gain more insight into the human B-SCID defect and its effect on the Ab repertoire, we examined the Ig heavy (H) chain genes of the peripheral blood leaky B cells from three B-SCID patients. Although the number of B cells in their peripheral blood was very limited, we could obtain 41 productive VDJ recombinations from the 58 joints. The recombinations showed a grossly altered pattern characterized by short N nucleotides, short deleted nucleotides from 5' JH segments, immature JH and D segment utilization, absence of VDDJ recombination, and all but one JH segment equal to germline JH segments. Therefore, Ab repertoire of IgH chain gene in human B-SCID was limited because of restricted junctional and combinatorial diversity and few somatic mutations. Furthermore, unusually long P nucleotides were inserted in junctional sequences, which might indicate that resolution of hairpin is impaired in human B-SCID as in the murine SCID.
In vivo induction of CTL responses by recombinant adenylate cyclase of Bordetella pertussis carrying viral CD8+ T cell epitopes.
Authors: Fayolle C , Sebo P , Ladant D , Ullmann A , Leclerc C 
Published: December 2022

Abstract
Exogenous Ags enter the endosomal pathway and are presented to CD4+ T cells in association with class II molecules whereas endogenously synthesized Ags, such as viral proteins, are presented to CD8+ T cells in association with MHC class I molecules. Therefore, most CTL activation strategies use live vectors although an alternative possibility could be to deliver the epitope into the cytosol by targeting it to an invasive nonreplicative vector. The adenylate cyclase toxin of Bordetella pertussis is able to invade a large number of eukaryotic cells and to deliver its catalytic domain to the cytosol of the cells. In the present study, we have tested the in vivo immunogenicity of recombinant adenylate cyclase toxins expressing CTL epitopes either from the nucleoprotein of lymphocytic choriomeningitis virus or from the V3 region of HIV-1 gp120. BALB/c mice immunized with these toxins developed high specific CTL responses that were shown to be mediated by class I-restricted CD8+ CTL. The induction of CTL responses by recombinant toxins did not require CD4+ T cells and the cytotoxic activity persisted 2 mo after immunization. The activation of CTL responses by the recombinant adenylate cyclase toxin required the full-length invasive activity of the toxin but did not depend upon its catalytic adenylate cyclase activity as demonstrated with a genetically inactivated recombinant toxin expressing the lymphocytic choriomeningitis virus epitope. This genetically detoxified invasive toxin represents, therefore, an attractive new vector for CTL activation.
Characterization of early IL-12, IFN-alphabeta, and TNF effects on antiviral state and NK cell responses during murine cytomegalovirus infection.
Authors: Orange J S , Biron C A 
Published: December 2022

Abstract
Murine cytomegalovirus (MCMV) infection of mice induces early cytokines. Although certain of these can directly inhibit viral replication, they also can promote defense by activating NK cells. MCMV induces IFN-alphabeta-dependent NK cell cytotoxicity and IL-12-dependent NK cell IFN-gamma production. Studies were initiated to define cytokine-mediated NK and T cell-independent antiviral defense and specific cytokine-elicited NK cell responses during MCMV infections. IFN-alphabeta, TNF, IL-12, and IFN-gamma were all shown to be induced 2 days after infection of immunocompetent mice. Infections of NK and T cell-deficient mice demonstrated that virus-induced IFN-alphabeta, TNF, and IL-12, but not IFN-gamma, were produced independently of these populations, and that IL-12 production occurred in the absence of detectable IFN-gamma. In vivo neutralization studies of IFN-alphabeta, TNF, and IL-12 showed that each of these factors had NK and T cell-independent antiviral functions, as well as specific effects on NK cell responses. Examination of NK cell cytotoxicity, blastogenesis, and IFN-gamma production demonstrated that: IL-12 was required for NK cell IFN-gamma production but not blastogenesis and cytotoxicity; IFN-alphabeta was necessary for NK cell blastogenesis and cytotoxicity but not IFN-gamma production; and TNF facilitated IFN-gamma production but inhibited NK cell cytotoxicity. This work defines the biologic consequences of early cytokine expression during viral infection.
Both N- and C-terminal regions of the bioactive N-terminal fragment of the neutrophil granule bactericidal/permeability-increasing protein are required for stability and function.
Authors: Capodici C , Weiss J 
Published: December 2022

Abstract
An N-terminal fragment (residues 1-199) of the 456-residue human bactericidal/permeability-increasing protein (BPI), isolated after limited proteolysis, exhibits antibacterial and LPS-neutralizing activities equal to or greater than those of holo-BPI. To assess minimal structural requirements for bioactivity, mutant species of BPI were expressed in vivo by transient transfection and in vitro by cellfree transcription/translation. BPI1-456 and BPI1-193 demonstrated the expected antibacterial and LPS-binding activities. Deletion of the N-terminal 12 residues did not diminish BPI function. However, further truncation either from the C-terminus to residue 169 (BPI1-169) or from the N-terminus (BPIdelta15-56) yielded in vitro products with little or no LPS-binding activity and in vivo products that could not be recovered from the culture medium or cellular acid extracts. The possible role of cysteine-175 (the three cysteines in human BPI are at residues 132, 135, and 175) in BPI stability/function was examined by substitution of Cys(175) with serine. Recovery of C175S BPI from extracellular medium was reduced 10-fold, and C175S BPI produced in vitro had little LPS-binding activity. Compared with wild-type holo-BPI and BPI1-193, BPI1-169, BPIdelta15-56, and C175S BPI showed increased susceptibility to cleavage by elastase in the region 1-193 (but not in the region 200-456), indicating conformational changes that may account for the loss of function. These findings suggest that the proteolytic N-terminal fragment of BPI corresponds closely to the minimum functional (antibacterial/anti-LPS) domain of BPI and that residues near both ends of this fragment are essential for structural stability and functional integrity.
Identification of surface molecules associated with physiologic activation of eosinophils. Application of whole-blood flow cytometry to eosinophils.
Authors: Mawhorter S D , Stephany D A , Ottesen E A , Nutman T B 
Published: December 2022

Abstract
Activation is central to the eosinophil's functional role as an immune responder cell. To evaluate such activation in cells freshly isolated from peripheral blood, a method for whole-blood immunostaining and flow cytometry-based eosinophil selection was developed. Simultaneous comparison of purified eosinophils and whole-blood cells revealed significant differences in the levels of expression of various surface molecules, which suggested that the purification process activated the eosinophils. Subsequent analyses were conducted with the whole-blood assay. When eosinophils from helminth-infected persons (n = 18) were compared with those from normal individuals (n = 10), the early activation marker CD69 was found to be significantly increased (geometric mean (GM) = 4.3 vs. 1.0%, p = 0.04). The granulocyte activation marker CD66 was also up-regulated on eosinphils from helminth patients (GM = 53.3 vs. 31.0%, p = 0.044), as was the tetraspan family molecule CD81 (TAPA-1; GM = 79.4 vs. 48.2%, p = 0.02). Conversely, in vivo CD23 (FcepsilonRII) expression on eosinophils was decreased in the presence of parasitic infection (GM = 0.9 vs. 5.7%, p = 0.02). Expression of the eosinophil surface molecules CD69, CD81, and CD23 was significantly enhanced after cytokine stimulation in vitro with IL-3 or GM-CSF. In vivo, specific anthelmintic therapy resulted in decreased CD66 and CD25 expression (p &lt; 0.05 compared with pretreatment) to levels approaching those seen in uninfected normal individuals. These findings indicate the dynamic nature of eosinophil surface molecules and demonstrate an important role for whole-blood staining in developing an understanding of the nature of eosinophil activation and of their role in inflammatory reactions to helminth parasites.
Constitutive production of IL-4 and IL-10 and stimulated production of IL-8 by normal peripheral blood eosinophils.
Authors: Nakajima H , Gleich G J , Kita H 
Published: December 2022

Abstract
To study the capacity and regulation of cytokine production by normal peripheral blood eosinophils, we isolated eosinophils from healthy individuals and stimulated them with immobilized Ig or TNF-alpha, with or without exogenous IL-5. By reverse transcription-PCR, uncultured, freshly isolated eosinophils constitutively expressed mRNA for IL-4, IL-10, and TGF-beta1. Eosinophils stimulated by immobilized secretory IgA, immobilized IgA, immobilized IgG, or TNF-alpha for 3 h expressed mRNA encoding IL-3, IL-4, IL-8, IL-10, granulocyte-macrophage CSF, TNF-alpha, TGF-beta, and RANTES. The mRNA for IL-2, IL-5, or IFN-gamma was not detected. IL-4 and IL-10 protein, but not IL-8, were measurable in lysates of fresh eosinophils or eosinophils cultured with medium alone for 24 h. Eosinophils incubated with immobilized Ig or TNF-alpha released IL-8 protein into the supernatants. In contrast, IL-4 and IL-10 proteins were not detectable. Soluble secretory IgA immune complexes also induced degranulation, as measured by eosinophil-derived neurotoxin, and IL-8 release, but not IL-4 or IL-10 release, from eosinophils. Release of IL-8 protein and storage of IL-4 and IL-10 proteins were enhanced by exogenous IL-5 and inhibited by a transcription inhibitor, actinomycin D. Degranulation of stored granule proteins was not affected by actinomycin D. Therefore, normal peripheral blood eosinophils can transcribe and synthesize several cytokines, including IL-4, IL-8, and IL-10; some are stored, and some are released. These cytokines may play important roles in modulating immune responses in diseases associated with eosinophils.
Characterization of murine intercellular adhesion molecule-2.
Authors: Xu H , Bickford J K , Luther E , Carpenito C , Takei F , Springer T A 
Published: December 2022

Abstract
Rat mAbs were raised against murine intercellular adhesion molecule-2 (ICAM-2). Immune precipitation and purification reveal that the murine ICAM-2 glycoprotein is 55 kDa and is similar in size to human ICAM-2. ICAM-2 is expressed on a variety of leukocyte cell lines, including T and B lymphoma, mastocytoma, and macrophage lines. ICAM-2 is well expressed on endothelioma cell lines, and in contrast to ICAM-1, expression is not increased by inflammatory cytokines. One of the mAb to ICAM-2 partially or completely inhibits binding of cells expressing LFA-1 to purified ICAM-2, and binding of cells expressing ICAM-2 to purified LFA-1. The findings in the mouse are congruent with those in the human, suggesting functional conservation of ICAM-2 across species.
Differential effects of CTLA-4 substitutions on the binding of human CD80 (B7-1) and CD86 (B7-2).
Authors: Morton P A , Fu X T , Stewart J A , Giacoletto K S , White S L , Leysath C E , Evans R J , Shieh J J , Karr R W 
Published: December 2022

Abstract
CTLA-4 expressed on activated T cells binds to CD80 (B7-1) and CD86 (B7-2) molecules present on APC with high avidity and appears to deliver a negative regulatory signal to the T cell. We have investigated the kinetics of CTLA-4 binding to CD80 and CD86, together with the effects of selected CTLA-4 mutations on binding activity. The dissociation constants (Kd) for binding of CTLA-4-Ig to CD80 and CD86 transfectants were 8.1 and 6.7 nM, respectively. Surface plasmon resonance was used to determine kinetic parameters of CTLA-4-Ig binding to CD80-Ig and CD86-Ig fusion proteins and revealed enhanced association (ka) and dissociation (kd) rate constants for CD86-Ig compared with CD80-Ig. Furthermore, CD80-Ig and CD86-Ig fusion molecules demonstrated variable abilities to cross-compete for binding to several modified forms of CTLA-4-Ig. Differential binding of CD80 and CD86 to CTLA-4 was further revealed by analysis of 10 discrete CTLA-4 mutants. Five single amino acid substitutions within the CTLA-4 MYPPPY domain exerted modest effects on CD80 binding, but each of these substitutions completely abrogated CD86 binding. In addition, substitutions just N-terminal of the MYPPPY region, and within the CDR1-like region of CTLA-4, eliminated both CD80 and CD86 binding. Hence, CD80 and CD86 bind with different association/dissociation kinetics to similar, but distinct, sites on CTLA-4.
Macrophages have cell surface IL-10 that regulates macrophage bactericidal activity.
Authors: Fleming S D , Campbell P A 
Published: December 2022

Abstract
IL-10, which is secreted by multiple cell types, has regulatory effects on macrophages, including decreasing their ability to kill some microorganisms. The experiments presented here test the hypothesis that endogenous IL-10 inhibits the ability of macrophages to kill the facultative intracellular bacterium, Listeria monocytogenes. We show that the nonbactericidal macrophage hybrid, H36.12j (12j), can kill Listeria after incubation for 3 days with anti-IL-10 mAb. IL-10 was not detected in 12j macrophage supernatants by ELISA. However, flow cytometric analysis revealed high levels of IL-10 on the 12j cell surface. This indicates that macrophages that fail to secrete IL-10 may express IL-10 on the cell surface, and this IL-10 appears to suppress listericidal activity. Surface IL-10 is not unique to the 12j macrophage hybrid and may correlate with the absence of bactericidal activity in other macrophages. For instance, nonlistericidal resident and thioglycolate-elicited peritoneal exudate cells have 24 to 72% IL-10-positive macrophages. In contrast listericidal proteose peptone-elicited peritoneal exudate cells contained &lt; 5% IL-10-positive macrophages. Whether this IL-10 is an integral membrane protein or is bound to IL-10 receptors is not yet known. However, the IL-10 does not elute with acid as other passively bound molecules do, nor does exogenous IL-10 bind to macrophages. In either case, since anti-IL-10 induces nonbactericidal macrophages to become bactericidal, the surface IL-10 is biologically active, and it appears to regulate macrophage bactericidal activity.
Blood clearance kinetics and liver uptake of mononucleosomes in mice.
Authors: Gauthier V J , Tyler L N , Mannik M 
Published: December 2022

Abstract
Nucleosomes generated by apoptosis have become of considerable interest in relation to pathogenesis of systemic lupus erythematosus in mice and humans. Therefore, the fate of circulating mononucleosomes was examined in normal C57Bl/6J mice. The mononucleosomes were prepared from chicken erythrocytes and radiolabeled on the histone component. The removal of nucleosomes from circulation at doses less than 11 micrograms of injected mononucleosomes was rapid, but with increasing doses of injected nucleosomes, the slopes of the removal curves decreased. Liver was the major organ for removal of circulating nucleosomes, accounting for 71.0 to 84.7% of nucleosomes removed from circulation at 10 min. After i.v. injection of nucleosomes, 0.52 +/- 0.15% localized in kidneys. With prior i.v. injection of histones, the glomerular localization of mononucleosomes increased threefold. The clearance of mononucleosomes was decreased sixfold by concurrent injection of ssDNA. These studies show that in mice, circulating mononucleosomes are handled similar to DNA, and they do not avidly localize in glomeruli unless histones have already bound to renal glomeruli.
Regulation of murine macrophage IL-12 production. Activation of macrophages in vivo, restimulation in vitro, and modulation by other cytokines.
Authors: Skeen M J , Miller M A , Shinnick T M , Ziegler H K 
Published: December 2022

Abstract
IL-12 is important in the host response to a variety of pathogens. It plays an adjuvant-like role in an initial immune response as well as a therapeutic role in established infections. Despite its well documented importance, comparatively little is known about the regulation of IL-12 production. In this study, we examined IL-12 production by cultured murine peritoneal macrophages from two perspectives: 1) macrophage activation in vivo, and 2) stimulation of IL-12 secretion in vitro. Macrophages were maximally activated within 48 h in vivo during infection with Listeria. Interestingly, although avirulent or heat-killed Listeria induced only minimal production of IL-12 by macrophages, the immunogenic combination of heat-killed bacteria and rIL-12 was highly stimulatory for IL-12 production. LPS and peritoneal inflammatory agents were also stimulatory, but latex beads were ineffective, indicating that microbial components were essential and phagocytosis alone was insufficient. Restimulation in vitro revealed similar patterns, in that infection and LPS were stimulatory but latex beads were not. A systematic survey of potential stimulatory agents showed that microbial heat shock proteins, crude bacterial extracts, bacterial superantigens, a yeast extract, and dsRNA induced IL-12 in vitro. Other cytokines also influenced IL-12 induction. IFN-gamma, which is up-regulated during infection, acted in synergy with other stimuli, suggesting an amplification loop for IL-12 production, whereas IL-4, IL-10, IL-13, and TGF-beta were inhibitory. The existence of a broad range of stimuli from a wide variety of pathogenic organisms underscores the fundamental importance of IL-12 in host defense.