bluuebunny/crossref_metadata_2025_split huggingface dataset:
Regulation of B-lineage specification by the IL-7/JAK3/STAT5 pathway (83.6)
Authors: Gerstein Rachel Maurie , Tian Linhua , Wallace Morgan , De Pallabi , Prince Amanda , Berg Leslie , Allman David 
Published: January 2023

Abstract
The cytokine IL-7 is essential for early B cell development in adult bone marrow. We previously showed that B cell genesis arrests at the common lymphoid progenitor (CLP) stage in mice lacking the common gamma chain or the alpha-chain of the IL-7 receptor (IL-7R). Other studies suggest that CLPs are enriched for B-lineage specified (but uncommitted) precursors, as CLPs are not requisite for T cell development, and V(D)J recombinase activity in CLPs requires a B-specific enhancer element in the RAG locus. Here we probe events downstream of the IL-7R that promote B-lineage specification. We find that JAK3, the principal kinase downstream of the IL-7R, is essential for B cell development beyond the CLP stage. We further demonstrate that JAK3-deficient CLPs exhibit a dramatic loss in RAG1/2 expression and V(D)J recombinase activity. JAK3-null CLPs also lacked transcripts for EBF1, a B-lineage restricted transcription factor previously suggested to promote RAG expression. We also find that conditional inactivation of STAT5, the key transcription factor activated by JAK3, results in loss of B-lineage precursors beyond the CLP and diminished V(D)J recombinase activity. Together these data suggest that IL-7R activation of the JAK3/STAT5 pathway plays a key role in initiating several molecular events required for early B cell development in CLPs.
Novel aspects of the FADD function in lymphocytes revealed using hypomorphic FADD mutant and conditinal FADD-deficient mice (84.4)
Authors: Zhang Jianke , Imtiyaz Hongxia , Rosenberg Stephen 
Published: January 2023

Abstract
FADD was initially isolated as a death domain-containing protein interacting with the death receptor Fas. In the context of apoptotic signal transduction, the death domain of FADD interacts directly with the death domain of Fas and the death effector domain of FADD interacts with the death effector domain of pro-caspase-8. This leads to activation of the apical caspase-8 and subsequently downstream caspases such as caspase-3, -6 and -7. Fas-induced apoptosis is essential for maintaining lymphoid homeostasis and suppressing autoimmunity. Mutations in the Fas gene result in massive accumulation of lymphocytes of potential auto-reactivity, and lead to lymphadenopathy and autoimmune diseases in the mouse and human. However, deletion of FADD resulted in early embryonic lethality. To further analyze the function of FADD, we generated several lines of mutant mice carrying point mutations of FADD. Analysis these hypomorphic mutant mice as well as the previously generated conditional FADD-deficient mice revealed novel aspects of the mechanism involved in the regulation of innate and adaptive immune responses mediated by FADD.
T CELLS UNDERGO ASYMMETRIC CELL DIVISION – A NEW MECHANISM TO DICTATE T CELL FATE (84.5)
Authors: Russell Sarah May , Oliaro Jane , Pasam Anupama , Sacirbegovic Faruk , Pham Kim 
Published: January 2023

Abstract
We have previously shown that T cells utilize an evolutionarily conserved network of polarity proteins to orchestrate cell shape and polarity, and that these proteins are required for migration and immunological synapse formation in T cells (1). We describe here in vitro evidence using the OT-1 model system that T cells utilize this polarity network to conduct a physiological process not previously ascribed to lymphocytes, that of asymmetric cell division. We demonstrate that naive T cells remain attached to antigen presenting cells (dendritic cells pulsed with ovalbumin peptide) throughout cell division, and utilize this attachment to orient their axis of cell division. By maintaining the asymmetry originally associated with immunological synapse formation, the daughters of the T cell division inherit different molecular characteristics, which provide the capacity to dictate different subsequent fates.
A network of PDZ-containing proteins regulates T cell polarity and morphology in motility and immunological synapse formation
Runx1/AML1 and hematopoietic dysplasia (84.6)
Authors: Telfer Janice C , Malcuit Nancy , Hedblom Emmett , Kane Christyne 
Published: January 2023

Abstract
We expressed several mutated forms of the Runx1 transcription factor in hematopoietic stem cells (HSC) and used them to reconstitute lethally irradiated mice. We found that the Runx1 mutant truncated shortly after the DNA-binding runt domain (Runx1.d190) transported appropriately to the nucleus and had strong dominant negative activity. Surprisingly, Runx1 mutants truncated before the runt DNA-binding site (Runx1.d49) also reiterated some of the effects of the Runx1.d190 dominant negative mutant, despite the lack of a nuclear localization site and DNA-binding capacity, suggesting that the N-terminus plays an active role in some Runx functions and that the N-terminal activity may be significant in Runx mutants lacking DNA-binding activity. The Runx1.d190 mutant, when expressed in HSC, results in the expansion of the cellular compartment containing HSC. In a competitive reconstitution in a lethally irradiated mouse, these Runx1.d190-positive cells and their progeny almost totally out-compete untransduced cells and their progeny. Some of the Runx1.d190-positive hematopoietic stem cells are able to reconstitute a sub-lethally irradiated mouse in all hematopoietic lineages and maintain that reconstitution for over a year, indicating transformation of a hematopoietic stem cell or its immediate progeny. The progeny of the Runx1.d190-positive hematopoietic stem cells are defective in several lineages, such as B cells, T cells, neutrophils, megakaryocytes, and erythrocytes. There is a significant loss of erythropoiesis in the bone marrow and the occurrence of splenic extramedullary hematopoiesis.
Impaired GATA3-dependent chromatin remodeling and Th2 cell differentiation leading to attenuated allergic airway inflammation in aging mice (85.1)
Authors: Hasegawa Akihiro , Nakayama Toshinori 
Published: January 2023

Abstract
Age-related changes in lymphocytes are most prominent in the T cell compartment. In the present study, we used 8–12 month-old aging mice and a well-established in vitro Th1/Th2 cell differentiation culture system to identify molecular defects in Th1/Th2 cell differentiation that can be detected in the relatively early stages of aging. The capability to differentiate into Th2 cells is reduced in aging mouse CD4+ T cells. Decreased activation of the ERK MAPK cascade upon TCR stimulation, but normal [Ca2+]i mobilization and normal IL-4-induced STAT6 activation were observed in aging mouse CD4+ T cells. In addition, reduced expression of GATA3 was detected in developing Th2 cells. Chromatin remodeling of the Th2 cytokine gene locus was found to be impaired. Th2-dependent allergic airway inflammation was milder in aging mice compared with in young adult mice. These results suggest that the levels of Th2 cell differentiation and resulting Th2-dependent immune responses, including allergic airway inflammation, decline during aging through defects in the activation of the ERK MAPK cascade, expression of GATA3 protein and GATA3-dependent chromatin remodeling of the Th2 cytokine gene locus. In the present study, we provide the first evidence indicating that a chromatin-remodeling event in T cells is impaired by aging.
Neonatal recent thymic emigrants (RTE): phenotypic and functional comparison to adult RTE (85.16)
Authors: Opiela Shannon Jacqueline , Adkins Becky 
Published: January 2023

Abstract
Neonatal CD4+ T cells typically produce high levels of IL-4, resulting in Th2-biased responses. The neonatal CD4+ compartment contains a high frequency of recent thymic emigrants (RTE), in contrast to the small proportion found in adults. Using intrathymic labeling to identify RTE, it has been described that adult RTE produce high levels of IL-4. Thus, neonatal Th2 biased responses may result from their over-represented RTE population. Here we have compared neonatal and adult CD4+ RTE for the first time, using a mouse strain that allows for the identification and purification of RTE from the periphery. In contrast to the intrathymic labeling system, adult RTE from these mice produced less IL-4 and IFNγ than the resident cells. Similarly, neonatal RTE produced less of both IL-4 and IFNγ than resident neonatal cells. The phenotypic changes accompanying post-thymic maturation of RTE were also similar in neonates and adults. Thus, both neonatal and adult RTE appear to require a period of post-thymic maturation to acquire mature Th2 and Th1 function and phenotype. Importantly, despite these similarities, neonatal RTE produced more IL-4 than adult RTE. Together, these results indicate that neonatal and adult RTE differ functionally but the subsequent processes of post-thymic maturation are similar in early development and adult life.
This work was supported by NIAID grant number R01 AI44923-02 (B.A.)
Effector CD8 T cells transit to memory cells in the presence of tumor-associated antigen (85.17)
Authors: Rolle Cleo E. , Carrio Roberto , Malek Thomas R. 
Published: January 2023

Abstract
It is difficult to study the time frame and requirements for antigen removal as CD8 T effector cells transit to memory cells during an immune response because memory cells only readily appear after contraction of the effector response and clearance of antigen. To overcome these limitations, we have modeled the effector to memory transition in vitro and by the adoptive transfer of effector CTL to normal mice. When OVA-specific OT-I CTL were cultured in IL-15 without antigen, they acquired phenotypic and functional properties of memory cells 48 hr later. Such memory conversion occurred in the presence of 0.01 nM OVA peptide and APC, a dose that only induces a strong recall response, but not at a higher dose (0.1 nM) that readily activates naïve OT-I T cells. Following adoptive transfer of OT-I CTL to antigen-free normal mice, OT-I effector cells developed into central memory-like cells by 3 days post-transfer. Upon adoptive transfer to mice bearing the OVA-expressing E.G7 tumor, the OT-I CTL effector cells also readily converted to memory-like cells by day 3 post-transfer while the effector cells rejected the tumor. However, under conditions where the tumor was not cleared, memory production was impaired. Collectively, these data suggest that some CTL rapidly convert to memory cells concurrent with an effector response, without complete clearance of antigen, provided that antigen level is not too high.
(Supported by the NIH)
Epigenetic patterns at the neonatal Th2 cytokine locus are developmentally regulated (85.2)
Authors: Foote Monica Ruth , Rose Shawn , Lichtenheld Mathias , Adkins Becky 
Published: January 2023

Abstract
Murine neonatal immune responses are commonly Th2 biased, characterized by rapid and high level Th2 cytokine production. These Th2-biased responses entail cell-intrinsic properties whose molecular basis is now beginning to become unveiled. We have recently found that the Th2 regulatory region CNS-1 is nearly 25% more demethylated in naïve neonatal CD4+ lymph node T cells and in CD4+ single positive (SP) thymocytes than in the same adult populations. Importantly, IL-4-expressing neonatal thymocytes exhibit substantially greater levels of hypomethylation at CNS-1 compared to unactivated cells. These results suggest that a hypomethylated state at CNS-1 is permissive for IL-4 expression in neonatal cells. Additional studies have revealed that CNS-1 exists in this highly demethylated state in freshly isolated fetal (d15 gestation) thymocytes, which are predominantly double negative cells and are the precursors of CD4+ SP thymocytes found in the neonate. These new findings suggest that epigenetic patterns at the neonatal Th2 cytokine locus are established within the fetal thymus, or even earlier, possibly in fetal liver precursor cells. Together, these observations lead to the intriguing idea that epigenetic modifications may be used as a developmental strategy within the CD4+ T helper cell lineage to achieve differential expression of cytokine genes at different times of life.
This work was supported by NIAID grant number R01 AI44923-02 (B.A.).
Effects of aging on the ability of B lymphocytes to undergo early activation events and their proliferative capability (85.26)
Authors: Blaeser Tony Ryan , McGlauchlen Kiley S , Vogel Laura A 
Published: January 2023

Abstract
Dysfunction of the humoral immune response is associated with aging. It is uncertain, however, if this dysfunction is due to intrinsic B cell defects or defects of the aged microenvironment, such as lack of appropriate T cell help. Previous in vivo studies by our lab found decreased antigen-induced expansion by aged B cells but could not rule out the possibility of decreased migration. Here we examine early activation events in vitro in response to anti-CD40 and LPS stimulation. Aged B cells showed similar resting levels of CD40 to that of their young counterparts but were less able to respond to CD40 induced signals. Aged cells were defective in their ability to down-regulate CD38 and up-regulate CD69 over a 48 hour period. Aged cells, however, were able to up-regulate CD86 at similar levels to that of young cells. There also was a decrease in blast formation with aged B-lymphocytes as well as slightly decreased proliferative response. Hence, aged B cells appear to be defective in their response to some early activation events but appear to always show a partial response.
Costimulation through ICAM-1 induces differentiation of naive human CD4+ T cells from aging individuals (85.27)
Authors: Dotson Abby L. , Kohlmeier Jacob E. , Cool Kelli M. , Benedict Stephen H. 
Published: January 2023

Abstract
With age, the immune response is less effective at protection and less responsive to vaccines. The events leading to immunosenescence have not been fully described. We have been investigating the hypothesis that the nature of the T cell costimulatory signal governs in part the phenotype of the post thymic developing naïve T cell as it responds to cognate antigen. The costimulatory molecules, CD28 and LFA-1 are the best characterized; however we have demonstrated that ICAM-1, resident on a T cell, can receive signals that drive naïve human CD4+ T cells taken from young individuals to effector and memory phenotypes that differ from those induced by CD28 or LFA-1. For the present study, we are investigating the participation of these three costimulatory signals in activation and differentiation of human naive CD4+ T cells from aging individuals. We will describe differential effects on development in response to costimulation of naïve T cells taken from older as compared with young human subjects.
TRAF3 is a critical regulator of B cell homeostasis in secondary lymphoid organs (86.2)
Authors: Xie Ping , Stunz Laura L , Larison Karen D , Yang Baoli , Bishop Gail A 
Published: January 2023

Abstract
TRAF3, a cytoplasmic adaptor protein, is utilized by receptors of the tumor necrosis factor receptor (TNF-R) superfamily and Toll-like receptors for signaling. Despite in vitro evidence that TRAF3 plays diverse roles in different cell types, little is known about the in vivo functions of TRAF3. To address this gap in knowledge and to circumvent the early lethal effect of TRAF3 null mutations, we generated conditional TRAF3-deficient mice. We found that specific ablation of TRAF3 in the B cell lineage led to remarkably prolonged B cell survival and greatly expanded B cell compartments in secondary lymphoid organs. This culminated in splenomegaly and lymphadenopathy, hyperimmunoglobulinemia, and autoimmune reactivity. These findings identify a novel critical role for TRAF3 in regulating B cell homeostasis in secondary lymphoid organs, and implicate the involvement of TRAF3 in peripheral self-tolerance induction.
This study is supported by a grant from the American Heart Association (PX), NIH grants AI28847, AI49993, CA099997, and a VA Career Award (GAB).
Class IA PI3K is involved in the pre-B cell antigen receptor-mediated signaling (86.6)
Authors: Koyasu Shigeo , Fujiwara Mari , Matsuda Satoshi , Kadowaki Takashi , Kawano Yohei , Maki Kazushige , Karasuyama Hajime 
Published: January 2023

Abstract
We have previously generated p85α−/− mice deficient for the most abundantly and ubiquitously expressed regulatory subunit of class IA PI3Ks. In p85α−/− mice, B cell development from pro-B cells to pre-B cells in the bone marrow is impaired and the number of mature B cells in the periphery is decreased. Here we further investigated the role of PI3K in early B cell development. First, we crossed p85α−/− mice with a transgenic mouse line expressing rearranged IgH and IgL chains Ig(H+L) specific for hen egg lysozyme (Hel-Tg). Introduction of functional Ig(H+L) chains did not restore the number of peripheral B cells in mice on a p85α−/− background. We next crossed p85α−/− mice with Rag-2−/− mice to generate p85α−/−Rag-2−/− double deficient mice. We compared the transition from B200+c-kit+CD25− pro-B cell stage to the B200+c-kit−CD25+ pre-B cell stage upon anti-Igβ antibody injection between Rag-2−/− mice and p85α−/−Rag-2−/− double deficient mice. While B200+c-kit−CD25+ cells were readily observed in Rag-2−/− mice after administration of anti-Igβ antibody, such transition was impaired in p85α−/−Rag-2−/− double deficient mice, indicating that the class IA PI3K is involved in the pre-BCR signaling. Our results indicate that class IA PI3K is important in pre-B cell antigen receptor-mediated signaling to induce pre-B cell expansion rather than the Ig gene rearrangement.
NON-APOPTOTIC INDUCTION OF CASPASE-8 IN T-CELLS DEPENDS ON FADD AND CELL CYCLE PROGRESSION (87.1)
Authors: Leverrier Sabrina , Weist Brian M , Walsh Craig M 
Published: January 2023

Abstract
Upon triggering of apoptosis by tumor necrosis factor (TNF) receptor family member engagement, FADD (Fas-Associated Death Domain-containing protein) acts as an adaptor protein by recruiting caspase-8 and promoting its autocatalytic activation. Surprisingly, it was found that FADD and caspase-8 are also critical for T lymphocytes proliferation. Indeed, T cell specific overexpression of a FADD dominant-negative mutant (FADDdd) or conditional deletion of caspase-8 or FADD in T cells leads to profound defects in proliferation. While it is known that FADD transmits an apoptotic signal by recruiting caspase-8 within the cytoplasm, it is unclear how FADD and caspase-8 promote T cell proliferation. Since it has been shown that both proteins can localize within the nucleus, we investigated caspase-8 catalytic activity in the nucleus of proliferating T cells and detected an increasing level of caspase-8 activity upon stimulation with anti-CD3 and anti-CD28. Using FADDdd T cells, we determined that this nuclear catalytic activity was dependent on normal FADD function. Blocking cell cycle progression at different stages also drastically reduced caspase-8 activation in non-apoptotic T cells, whereas inhibiting TNF receptor activation did not appreciably diminish caspase-8 activity. We are currently attempting to identify caspase-8 nuclear substrates involved in T-cell proliferation. Taken together, our results suggest that specific subcellular compartmentalization is associated with a distinct magnitude in caspase-8 activity, possibly leading to new substrate selectivity during cell cycle progression. These findings may explain how two apoptotic regulatory proteins, FADD and caspase-8, alternatively promote cell death or proliferation in T cells.
IFN-gamma production by CD4 T cells requires Histamine H1 receptor during their initial phase of activation (87.25)
Authors: Noubade Rajkumar , Rincon Mercedes , Teuscher Cory 
Published: January 2023

Abstract
Histamine H1 receptor (H1R) signaling in T cells plays an important role Th1 effector functions. H1R is an autoimmune susceptibility gene controlling experimental autoimmune encephalomyelitis (EAE). H1R knockout (H1RKO) mice also develop significantly less severe EAE compared to C57BL/6J wild-type mice in association with immune deviation of the CD4+ T-cell response from a Th1- to a Th2-like response. Little is known about the role of direct H1R signaling in the regulation of T-cell effector responses. In this study, T-cells from C57BL/6J and H1RKO mice were used to study H1R signaling in directly regulating such responses. Attempts to restore IFN-gamma&#61472;production in H1RKO T-cells following retroviral transduction of the H1R were unsuccessful. In contrast, H1RKO transgenic mice selectively expressing the H1R in peripheral CD4+ T-cells under the control of the distal-lck promoter restored the IFN-gamma response and susceptibility to EAE in an H1R gene dose-dependent fashion. Moreover, activated H1RKO CD4+ T-cells show reduced phosphorylation of p38 MAP kinase compared to T-cells from wild-type mice which was again restored in activated T-cells from transgenic mice. These results show that H1R signaling regulates IFN-gamma production in CD4+ effector T-cells by direct signaling during initial activation of naïve T-cells through phosphorylation of p38 MAP kinase.
Upregulation of Th1-specific transcription factors and inflammatory responses by IFNg and IL27 in splenocytes from estrogen treated mice (87.33)
Authors: Karpuzoglu Ebru , Phillips Rebecca A , Dai Rujuan , Lengi Andrea J , Ahmed S. Ansar 
Published: January 2023

Abstract
Estrogen, an immunomodulator, is believed to be involved in many autoimmune inflammatory conditions. We reported that estrogen treatment of C57BL/6 mice favors the induction of Th1 responses such as secretion of IFNγ. However, the mechanisms involved in response to IFNγ are not well known. Therefore, we investigated the molecular pathways in splenocytes from estrogen-treated mice following in vitro exposure to Th1(IFNγ)-inducing cytokines: IFNγ, IL12 and IL27. ConA activated splenocytes from estrogen treated mice induced an IFNγ-dependent-increase in iNOS, nitric oxide, COX2 and MCP1. In vitro addition of IFNγto ConA activated splenocytes from IFNγ −/− mice induced iNOS and MCP1 primarily in estrogen-treated mice. Since IFNγ is a potent inducer of IRF1, interestingly that neither direct addition of IFNγ to splenocytes from wildtype or IFNγ −/− mice nor the addition of IFNγ to T cells, induced IRF1 in cells from estrogen-treated mice. Activated splenocytes from estrogen-treated mice had noticeably increased levels of the IFNγ-specific transcription factor T-bet, although there were no marked changes in phosphorylated STAT1. Estrogen-induced upregulation of T-bet was largely due to IFNγ and IL27, but not IL12. Thus, these findings contribute novel insight regarding the pro-inflammatory effects of estrogen on the immune system and may lead to novel therapeutic approaches for autoimmune diseases.
Supported by NIH grant 5RO1 AI51880.