bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Cytoplasmic Domain of CD8β Regulates Lck Kinase Activation and CD8 T Cell Development
Authors: Irie Hanna Yoko , Mong Mimi S. , Itano Andrea , Crooks M. E. Casey , Littman Dan R. , Burakoff Steven J. , Robey Ellen 
Published: January 2023

AbstractPrevious studies have shown that CD8β plays a role in both enhancing CD8α-associated Lck kinase activity and promoting the development of CD8-lineage T cells. To examine the role of this enhancement in the maturation of CD8-lineage cells, we assessed CD8α-associated Lck kinase activity in both T cell hybridomas and thymocytes of mice expressing CD8β mutations known to impair CD8 T cell development. Lack of CD8β expression or expression of a cytoplasmic domain-deleted CD8β resulted in a severalfold reduction in CD8α-associated Lck kinase activity compared with that observed with cells expressing wild-type CD8β chain. This analysis indicated a critical role for the cytoplasmic domain of CD8β in the regulation of CD8α-associated Lck activity. Decreased CD8α-associated Lck activity observed with the various CD8β mutations also correlated with diminished in vivo cellular tyrosine phosphorylation. In addition, analysis of CD8β mutant mice (CD8β−/− or cytoplasmic domain-deleted CD8β transgenic) indicated that the degree of reduction in CD8α-associated Lck activity associated with each mutation correlated with the severity of developmental impairment. These results support the importance of CD8β-mediated enhancement of CD8α-associated Lck kinase activity in the differentiation of CD8 single-positive thymocytes.
Fas/Fas Ligand Interactions Are Involved in Ultraviolet-B-Induced Human Lymphocyte Apoptosis
Authors: Caricchio Roberto , Reap Elizabeth A. , Cohen Philip L. 
Published: January 2023

Abstract
We wondered whether the apoptosis known to occur after UV-B irradiation might involve the Fas/Fas ligand (FasL) signaling pathway. We exposed PBLs from normal individuals, and also the Jurkat (E6-1) and U937 cell lines, to graded doses of UV-B irradiation and observed a prompt and marked increase in Fas expression at doses as low as 0.5 mJ/cm2. Increased Fas expression did not require new protein synthesis, since cycloheximide-treated cells also showed an increase in Fas after UV-B. UV-B-irradiated cells cultured in the presence of zinc showed inhibition of apoptosis coincident with a marked increase in Fas+ cells, apparently indicating the accumulation of Fas-bearing cells unable to undergo apoptosis. After UV-B irradiation, PBLs showed increased expression of Fas ligand; the E6-1 lymphocytic cell line also released soluble FasL. UV-B induced apoptosis could be partially blocked by neutralizing FasL Abs, and a FasL-resistant variant of E6-1 cell line showed reduced apoptosis after UV-B irradiation, implying that the increase in Fas expression signified a role for Fas in UV-induced apoptosis. UV-induced Fas expression may serve to target stress-injured cells for removal by FasL-bearing cells or by FasL produced by the cells themselves in response to the stimuli, and may represent a general function of the Fas/FasL pathway in facilitating the apoptosis and elimination of undesirable or harmful cells.
Role of μ Heavy Chain in B Cell Development. I. Blocked B Cell Maturation But Complete Allelic Exclusion in the Absence of Igα/β
Authors: Cronin Frank E. , Jiang Ming , Abbas Abul K. , Grupp Stephan A. 
Published: January 2023

AbstractThere is good evidence for a signaling role played by Ig heavy chain in the developmental transition through the pre-B cell stage. We have previously described signal-capable or signal-incapable mutants of μ heavy chain in which a signaling defect is caused by failure to associate with the Igα/β heterodimer. To further characterize the role of Ig heavy chain-mediated signaling in vivo, as well as in B cell development and allelic exclusion, we have created transgenic mice in which the B cells express these signal-capable and signal-incapable mutant μ chains. Failure of μ to signal via Igα/β results in a block in B cell development in mice expressing the signal-incapable μ. A small number of B cells in these animals do escape the developmental block and are expressed in the spleen and the periphery as B220+ transgenic IgM+ cells. These cells respond to LPS by proliferating but show no response to T-independent-specific Ag. In contrast, B cells expressing the signal-capable B cell receptor show a strong signaling response to Ag-specific stimulus. There is no Igα seen in association with signal-deficient IgM. Thus, the B cell receptor complex is not assembled, and no signal can be delivered. Despite the block in developmental signaling, allelic exclusion is complete. There is no detectable coexpression of transgenic IgM and endogenous murine IgM, nor is there rearrangement of the endogenous heavy chain genes. This suggests that differing signaling mechanisms are responsible for the developmental transition and allelic exclusion and thus allows for separate examination of these signaling mechanisms.
Expression and Characterization of Recombinant Subunits of Human Complement Component C8: Further Analysis of the Function of C8α and C8γ
Authors: Schreck Steven F. , Plumb Mnason E. , Platteborze Peter L. , Kaufman Kenneth M. , Michelotti Gregory A. , Letson Carole S. , Sodetz James M. 
Published: January 2023

Abstract
Human C8 is composed of three nonidentical subunits (C8α, C8β, and C8γ) that are encoded in separate genes. In C8 isolated from serum, these are arranged as a disulfide-linked C8α-γ dimer that is noncovalently associated with C8β. In this study, a recombinant form of C8α-γ was expressed independently of C8β in insect cells and COS-7 cells and was shown to be equivalent to serum-derived C8α-γ with respect to its ability to combine with C8β and form functional C8. Also expressed separately were mutant (mut) forms of C8α and C8γ in which the single interchain disulfide bond was eliminated. MutC8α exhibited the ability to combine with C8β and express hemolytic activity, although at a lower level than human C8. Addition of purified mutC8γ increased this activity, presumably by binding to mutC8α. A possible role for C8γ as a retinol binding protein was also investigated. Absorbance spectroscopy and fluorescence emission and quenching revealed no specific binding of retinol to mutC8γ. Together, these results indicate that 1) the biosynthesis and secretion of C8α-γ is not dependent on C8β, which is consistent with in vivo observations in C8β-deficient humans; 2) C8α can be synthesized independently of C8γ; therefore, protection of C8α from premature membrane interactions during biosynthetic processing is not a likely function of C8γ; 3) C8γ enhances but is not required for expression of C8 activity; and 4) C8γ does not bind retinol; therefore, it cannot function as a retinol transport protein.
A Longitudinal Study of Type-Specific Antibody Responses toPlasmodium falciparumMerozoite Surface Protein-1 in an Area of Unstable Malaria in Sudan
Authors: Cavanagh David R. , Elhassan Ibrahim M. , Roper Cally , Robinson V. Jane , Giha Haider , Holder Anthony A. , Hviid Lars , Theander Thor G. , Arnot David E. , McBride Jana S. 
Published: January 2023

AbstractMerozoite surface protein-1 (MSP-1) of Plasmodium falciparum is a malaria vaccine candidate Ag. Immunity to MSP-1 has been implicated in protection against infection in animal models. However, MSP-1 is a polymorphic protein and its immune recognition by humans following infection is not well understood. We have compared the immunogenicity of conserved and polymorphic regions of MSP-1, the specificity of Ab responses to a polymorphic region of the Ag, and the duration of these responses in Sudanese villagers intermittently exposed to P. falciparum infections. Recombinant Ags representing the conserved N terminus (Block 1), the conserved C terminus, and the three main types of the major polymorphic region (Block 2) of MSP-1 were used to determine the specificity and longitudinal patterns of IgG Ab responses to MSP-1 in individuals. Abs from 52 donors were assessed before, during, and after malaria transmission seasons for 4 yr. Ags from the Block 1 region were rarely recognized by any donor. Responses to the C-terminal Ag occurred in the majority of acutely infected individuals and thus were a reliable indicator of recent clinical infection. Ags from the polymorphic Block 2 region of MSP-1 were recognized by many, although not all individuals after clinical malaria infections. Responses to Block 2 were type specific and correlated with PCR typing of parasites present at the time of infection. Responses to all of these Ags declined within a few months of drug treatment and parasite clearance, indicating that naturally induced human Ab responses to MSP-1 are short lived.
Lymphocyte Activation Gene-3 (LAG-3) Expression and IFN-γ Production Are Variably Coregulated in Different Human T Lymphocyte Subpopulations
Authors: Scala Enrico , Carbonari Maurizio , Del Porto Paola , Cibati Marina , Tedesco Tiziana , Mazzone Anna Maria , Paganelli Roberto , Fiorilli Massimo 
Published: January 2023

AbstractWe evaluated the relationship between cytokine profile and the expression of the lymphocyte activation gene-3 (LAG-3) in both T cell clones and polyclonal T cell lines; LAG-3 is a CD4-like protein whose expression is reportedly restricted to Th1/0 cells and dependent upon IFN-γ. We found that, while LAG-3 was expressed only by CD4+ T cell clones producing IFN-γ, most CD8+ clones producing IL-4 but not IFN-γ (i.e., with a T cytotoxic-2-like profile) were LAG-3+. The intensity of LAG-3 expression by CD8+ clones correlated with the amount of released IFN-γ, suggesting that this cytokine is not required for expression but rather for the up-regulation of LAG-3. Flow cytometric analyses of polyclonal T cell lines confirmed that LAG-3 could be expressed by both CD4+ and CD8+ cells that did not contain cytoplasmic IFN-γ. In these cell lines, large proportions of CD4+ and CD8+ cells coexpressed LAG-3 and CD30, a putative marker of Th2-like cells. Overall, our data do not support the earlier suggestion that LAG-3 and CD30 are selective markers of T cells with type-1 and type-2 cytokine profiles, respectively.
Polyclonality and Multispecificity of the CTL Response to a Single Viral Epitope
Authors: Ishikawa T. , Kono D. , Chung J. , Fowler P. , Theofilopoulos A. , Kakumu S. , Chisari F. V. 
Published: January 2023

AbstractThe molecular anatomy of an immunodominant, Ld restricted CTL epitope located between residues 28–39 in hepatitis B surface Ag was defined to explore the immunologic constraints on mutational escape from the CTL response during a viral infection. Using a panel of hepatitis B surface Ag residue 28–39-specific CTL clones, the response to this epitope was found to be extremely diverse at the level of TCR fine specificity and β-chain usage. Although each clone recognized shared as well as unique residues within the epitope as TCR contact sites, even the shared residues were recognized differently by different TCRs. Despite these differences, all clones were comparably cytolytic following Ag stimulation and produced similar amounts of antiviral cytokines previously shown to inhibit HBV replication. These results demonstrate that the CTL response to individual viral epitopes can be markedly polyclonal and multispecific, such that mutational inactivation of a single TCR contact site will not usually lead to viral escape from all CTL clones of the same epitope specificity. Given these constraints and the fact that the CTL response is usually directed against several different epitopes during most viral infections, mutational inactivation of a single epitope is not likely to be sufficient to cause viral persistence.
A Limited Role for β-Selection During γδ T Cell Development
Authors: Wilson Anne , MacDonald H. Robson 
Published: January 2023

AbstractT cells belong to two distinct lineages expressing either αβ or γδ TCR. During αβ T cell development, it is clearly established that productive rearrangement at the TCR β locus in immature precursor cells leads to the expression of a pre-TCR complex. Signaling through the pre-TCR results in the selective proliferation and maturation of TCR β+ cells, a process that is known as β-selection. However, the potential role of β-selection during γδ T cell development is controversial. Whereas PCR-RFLP and sequencing techniques have provided evidence for a bias toward in-frame VDJβ rearrangements in γδ cells (consistent with β-selection), γδ cells apparently develop normally in mice that are unable to assemble a pre-TCR complex due to a deficiency in TCR β or pTα genes. In this report, we have directly addressed the physiologic significance of β-selection during γδ cell development in normal mice by quantitating intracellular TCR β protein in γδ cells and correlating its presence with cell cycle status. Our results indicate that β-selection plays a significant (although limited) role in γδ cell development by selectively amplifying a minor subset of γδ precursor cells with productively rearranged TCR β genes.
Regulation of NF-κB, AP-1, NFAT, and STAT1 Nuclear Import in T Lymphocytes by Noninvasive Delivery of Peptide Carrying the Nuclear Localization Sequence of NF-κB p50
Authors: Torgerson Troy R. , Colosia Ann D. , Donahue John P. , Lin Yao-Zhong , Hawiger Jacek 
Published: January 2023

Abstract
Activation of T lymphocytes by Ags or cytokines results in translocation of the transcription factors NF-κB, AP-1, NFAT, and STAT from the cytoplasm into the nucleus. The first step in the nuclear import process is recognition of a nuclear localization sequence (NLS) within the karyophilic protein by a cytoplasmic receptor such as the importin (karyopherin)-α subunit. The NLSs of NF-κB, AP-1, and NFAT differ and the NLS of STAT1 has not yet been identified. Herein we demonstrate that the inducible nuclear import of NF-κB, AP-1, NFAT, and STAT1 in Jurkat T lymphocytes is significantly inhibited by a cell-permeable peptide carrying the NLS of the NF-κB p50 subunit. NLS peptide-mediated disruption of the nuclear import of these transcription factors results in inhibition of IκBα and IL-2 gene expression, processes dependent on NF-κB or the combination of NF-κB, AP-1, and NFAT. Further, we show that inhibitory NLS peptide interacts in vitro with a cytoplasmic NLS receptor complex comprised of the Rch1/importin (karyopherin)-β heterodimer expressed in Jurkat T cells. Taken together, these data indicate that the inducible nuclear import of NF-κB, AP-1, NFAT, and STAT1 in Jurkat T cells can be regulated by NLS peptide delivered noninvasively to the cytoplasm of Jurkat T cells to target members of the importin (karyopherin)-αβ NLS receptor complex.
Mice withSTAT6-Targeted Gene Disruption Develop a Th1 Response and Control Cutaneous Leishmaniasis
Authors: Stamm Luisa M. , Räisänen-Sokolowski Anne , Okano Mitsuhiro , Russell Mary E. , David John R. , Satoskar Abhay R. 
Published: January 2023

AbstractThe cutaneous growth of Leishmania mexicana was measured in STAT6-deficient mice (STAT6−/−) and compared with that in similarly infected wild-type (STAT6+/+) mice. Following s.c. inoculation with 5 × 106 amastigotes of L. mexicana into the shaven rump, STAT6+/+ mice developed large, nonhealing cutaneous lesions, while STAT6−/− mice failed to develop detectable lesions during most of the course of study. As infection progressed, STAT6+/+ mice infected with L. mexicana displayed significantly higher titers of Leishmania-specific IgG1 and IgE compared with STAT6−/− mice, which conversely produced significantly higher titers of Leishmania-specific IgG2a, indicating development of a Th1-like response in the latter group. At 12 wk postinfection, Leishmania Ag-stimulated lymph node cells from STAT6−/− mice produced significantly higher amounts of IL-12 and IFN-γ than those from STAT6+/+ mice as measured by ELISA. However, there was no significant difference in IL-4 production between the two groups. Semiquantitative RT-PCR of transcript levels in intact draining lymph nodes and skin from inoculation sites confirmed a similar pattern of cytokines in vivo as that observed in stimulated lymph node cells in vitro. These results indicate that STAT6-mediated IL-4 signaling is critical for progression of L. mexicana infection in genetically susceptible mice and demonstrate that in the absence of STAT6, susceptible mice default toward a Th1-like response and control cutaneous L. mexicana infection.
Experimental MurineTrypanosoma congolenseInfections. II. Role of Splenic Adherent CD3+ Thy1.2+ TCR-αβ− γδ− CD4+8− and CD3+ Thy1.2+ TCR-αβ− γδ− CD4−8− Cells in the Production of IL-4, IL-10, and IFN-γ and in Trypanosome-Elicited Immunosuppression
Authors: Uzonna Jude E. , Kaushik Radhey S. , Zhang Ying , Gordon John R. , Tabel Henry 
Published: January 2023

AbstractTrypanosome-induced suppression of T and B cell responses to parasite-related and -unrelated Ags is considered a major mechanism of evasion of the host’s immune defenses by the parasite. Reduced T and B cell responses have been attributed to suppressor T cells, suppressor macrophages, or both. We have previously shown that endogenously produced IL-10 and IFN-γ mediate the suppression of T cell responses in Trypanosoma congolense-infected mice. Here, we show for the first time that splenic CD3+ Thy1.2+ αβ− γδ− CD4+8− and CD3+ Thy1.2+ αβ− γδ− CD4−8− cells that copurify with plastic-, nylon wool-, or Sephadex G-10-adherent cell populations, in synergy with adherent Thy1.2− cells, are the major producers of IL-4, IL-10, and IFN-γ in T. congolense-infected mice. We further demonstrate the involvement of these cells in the suppression of T cell proliferative responses to mitogen and in B cell responses to a parasite-unrelated Ag.
Identification of a Truncated Form of the CC Chemokine CKβ-8 Demonstrating Greatly Enhanced Biological Activity
Authors: Macphee Colin H. , Appelbaum Edward R. , Johanson Kyung , Moores Kitty E. , Imburgia Christina S. , Fornwald Jim , Berkhout Theo , Brawner Mary , Groot Pieter H. E. , O’Donnell Kevin , O’Shannessy Daniel , Scott Gil , White John R. 
Published: January 2023

Abstract
A new CC chemokine, designated CKβ-8 or myeloid progenitor inhibitor factor-1, was recently identified in a large scale sequencing effort and was cloned from a human aortic endothelial library. CKβ-8 cDNA encodes a signal sequence of 21 amino acids, followed by a 99-amino acid predicted mature form. CKβ-8 was expressed and purified from a baculovirus insect cell expression system, which resulted in the identification of different N-terminal variants of the secreted chemokine. The three major forms (containing amino acids 1–99, 24–99, and 25–99 of the secreted chemokine) showed a large variation in potency. CKβ-8 activated both monocytes and eosinophils to mobilize intracellular calcium; however, the shortest form of CKβ-8 (25–99) was &gt;2 orders of magnitude more potent than the longest form. Cross-desensitization experiments in both monocytes and eosinophils suggested that the CCR1 receptor was probably the predominant receptor that mediates this chemokine’s physiologic response. However, incomplete desensitization was encountered in both cell systems, suggesting involvement of an additional receptor(s). Interestingly, the short form of CKβ-8 was the most potent chemotactic chemokine that we have ever evaluated in the monocyte system (EC50 = 54 pM). However, in contrast to its action on monocytes, CKβ-8 was a very poor chemotactic factor for eosinophils.
A High Endothelial Cell-Derived Chemokine Induces Rapid, Efficient, and Subset-Selective Arrest of Rolling T Lymphocytes on a Reconstituted Endothelial Substrate
Authors: Tangemann Kirsten , Gunn Michael D. , Giblin Patricia , Rosen Steven D. 
Published: January 2023

Abstract
The homing of lymphocytes to secondary lymphoid organs is thought to involve the action of chemokines. Secondary lymphoid- tissue chemokine (SLC), a high endothelial venule (HEV)-associated chemokine, has emerged as a candidate for participating in this process. We now show that immobilized SLC strongly induces β2 integrin-mediated binding of T lymphocytes of naive phenotype and B lymphocytes to ICAM-1 under static conditions. This effect is not mediated by β2 integrin affinity modulation, because SLC does not elicit a β2 integrin activation epitope (mAb24) on naive T lymphocytes. In a parallel plate flow chamber, lymphocytes rolling via L-selectin are rapidly arrested through β2 integrins in a pertussis toxin-sensitive manner on a substrate consisting of L-selectin ligands (peripheral lymph node addressins) together with ICAM-1 and SLC. Naive T lymphocytes are arrested on the HEV substrate with sixfold higher efficiency than memory cells. Neutrophils roll, but are not arrested by SLC, whereas they respond to immobilized IL-8 with rapid arrest. Thus, our artificial HEV system recapitulates critical features of lymphocyte interactions with HEV in vivo. These observations strongly point to the participation of SLC in homing of lymphocytes to secondary lymphoid organs.
Mechanisms of Nasal Tolerance Induction in Experimental Autoimmune Myasthenia Gravis: Identification of Regulatory Cells
Authors: Shi Fu-Dong , Li Hulun , Wang Huabing , Bai Xuefeng , van der Meide Peter H. , Link Hans , Ljunggren Hans-Gustaf 
Published: January 2023

Abstract
Autoantigen administration via nasal mucosal tissue can induce systemic tolerance more effectively than oral administration in a number of experimental autoimmune diseases, including Ab-mediated experimental autoimmune myasthenia gravis, a murine model of myasthenia gravis. The mechanisms underlying nasal tolerance induction are not clear. In this study, we show that nasal administration of acetylcholine receptor (AChR) in C57BL/6 mice, before immunizations with AChR in adjuvant, results in delayed onset and reduced muscle weakness compared with control mice. The delayed onset and reduced muscle weakness were associated with decreased AChR-specific lymphocyte proliferation and decreased levels of anti-AChR Abs of the IgG2a and IgG2b isotypes in serum. The clinical and immunological changes in the AChR-pretreated C57BL/6 wild-type (wt) mice were comparable with those observed in AChR-pretreated CD8−/− mice, indicating that CD8+ T cells were not required for the generation of nasal tolerance. AChR-pretreated wt and CD8−/− mice showed augmented TGF-β and reduced IFN-γ responses, whereas levels of IL-4 were unaltered. Splenocytes from AChR-pretreated wt and CD8−/− mice, but not from CD4−/− mice, suppressed AChR-specific lymphocyte proliferation. This suppression could be blocked by Abs against TGF-β. Thus, our results demonstrate that the suppression induced in the present model is independent of CD8+ T cells and suggest the involvement of Ag-specific CD4+ Th3 cells producing TGF-β.