bluuebunny/crossref_metadata_2025_split huggingface dataset:
Allylstannation of N‐Acyliminium Intermediates: A Possible Method for the Stereocontrolled Synthesis of Polyhydroxypiperidines.
Authors: Chevallier Floris , Beaudet Isabelle , Le Grognec Erwan , Toupet Loic , Quintard Jean‐Paul 
Published: April 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
Discovery of a Potent, Selective and Orally Active Canine COX‐2 Inhibitor, 2‐(3‐Difluoromethyl‐5‐phenyl‐pyrazol‐1‐yl)‐5‐methanesulfonyl‐pyridine.
Authors: Li Jin , et al. et al. 
Published: April 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
New Orally Active PDF4 Inhibitors with Therapeutic Potential.
Authors: Ochiai Hiroshi , Ishida Akiharu , Ohtani Tazumi , Kusumi Kensuke , Kishikawa Katuya , Obata Takaaki , Nakai Hisao , Toda Masaaki 
Published: April 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
Synthesis of Fused Dihydropyrimidinones from Cyclic‐1,3‐dicarbonyl Compounds: Modified Biginelli Synthesis of 1,2,3,4,5,6,7,8‐Octahydroquinazolinediones and 3,4‐Dihydro‐1H‐indeno[1,2‐d]pyrimidine‐2,5‐diones.
Authors: Shanmugam Pachaiyappan , Sabastein Cruz , Perumal Paramasivan T. 
Published: April 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
Thiadiazolyl Quinazolones as Potential Antiviral and Antihypertensive Agents.
Authors: Pandey V. K. , Tusi Sarah , Tusi Zehra , Raghubir R. , Dixit M. , Joshi M. N. , Bajpai S. K. 
Published: April 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
Reaction of 2‐Amino‐4‐arylamino‐6‐chloromethyl‐sym‐triazines with S,O‐Nucleophiles.
Authors: Krylski D. W. , Shikhaliev Kh. S. , Liberman M. M. , Solov'ev A. S. 
Published: April 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
A Trypanocidal Diterpene with Novel Skeleton from Dracocephalum komarovi.
Authors: Uchiyama Nahoko , Ito Michiho , Kiuchi Fumiyuki , Honda Gisho , Takeda Yoshio , Khodzhimatov Olimjon K. , Ashurmetov Ozodbek A. 
Published: April 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
CBr4‐Photoirradiation Protocol for Chemoselective Deprotection of Acid Labile Primary Hydroxyl Protecting Groups.
Authors: Chen Ming‐Yi , Patkar Laxmikant N. , Jan Mi‐Dan , Lee Adam Shih‐Yuan , Lin Chun‐Cheng 
Published: April 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
Directed Phosphorylation of 2‐C‐Hydroxymethyl‐2,3:5,6‐di‐O‐isopropylidene‐D‐mannofuranose.
Authors: Lipovtsin E. V. , Koroteev M. P. , Vasyanina L. K. , Nifant'ev E. E. 
Published: April 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
Total Synthesis of (+)‐Phorboxazole A, a Potent Cytostatic Agent from the Sponge Phorbas sp.
Authors: Pattenden Gerald , Gonzalez Miguel A. , Little Paul B. , Millan David S. , Plowright Alleyn T. , Tornos James A. , Ye Tao 
Published: April 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
Two New Furanocoumarins from the Roots of Angelica dahurica
Authors: Lee Seung‐Ho , Li Gao , Kim Hyo‐Jin , Kim Ji‐Yeon , Chang Hyeun‐Wook , Jahng Yurngdong , Woo Mi‐Hee , Song Dong‐Keun , Son Jong‐Keun 
Published: April 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
Formation of Zn1‐xMnxS Nanowires within Mesoporous Silica of Different Pore Sizes.
Authors: Brieler Felix J. , Grundmann Petra , Froeba Michael , Chen Limei , Klar Peter J. , Heimbrodt Wolfram , Krug von Nidda Hans‐Albrecht , Kurz Thomas , Loidl Alois 
Published: April 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
Dome‐Shaped Magnetic Phase Diagram of Thermoelectric Layered Cobaltites
Authors: Sugiyama J. , Brewer J. H. , Ansaldo E. J. , Itahara H. , Tani T. , Mikami M. , Mori Y. , Sasaki T. , Hebert S. , Maignan A. 
Published: April 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
Structure—Reactivity Correlations in Extended Multiporphyrinic Architectures
Authors: Solladie Nathalie , Aubert Nicolas , Bouatra Souhaila , Bourgogne Cyril , Bregier Frederique , Brettar Julie , Gisselbrecht Jean‐Paul , Gross Maurice , Rein Regis , Sooambar Chloe , et al. et al. 
Published: April 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
Stabilization of New Forms of the Intermetallic Phases β‐LnNiGe2 (Ln: Dy, Ho, Er, Tm, Yb, Lu) in Liquid Indium.
Authors: Salvador J. R. , Gour J. R. , Bilc D. , Mahanti S. D. , Kanatzidis M. G. 
Published: April 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
Highly Enantioselective Spiro Cyclization of 1,6‐Enynes Catalyzed by Cationic Skewphos Rhodium(I) Complex.
Authors: Mikami Koichi , Yusa Yukinori , Hatano Manabu , Wakabayashi Kazuki , Aikawa Kohsuke 
Published: April 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
Practical Synthesis of New and Highly Efficient Ligands for the Suzuki Reaction of Aryl Chlorides.
Authors: Zapf Alexander , Jackstell Ralf , Rataboul Franck , Riermeier Thomas , Monsees Axel , Fuhrmann Christa , Shaikh Nadim , Dingerdissen Uwe , Beller Matthias 
Published: April 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
Synthesis of α‐Ketobutyrolactones and γ‐Hydroxy‐α‐Keto Acids.
Authors: Kang Han‐Young , Ji Yumi , Yu Yeon‐Kwon , Yu Ji‐Yeon , Lee Younghoon , Lee Sang‐Joon 
Published: April 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
Benzo[c][2,7]naphthyridines from 2,6‐Dinor‐nifedipine and Its Dimethyl 2,5‐Dicarboxylate Isomer.
Authors: Goerlitzer K. , Bode M. , Frohberg P. , Drutkowski G. 
Published: April 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
Synthesis of Functionally Substituted Pyrrolo[3,2‐h]quinolines from 2,3‐Dimethyl‐ and 1,2,3‐Trimethyl‐7‐aminoindoles.
Authors: Yamashkin S. A. , Romanova G. A. , Romanova I. S. , Yurovskaya M. A. 
Published: April 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
Synthesis of Potent and Selective 2‐Azepanone Inhibitors of Human Tryptase.
Authors: Zhao Guohua , Bolton Scott A. , Kwon Chet , Hartl Karen S. , Seiler Steven M. , Slusarchyk William A. , Sutton James C. , Bisacchi Gregory S. 
Published: April 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
Synthesis and Cardiovascular Activity of Metoprolol Analogues.
Authors: Melgar‐Fernandez Roberto , Demare Patricia , Hong Enrique , Rosas Miguel Angel , Escalante Jaime , Munoz‐Muniz Omar , Juaristi Eusebio , Regla Ignacio 
Published: April 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
Large‐Scale Synthesis of High‐Quality Single‐Walled Carbon Nanotubes by Catalytic Decomposition of Ethylene.
Authors: Lyu S. C. , Liu B. C. , Lee S. H. , Park C. Y. , Kang H. K. , Yang C. W. , Lee C. J. 
Published: April 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
Roles for two partially redundant α‐tubulins during mitosis in early Caenorhabditis elegans embryos
Authors: Phillips Jennifer B. , Lyczak Rebecca , Ellis Gregory C. , Bowerman Bruce 
Published: April 2004

AbstractThe Caenorhabditis elegans genome encodes multiple isotypes of α‐tubulin and β‐tubulin. Roles for a number of these tubulins in neuronal development have been described, but less is known about the isoforms that function during early embryonic development. Microtubules are required for multiple events after fertilization produces a one‐cell zygote in C. elegans, including pronuclear migration, mitotic spindle assembly and function, and proper spindle positioning. Here we describe a conditional and dominant mis‐sense mutation in the C. elegans α‐tubulin gene tba‐1 that disrupts pronuclear migration and positioning of the first mitotic spindle, and results in a highly penetrant embryonic lethality, at the restrictive temperature of 26°C. Our analysis of the dominant tba‐1 (or346ts) allele suggests that TBA‐1 assembles into microtubules in early embryonic cells. However, we also show that reduction of tba‐1 function using RNA interference results in defects much less severe than those caused by the dominant or346ts mutation, due to partial redundancy of TBA‐1 and another α‐tubulin called TBA‐2. Reducing the function of both TBA‐1 and TBA‐2 results in severe defects in microtubule‐dependent processes. We conclude that microtubules in the early C. elegans embryo are composed of both TBA‐1 and TBA‐2, and that the dominant tba‐1(or346ts) mutation disrupts MT assembly or stability. Cell Motil. Cytoskeleton 58:112–126, 2004. © 2004 Wiley‐Liss, Inc.
P53 and K‐ras mutations are frequent events in microscopically negative surgical margins from patients with nonsmall cell lung carcinoma
Authors: Jassem Jacek , Jassem Ewa , Jakóbkiewicz‐Banecka Joanna , Rzyman Witold , Badzio Andrzej , Dziadziuszko Rafał , Kobierska‐Gulida Grażyna , Szymanowska Amelia , Skrzypski Marcin , Żylicz Maciej 
Published: April 2004

AbstractBACKGROUNDThe objective of the current study was to determine whether tumor cells harboring P53 and K‐ras mutations could be detected in histopathologically tumor‐free surgical margins in patients with nonsmall cell lung carcinoma who underwent complete pulmonary resection.METHODSIn 118 consecutive patients, DNA obtained from primary tumors and from surgical margins was extracted for molecular analysis. A fragment of P53 gene encompassing exons 5–8 and codon 12 of the K‐ras gene were amplified with the polymerase chain reaction technique and were assayed for the presence of mutations.RESULTSP53 and K‐ras mutations were found in 30% and 39% of primary tumors, respectively, and in 11 (9%) and 22 (18%) apparently tumor‐free surgical margins, respectively. At least 1 of those mutations was found in surgical margins in 29 patients (25%), and both mutations were found in 2 patients (1.7%). P53 mutations in surgical margins accompanied mutations in primary tumors in 9 of 35 patients (26%), and K‐ras mutations accompanied mutations in primary tumors in 20 of 46 patients (44%). Among patients with either mutation in primary tumors, the incidence of at least 1 mutation in surgical margins was 43% (28 of 65 patients). In four patients, mutations (two K‐ras mutations and two P53 mutations) were found in surgical margins despite the absence of the corresponding mutations in primary tumors. The presence of mutations in primary tumors and in surgical margins was not related significantly to clinical characteristics or to patient outcomes.CONCLUSIONSP53 and K‐ras mutations are frequent events in surgical margins determined to be tumor free on light microscopy. The clinical relevance of these findings remains to be established. Cancer 2004. © 2004 American Cancer Society.
Gemcitabine‐related radiation recall preferentially involves internal tissue and organs
Authors: Friedlander Philip A. , Bansal Roopa , Schwartz Lawrence , Wagman Raquel , Posner Jerome , Kemeny Nancy 
Published: April 2004

AbstractRadiation recall refers to inflammatory reactions triggered by cytotoxic agents and develops in previously irradiated areas. Most reactions develop cutaneously. The most common chemotherapeutic agents implicated are anthracyclines and taxanes. Gemcitabine, a nucleotide analog, recently was implicated in several cases. The authors performed a literature search using PubMed and the search terms “gemcitabine” and “radiation recall” to find prior cases of radiation recall attributed to gemcitabine. These cases were compared with those attributed to anthracyclines and taxanes. The literature search found 12 cases of radiation recall caused by gemcitabine. The authors also determined that their case of myositis developing in the rectus abdominus muscle of a patient with pancreatic adenocarcinoma was the manifestation of radiation recall, thereby bringing the number of patients who developed radiation recall to gemcitabine and were discussed in the current study to 13. Approximately 70% of the cases manifested as inflammation of internal organs or tissues and 30% manifested as a dermatitis or mucositis. This finding differs from other common agents, in which 63% of the radiation recall events are reported to manifest as a dermatitis. Compared with anthracyclines and taxanes, the interval from the completion of radiation therapy to the initiation of chemotherapy is less for gemcitabine (median time of 56 days for gemcitabine, compared with 218 days for the taxanes and 646 days for doxorubicin). The majority of radiation recall reactions attributed to gemcitabine are reported to affect internal tissue or organs. In contrast, other common agents for the most part trigger cutaneous inflammation. The development of internal tissue inflammation is reportedly correlated with a shorter interval from the time of completion of radiation therapy to the initiation of chemotherapy. Cancer 2004. © 2004 American Cancer Society.
Compared to glibenclamide, repaglinide treatment results in a more rapid fall in glucose level and beta‐cell secretion after glucose stimulation
Authors: Abbink Evertine J. , van der Wal Pieter S. , Sweep C. G. J. (Fred) , Smits Paul , Tack Cees J. 
Published: April 2004

AbstractBackgroundThe more rapid onset of action and the shorter half‐life of repaglinide may reduce the post‐load glucose excursion and limit sustained insulin secretion compared to sulphonylurea (SU) derivatives.MethodsWe studied 12 patients with type 2 diabetes (age 62 ± 2 years, BMI 28.3 ± 1.3 kg m−2, HbA1c 6.7 ± 0.2%) on SU monotherapy at submaximal dose. Patients were treated for 3 weeks with repaglinide or glibenclamide in a randomized, crossover trial. At the end of each treatment period, patients underwent a 60‐min hyperglycaemic clamp (glucose 12 mmol L−1) followed by 4‐h observation (60–300 min) with frequent blood sampling for determination of glucose, insulin, proinsulin and C‐peptide levels. Before the clamp (5 min for repaglinide, 30 min for glibenclamide), patients ingested their usual morning drug dose.ResultsAfter the end of the hyperglycaemic clamp, mean plasma glucose fell to a level of 5 mmol L−1 after approximately 150 min with repaglinide, and after approximately 190 min with glibenclamide. While initially quite similar, in the period from 240 to 300 min, insulin, proinsulin and C‐peptide levels were lower during repaglinide treatment (insulin 133 ± 20 vs 153 ± 25 pmol L−1 (P < 0.05), proinsulin 14 ± 3 vs 19 ± 4 pmol L−1 (P = 0.06) and C‐peptide 0.81 ± 0.19 vs 1.14 ± 0.18 nmol L−1 (P = 0.05) for repaglinide vs glibenclamide, respectively).ConclusionsFollowing glucose stimulation, plasma glucose levels, and insulin concentration decrease more rapidly after repaglinide treatment than after glibenclamide. Proinsulin and C‐peptide secretion tended to fall more rapidly as well. These findings are consistent with a more rapid onset and shorter duration of beta‐cell stimulation associated with repaglinide. Copyright © 2004 John Wiley & Sons, Ltd.
Coupling of antigen to cholera toxin for dendritic cell vaccination promotes the induction of MHC class I‐restricted cytotoxic T cells and the rejection of a cognate antigen‐expressing model tumor
Authors: Eriksson Kristina , Sun Jia‐Bin , Nordström Inger , Fredriksson Margareta , Lindblad Marianne , Li Bin‐Ling , Holmgren Jan 
Published: April 2004

AbstractWe previously demonstrated that cholera toxin (CT) is highly efficient as a combined carrier and adjuvant for dendritic cell (DC) vaccination, inducing strong Th1‐dominated B cell and CD4+ T cell responses. In this study we show that vaccination with DC pre‐pulsed ex vivo with CT‐conjugated OVA (OVA‐CT) gives rise to OVA‐specific CD8+ T cells that produce IFN‐γ and are cytotoxic for OVA‐expressing E.G7 tumor cells both in vitro and in vivo. The induction of specific CD8+ CTL by OVA‐CT‐treated DC was associated with enhanced presentation of OVA peptide (SIINFEKL) on MHC class I in combination with an overall activation of the pulsed DC. Vaccination of mice with OVA‐CT‐pulsed DC resulted in rejection of already established MHC class I‐positive, MHC class II‐negative, OVA‐expressing E.G7 tumors in an antigen‐specific, CD8+ T cell‐dependent fashion and was associated with high numbers of tumor‐infiltrating CD8+ T cells. Conjugation of antigen to CT facilitated DC uptake of the linked antigen through the GM1 receptor‐binding B subunit and induced strong activation‐maturation signals through the biologically active A subunit. These results have interesting implications for DC vaccination aimed at inducing CTL immune responses.
ICOS‐mediated signaling regulates cytokine production by human T cells and provides a unique signal to selectively control the clonal expansion of Th2 helper cells
Authors: Vieira Pedro L. , Wassink Lianne , Smith L. Mary , Nam Samuel , Kingsbury Gillian A. , Gutierrez‐Ramos Jose Carlos , Coyle Anthony J. , Kapsenberg Martien L. , Wierenga Eddy A. 
Published: April 2004

AbstractThe CD28 homologue inducible costimulator (ICOS) has been demonstrated to regulate a number of T cell‐dependent immune responses in vivo. However, the expression and functional importance of ICOS during APC‐Th cell interaction in the human is not fully understood. Here, we demonstrate that ICOS‐mediated signaling plays an important role in the production of selective cytokines during both primary and subsequent Th cell responses upon allospecific or superantigen activation. In contrast, ICOS does not play a role in the differentiation of naive cells into Th1 or Th2 effector cells, nor does it determine the type of effector function of memory cells upon subsequent allogeneic challenge. In addition, our data demonstrate that ICOS provides a novel and unique role in regulating DC‐mediated Th2, but not Th1 cell clonal expansion. These data suggest that ICOS‐mediated signaling plays a discrete role in the regulation of human T helper cell responses.
Porphyromonas gingivalis lipopolysaccharides induce maturation of dendritic cells with CD14+CD16+ phenotype
Authors: Kanaya Sousuke , Nemoto Eiji , Ogawa Tomohiko , Shimauchi Hidetoshi 
Published: April 2004

AbstractPrimary immune responses are initiated by dendritic cells (DC) that inform naive T helper cells about invading pathogens. DC undergo sequential events leading to irreversible maturation upon bacterial stimulation. To investigate the responses of DC during periodontal infection, we studied the effects of LPS from Porphyromonas gingivalis on DC. DC generated from human peripheral monocytes by culture with IL‐4 and GM‐CSF were incubated with P. gingivalis LPS (Pg LPS) or Escherichia coli LPS (Ec LPS). Flow cytometry and real‐time quantitative RT‐PCR analysis revealed that Pg LPS, but not Ec LPS, preferentially up‐regulated CD14 and CD16 expression at protein and mRNA levels. Furthermore, Pg LPS preferentially induced the secretion of soluble CD14. CD1a, HLA‐DR and CD54 were highly expressed on DC stimulated with both kinds of LPS; however, CD40, CD80, CD83 and CD86 expression on Pg LPS‐stimulated DC was lower than on Ec LPS‐stimulated DC. With regard to IL‐6, IL‐8, IL‐10, IL‐12 and RANTES production from DC and allogeneic T cell proliferation, Pg LPS was a weaker stimulator than Ec LPS. These results suggested that Pg LPS triggers maturation of DC with unique characteristics, which exhibited weak immunostimulatory activity and may contribute to induction of chronic inflammation at the site of periodontal infection.
Expression of L‐histidine decarboxylase in granules of elicited mouse polymorphonuclear leukocytes
Authors: Tanaka Satoshi , Deai Katsuya , Konomi Ayako , Takahashi Kohji , Yamane Hana , Sugimoto Yukihiko , Ichikawa Atsushi 
Published: April 2004

AbstractInfiltrating polymorphonuclear leukocytes (PMN) in the peritoneal cavity were found to express L‐histidine decarboxylase (HDC), the rate‐limiting enzyme of histamine synthesis, in a csein‐induced peritonitis model. Expression of HDC was detected in the elicited PMN, but not in the peripheral blood leukocytes. The peritoneal lavage fluids in this model were found to augment histamine synthesis in PMN isolated from the bone marrow. Rapid post‐translational processing of HDC was observed in PMN, and the dominant form of HDC was the mature 53‐kDa form, which was found to co‐localize with a granule enzyme, matrix metalloproteinase‐9 (MMP‐9). Treatment of PMN with the phorbol ester PMA, which stimulates the release of MMP‐9, did not liberate the granular HDC. Immunofluorescence studies using an anti‐HDC antibody strongly suggested that HDC is bound to the cytosolic side of the granule membranes. These observations suggest that HDC is induced upon infiltration of PMN into the mouse peritoneal cavity and that histamine is synthesized by HDC attached to the granule membranes of PMN.
Human CD25+ regulatory T cells: two subsets defined by the integrins α4β7 or α4β1 confer distinct suppressive properties upon CD4+ T helper cells
Authors: Stassen Michael , Fondel Sabine , Bopp Tobias , Richter Christoph , Müller Christian , Kubach Jan , Becker Christian , Knop Jürgen , Enk Alexander H. , Schmitt Steffen , Schmitt Edgar , Jonuleit Helmut 
Published: April 2004

AbstractDown‐regulation of autoreactive T cell responses in vivo includes cell‐contact‐dependent as well as contact‐independent mechanisms. Infectious tolerance is a contact‐dependent mechanism used by naturally occurring CD25+ T regulatory cells (Tregs) to confer suppressive activity upon conventional CD4+ T cells thereby generating secondary T helper suppressor cells(Thsup), which inhibit T cell activation via soluble mediators. Here, we describe two distinct subsets of human Tregs, characterized by expression of either the α4β7 integrin or the α4β1 integrin. Upon activation, both subsets show an enhanced expression of FoxP3, recently described as a key transcription factor of murine Tregs. In addition, both are able to convey suppressive capacity to conventional CD4+ T cells. However, the properties of Treg subsets are rather distinct: α4β7+Tregs induce IL‐10‐producing Thsup (Tr1‐like), whereas α4β1+ Tregs induce TGF‐β‐producing Thsup (Th3‐like). Our findings reconcile conflicting results by clearly demonstrating that suppression through naturally occurring CD25+ Tregs is primary cell‐contact‐dependent but is subsequently followed by cell‐contact‐independent T cell inhibition mediated by second‐generation Tr1‐ and Th3‐like Thsup via the soluble factors IL‐10 and TGF‐β.
Impaired lymphocyte development and function in Clast5/Stra13/DEC1‐transgenic mice
Authors: Seimiya Mika , Wada Akihiko , Kawamura Kiyoko , Sakamoto Akemi , Ohkubo Yusuke , Okada Seiji , Hatano Masahiko , Tokuhisa Takeshi , Watanabe Takeshi , Saisho Hiromitsu , Tagawa Masatoshi , O‐Wang Jiyang 
Published: April 2004

AbstractClast5/Stra13/DEC1 is a member of the helix‐loop‐helix family of transcriptional repressors. We have previously shown that Clast5 is rapidly down‐regulated upon B cell activation and its overexpression inhibits cell cycle progression in B lymphoma cells. In the present study, we show that Clast5 expression is developmentally regulated during B cell differentiation, being expressed at theprogenitor B cells, down‐regulated at the precursor B cells, elevated in immature and mature resting B lymphocytes, and down‐regulated again in germinal center B ells. To investigate the function of Clast5 in regulating lymphocyte development, we have generated transgenic mice expressing Clast5 in B‐ and T‐lineage cells (Clast5‐Tg). Clast5‐Tg mice grew and bred normally but their spleen and thymus cellularity was reduced compared with control littermates. The development of B cells in the bone marrow and T cells in the thymus was impaired, with the expansion of progenitor B and T cells most strongly affected. The frequency of IL‐7‐responsive cells in the bone marrow of Clast5‐Tg mice was reduced by >80% and their proliferative response to IL‐7 was also compromised. Mature B cells from Clast5‐Tg mice were hyporesponsive to antigen receptor cross‐linking and exhibited mild reduction in the proliferative response to CD40 ligation or lipopolysaccharide stimulation. Moreover, thedevelopment of germinal center B cells and antibody production against a T‐dependent antigen were reduced in Clast5‐Tg mice. These results reveal a critical role for Clast5/Stra13/DEC1 in negatively regulating lymphocyte development and function in vivo.