bluuebunny/crossref_metadata_2025_split huggingface dataset:
Wortmannin, a phosphatidylinositol 3-kinase inhibitor, blocks antigen-mediated, but not CD3 monoclonal antibody-induced, activation of murine CD4+ T cells.
Authors: Shi J , Cinek T , Truitt K E , Imboden J B 
Published: December 2022

Abstract
Perturbation of several distinct T cell molecules, including the CD3/TCR complex, CD7, and CD28, activates phosphatidylinositol 3-kinase (PI3-K), but a clear consensus on the role of PI3-K in T cell activation has yet to emerge. We report here that CD3 mAb-induced IL-2 production by CD4+ T cells from DO11.10 TCR-alphabeta-transgenic mice is refractory to the potent PI3-K inhibitor, wortmannin, demonstrating that activation under these conditions is independent of PI3-K. In marked contrast, wortmannin substantially inhibits IL-2 production elicited by Ag (OVA(323-339) peptide) presented by appropriate APCs (syngeneic B7+ B cell blasts) and blocks Ag-induced differentiation of naive CD4+ DO11.10 T cells into IL-4-producing cells. Wortmannin inhibits Ag-induced conjugate formation between T cells and B7+ B cell blasts. Because T cell activation by Ag requires stable interactions with APCs, this inhibitory effect on conjugate formation may underlie the ability of wortmannin to block Ag-induced IL-2 production and differentiation.
CD28 engagement and proinflammatory cytokines contribute to T cell expansion and long-term survival in vivo.
Authors: Vella A T , Mitchell T , Groth B , Linsley P S , Green J M , Thompson C B , Kappler J W , Marrack P 
Published: December 2022

Abstract
To mount a productive response to Ag, CD4+ T cells in mice must divide, differentiate, and survive at least until the Ag has been eliminated. It has been suggested that to accomplish this, T cells must receive two signals, one through their TCRs and a second through CD28. The second signal through CD28 has been thought to fulfill two roles, to stimulate T cell proliferation and to promote T cell survival. In this paper we confirm that CD28 engagement can contribute to vigorous T cell expansion in mice injected with superantigens. However, CD28 engagement does not protect T cells produced during a superantigen-specific proliferative response from undergoing subsequent deletion. Even if CD28 is bound, 4 days after superantigen exposure, the majority of T cells produced in response to superantigen exposure are eliminated in vivo. In contrast, this loss of superantigen-stimulated T cells can be prevented by the inflammatory stimuli created by injection of bacterial LPS. This protection does not require engagement of CD28 by its ligands, B7-1 and B7-2. These data suggest that productive T cell responses in mice involve a number of signals, including those initiated through TCR and CD28, which are primarily involved in the activation and expansion of T cells, and others delivered by proinflammatory cytokines that protect an activated T cell from subsequent deletion.
CIITA-dependent and -independent class II MHC expression revealed by a dominant negative mutant.
Authors: Zhou H , Su H S , Zhang X , Douhan J , Glimcher L H 
Published: December 2022

Abstract
The MHC class II transactivator gene (CIITA) coordinately controls the expression of the three major human class II genes, HLA-DR, HLA-DQ, and HLA-DP. Indeed, patients with one form of MHC class II immunodeficiency disease, due to defective CIITA genes, lack expression of all three isotypes. Nevertheless, there is substantial evidence that human class II genes are not always coordinately regulated, raising the possibility that CIITA-independent, isotype-specific class II regulatory pathways exist. To address this issue, we have generated a dominant negative mutant of CIITA that lacks the acidic transcription-activating N terminus, but retains the proline/serine/threonine-rich domain. Three newly produced anti-CIITA mAbs revealed that this mutant protein lacked N-terminal epitopes. In this study, we report that this CIITA dominant negative mutant repressed the constitutive expression of all three class II isotypes in human EBV-B cell lines, as well as IFN-gamma-induced class II transcription in HeLa cells. However, in a CIITA-deficient, EBV-transformed B cell line, clone 13, the dominant negative mutant did not alter the endogenous expression of the HLA-DQ gene. Taken together, these data demonstrate the existence of both CIITA-dependent and -independent class II regulatory pathways. Furthermore, our data provide evidence that the latter pathways can be isotype specific.
Dyad symmetry within the mouse 3' IgH regulatory region includes two virtually identical enhancers (C alpha3'E and hs3).
Authors: Saleque S , Singh M , Little R D , Giannini S L , Michaelson J S , Birshtein B K 
Published: December 2022

Abstract
The transcription of the murine Ig heavy chain locus is regulated not only by the intronic enhancer, E mu, but also by a 3' regulatory region located downstream of the C alpha membrane exon. Several DNase I-hypersensitive sites (hs1-4) and enhancer elements (e.g., C alpha3'E) have been identified in this 3' regulatory region, and some of these were suggested to comprise a locus control region. However, little is known about the coordinate regulation or function of these individual elements. Here we provide evidence that C alpha3'E and hs3 are virtually mirror images of each other and demarcate the edges of an approximately 25-kb region of quasi-dyad symmetry with 3'alphaE(hs1,2) at its center. Flanking 3'alphaE(hs1,2) are inverted repeats and families of repetitive sequences uniquely located in this region. We have observed that, like 3'alphaE(hs1,2) and hs3, C alpha3'E is DNase I hypersensitive in plasma cell lines, but not in a pre-B cell line. Additionally, we found that C alpha3'E and hs3 show significant transcriptional synergy in transfection assays only in a plasma cell line. The DNA topology of the 3' regulatory region coupled with new and existing data on the activity of its individual enhancers during B cell differentiation lead us to propose a biphasic model for the activity of this region. According to our model, one unit, consisting of the 3'-most enhancer, hs4, is active early and throughout B cell development. The second unit, which comprises C alpha3'E, 3'alphaE(hs1,2), and hs3, becomes active later in development, when it contributes to such processes as class switching and increased levels of Ig heavy chain gene transcription in plasma cells.
HLA-DMA and HLA-DMB gene expression functions through the conserved S-X-Y region.
Authors: Westerheide S D , Louis-Plence P , Ping D , He X F , Boss J M 
Published: December 2022

Abstract
The MHC class II homologous proteins HLA-DMA and HLA-DMB function in the loading of peptides onto class II molecules. Like the class II genes, the HLA-DM genes contain upstream regulatory sequences similar to the S-X-Y regulatory region as well as additional putative regulatory sites. To determine whether the DM genes are regulated in a similar manner as class II genes, a series of in vivo and in vitro analyses was performed. Deletion analysis showed that expression from the DM promoters is dependent on the conserved S-X-Y region. The class II-specific transcription factors RFX and CIITA are also required for expression, as cell lines deficient in these factors failed to allow transcription from the DM promoters. In addition, in vivo footprint analysis showed the putative X and Y boxes to be occupied by transcription factors in wild-type B cells, but not in RFX-deficient B cells. In astrocytes, IFN-gamma treatment induced increased occupancy of these sites. None of the other putative regulatory sites was occupied in vivo, indicating that they may not be functional. Finally, gel shift analysis showed synergistic complex formation between proteins that bind to the putative X boxes of the DM genes, as is found for the DRA gene. Therefore, the DM genes share a common mechanism of regulation with the class II genes.
Immunosuppressive activity of cloned natural killer (NK1.1+) T cells established from murine tumor-infiltrating lymphocytes.
Authors: Tamada K , Harada M , Abe K , Li T , Tada H , Onoe Y , Nomoto K 
Published: December 2022

Abstract
To elucidate the role of NK1.1+ T cells in the antitumor immune response, we established cloned NK1.1+ T cell lines from tumor-infiltrating lymphocytes (TIL) of B16 melanoma, and examined their mode of action in generating antitumor effector T cells both in vitro and in vivo. An NK1.1+ T cell clone (TM4.2) was phenotypically CD3+ TCR-alphabeta+ CD4- CD8- NK1.1+, and CD28+. The TM4.2 cells suppressed the in vitro generation of anti-B16 melanoma CTLs, but not the effector function of CTLs. The results using a transwell membrane suggested that their suppressive activity was mediated by both soluble factors and a direct cell to cell interaction. As for the soluble factors, the suppressive activity of the culture supernatant of TM4.2 cells was neutralized by anti-TGF-beta mAb, and the TM4.2 cells actually produced a considerable amount of TGF-beta. On the other hand, the TM4.2 cells showed a high level of cytolytic activity against B cell blasts and CD80-transfected P815, and such cytolytic activity was reduced by the addition of anti-CD80 mAb. In addition, NK1.1+ T cells in the freshly isolated TIL were revealed to express CD28. Furthermore, the TM4.2 cells suppressed the in vitro generation of anti-allo CTLs irrespective of the MHC haplotype. Finally, the TM4.2 cells suppressed the in vivo antitumor immune response. Collectively, these findings demonstrate that NK1.1+ T cells in TIL show immunosuppressive activity in the antitumor immune response through the production of TGF-beta and the preferential cytolysis of B7-expressing cells.
Early embryo loss is associated with the prior expression of macrophage activation markers in the decidua.
Authors: Haddad E K , Duclos A J , Lapp W S , Baines M G 
Published: December 2022

Abstract
In early embryo loss, the activation of maternal immune effector mechanisms play a critical role in determining the success or failure of a pregnancy. We have previously shown that increased nitric oxide production by decidual macrophages is involved in early embryo loss occurring at day 12 of gestation. In this study, using reverse transcription-PCR and Southern blotting, the expression of inducible nitric oxide synthases (iNOS) and TNF-alpha mRNA was determined to quantify macrophage activation in individual murine embryos in a model of spontaneous early embryo loss. At day 8 of gestation, 32 and 29% of embryos with no apparent pathology showed an increase in iNOS and TNF-alpha mRNA expression, respectively. This corresponds to the natural resorption rate seen in the mouse model. In addition, the percentage of embryos with increased iNOS and TNF-alpha mRNA expression was further augmented when pregnant mice were induced to abort at a higher rate. These results showed, for the first time, a correlation between increased iNOS and TNF-alpha expression and embryo resorption. The results provide evidence for the presence of activated macrophages at implantation sites before overt embryo damage occurs.
Inflammatory cytokines IFN-gamma plus TNF-alpha induce regulated expression of CD80 (B7-1) but not CD86 (B7-2) on murine fibroblasts.
Authors: Pechhold K , Patterson N B , Craighead N , Lee K P , June C H , Harlan D M 
Published: December 2022

Abstract
Optimal T cell activation requires signals delivered via both the TCR and the costimulatory receptors. Considerable experimental data now suggest that this costimulatory signal is generated predominantly by CD28 when engaged by its ligands CD80 (B7-1) and/or CD86 (B7-2). Whether T cell activation is controlled in part by regulated CD80 and/or CD86 expression has been incompletely explored. Here, we report that CD80 can be expressed constitutively by murine fibroblasts and up-regulated after treatment with IFN-gamma plus TNF-alpha. CD80 expression and function was confirmed by 1) Northern analysis, 2) specific immunoprecipitation of a approximately 69-kDa surface protein that comigrated with CD80 precipitated from CD80-transfected CHO cells, and 3) two independent assays for costimulation of Ag-specific T cell activation. Taken together, these observations suggest that CD28/CTLA-4 ligands are expressed on a wider variety of tissues than previously suspected and that their expression is dynamically regulated. Consequently, these results might explain previous observations that inflammatory cytokines can result in autoimmune responses.
Adenosine metabolism during phorbol myristate acetate-mediated induction of HL-60 cell differentiation: changes in expression pattern of adenosine kinase, adenosine deaminase, and 5'-nucleotidase.
Authors: Spychala J , Mitchell B S , Barankiewicz J 
Published: December 2022

Abstract
Adenosine has potent immunosuppressive activity. Since the source of adenosine and the mechanism of its release in the immune system is largely unknown and may vary according to cell type, we have evaluated the relationship between adenosine metabolism and the enzymatic activities and mRNA levels of adenosine-metabolizing enzymes in myeloid and lymphoid cell lines. Induction of HL-60 cell differentiation along the macrophage lineage by PMA resulted in a reduction in the activities of adenosine deaminase (ADA), adenosine kinase (AK), and inosine monophosphate-specific cytosolic 5'-nucleotidase and an elevation of ecto-5'-nucleotidase (ecto-5'-NT). These changes were accompanied by an elevation of ecto-5'-NT mRNA and a decrease in ADA and AK mRNAs in a time-dependent fashion. Comparison of AK and ADA mRNA levels in several other leukemic cell lines revealed generally similar responses to PMA with much stronger suppression in immature T cells than in B cells. The metabolism of adenosine either through phosphorylation (AK) or deamination (ADA) was reduced in PMA-stimulated cells. Furthermore, the cumulative changes in enzyme expression resulted in a 2.5-fold increase in intracellular adenosine formation in PMA-stimulated cells. The inhibition of AK by 5'-iodotubercidin further increased adenosine formation by 6-fold over that in untreated cells. In accord with the increase in ecto-5'-NT activity, extracellular AMP dephosphorylation increased dramatically, but there was no increase in extracellular ATP degradation. These results indicate that a coordinated shift in adenosine-metabolizing enzyme levels during PMA-induced HL-60 cell differentiation is accompanied by a decrease in adenosine uptake and an increase in adenosine release.
Monocyte chemotactic protein-3 (MCP-3)/fibroblast-induced cytokine (FIC) in eosinophilic inflammation of the airways and the inhibitory effects of an anti-MCP-3/FIC antibody.
Authors: Stafford S , Li H , Forsythe P A , Ryan M , Bravo R , Alam R 
Published: December 2022

Abstract
Monocyte chemotactic protein-3 (MCP-3)/fibroblast-induced cytokine (FIC), a CC chemokine, is chemotactic for cells that typically infiltrate the late-phase allergic reaction. We developed a mouse model of airway inflammation to study the role of MCP-3/FIC. The immunization of mice with OVA resulted in Ag-specific IgE Ab production and the expression of mRNA for IL-4 in the lung tissue. Two weeks after immunization mice were challenged with the allergen by inhalation. Lungs were lavaged, and the tissue was examined at 2 or 24 h. Allergen challenge resulted in the increased recovery of leukocytes in the lavage fluid, but saline challenge did not. There was a significant increase in eosinophils (29 +/- 8% vs 1.2 +/- 0.2%) and lymphocytes (25 +/- 4% vs 5 +/- 2%) in the bronchoaveolar lavage fluid. Histologic examination of the lung demonstrated intense airway inflammation following OVA challenge. The expression of MCP-3/FIC and other CC chemokines (MCP-1, macrophage inflammatory protein-1alpha, and RANTES) was investigated by reverse transcription-PCR followed by densitometric analyses. The allergen challenge up-regulated the expression of mRNA for MCP-1, MCP-3/FIC, and macrophage inflammatory protein-1alpha at 2 and/or 24 h. Immunocytochemical staining for MCP-3/FIC showed that the allergen challenge induced the expression of MCP-3/FIC predominantly in the airway epithelium. Pretreatment of mice with an anti-MCP-3/FIC Ab significantly inhibited the OVA-induced airway inflammation and the bronchoalveolar lavage eosinophilia (8 +/- 2% vs 46 +/- 11% after control Ab, p &lt; 0.03). We conclude that MCP-3/FIC plays a significant role in the allergen-induced eosinophilic inflammation of the airways.
Sezary lineage cells can be induced to proliferate via CD28-mediated costimulation.
Authors: McCusker M E , Garifallou M , Bogen S A 
Published: December 2022

Abstract
Sezary syndrome and mycosis fungoides are related chronic lymphoproliferative diseases caused by the malignant growth of CD4+ T lymphocytes that display hyperconvoluted nuclei and a predilection for skin homing. Despite the malignant nature of these cells, they paradoxically do not grow in vitro, either spontaneously or following exposure to mitogens. Partly because of this technical limitation, the cellular lineage and causes of abnormal growth resulting in a classical hyperconvoluted Sezary cell are poorly characterized. To better understand these aspects, we examined Sezary lineage cell growth in vitro. We found that, contrary to previous reports, Sezary lineage cells are capable of in vitro proliferation in response to either PHA or anti-CD3 mAb, if exogenous costimulation is provided. The CD28-B7 interaction provides at least one of the costimulatory signals capable of inducing Sezary lineage cell growth. Namely, Sezary lineage cells from three of six Sezary syndrome patients proliferated in response to PHA if an anti-CD28 mAb was also added to the in vitro culture. The remaining three patients' Sezary lineage cells were dependent upon CD28-B7-mediated costimulation, but in addition required other intercellular signals present on blood mononuclear cells. The relative lack of costimulation from the patients' own PBMC is not due to an intrinsic defect in the mycosis fungoides/Sezary syndrome patients' immune accessory cells. Rather, it appears primarily due to an inability of Sezary cells to significantly up-regulate CD40 ligand (gp39) following in vitro exposure to PHA.
Anti-IL-4 monoclonal antibody prevents antibiotics-induced active fatal anaphylaxis.
Authors: Park J S , Choi I H , Lee D G , Han S S , Ha T Y , Lee J H , Lee W H , Park Y M , Lee H K 
Published: December 2022

Abstract
We previously reported that anti-IL-4 mAb (11B11) failed to prevent protein-induced fatal murine anaphylaxis. To investigate the effect of anti-IL-4 on hapten-induced anaphylaxis, a model of murine anaphylaxis induced by antibiotics, penicillin V (Pen V) and cephalothin (CET), was developed, and the effect of anti-IL-4 on the anaphylaxis was observed. Pen V and CET induced 100 and 70 to 90% fatal reactions, respectively, when C57BL/6 mice were sensitized i.p. with 500 microg of antibiotic-OVA conjugate with 2 x 10(9) Bordetella pertussis and 1.0 mg of alum and challenged i.v. with 100 microg of antibiotic-BSA conjugate 14 days later. Serum taken from mice sensitized to Pen V passively sensitized normal mice to develop systemic anaphylaxis, and this ability of the serum was abrogated by heating at 56 degrees C for 2 h or depletion of IgE, but not IgG, Abs. Thus, the antibiotic-induced fatal reaction was an IgE-dependent anaphylactic reaction. Administration of anti-IL-4 at the beginning of sensitization completely prevented the fatal anaphylactic reactions to both Pen V and CET. This effect of anti-IL-4 was associated with its suppressive activity on antibiotic-specific serum IgE, but not IgG, levels. More importantly, anti-IL-4 therapy in previously sensitized mice was also effective in preventing the fatal reactions and rapidly reduced the established IgE levels. This study provides a new animal model of hapten-induced anaphylaxis and indicates that blocking of IL-4 activity may be beneficial in allergic diseases caused by a variety of haptens in which IgE Abs play a major role.
Somatic mutation leads to efficient affinity maturation when centrocytes recycle back to centroblasts.
Authors: Oprea M , Perelson A S 
Published: December 2022

Abstract
Although most mutations are deleterious, an interplay between somatic mutation and selection within germinal centers (GC) results in rapid generation of high affinity memory B cells. How high affinity B cells with large numbers of mutations are generated and preserved within GC containing at their peak only a few thousand cells has been puzzling. We have developed a model of somatic mutation and B cell expansion within a GC that resolves this puzzle. We show that the frequent recycling of Ag-selected centrocytes back into centroblasts can lead to efficient affinity maturation. Memory cells are generated in large numbers even when most of the selected centrocytes recycle back into centroblasts. Our model suggests that a germinal center reaction in which the output of cells is low up to the point of GC dissociation, followed by the release of centrocytes into the periphery, is advantageous for generating high affinity memory.
L-selectin is involved in lymphocyte migration to sites of inflammation in the skin: delayed rejection of allografts in L-selectin-deficient mice.
Authors: Tang M L , Hale L P , Steeber D A , Tedder T F 
Published: December 2022

Abstract
Adhesion of leukocytes to vascular endothelium is crucial for leukocyte migration into tissues. The contributions of L-selectin, P-selectin, and ICAM-1 to interactions between lymphocytes and endothelium was examined using allogeneic skin graft rejection as a model of cutaneous inflammation. L-selectin-deficient (L-selectin(-/-)) mice rejected both primary and secondary allogeneic (BALB/c) skin grafts significantly more slowly than L-selectin(+/+) littermates. Furthermore, skin graft rejection remained significantly delayed in L-selectin(-/-) mice, despite placement of grafts 7 days after i.p. immunization with allogeneic cells, when CTL responses in L-selectin(-/-) mice and L-selectin(+/+) littermates were confirmed to be equivalent. Indeed, specific CTL responses to BALB/c splenocytes were normal or elevated in L-selectin(-/-) mice following either skin grafts or immunization. However, the number of T lymphocytes within allogeneic grafts was lower in L-selectin(-/-) mice as compared with L-selectin(+/+) littermates. Therefore, delayed rejection of skin grafts by L-selectin(-/-) mice reflects impaired migration of effector cells into the graft rather than delayed or impaired generation of a CTL response. In contrast to L-selectin(-/-) mice, P-selectin-deficient and ICAM-1-deficient mice rejected allogeneic skin grafts normally. These findings delineate an important role for L-selectin in lymphocyte recruitment to cutaneous sites of inflammation.
Neutrophil production of IL-12 and IL-10 in candidiasis and efficacy of IL-12 therapy in neutropenic mice.
Authors: Romani L , Mencacci A , Cenci E , Spaccapelo R , Del Sero G , Nicoletti I , Trinchieri G , Bistoni F , Puccetti P 
Published: December 2022

Abstract
Neutrophil defects predispose to severe fungal infections, yet the immunomodulatory role of these cells is poorly defined. The contribution of neutrophils to the early cytokine balance governing Th1 and Th2 cell development was examined in mice with candidiasis. Neutrophils secreted IL-12 and IL-10, correlating with the respective development of self-limiting (Th1-associated) and progressive (Th2-associated) disease. Exogenous IL-12 was effective in protecting neutropenic hosts susceptible to infection. These results suggest that 1) neutrophils, via their ability to release cytokines, play an active role in determining the qualitative development of the T cell response, and 2) their early role in anticandidal immunity can be replaced by exogenous IL-12.