Showing papers by "University College Dublin published in 2001"
TL;DR: A protein is described, Mal (MyD88-adapter-like), which joins MyD88 as a cytoplasmic TIR-domain-containing protein in the human genome, which is therefore an adapter in TLR-4 signal transduction.
Abstract: The recognition of microbial pathogens by the innate immune system involves Toll-like receptors (TLRs), which recognize pathogen-associated molecular patterns. Different TLRs recognize different pathogen-associated molecular patterns, with TLR-4 mediating the response to lipopolysaccharide from Gram-negative bacteria. All TLRs have a Toll/IL-1 receptor (TIR) domain, which is responsible for signal transduction. MyD88 is one such protein that contains a TIR domain. It acts as an adapter, being involved in TLR-2, TLR-4 and TLR-9 signalling; however, our understanding of how TLR-4 signals is incomplete. Here we describe a protein, Mal (MyD88-adapter-like), which joins MyD88 as a cytoplasmic TIR-domain-containing protein in the human genome. Mal activates NF-kappaB, Jun amino-terminal kinase and extracellular signal-regulated kinase-1 and -2. Mal can form homodimers and can also form heterodimers with MyD88. Activation of NF-kappaB by Mal requires IRAK-2, but not IRAK, whereas MyD88 requires both IRAKs. Mal associates with IRAK-2 by means of its TIR domain. A dominant negative form of Mal inhibits NF-kappaB, which is activated by TLR-4 or lipopolysaccharide, but it does not inhibit NF-kappaB activation by IL-1RI or IL-18R. Mal associates with TLR-4. Mal is therefore an adapter in TLR-4 signal transduction.
1,250 citations
TL;DR: In this paper, a meta-analysis of the literature on multinational companies and productivity spillovers is presented, and the authors investigate whether certain aspects of the study design affect the results, and whether there is publication bias in the literature.
Abstract: This paper presents a meta-analysis of the literature on multinational companies and productivity spillovers. By collecting information from a sample of published and unpublished papers on the impact of multinational presence on domestic productivity, we investigate whether certain aspects of the study design affect the results, and whether there is publication bias in the literature. Our findings show that some aspects of the empirical methods used, namely, how the presence of multinationals is defined, and whether cross-section or panel analysis is employed, may have an effect on the results. We also discover some evidence that there may be publication bias.
886 citations
TL;DR: Sequence-level studies on model organisms whose genomes show clearer evidence of ancient polyploidy are invaluable because they indicate what the evolutionary products of genome duplication can look like.
Abstract: Thirty years after Susumu Ohno proposed that vertebrate genomes are degenerate polyploids, the extent to which genome duplication contributed to the evolution of the vertebrate genome, if at all, is still uncertain. Sequence-level studies on model organisms whose genomes show clearer evidence of ancient polyploidy are invaluable because they indicate what the evolutionary products of genome duplication can look like. The greatest mystery is the molecular basis of diploidization, the evolutionary process by which a polyploid genome turns into a diploid one.
732 citations
TL;DR: This article examined mitochondrial DNA control-region sequence variation from 392 extant animals sampled from Europe, Africa and the Near East, and compared this with data from four extinct British wild oxen.
Abstract: The limited ranges of the wild progenitors of many of the primary European domestic species point to their origins further east in Anatolia or the fertile crescent. The wild ox (Bos primigenius), however, ranged widely and it is unknown whether it was domesticated within Europe as one feature of a local contribution to the farming economy. Here we examine mitochondrial DNA control-region sequence variation from 392 extant animals sampled from Europe, Africa and the Near East, and compare this with data from four extinct British wild oxen. The ancient sequences cluster tightly in a phylogenetic analysis and are clearly distinct from modern cattle. Network analysis of modern Bos taurus identifies four star-like clusters of haplotypes, with intra-cluster diversities that approximate to that expected from the time depth of domestic history. Notably, one of these clusters predominates in Europe and is one of three encountered at substantial frequency in the Near East. In contrast, African diversity is almost exclusively composed of a separate haplogroup, which is encountered only rarely elsewhere. These data provide strong support for a derived Near-Eastern origin for European cattle.
582 citations
TL;DR: In this article, a framework for understanding the effects of commercial sponsorship on consumers is proposed, which defines and explores certain tenets essential to understanding sponsorship effects, namely, goodwill, image transfer and the concept of fan involvement, and relates these tenets to the achievement of a consumer response.
Abstract: This article offers a framework for understanding the effects of commercial sponsorship on consumers. It defines and explores certain tenets essential to understanding sponsorship effects, namely, goodwill, image transfer, and the concept of fan involvement, and relates these tenets to the achievement of a consumer response, building to a proposed model of how sponsorship “works” in relation to consumers. © 2001 John Wiley & Sons, Inc.
560 citations
TL;DR: Evidence to support the hypothesis that glutamine is beneficially immunomodulatory in animal models of infection and trauma, as well as trauma in humans, is provided.
Abstract: Glutamine is normally considered to be a nonessential amino acid. However, recent studies have provided evidence that glutamine may become "conditionally essential" during inflammatory conditions such as infection and injury. It is now well documented that under appropriate conditions, glutamine is essential for cell proliferation, that it can act as a respiratory fuel and that it can enhance the function of stimulated immune cells. Studies thus far have determined the effect of extracellular glutamine concentration on lymphocyte proliferation and cytokine production, macrophage phagocytic plus secretory activities and neutrophil bacterial killing. Other cells of the immune system remain to be studied. The high rate of glutamine utilization and its importance to the function of lymphocytes, macrophages and neutrophils have raised the question "why glutamine?" because these cells have access to a variety of metabolic fuels both in vivo and in vitro. I have attempted to answer this question in this article. Additionally, knowledge of the rate of utilization and the pathway of metabolism of glutamine by cells of the immune system raises some intriguing questions concerning therapeutic manipulation of utilization of this amino acid such that the proliferative, phagocytic and secretory capacities of cells of the defense system may be beneficially altered. Evidence to support the hypothesis that glutamine is beneficially immunomodulatory in animal models of infection and trauma, as well as trauma in humans, is provided.
526 citations
Posted Content•
TL;DR: In this paper, the extent to which a sample of 11 knowledge-based Irish listed companies is adopting methodologies for reporting of intellectual capital in their annual reports was examined and a content analysis of the annual reports of the 11 listed companies was conducted.
Abstract: This paper examines the extent to which a sample of 11 knowledge-based Irish listed companies is adopting methodologies for reporting of intellectual capital in their annual reports. Their market and book values were compared and a content analysis of the annual reports of the 11 listed companies was conducted. With the exception of two of the 11 listed companies, significant differences in market and book values were found suggesting that knowledge-based Irish listed companies have a substantial level of non-physical, intangible, intellectual capital assets. The level of disclosure of intellectual capital attributes by the 11 listed companies studied was low.
470 citations
TL;DR: Flow cytometric analysis revealed reduced damage with respect to cytoplasmic membrane potential and integrity in cells grown in the dynamic environments of the large scale reactor and the scale-down reactor.
443 citations
TL;DR: In this paper, the extent to which 11 knowledge-based Irish listed companies are adopting methodologies for reporting of intellectual capital in their annual reports was examined and a content analysis of the annual reports of the 11 listed companies was conducted.
Abstract: Examines the extent to which 11 knowledge‐based Irish listed companies are adopting methodologies for reporting of intellectual capital in their annual reports. Their market and book values were compared and a content analysis of the annual reports of the 11 listed companies was conducted. With the exception of two of the 11 listed companies, significant differences in market and book values were found, suggesting that knowledge‐based Irish listed companies have a substantial level of non‐physical, intangible, intellectual capital assets. The level of disclosure of intellectual capital attributes by the 11 listed companies studied was low.
425 citations
02 Aug 2001
TL;DR: This paper proposes and evaluates strategies for improving retrieval diversity in CBR systems without compromising similarity or efficiency and argues that often diversity can be as important as similarity.
Abstract: Case-based reasoning systems usually accept the conventional similarity assumption during retrieval, preferring to retrieve a set of cases that are maximally similar to the target problem. While we accept that this works well in many domains, we suggest that in others it is misplaced. In particular, we argue that often diversity can be as important as similarity. This is especially true in case-based recommender systems. In this paper we propose and evaluate strategies for improving retrieval diversity in CBR systems without compromising similarity or efficiency.
416 citations
TL;DR: Evidence for previously undetected early Holocene cooling events is presented, but mid- to late-Holocene ice rafting in the North Atlantic appears to have had little impact on δ18O at this ocean margin site.
Abstract: Evaluating the significance of Holocene submillennial δ 18 O variability in the Greenland ice cores is crucial for understanding how natural climate oscillations may modulate future anthropogenic warming. A high-resolution oxygen isotope record from a speleothem in southwestern Ireland provides evidence for centennial-scale δ 18 O variations that correlate with subtle δ 18 O changes in the Greenland ice cores, indicating regionally coherent variability in the early Holocene. Evidence for previously undetected early Holocene cooling events is presented, but mid- to late-Holocene ice rafting in the North Atlantic appears to have had little impact on δ 18 O at this ocean margin site.
University of Essex1, University of Illinois at Urbana–Champaign2, Rutgers University3, Boston University4, University of Sheffield5, University of Edinburgh6, University of Maryland, College Park7, University College Dublin8, Bedford Institute of Oceanography9, Max Planck Society10, University of Dundee11, Duke University12, Alfred Wegener Institute for Polar and Marine Research13, Dalhousie University14, West Virginia University15, University of Wyoming16, University of Wales17
TL;DR: Meereskunde and Weghe as mentioned in this paper proposed a method to extract the structure of the skeleton of a coral reef from the seafloor of a tropical coral reef.
Abstract: R I C H A R D J . G E I D E R , 1 E V A N H . D E L U C I A , 2 P A U L G . F A L K O W S K I , 3 A D R I E N C . F I N Z I , 4 J . P H I L I P G R I M E , 5 J O H N G R A C E , 6 T O D D M . K A N A , 7 J U L I E L A R O C H E , 8 S T E P H E N P . L O N G , 2 , 9 B R U C E A . O S B O R N E , 1 0 T R E V O R P L A T T , 1 1 I . C O L I N P R E N T I C E , 1 2 J O H N A . R A V E N , 1 3 W I L L I A M H . S C H L E S I N G E R , 1 4 V I C T O R S M E T A C E K , 1 5 V E N E T I A S T U A R T , 1 6 S H U B H A S A T H Y E N D R A N A T H , 1 1 , 1 6 R I C H A R D B . T H O M A S , 1 7 T O M C . V O G E L M A N N , 1 8 P E T E R W I L L I A M S , 1 9 F . I A N W O O D W A R D 5 Department of Biological Sciences, University of Essex, Colchester CO4 3SQ, UK, Department of Plant Biology, University of Illinois, Urbana, IL 61801, USA, Institute of Marine and Coastal Sciences and Department of Geology, Rutgers University, 71 Dudley Road, New Brunswick, New Jersey 08901, USA, Biology Department, Boston University, Boston, MA 02215, USA, Department of Animal and Plant Sciences, The University of Shef®eld, Shef®eld S10 2TN, UK, Institute of Ecology and Resource Management, The University of Edinburgh, Edinburgh EH9 3JU, UK, Horn Point Laboratory, University of Maryland, PO Box 775, Cambridge MD 21613, USA, Institut fuÈr Meereskunde, DuÈstenbrooker Weg 20, Kiel 24105, Germany, Department of Crop Science, University of Illinois, Urbana, IL 61801, USA, Botany Department, University College Dublin, Bel®eld, Dublin 4, Ireland, Bedford Institute of Oceanography, Dartmouth, Nova Scotia B2Y 4A2, Canada, Max Plank Insttitute for Biogeochemistry, Carl-Zeiss-Promenade 10, Jena D-07743, Germany, Department of Biological Sciences, University of Dundee, Dundee DD1 4HN, UK, Department of Botany, Duke University, Durham, NC 27708, USA, Alfred Wegener Institute for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany, Dalhousie University, Halifax, Nova Scotia, B3H 4J1, Canada, Department of Biology, West Virginia University, Morgantown, WV 26506, USA, Botany Department, University of Wyoming, Laramie, WY 82071, USA, School of Ocean Sciences, University of Wales, Bangor, Menai Bridge, Gywnedd, PP59 5EY, UK
TL;DR: In this article, microencapsulation efficiency and redispersion behavior of spray-dried emulsions were examined and the results showed that the microencapulation efficiency increased with increasing DE and decreased at Na Cas/carbohydrate ratios <1.19 and at high core/wall ratios.
TL;DR: The challenge remains to modify nutritional and management strategies in high-yielding dairy cows to maintain the levels of production made possible by genetic selection and still maintain an acceptable level of fertility.
TL;DR: In this paper, a database of 300 case histories of wall and ground movements due to deep excavations worldwide is presented, and a large database is used to extract case histories from these case histories.
Abstract: A database of some 300 case histories of wall and ground movements due to deep excavations worldwide is presented. Although recognizing the weakness in the approach, a large database is used to exa...
TL;DR: It is argued that on neuroanatomical, physiological and functional grounds, the subiculum is properly part of the hippocampal formation, given its pivotal role in the hippocampusal circuit.
TL;DR: In this paper, the authors investigate the mechanisms of chip formation for a Ti-6Al-4V alloy and assess the influences of such on acoustic emission (AE) within the range of conditions employed (cutting speed, v c = 0.25-3.0 m/s, feed, f=20-100 μm ).
Abstract: Orthogonal cutting tests were undertaken to investigate the mechanisms of chip formation for a Ti–6Al–4V alloy and to assess the influences of such on acoustic emission (AE). Within the range of conditions employed (cutting speed, v c =0.25–3.0 m/s , feed, f=20–100 μm ), saw-tooth chips were produced. A transition from aperiodic to periodic saw-tooth chip formation occurring with increases in cutting speed and/or feed. Examination of chips formed shortly after the instant of tool engagement, where the undeformed chip thickness is slightly greater than the minimum undeformed chip thickness, revealed a continuous chip characterised by the presence of fine lamellae on its free surface. In agreement with the consensus that shear localisation in machining Ti and its alloys is due to the occurrence of a thermo-plastic instability, the underside of saw-tooth segments formed at relatively high cutting speeds, exhibiting evidence of ductile fracture. Chips formed at lower cutting speeds suggest that cleavage is the mechanism of catastrophic failure, at least within the upper region of the primary shear zone. An additional characteristic of machining Ti–6Al–4V alloy at high cutting speeds is the occurrence of welding between the chip and the tool. Fracture of such welds appears to be the dominant source of AE. The results are discussed with reference to the machining of hardened steels, another class of materials from which saw-tooth chips are produced.
TL;DR: It is concluded that larger mature fallow bucks have advantages over other males when competing for matings, and sexual selection therefore continues to act on sexual size dimorphism in this species.
Abstract: Sexual size dimorphism may evolve as a result of both natural and sexual selection. In polygynous mammals, the main factor resulting in the evolution of large body size in males is the advantage conferred during competition for mates. In this study, we examined whether sexual selection acts on body size in mature fallow bucks (Dama dama) by examining how the following traits are inter-related: age, body (skeletal) size, body mass, prerut dominance rank, rut dominance rank and mating success. This is the first study to examine how all these factors are together related to the mating success of a large sexually dimorphic and polygynous mammal. We found that male mating success was directly related to body size, but not to body mass. However body mass was related to prerut dominance rank which was in turn strongly related to rut dominance rank, and thus there was an indirect relationship between mating success and body mass. Rut dominance rank was the variable most strongly related to mating success. Mating success among mature males was unrelated to age. We conclude that larger mature fallow bucks have advantages over other males when competing for matings, and sexual selection therefore continues to act on sexual size dimorphism in this species. Heavier fallow bucks also have advantages, but these are mediated through the dominance ranks attained by males before the rut.
TL;DR: It is shown here that light-evoked retinal responses in fact originate from rods, and it is found that lack of RPE65 enables rods to mimic cone function by responding under normally cone-isolating lighting conditions.
Abstract: Leber congenital amaurosis (LCA) is the most serious form of the autosomal recessive childhood-onset retinal dystrophies. Mutations in the gene encoding RPE65, a protein vital for regeneration of the visual pigment rhodopsin in the retinal pigment epithelium1, account for 10–15% of LCA cases2,3. Whereas previous studies of RPE65 deficiency in both animal models1,4 and patients5,6 attributed remaining visual function to cones, we show here that light-evoked retinal responses in fact originate from rods. For this purpose, we selectively impaired either rod or cone function in Rpe65−/− mice by generating double– mutant mice with models of pure cone function7 (rhodopsin-deficient mice; Rho−/−) and pure rod function8 (cyclic nucleotide–gated channel α3–deficient mice; Cnga3−/−). The electroretinograms (ERGs) of Rpe65−/− and Rpe65−/−Cnga3−/− mice were almost identical, whereas there was no assessable response in Rpe65−/−Rho−/− mice. Thus, we conclude that the rod system is the source of vision in RPE65 deficiency. Furthermore, we found that lack of RPE65 enables rods to mimic cone function by responding under normally cone-isolating lighting conditions. We propose as a mechanism decreased rod sensitivity due to a reduction in rhodopsin content to less than 1%. In general, the dissection of pathophysiological processes in animal models through the introduction of additional, selective mutations is a promising concept in functional genetics.
TL;DR: Persistent occiput posterior position led to a sevenfold increase in the incidence of anal sphincter injury, and was associated with significantly higher incidences of prolonged pregnancy, induction of Labor, oxytocin augmentation of labor, epidural use, and prolonged labor.
TL;DR: The availability of these genes and the development of a method for gene disruption and replacement in S. nodosus should allow production of novel amphotericins, and a panel of analogues could lead to identification of derivatives with increased solubility, improved biological activity and reduced toxicity.
TL;DR: It is concluded that high carcass growth can be achieved on a grass-based diet without a deleterious effect on meat quality.
TL;DR: In this article, managers are increasingly undertaking action research projects in their own organizations, where they need to manage the political dynamics, which involves balancing the organization's formal justification of what it wants in the project with their own tactical personal justification for the project.
Abstract: Managers are increasingly undertaking action research projects in their own organizations. Action research involves opportunistic planned interventions in real time situations and a study of those interventions as they occur, which in turn informs further interventions. Insider action research has its own dynamics, which distinguish it from an external action researcher approach. The manager-researchers are already immersed in the organization and have a preunderstanding from being an actor in the processes being studied. Challenges facing such manager-researchers are that they need to combine their action research role with their regular organizational roles and this role duality can create the potential for role ambiguity and conflict. They need to manage the political dynamics, which involves balancing the organization's formal justification of what it wants in the project with their own tactical personal justification for the project. Manager-researchers' preunderstanding, organizational role and abil...
TL;DR: In this paper, an exact connection between the Choptuik scaling parameter for the three-dimensional Ba\~nados-Teitelboim-Zanelli black hole, and the imaginary part of the quasinormal frequencies for scalar perturbations was established.
Abstract: We establish an exact connection between the Choptuik scaling parameter for the three-dimensional Ba\~nados-Teitelboim-Zanelli black hole, and the imaginary part of the quasinormal frequencies for scalar perturbations. Via the anti--de Sitter space/conformal-field theory correspondence, this leads to an interpretation of Choptuik scaling in terms of the time scale for return to equilibrium of the dual conformal field theory.
TL;DR: In this article, the authors proposed a non-local material response model that predicts that the spatial frequency response might be improved by decreasing the mean polymer chain lengths and/or by increasing the mobility of the molecules used in the material.
TL;DR: This study suggests that there has been a significant reduction in bleeding related mortality in patients with cirrhosis and portal hypertension over the past 40 years.
Abstract: BACKGROUND—Variceal bleeding is a frequent cause of death in patients with cirrhosis and portal hypertension. Over the past 40 years a number of new techniques have been introduced to control active variceal haemorrhage. Many randomised controlled trials were performed to evaluate these new therapies. While most have demonstrated efficacy in controlling haemorrhage few showed improved survival.
AIM—The aim of this study was to investigate whether the prognosis for cirrhotic patients following a first variceal haemorrhage has improved over the past four decades.
PATIENTS AND METHODS—A total of 1475 patients included in the control or untreated arms of randomised controlled prophylactic trials for the primary prevention of variceal haemorrhage between 1960 and 2000. Twenty eight eligible randomised controlled studies were included. Over the 40 year period of observation there was a reduction in bleeding related mortality over time from approximately 65% to approximately 40% (p=0.024).
CONCLUSION—This study suggests that there has been a significant reduction in bleeding related mortality in patients with cirrhosis and portal hypertension over the past 40 years.
Keywords: portal hypertension; cirrhosis; variceal bleeding; primary prophylaxis; prognosis
TL;DR: The mutation analysis shows that the MS/MS-based method is excellent for detection of MCAD deficiency but that the frequency of the 985A-->G mutant allele in newborns with a positive acylcarnitine profile is much lower than that observed in clinically affected patients.
Abstract: Medium-chain acyl-CoA dehydrogenase (MCAD) deficiency is the most frequently diagnosed mitochondrial β-oxidation defect, and it is potentially fatal. Eighty percent of patients are homozygous for a common mutation, 985A→G, and a further 18% have this mutation in only one disease allele. In addition, a large number of rare disease-causing mutations have been identified and characterized. There is no clear genotype-phenotype correlation. High 985A→G carrier frequencies in populations of European descent and the usual avoidance of recurrent disease episodes by patients diagnosed with MCAD deficiency who comply with a simple dietary treatment suggest that MCAD deficiency is a candidate in prospective screening of newborns. Therefore, several such screening programs employing analysis of acylcarnitines in blood spots by tandem mass spectrometry (MS/MS) are currently used worldwide. No validation of this method by mutation analysis has yet been reported. We investigated for MCAD mutations in newborns from US populations who had been identified by prospective MS/MS-based screening of 930,078 blood spots. An MCAD-deficiency frequency of 1/15,001 was observed. Our mutation analysis shows that the MS/MS-based method is excellent for detection of MCAD deficiency but that the frequency of the 985A→G mutant allele in newborns with a positive acylcarnitine profile is much lower than that observed in clinically affected patients. Our identification of a new mutation, 199T→C, which has never been observed in patients with clinically manifested disease but was present in a large proportion of the acylcarnitine-positive samples, may explain this skewed ratio. Overexpression experiments showed that this is a mild folding mutation that exhibits decreased levels of enzyme activity only under stringent conditions. A carrier frequency of 1/500 in the general population makes the 199T→C mutation one of the three most prevalent mutations in the enzymes of fatty-acid oxidation.
TL;DR: Emulsions were prepared with 5% (w/v) solutions of sodium caseinate and soy oil at oil/protein ratios of 0.25-3.0 by homogenization at 10--50 MPa and reconstituted to yield powders with 20--75% oil, suggesting destabilization of high-oil emulsions during the spray-drying process.
Abstract: Emulsions were prepared with 5% (w/v) solutions of sodium caseinate (Na Cas) and soy oil at oil/protein ratios of 0.25-3.0 by homogenization at 10--50 MPa. Emulsions were spray-dried to yield powders with 20--75% oil (w/w). Emulsion oil droplet size and interfacial protein load were determined. Microencapsulation efficiency (ME), redispersion properties, and structure of the powders were analyzed. The size of emulsion oil droplets decreased with increasing homogenization pressure but was not influenced by oil/protein ratio. Emulsion protein load values were highest at low oil/protein ratios. ME of the dried emulsions was not affected by homogenization pressure but decreased from 89.2 to 18.8% when the oil/protein ratio was increased from 0.25 to 3.0, respectively. Mean particle sizes of reconstituted dried emulsions were greater than those of the original emulsions, particularly at high oil/protein ratios (>1.0), suggesting destabilization of high-oil emulsions during the spray-drying process.
TL;DR: The results indicate that IL-2 and IL-15 act at different stages of the immune response by expanding and partially activating NK receptor-positive lymphocytes, but, on their own, do not influence the Th1/Th2 balance of adaptive immune responses.
Abstract: IL-2 and IL-15 are lymphocyte growth factors produced by different cell types with overlapping functions in immune responses. Both cytokines costimulate lymphocyte proliferation and activation, while IL-15 additionally promotes the development and survival of NK cells, NKT cells, and intraepithelial lymphocytes. We have investigated the effects of IL-2 and IL-15 on proliferation, cytotoxicity, and cytokine secretion by human PBMC subpopulations in vitro. Both cytokines selectively induced the proliferation of NK cells and CD56(+) T cells, but not CD56(-) lymphocytes. All NK and CD56(+) T cell subpopulations tested (CD4(+), CD8(+), CD4(-)CD8(-), alphabetaTCR(+), gammadeltaTCR(+), CD16(+), CD161(+), CD158a(+), CD158b(+), KIR3DL1(+), and CD94(+)) expanded in response to both cytokines, whereas all CD56(-) cell subpopulations did not. Therefore, previously reported IL-15-induced gammadelta and CD8(+) T cell expansions reflect proliferations of NK and CD56(+) T cells that most frequently express these phenotypes. IL-15 also expanded CD8alpha(+)beta(-) and Valpha24Vbeta11 TCR(+) T cells. Both cytokines stimulated cytotoxicity by NK and CD56(+) T cells against K562 targets, but not the production of IFN-gamma, TNF-alpha, IL-2, or IL-4. However, they augmented cytokine production in response to phorbol ester stimulation or CD3 cross-linking by inducing the proliferation of NK cells and CD56(+) T cells that produce these cytokines at greater frequencies than other T cells. These results indicate that IL-2 and IL-15 act at different stages of the immune response by expanding and partially activating NK receptor-positive lymphocytes, but, on their own, do not influence the Th1/Th2 balance of adaptive immune responses.