Search

Interpolation of interval data where the mean is preserved, e.g., estimating smoothed, pseudodaily meteorological variables based on monthly means, is a common problem in the geosciences. Existing methods for mean-preserving interpolation are computationally intensive and/or do not readily accommodate bounded interpolation, where the interpolated data cannot exceed a threshold value. Here we present a mean-preserving, continuous, easily implementable, and computationally efficient method for interpolating one-dimensional interval data. Our new algorithm provides a straightforward solution to the interpolation problem by utilizing Hermite cubic splines and midinterval control points to interpolate interval data into smaller partitions. We further include adjustment schemes to restrict the interpolated result to user-specified minimum and maximum bounds. Our method is fast, portable, and broadly applicable to a range of geoscientific data, including interpolating unbounded time series such as mean temperature, and bounded data including mean wind speed or cloud-cover fraction. [ABSTRACT FROM AUTHOR]

This article provides an overview of the history of the Japanese Society of Biofeedback Research (JSBR) and presents some of its recent advances. Most of the research papers published in the JSBR journal (Biofeedback Kenkyu) have been written in Japanese, and therefore have had very few opportunities to reach global readers. We would like to present some of important findings previously published there. First, we present the history of the JSBR. Secondly, we will focus on paced breathing, which is instrumental in achieving relaxation in heart rate variability biofeedback (HRV-BF). We will look back on the origin of slow-paced breathing in Japan, that could be attributed to the concept of Tanden breathing (abdominal paced breathing) practiced in Zen meditation. Thirdly, we will introduce some of the current research progresses of JSBR, especially focusing on the development of a non-contact sensing technology and relaxation device. Finally, we will explain about a very recent trial, the "Suu-Haa" Relaxation Technique, which we hope may be useful for helping people cope with the SARS-CoV-2 (COVID-19) crisis. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the perception of Brazilian dairy processors (n = 31) concerning food defense. The results showed that respondents consider the implementation of control procedures related to facilities, products, materials, and individuals as important measures in food defense. The higher agreement rates (strongly agreed + slightly agreed) of the companies in relation to the perception of food defense were 84% for external security, followed by personnel security (82%), generalities (81%), and internal security (74%). Thus, protecting facilities and controlling the traffic flow were considered to be the most important actions under the participants' perspectives. Employee satisfaction and identification of end products and raw materials are also considered relevant in the food defense program. Although food defense is not a formal requirement in Brazilian law, the results show that there is adequate awareness of this topic by the Brazilian dairy companies. [ABSTRACT FROM AUTHOR]

Sixty non-pregnant, non-lactating double-muscled Belgian Blue (DMBB) cows were used to estimate the energy required to maintain body weight (BW). They were fed one of three energy levels for 112 or 140 days, corresponding to approximately 100%, 80% or 70% of their total energy requirements. The relationship between daily energy intake and BW and daily BW change was developed using regression analysis. Maintenance energy requirements were estimated from the regression equation by setting BW gain to zero. Metabolizable and net energy for maintenance amounted to 0.569 ± 0.001 and 0.332 ± 0.001 MJ per kg BW0.75/d, respectively. Maintenance energy requirements were not dependent on energy level (p > 0.10). Parity affected maintenance energy requirements (p < 0.001), although the small numerical differences between parities may hardly be nutritionally relevant. Maintenance energy requirements of DMBB beef cows were close to the mean energy requirements of other beef genotypes reported in the literature. [ABSTRACT FROM AUTHOR]

Molecular biology has enabled the identification of the mechanisms whereby inactive myostatin increases skeletal muscle growth in double-muscled (DM) animals. Myostatin is a secreted growth differentiation factor belonging to the transforming growth factor-β superfamily. Mutations make the myostatin gene inactive, resulting in muscle hypertrophy. The relationship between the different characteristics of DM cattle are defined with possible consequences for livestock husbandry. The extremely high carcass yield of DM animals coincides with a reduction in the size of most vital organs. As a consequence, DM animals may be more susceptible to respiratory disease, urolithiasis, lameness, nutritional stress, heat stress and dystocia, resulting in a lower robustness. Their feed intake capacity is reduced, necessitating a diet with a greater nutrient density. The modified myofiber type is responsible for a lower capillary density, and it induces a more glycolytic metabolism. There are associated changes for the living animal and post-mortem metabolism alterations, requiring appropriate slaughter conditions to maintain a high meat quality. Intramuscular fat content is low, and it is characterized by more unsaturated fatty acids, providing healthier meat for the consumer. It may not always be easy to find a balance between the different disciplines underlying the livestock husbandry of DM animals to realize a good performance and health and meat quality. [ABSTRACT FROM AUTHOR]

Background: Impedance cardiography (ICG) technology has improved dramatically, and at least one device now can give a measurement of fluid status by using thoracic fluid content (TFC), along with cardiac output (CO) and cardiac index (CI). With a built-in sphygmomanometer cuff, it can also provide blood pressure (BP) and systemic vascular resistance index (SVRI). A currently available small portable ICG that provides reliable measures of fluid status could be an ideal noninvasive monitor for hemodialysis (HD), with the potential of helping avoid significant hemodynamic instability during HD. Methods: A case series of patients with chronic renal failure was studied while undergoing HD using ICG (BioZ®, CardioDynamics, Int. Corp., San Diego, CA). Parameters recorded at 15-min intervals included TFC, CI, BP (systolic, diastolic, and mean arterial), SVRI, and heart rate. Using the Pearson method, the percentage changes in each of the parameters during the HD session were correlated to the amount of fluid removed (FR), normalized to body weight. Results: Forty-one patients were enrolled, but six patients were excluded due to incomplete data; therefore, 35 patients (13 men and 22 women) formed the basis of the analysis. The age range was 28 to 87 (mean 55.1 ± 16.1) years. The amount of FR was 2.88 ± 1.13 L (37.3 ± 14.6 ml/kg). TFC decreased in all patients during the HD session (average reduction 12.7 ± 8 kohms−1); whereas all other hemodynamic parameters showed both increases and decreases. The correlation of change in TFC with FR was moderate (r = 0.579, P = 0.0003); other hemodynamic parameters showed a poor correlation with FR. Neither the standard hemodynamic parameters nor the ICG device’s special parameters were able to identify the five patients in this series who experienced significant hemodynamic instability or intradialytic hypotension. Conclusion: TFC, measured easily and noninvasively using ICG, correlates with the amount of fluid removed during HD. In comparison with the other hemodynamic parameters measured, TFC changed most consistently with fluid removal. Whether or not serial TFC measurements in a given patient at different HD sessions can guide the extent of FR will require additional study. This compact, easily operated, and nonobtrusive ICG device with the capability for continuously providing the standard hemodynamic parameters plus CO, TFC, and standard limb lead electrocardiography could replace current monitoring systems. [Copyright &y& Elsevier]

Hyperoxia generates an oxidative stress in the mouse lung, which activates the major stress-inducible kinase pathways, including c-Jun NH[sub 2]-terminal kinase (JNK). We examined the effect of Jnk1 gene deletion on in vivo responses to hyperoxia in mice. The survival of Jnk1[sub -/-] mice was reduced relative to wild-type mice after exposure to continuous hyperoxia. Jnk1[sup -/-] mice displayed higher protein concentration in bronchoalveolar lavage (BAL) fluid and increased expression of heme oxygenase-1, a stress-inducible gene, after 65 h of hyperoxia. Contrary to other markers of injury, the leukocyte count in BAL fluid of Jnk1[sup -/-] mice was markedly diminished relative to that of wild-type mice. The decrease in BAL leukocyte count was not associated with any decrease in lung myeloperoxidase activity at baseline or after hyperoxia treatment. Pretreatment with inhaled lipopolysaccharide increased BAL neutrophil content and extended hyperoxia survival time to a similar extent in Jnk1[sup -/-] and wild-type mice. Associated with increased mortality, Jnk1[sup -/-] mice had increased pulmonary epithelial cell apoptosis after exposure to hyperoxia compared with wild-type mice. These results indicate that JNK pathways participate in adaptive responses to hyperoxia in mice. [ABSTRACT FROM AUTHOR]

Many viruses have evolved structured RNA elements that can influence transcript abundance and translational efficiency, and help evade host immune factors by hijacking cellular machinery during replication. Here, we evaluated the functional impact of sub-genomic flaviviral RNAs (sfRNAs) known to stall exoribonuclease activity, by incorporating these elements into recombinant adeno-associated viral (AAV) genome cassettes. Specifically, sfRNAs from Dengue, Zika, Japanese Encephalitis, Yellow Fever, Murray Valley Encephalitis, and West Nile viruses increased transcript stability and transgene expression compared to a conventional woodchuck hepatitis virus element (WPRE). Further dissection of engineered transcripts revealed that sfRNA elements (i) require incorporation in cis within the 3′ untranslated region (UTR) of AAV genomes, (ii) require minimal dumbbell structures to exert the observed effects, and (iii) can stabilize AAV transcripts independent of 5′−3′ exoribonuclease 1 (XRN1)-mediated decay. Additionally, preliminary in vivo assessment of AAV vectors bearing sfRNA elements in mice achieved increased transcript abundance and expression in cardiac tissue. Leveraging the functional versatility of engineered viral RNA elements may help improve the potency of AAV vector-based gene therapies. IMPORTANCE Viral RNA elements can hijack host cell machinery to control stability of transcripts and consequently, infection. Studies that help better understand such viral elements can provide insights into antiviral strategies and also potentially leverage these features for therapeutic applications. In this study, by incorporating structured flaviviral RNA elements into recombinant adeno-associated viral (AAV) vector genomes, we show improved AAV transcript stability and transgene expression can be achieved, with implications for gene transfer. [ABSTRACT FROM AUTHOR]

The T-cell differentiation antigen, CD4, is expressed by major histocompatibility (MHC) class II restricted I lymphocytes. CD4+CD8+ T cells use their T-cell receptor to recognize foreign antigens in association with MHC class If products (Ia). The association between CD4 expression and restriction by MHC class II products has led to the hypothesis that CD4 may interact with monomorphic determinants of MHC class II molecules. A large body of experimental evidence suggests that CD4 interaction with MHC class II molecules leads to an increase in the binding avidity of T cell-stimulator cell interactions. A direct test for a functional CD4-MHC class II interaction in T-cell activation requires a separate evaluation of CD4-Ia interactions from T-cell receptor (TcR)-antigen (Ag)/Ia recognition. However, a separate evaluation proves difficult since the T-cell receptor and CD4 may interact with the same MHC class II molecule. In this report, we use a T-cell activation protocol where TcR-Ag/Ia recognition is replaced by TcR complex-anti-CD3 antibody interactions. Therefore, the affinity of the TcR complex for its ligand (the anti-CD3 mAb) is independent from MHC expression on target cells and allows a separate evaluation of the role of accessory molecules in T-cell activation. We have analysed the effects of monoclonal anti-MHC class II antibodies on the activation of a CD4 T-cell hybridoma in the absence of its TcR restricting MHC class II molecule (f!Ek) but in the presence of unrelated MHC class II molecules (I-Ed, I-Ad). The data obtained indicate a functional interaction between the CD4 molecule and a non-polymorphic region of the MHC class II product in T-cell triggering. [ABSTRACT FROM AUTHOR]

The perception of Brazilian non-bovine dairy processors (goat, sheep and buffalo, n = 32) located in eight states of Brazil (Rio de Janeiro, Sao Paulo, Minas Gerais, Parana, Goiás, Bahia, Rio Grande do Sul, and Ceará), regarding the implementation of traceability was investigated. A questionnaire consisting of 16 statements using a 5-point Likert Scale was applied and the data were evaluated by descriptive statistics and factor analysis. It was agreed that the implementation of a traceability system allows a quick recall of products, and reduces the negative impact, the number of consumer complaints and the loss of products. In addition, it can result in increased supplier control and process safety, protecting consumer's health and increasing their confidence. However, the relationship between the traceability system and the cost savings in the process and/or price of the final product was not a consensus. Although dairy companies agreed that traceability is highly relevant to the company, many are unwilling to invest in implementation of the system. Therefore, non-bovine milk-producing units in Brazil are aware of the impact of implementing traceability, but still have doubts about the costs involved, which restrict investments in the system. • Perceptions and attitude of Brazilian non-bovine dairy processors regards the traceability. • Traceability system provides a quick recall of products. • The relationship between the traceability system and the cost savings needs more clarification. [ABSTRACT FROM AUTHOR]

We developed a simple method for identifying resonance frequency by focusing on the spectral peak of the low-frequency (LF) component of heart rate variability (HRV) and examined the hypothesis that paced breathing at an accurate resonance frequency increases HRV and baroreflex sensitivity (BRS). We assessed a peak frequency of the LF component of the resting HRV by using power spectral analysis under respiratory control at 0.25 Hz, and a resonance frequency, which was evaluated by using the standard breathing maneuver (Lehrer 2007). We examined the effects of paced breathing at the peak frequency of the LF component (Spectral condition) and paced breathing at the resonance frequency as determined by the standard breathing maneuver (Standard condition) on HRV and BRS in 28 healthy college students and young adults. Electrocardiogram, respiration, and noninvasive continuous blood pressure was recorded during a 5-min baseline, followed by a 5-min paced breathing session. Results indicated that the BRS increased during the breathing session under both conditions, but the increase in BRS under the Spectral condition was higher than the Standard condition (p <.05). The LF amplitude increased during the breathing session under both conditions (p <.001), although the difference between the conditions was not significant. These results suggest that paced breathing at the peak frequency of the LF component enhanced the autonomic baroreflex function. Moreover, assessment of the LF-peak may provide more accurate information on resonance frequency for paced breathing during HRV biofeedback. [ABSTRACT FROM AUTHOR]

Intravenous injection of 2 × 108 DBA/2 spleen cells into adult intact (C57BL/6 × DBA/2) Fl mice results in a stimulatory graft-versus-host reaction (GVHR) linked to the recognition by donor CD4+ T cells of Ia alloantigens on host B cells. In the experiments presented here, we found that this GVHR is associated with a major increase in IgE serum levels which was already present 7 days after the cell transfer. At 6 weeks, mean IgE levels were more than 200-fold above the control values. Host B cells were responsible for the hypersecretion of IgE in stimulatory GVHR since it was also observed when the DBA/2 donor inoculum was depleted of B cells but not when the Fl recipients were irradiated. The induction of IgE secretion required donor CD4+ T cells as treatment of the donor inoculum with lytic anti-CD4 monoclonal antibody (MoAb) completely prevented the occurrence of the hyper IgE whereas depletion of CD8+ cells had no influence on this parameter. The role played by interleukin-4 (IL-4) in this model was analysed in vivo by the administration of the 11B11 anti-IL-4 rat MoAb (total dose 36 mg) during the first 12 days following induction of stimulatory GVHR by 8 × 107 DBA/2 spleen cells. This treatment completely prevented the development of hyper IgE whereas the administration of a control rat MoAb had no significant effect. We conclude that stimulatory GVHR in mice is associated with a major increase in serum IgE which is mediated by IL-4. [ABSTRACT FROM AUTHOR]

Background: Most women with primary breast cancers that express estrogen receptor alpha (ER or ESR1) are treated with endocrine therapies including the anti-estrogen tamoxifen, but resistance to these anti-endocrine therapies often develops. This study characterizes the expression of hormone receptors, and the mRNA and DNA methylation levels of docking protein 7 (DOK7), and E74-like factor 5 (ELF5), in 21 novel tamoxifen-resistant cell lines and extends the findings to primary and recurrent human breast tumors. Methods: Twenty-one tamoxifen-selected cell lines were developed through cloning by limiting dilution of an MCF-7 cell culture treated with 1 µM tamoxifen for 6 months. The parent (MCF-7) and tamoxifen-selected cell lines were characterized for protein expression of ER, progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2) using immunohistochemistry (IHC). The mRNA levels of ER, DOK7, and ELF5 were assessed using quantitative RT-PCR. Promoter methylation levels of DOK7 and ELF5 were determined by pyrosequencing of bisulfitemodified DNA. The relationship between hormone receptor status and promoter methylation of DOK7 and ELF5 was further examined using available methylation array data (Illumina HM450) from a set of paired primary and second breast tumors from 24 women. Results: All 21 of the novel tamoxifen-selected cell lines are ER-positive, and HER2-negative, and 18 of the cell lines are PR-negative while the MCF-7 cells were scored as ER-positive, modestly PR-positive and HER2 negative. Expression of DOK7 and ELF5 is significantly up-regulated in half of the tamoxifen-selected cell lines as compared to the parental MCF-7. In contrast, the previously established ER-negative TMX2-28 cell line has decreased expression of both DOK7 and ELF5 and increased DNA methylation in the transcriptional start site region of these genes. ELF5 methylation was lower in second versus primary tumors in women who received anti-estrogen treatment, in PR-negative versus PRpositive tumors, and in the subset of PR-positive first tumors from the group of women who had second PR-negative tumors as compared to those who had second PR-positive tumors. Conclusions: The distinct ELF5 methylation of PR-positive primary tumors from women who had a PR-negative recurrence indicates the possibility of stratification of women for tailored treatment in the early stages of disease. [ABSTRACT FROM AUTHOR]

ABSTRACT The dependence of much of Africa on rainfed agriculture leads to a high vulnerability to fluctuations in rainfall amount. Hence, accurate monitoring of near-real time rainfall is particularly useful, for example in forewarning of possible crop shortfalls in drought-prone areas. Unfortunately, ground based observations are often inadequate. Rainfall estimates from satellite-based algorithms and numerical model outputs can fill this data gap, however rigorous assessment of such estimates is required. In this case, three satellite based products (NOAA-RFE 2.0, GPCP-1DD and TAMSAT) and two numerical model outputs (ERA-40 and ERA-Interim) have been evaluated for Uganda in East Africa using a network of 27 rain gauges. The study focuses on the years 2001-2005 and considers the main rainy season (February to June). All data sets were converted to the same temporal and spatial scales. Kriging was used for the spatial interpolation of the gauge data. All three satellite products showed similar characteristics and had a high level of skill that exceeded both model outputs. ERA-Interim had a tendency to overestimate whilst ERA-40 consistently underestimated the Ugandan rainfall. [ABSTRACT FROM AUTHOR]

Abstract: Crop monitoring systems that rely on agrometeorologic models require estimates of global radiation. These estimates are difficult to obtain due to the limited number of weather stations that measure this variable. In the present study, we validated the global radiation estimates derived from MeteoSat Second Generation (MSG) and evaluated their use in the European Crop Growth Monitoring System (CGMS). A validation with measurements from four CarboEurope flux towers showed that the MSG estimates are accurate and unbiased (standard deviation between 30 and 51W/m2). Moreover, a comparison with global radiation estimates from about 300 operational weather stations throughout Europe confirmed that the quality of the MSG product is high and spatially uniform. We also made an intercomparison between the MSG product and the ECMWF (ERA-INTERIM) and CGMS products at 25km resolution, thus demonstrating that the CGMS and ECMWF products generally underestimate radiation. Nevertheless, the CGMS product showed irregular spatial patterns of local over- and underestimation, while the ECMWF product consistently underestimated. A trend analysis using a seasonal Mann-Kendall test between 2005 and 2009 did not reveal any significant monotonic trends in the MSG radiation estimates, except for 1 location out of 15. Finally, when we applied the WOFOST crop model for maize throughout Europe, the simulated potential total biomass increased due to higher estimates of global radiation made by MSG. In contrast, the water-limited simulated total-biomass generally decreased due to a higher reference evapotranspiration, causing faster depletion of soil moisture and increased water stress. [Copyright &y& Elsevier]

Exposure of healthy people to lipopolysaccharide (LPS; endotoxin) produces a pro-inflammatory response, subjective symptoms, and decreased heart rate variability (HRV). Given the efficacy of HRV biofeedback (BF) for treating asthma, the large autonomic effects of HRV BF, and the link between vagus nerve activity and inflammation, we hypothesized that HRV BF would dampen the acute manifestations of systemic inflammation induced by LPS challenge. Healthy participants age 18-40 were randomly assigned to four-one-hour training sessions of either HRV BF ( n = 6) or a control 15/min paced breathing condition ( n = 5) prior to acute experimentally induced LPS exposure. Participants were coached to do the procedures for 10 min each at five hourly time points after LPS injection, and then 2 h later. Subjective symptoms, HRV parameters, and plasma cytokine levels were measured at each time point, 2 h afterward, and the following morning. Participants were able to perform the procedures both during four pre-exposure training sessions and while experiencing LPS-induced symptoms. The HRV BF group showed significant attenuation of the LPS-induced decline in HRV for the 6 h following LPS exposure, suggesting that HRV BF decreased autonomic dysfunction produced by LPS-induced inflammation. HRV BF also reduced symptoms of headache and eye sensitivity to light, but did not affect LPS-induced levels of pro-inflammatory cytokines or symptoms of nausea, muscle aches, or feverishness. Further evaluation of HRV BF appears to be warranted among patients with inflammatory conditions . [ABSTRACT FROM AUTHOR]

The article highlights several court cases in the U.S. The Air Transport Association of America versus Andrew Cuomo regarding the New York's Passenger Bill of Rights has preempted the states from exercising law related to price, route, service of an air carrier, however, it requires the airlines to provide the basic needs of its passengers which include water, restroom and food. Reliable Consultants Inc. against Ronnie Earle cites that the Texas law on selling, advertising or lending sexual device violates Due Process. The Chicago Lawyers' Commission for Civil Rights Under Law Inc. against Craigslist Inc. questioned the move of Craigslist to create an Internet meeting place that discriminates some of its participants.

Severe injury and infection are associated with autonomic dysfunction. Diminished heart rate variability (HRV) is also observed as a component of autonomic dysfunction and is induced by endotoxin administration to healthy subjects. It is established that low-dose glucocorticoid administration diminishes the systemic inflammatory manifestations of endotoxinemia but the influence of this anti-inflammatory intervention on overall autonomic dysfunction and HRV responses to endotoxin is unknown. This study was designed to assess the influence of a low-dose hydrocortisone infusion upon endotoxin-elicited systemic inflammatory responses including phenotypic features, cytokine production, and parameters of HRV. Of 19 subjects studied, nine received a continuous infusion of hydrocortisone (3 µg/kg/min continuously over 6 h) prior to intravenous administration of Escherichia coli endotoxin (2 ng/kg, CC-RE, Lot #2) while 10 healthy subjects received only the endotoxin after a 6-h period of saline control infusion. Serial determinations of vital signs, heart rate variability assessments, and cytokine levels were obtained over the subsequent 24 h. Prior cortisol infusion diminished the peak TNF-α (P < 0.01) and IL-6 (P < 0.0001) responses after endotoxin challenge, as compared to saline infusion controls and diminished the peak core temperature response to endotoxin (P < 0.01). In contrast to the influence of cortisol on the above parameters of systemic inflammation, the significant endotoxin-induced decreases in HRV time and frequency domains were not influenced by prior hydrocortisone treatment. Hence, alterations in autonomic dysfunction occur despite hydrocortisone attenuation of other traditional systemic manifestations of endotoxinemia. The maintenance or restoration of autonomic balance is not influenced by glucocorticoid administration. [ABSTRACT FROM AUTHOR]

BALB/c mice made tolerant to A/J alloantigens by neonatal injection of (A/J × BALB/c)F1 spleen cells develop a host-versus-graft (HVG) disease due to the activation of donor B cells by a subset of host alloreactive helper T cells. We have investigated the effects of a single neonatal injection of the 145-2C11 anti-mouse CD3 monoclonal antibody (MoAb) on the establishment of allotolerance and on the development of the immunopathological features of HVG disease. First, this treatment did not modify the specific anti-donor cytotoxic T lymphocyte (CTL) unresponsiveness or the persistence of circulating immunoglobulins bearing donor allotype. Second, the hyper IgE, the hyper IgG 1 and the increased expression of Ia antigens on B cells found in untreated HVG mice were not observed after injection of the 145-2C11 MoAb. Likewise, treated mice displayed lower levels of anti-DNA IgG antibodies and less glomerular immune deposits as compared with untreated HVG mice. We conclude that the administration of the anti-CD3 MoAb did not interfere with the induction of allotolerance but exerts a pronounced inhibitory effect on the associated immunopathological syndrome. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the mechanisms by which B7-related costimulatory molecules (CD80, CD86) increase T-cell responsiveness to extracellular ligands. As a model study, the in vitro response of purified splenic CD4+ T cells to a bacterial superantigen, SEB, was characterized. Previous analysis of this experimental model led us to conclude that expression of B7-related molecules is strictly required in order to activate CD4+ T cells in the presence of bacterial superantigens. In the present report, we demonstrate that antigen-presenting cell-derived costimulatory signals regulate the kinetics of interleukin-2 (IL-2) production by SEB-activated splenic CD4+ T cells. Indeed, experiments performed with purified subpopulutions of antigen- presenting cells and using B7-transfected cell lines indicated that increased levels of CD80 and/or CD86 cell surface expression is associated with a faster kinetics of IL-2 production in response to SEB. Accordingly, blocking of CD80 or CD86-derived signals by specific monoclonal antibodies led to a slower kinetics of IL-2 production in response to SEB. Thus these data demonstrate that similar strength of signal through the T-cell receptor can lead to immune responses displaying distinct kinetics depending on the level of costimulatory ligands on APC. [ABSTRACT FROM AUTHOR]