Can the Dose of Belimumab be Reduced in Patients with Systemic Lupus Erythematosus?

OBJECTIVES

The aims of this study were to investigate the prevalence of dose reduction in patients with SLE treated with belimumab (BEL) in Spain, analyze treatment modalities, and determine impact on control of disease activity.

METHODS

Retrospective longitudinal and multicentre study of SLE patients treated with BEL. Data on disease activity, treatments and outcomes were recorded before and after reduction (6-12 months), and they were compared.

RESULTS

A total of 324 patients were included. The dose was reduced in 29 patients (8.9%). The dosing interval was increased in 9 patients receiving subcutaneous BEL and in 6 patients receiving intravenous BEL. The dose per administration was reduced in 16 patients.Pre-reduction status was remission (2021 DORIS) in 15/26 patients (57.7%) and LLDAS in 23/26 patients (88.5%). After reduction, 2/24 patients (8.3%) and 3/22 patients (13.6%) lost remission at 6 months and 12 months, respectively (not statistically significant [NS]). As for LLDAS, 2/23 patients (8.7%) and 2/21 patients (9.5%) lost their status at 6 and 12 months, respectively (NS). Significantly fewer patients were taking glucocorticoids (GCs) at their 12-month visit, although the median dose of GCs was higher at the 12-month visit (5 [0.62-8.75] vs 2.5 [0-5] at baseline).

CONCLUSION

Doses of BEL can be reduced with no relevant changes in disease activity-at least in the short term-in a significant percentage of patients, and most maintain the reduced dose. However, increased clinical or serologic activity may be observed in some patients. Consequently, tighter post-reduction follow-up is advisable.

[Prevalence, knowledge and control of arterial hypertension in vulnerable neighborhoods of Argentina: A Cross-sectional Study]

INTRODUCTION

Hypertension (HTN) represents the primary individual risk factor, contributing significantly to the global burden of cardiovascular diseases (CVD). In our country, epidemiological research has highlighted substantial variations in the prevalence of these risk factors across different populations. However, there is a lack of epidemiological studies assessing exclusive cardiovascular risk factors within vulnerable neighborhoods characterized by extremely limited economic resources, sociocultural challenges, and inadequate healthcare access.

METHODS

A multicenter cross-sectional observational study was conducted among individuals residing in economically deprived and marginalized communities, including informal settlements and underprivileged neighborhoods. Simple random sampling of households was employed. Blood pressure measurements, anthropometric assessments, and epidemiological, economic, and sociocultural questionnaires were administered. Results encompass prevalence rates, awareness levels, and blood pressure control across diverse regions. Logistic regression was utilized to identify independent variables influencing primary outcomes.

RESULTS

A total of 989 participants were analyzed. The overall prevalence of hypertension was 48.2%. About 82% had a body mass index (BMI) >25. Approximately 45.3% had less than 6 years of formal education. Independent association was established between education levels below 6 years and higher hypertension prevalence. Among hypertensive individuals, 44% were unaware of their condition, with only 17.2% achieving control, correlated with having health insurance and a higher educational background. Merely 24% were receiving combined therapy.

CONCLUSION

The prevalence of hypertension within vulnerable neighborhoods is alarmingly high, surpassing rates in other social strata. Knowledge, treatment, and control levels of hypertension are suboptimal, comparable to other populations. Inadequate use of combination therapy was observed. This study underscores the urgent need for targeted interventions addressing cardiovascular risk factors in poor areas to mitigate the burden of CVD.

FRI0487 APREMILAST IN MONOTHERAPY OR COMBINED IN NON-ULCER MANIFESTATIONS OF BEHÇET’S DISEASE. NATIONAL MULTICENTER STUDY OF 34 REFRACTORY CASES OF CLINICAL PRACTICE

Background:

Apremilast (APR) has demonstrated efficacy in orogenital ulcers of Behçet´s disease (BD). Response of other clinical manifestations remains unknown.

Objectives:

To assess the efficacy and safety of APR in monotherapy or combined with disease-modifying anti-rheumatic drugs (DMARDs) in non-aphthous ulcers of BD.

Methods:

National multicenter open-label study on 34 BD patients treated with APR at maintained standard dose of 30 mg twice daily.

Results:

From a cohort of 51 patients with APR by refractory orogenital ulcers of BD, we selected 34 (24 women/10 men, mean age 43.8±14.3 years), cases with another clinical manifestation/s.

Excluding CTs, colchicine or NSAIDs, APR was given in monotherapy (n=21) or combined with conventional and/or biologic DMARDs in 13 cases (5 methotrexate, 3 azathioprine, 3 hydroxychloroquine, 1 sulfasalazine, 1 dapsone, 2 tocilizumab, 1 IFX). Other active manifestations present at APR onset were: arthralgia/arthritis (16, true arthritis in 5), folliculitis/pseudofolliculitis (14), erythema nodosum (3), furunculosis (2), paradoxical psoriasis by TNFi (2), intestinal ileitis (2), deep venous thrombosis (2), leg ulcers (1), erythematosus and scaly skin lesions (1), fever (1), unilateral anterior uveitis (1) and neurobehçet (1).

After a median follow-up of 6 [3-12] months, folliculitis and ileitis improved, neurobehçet remained stable and musculoskeletal manifestations evolved in a variable way.(TABLE)

TABLE.

Conclusion:

In addition of orogenital ulcers, APR in monotherapy or combined, seems to be useful in skin manifestations of BD

Disclosure of Interests:

Alba Herrero Morant: None declared, Belen Atienza Mateo: None declared, J. Loricera: None declared, Vanesa Calvo del Rio Grant/research support from: MSD and Roche, Speakers bureau: Abbott, Lilly, Celgene, Grünenthal, UCB Pharma, José Luis Martín-Varillas Grant/research support from: AbbVie, Pfizer, Janssen and Celgene, Speakers bureau: Pfizer and Lilly, Gerard Espinosa: None declared, Jenaro Graña: None declared, Clara Moriano: None declared, Trinidad Pérez Sandoval: None declared, Manuel Martín Martínez: None declared, Elvira Diez: None declared, María Dolores García-Armario: None declared, Esperanza Martínez: None declared, Ivan Castellví Consultant of: Boehringer Ingelheim, Actelion, Kern Pharma, Speakers bureau: Boehringer Ingelheim, Actelion, Bristol-Myers Squibb, Roche, Patricia Moya Alvarado: None declared, Francisca Sivera: None declared, Jaime Calvo Grant/research support from: Lilly, UCB, Consultant of: Abbvie, Jansen, Celgene, Isabel de la Morena: None declared, Francisco Ortiz Sanjuán: None declared, José Andrés Román Ivorra: None declared, Ana Pérez Gómez: None declared, Alejandro Olive: None declared, Carolina Díez: None declared, Juan José Alegre: None declared, D Ybáñez-García Speakers bureau: Lilly, Roche, Sanofi, Ángels Martínez-Ferrer: None declared, Javier Narvaez: None declared, Ignasi Figueras: None declared, Ana Isabel Turrión: None declared, Susana Romero-Yuste: None declared, Pilar Trénor: None declared, Soledad Ojeda Speakers bureau: AMGEN, LILLY, GEBRO, Miguel Á. González-Gay Grant/research support from: AbbVie, MSD and Roche, Speakers bureau: AbbVie, MSD and Roche, Ricardo Blanco Grant/research support from: Abbvie, MSD and Roche, Consultant of: Abbvie, Pfizer, Roche, Bristol-Myers, Janssen and MSD, Speakers bureau: Abbvie, Pfizer, Roche, Bristol-Myers, Janssen, Lilly and MSD

THU0307 RESPONSE OF BEHÇET’S REFRACTORY ORAL AND/OR GENITAL ULCERS TO APREMILAST IN COMBINATION VS MONOTHERAPY. NATIONAL MULTICENTER STUDY OF 51 CASES OF CLINICAL PRACTICE

Background:

Apremilast (APR) has demonstrated efficacy in the treatment of oral and/or genital aphthous ulcers in Behçet´s disease (BD). Combination of APR to other disease-modifying anti-rheumatic drugs (DMARDs) has not been assessed.

Objectives:

To compare the efficacy and safety of APR in monotherapy or combined with DMARDs in refractory BD.

Methods:

National multicenter open-label study on 51 BD patients with oral and/or genital ulcers refractory to conventional treatment.

Results:

We included 51 patients (35 women/16 men), mean age 44.7±13.2 years. Before APR, all patients had received several systemic conventional drugs. The main clinical symptoms for starting APR were oral (n=19) and genital (2) aphthous ulcers or both (30).

Excluding corticosteroids, colchicine or NSAIDs, APR was given at standard dose of 30 mg twice daily in monotherapy (n=31), or combined with conventional DMARDs in 16 cases (6 azathioprine, 5 methotrexate, 4 hydroxychloroquine, 4 sulfasalazine, 1 dapsone) or with biologic DMARDs in 4 (2 tocilizumab, 1 adalimumab, 1 infliximab). There were not found statistically significant differences in demographic features, previous therapy, clinical manifestations or reported adverse effects.

After a median follow-up of 6 [3-12] months, most of the patients experienced improvement of the orogenital ulcers in both groups (89.8% in the first 2 weeks), without statistically significant differences.(TABLE)

Conclusion:

APR leads to a rapid and maintained improvement in most patients with refractory BD orogenital ulcers. APR seems as effective and safe in monotherapy as combined.

TABLE:Week 1-2Week 4Month 6Month 12Month 24Outcome of oral and/or genital ulcers n, (%)Cn=19Mn=30Cn=19Mn=26Cn=12Mn=17Cn=7Mn=6Cn=1Mn=1 Complete resolution8 (42.1)11 (36.7)12 (63.2)20 (77)7 (58.4)14 (82.4)3 (42.8)3 (50)1 (100)1 (100) Partial resolution9 (47.4)16 (53.4)7 (36.8)3 (11.5)5 (41.6)2 (11.7)4 (57.2)3 (50)00 No response2 (10.5)3 (9.9)03 (11.5)01 (5.9)0000p value0.90.10.10.80.7

Abbreviations: C= combined; M= monotherapy; n= available data.

Disclosure of Interests:

Alba Herrero Morant: None declared, Belen Atienza Mateo: None declared, J. Loricera: None declared, Vanesa Calvo del Rio Grant/research support from: MSD and Roche, Speakers bureau: Abbott, Lilly, Celgene, Grünenthal, UCB Pharma, José Luis Martín-Varillas Grant/research support from: AbbVie, Pfizer, Janssen and Celgene, Speakers bureau: Pfizer and Lilly, Jenaro Graña: None declared, Gerard Espinosa: None declared, Clara Moriano: None declared, Trinidad Pérez Sandoval: None declared, Manuel Martín Martínez: None declared, Elvira Diez: None declared, María Dolores García-Armario: None declared, Esperanza Martínez: None declared, Ivan Castellví Consultant of: Boehringer Ingelheim, Actelion, Kern Pharma, Speakers bureau: Boehringer Ingelheim, Actelion, Bristol-Myers Squibb, Roche, Patricia Moya Alvarado: None declared, Francisca Sivera: None declared, Jaime Calvo Grant/research support from: Lilly, UCB, Consultant of: Abbvie, Jansen, Celgene, Isabel de la Morena: None declared, Francisco Ortiz Sanjuán: None declared, José Andrés Román Ivorra: None declared, Ana Pérez Gómez: None declared, Sergi Heredia: None declared, Alejandro Olive: None declared, Águeda Prior: None declared, Carolina Díez: None declared, Juanjo J Alegre-Sancho Consultant of: UCB, Roche, Sanofi, Boehringer, Celltrion, Paid instructor for: GSK, Speakers bureau: MSD, GSK, Lilly, Sanofi, Roche, UCB, Actelion, Pfizer, Abbvie, Novartis, D Ybáñez-García Speakers bureau: Lilly, Roche, Sanofi, Ángels Martínez-Ferrer: None declared, J. Narváez: None declared, Ignasi Figueras: None declared, Ana Isabel Turrión: None declared, Susana Romero-Yuste: None declared, Pilar Trénor: None declared, Soledad Ojeda Speakers bureau: AMGEN, LILLY, GEBRO, Miguel Á. González-Gay Grant/research support from: AbbVie, MSD and Roche, Speakers bureau: AbbVie, MSD and Roche, Ricardo Blanco Grant/research support from: Abbvie, MSD and Roche, Consultant of: Abbvie, Pfizer, Roche, Bristol-Myers, Janssen and MSD, Speakers bureau: Abbvie, Pfizer, Roche, Bristol-Myers, Janssen, Lilly and MSD

Quantum nanoconstrictions fabricated by cryo-etching in encapsulated graphene

We report on a novel implementation of the cryo-etching method, which enabled us to fabricate low-roughness hBN-encapsulated graphene nanoconstrictions with unprecedented control of the structure edges; the typical edge roughness is on the order of a few nanometers. We characterized the system by atomic force microscopy and used the measured parameters of the edge geometry in numerical simulations of the system conductance, which agree quantitatively with our low temperature transport measurements. The quality of our devices is confirmed by the observation of well defined quantized 2e²/h conductance steps at zero magnetic field. To the best of our knowledge, such an observation reports the clearest conductance quantization in physically etched graphene nanoconstrictions. The fabrication of such high quality systems and the scalability of the cryo-etching method opens a novel promising possibility of producing more complex truly-ballistic devices based on graphene.

Solitons in a nonlinear model of spin transport in helical molecules

We study an effective integrable nonlinear model describing an electron moving along the axis of a deformable helical molecule. The helical conformation of dipoles in the molecular backbone induces an unconventional Rashba-like interaction that couples the electron spin with its linear momentum. In addition, a focusing nonlinearity arises from the electron-lattice interaction, enabling the formation of a variety of stable solitons such as bright solitons, breathers, and rogue waves. A thorough study of the soliton solutions for both focusing and defocusing nonlinear interaction is presented and discussed.

Can we afford to offer pre-exposure prophylaxis to MSM in Catalonia? Cost-effectiveness analysis and budget impact assessment

Pre-exposure prophylaxis (PrEP) effectiveness has been well established. This study aims to assess the cost-effectiveness of providing PrEP, estimate the number of eligible MSM, and its budget impact in Catalonia. Cost-effectiveness analysis compared costs of on daily basis and "on demand" PrEP to prevent one infection with lifetime costs of one HIV infection. We estimated the total cost of providing PrEP by estimating number of eligible MSM, and included in the budget impact assessment antiretroviral and laboratory costs. Costs were lower for the on-demand PrEP group by €64015.1 and the incremental benefit was nearly 15 life-years and 17 quality-adjusted life-years gained. The incremental cost-effectiveness ratio (ICER) was cost-effective at €6281.62 when undiscounted PrEP was given daily. On-demand PrEP can be considered cost-saving in 20 years if the price is reduced by 90%. The number of eligible MSM in Catalonia ranges from 5,989 to 10,972. At current antiretroviral costs, the annual cost would range between €25.3-46.7 million/year (on demand PrEP), and €42.9-78.7 million/year (daily basis PrEP). PrEP is most cost-effective if targeted towards groups with high incidence rates of over 3%/year. Beneficial ICER depends on reducing the current price of Truvada® and ensuring that effectiveness is maintained at high levels.

Protection of cardiac cell-to-cell coupling attenuate myocardial remodeling and proarrhythmia induced by hypertension

Gap junction connexin channels are important determinants of myocardial conduction and synchronization that is crucial for coordinated heart function. One of the main risk factors for cardiovascular events that results in heart attack, congestive heart failure, stroke as well as sudden arrhythmic death is hypertension. Mislocalization and/or dysfunction of specific connexin-43 channels due to hypertension-induced myocardial remodeling have been implicated in the occurrence of life-threatening arrhythmias and heart failure in both, humans as well as experimental animals. Recent studies suggest that down-regulation of myocardial connexin-43, its abnormal distribution and/or phosphorylation might be implicated in this process. On the other hand, treatment of hypertensive animals with cardioprotective drugs (e.g. statins) or supplementation with non-pharmacological compounds, such as melatonin, omega-3 fatty acids and red palm oil protects from lethal arrhythmias. The antiarrhythmic effects are attributed to the attenuation of myocardial connexin-43 abnormalities associated with preservation of myocardial architecture and improvement of cardiac conduction. Findings uncover novel mechanisms of cardioprotective (antihypertensive and antiarrhythmic) effects of compounds that are used in clinical settings. Well-designed trials are needed to explore the antiarrhythmic potential of these compounds in patients suffering from hypertension.

Lump solitons in a higher-order nonlinear equation in 2+1 dimensions

We propose and examine an integrable system of nonlinear equations that generalizes the nonlinear Schrödinger equation to 2+1 dimensions. This integrable system of equations is a promising starting point to elaborate more accurate models in nonlinear optics and molecular systems within the continuum limit. The Lax pair for the system is derived after applying the singular manifold method. We also present an iterative procedure to construct the solutions from a seed solution. Solutions with one-, two-, and three-lump solitons are thoroughly discussed.

Vitamin E protection of obesity-enhanced vascular calcification in uremic rats

This study aimed to determine the extent of extraskeletal calcification in uremic Zucker rats, by comparing obese and lean phenotypes, and to evaluate the influence of vitamin E (VitE) on the development of calcifications in both uremic rats and human vascular smooth muscle cells (HVSMCs) cultured in vitro. Zucker rats of lean and obese phenotypes with normal renal function [control (C); C-lean and C-obese groups] and with uremia [5/6 nephrectomy (Nx); Nx-lean and Nx-obese groups] and uremic rats treated with VitE (Nx-lean + VitE and Nx-obese + VitE groups) were studied. Uremic groups were subjected to Nx, fed a 0.9% phosphorus diet, and treated with calcitriol (80 ng/kg ip). The aortic calcium concentration was significantly higher ( P < 0.05) in Nx-obese rats (10.0 ± 2.1 mg/g tissue) than in Nx-lean rats (3.6 ± 1.3 mg/g tissue). A decrease in plasma glutathione peroxidase activity was observed in Nx-obese rats compared with Nx-lean rats (217.2 ± 18.2 vs. 382.3 ± 15.5 nmol·min−1·ml−1, P < 0.05). Treatment with VitE restored glutathione peroxidase activity and reduced the aortic calcium concentration to 4.6 ± 1.3 mg/g tissue. The differences in mineral deposition between Nx-lean, Nx-obese, Nx-lean + VitE, and Nx-obese + VitE rats were also evidenced in other soft tissues. In HVSMCs incubated with high phosphate, VitE also prevented oxidative stress and reduced calcium content, bone alkaline phosphatase, and gene expression of core-binding factor-α1. In conclusion, uremic obese rats develop more severe calcifications than uremic lean rats and VitE reduces oxidative stress and vascular calcifications in both rats and cultures of HVSMCs.

Comparison of different treatments for oestrous induction in seasonally anovulatory mares

The aim of this study was to evaluate the effects of different treatments for induction and synchronization of oestrus and ovulation in seasonally anovulatory mares. Fifteen mares formed the control group (C), while 26 mares were randomly assigned to three treatment groups. Group T1 (n = 11) were treated with oral altrenogest (0.044 mg/kg; Regumate(®) ) during 11 days. Group T2 (n = 7) was intravaginally treated with 1.38 g of progesterone (CIDR(®) ) for 11 days. In group T3 (n = 8), mares were also treated with CIDR(®) , but only for 8 days. All mares received PGF2α 1 day after finishing the treatment. Sonographic evaluation of follicles, pre-ovulatory follicle size and ovulation time was recorded. Progesterone and leptin levels were analysed. Results show that pre-ovulatory follicles were developed after the treatment in 88.5% of mares. However, the pre-ovulatory follicle growth was dispersal, and sometimes it was detected when treatment was not finished. While in mares treated with intravaginal device, the follicle was soon detected (1.5 ± 1.2 days and 2.3 ± 2.0 days in T2 and T3 groups, respectively), in T1 group, the pre-ovulatory follicle was detected slightly later (3.9 ± 1.6 days). The interval from the end of treatment to ovulation did not show significant differences between groups (T1 = 13.1 ± 2.5 days; T2 = 11.0 ± 3.6 days; T3 = 13.8 ± 4.3 days). The pregnancy rate was 47.4%, similar to the rate observed in group C (46.7%; p > 0.05). Initial leptin concentrations were significantly higher in mares, which restart their ovarian activity after treatments, suggesting a role in the reproduction mechanisms in mares. It could be concluded that the used treatments may be effective for oestrous induction in mares during the late phase of the seasonally anovulatory period. Furthermore, they cannot synchronize oestrus, and then, it is necessary to know the reproductive status of mares when these treatments are used for oestrous synchronization.

Feline parathyroid hormone: validation of hormonal assays and dynamics of secretion

Validated assays for quantification of intact parathyroid hormone (I-PTH) are no longer available. Moreover, the third-generation PTH assay that only detects the whole PTH molecule (W-PTH) has never been tested in cats. The work presented here is aimed to validate a commercially available assay for measurement of I-PTH and W-PTH in cats and to study the dynamics of PTH secretion in healthy cats. Our results show that both assays are reliable for the measurement of feline PTH. In healthy adult cats W-PTH concentration (15.1 ± 1.6 pg/mL) was greater (P < 0.001) than I-PTH concentration (9.1 ± 0.7 pg/mL). The dynamics of PTH secretion in response to changes in extracellular calcium (Ca(2+)) were investigated in 13 cats by studying PTH-Ca(2+) curves. PTH-Ca(2+) curves were obtained by intravenous infusion of disodium ethylenediaminetetraacetic acid and CaCl(2). PTH was measured using both I-PTH and W-PTH assays. During hypocalcemia a sigmoidal curve that was similar when measured with I-PTH or W-PTH was obtained. The maximal PTH concentration in response to hypocalcemia was greater with W-PTH (179.6 ± 41.9 pg/mL) than with I-PTH (67.6 ± 10.5 pg/mL; P = 0.01). However, hypercalcemia resulted in an equivalent PTH inhibition, with both assays yielding PTH concentrations as follows: W-PTH = 4.0 ± 0.4 pg/mL and I-PTH = 4.9 ± 0.3 pg/mL (NS). Parameters of the feline PTH-Ca(2+) curve are similar to what has been previously reported in dogs.

[Paramedian forehead flap for the reconstruction of extensive nasal defects]

BACKGROUND

The Department of Dermatology at Hospital Universitario de Guadalajara in Spain is a referral center for Mohs micrographic surgery. Consequently, we are regularly faced with the problem of repairing large surgical defects on the nose. The paramedian forehead flap is currently one of the techniques of choice for the repair of such defects.

MATERIALS AND METHODS

We review our experience in the repair of nasal defects using the paramedian forehead flap over the period from 2004 to 2008. We describe the surgical technique, complications, and final results.

RESULTS

Ten patients (mean age, 75.1 years) were treated using this flap. Two patients also required cartilage grafts and reconstruction of the internal nasal lining. The most common complications were bleeding (60%) and partial necrosis (10%). The final cosmetic and functional results were considered good or excellent in 90% of cases.

CONCLUSIONS

The forehead flap continues to be one of the best options for the closure of surgical defects of the nasal pyramid larger than 2 cm. Adequate knowledge and careful application of the technique allows excellent results to be obtained with few complications.

Positional cloning of a quantitative trait locus contributing to pain sensitivity: possible mediation by Tyrp1

To identify novel pain-relevant genes, a set of 35 recombinant congenic strains derived from the sensitive C57BL/6 and resistant A/J strains were tested for their sensitivity to noxious heat on the radiant heat paw-withdrawal test. Nine strains were found to display differential sensitivity, and the two most extreme responders were used to generate independent secondary crosses for quantitative trait locus (QTL) mapping. From these genetic analyses, a QTL, which we call Tpnr5, was mapped to a 14-Mb interval of mouse chromosome 4 containing 39 genes. In addition to the paw-withdrawal test phenotype, Tpnr5 may be relevant to mechanical and inflammatory nociception. A series of strategies - including in silico analyses, reverse transcriptase polymerase chain reaction (RT-PCR) in multiple tissues and exonic DNA sequencing - were used to generate a list of six prioritized candidate genes. One of these, tyrosinase-related protein 1 (Tyrp1), displayed enriched expression in the dorsal root ganglia, an inactivating (C110Y) mutation in the resistant A/J strain, and a null mutant found to be more resistant to thermal nociception compared to its wild-type counterpart. Although other genes cannot be definitively ruled out, existing data are supportive of the candidacy of Tyrp1 as representing the Tpnr5 QTL. Tyrosinase-related protein 1 is the rate-limiting enzyme in the production of eumelanin, and possible relationships between eumelanin-expressing cells and thermal nociception are discussed. The positional cloning of Tpnr5 is also considered in light of the heuristic value but continuing challenges of QTL mapping in the mouse.

Near-perfect correlation of the resistance components of mesoscopic samples at the quantum Hall regime

We study the four-terminal resistance fluctuations of mesoscopic samples near the transition between the nu=2 and the nu=1 quantum Hall states. We observe near-perfect correlations between the fluctuations of the longitudinal and Hall components of the resistance. These correlated fluctuations appear in a magnetic-field range for which the two-terminal resistance of the samples is quantized. We discuss these findings in light of edge-state transport models of the quantum Hall effect. We also show that our results lead to an ambiguity in the determination of the width of quantum Hall transitions.

Comprehensive analysis of the frequency of recognition of melanoma-associated antigen (MAA) by CD8 melanoma infiltrating lymphocytes (TIL): implications for immunotherapy

Fifty-nine tumor-infiltrating lymphocyte (TIL) cultures established from melanoma-invaded lymph nodes were screened for recognition of 28 melanoma-associated antigens (MAA) in association with31 HLA molecules. Twenty-three (39%) TIL lines reacted to at least one melanoma antigen. Melanosomal proteins were recognized by 19 TIL populations and the most prominent responses against these proteins were directed against Melan-A/MART-1 (mainly in association with HLA-A*0201) and gp100 (in association with diverse HLA contexts). Ten TIL populations reacted against 10 tumor-specific antigens, in association with 8 different HLA molecules. HLA-A*0201 and B*3501-restricted responses were the most frequent with, respectively, 17 and 7 responses directed against 5 distinct antigens. Unexpectedly, the recognition by TIL of different MAA was frequently restricted by a single HLA in individual tumors, and there was no evidence for the existence of dominant MAA epitopes between tumors,except for Melan-A/MART-1 antigen. This analysis also led to the detection of 21 new HLA-peptide complexes recognized by melanoma TIL. This study, which is to our knowledge the most comprehensive analysis of TIL specificity to tumor antigens, has several implications for the design of immunotherapeutic strategies based on immunization against selected tumor epitopes.

Recombinant Congenic Strains Derived from A/J and C57BL/6J: A Tool for Genetic Dissection of Complex Traits

Complex genetic traits can be dissected in mice, using well-defined sets of recombinant inbred strains, congenic strains, and recombinant congenic strains (RCS). We report the creation of a series of 37 independent RCS derived from the commonly used inbred strains of laboratory mouse A/J (A) and C57BL/6J (B6). These RCS were derived by systematic inbreeding of independent pairs of animals from a (F1 x A) x A and a (F1 x B) x B double backcross (N3), to create AcB and BcA strains, respectively. Fifteen AcB strains and 22 BcA strains at between 18 and 30 generations of inbreeding have been generated, are healthy, and show stable breeding performance. These strains have been genotyped for a total of 625 informative microsatellite DNA markers covering the entire genome, with an average spacing of 2.6 cM. Haplotype analyses indicate that on average, AcB and BcA strains contain 13.25% of the donor genome, a value close to the 12.5% expected from the breeding scheme used in their creation. In the AcB set, approximately 79% of the B6 genome has been transferred in independent strains, while in the BcA set approximately 84% of the A genome is represented on the B6 background. This represents an excellent coverage of congenic segments from both parental genomes in the two sets of strains, which can now be used to map simple and complex traits in a genome-wide fashion. As an example of the power of AcB/BcA strains as a mapping tool, the 37 strains were typed for susceptibility to infection with Legionella pneumophila, a monogenic trait controlled by the Lgn1 locus on Chromosome 13. Analysis of the strain distribution pattern of L. pneumophila susceptibility allowed direct mapping of Lgn1 to a 3-cM interval. The AcB/BcA set should prove a useful tool with which to investigate the complex genetic basis of known interstrain differences between A and B6 for many important diseases.

SB-253514 and analogues; novel inhibitors of lipoprotein-associated phospholipase A2 produced by Pseudomonas fluorescens DSM 11579. I. Fermentation of producing strain, isolation and biological activity

Two new classes of inhibitors of LpPLA2 have been identified in fermentations of Pseudomonas fluorescens. The two structurally isomeric series differ in the geometry of closure of the bicyclic carbamate and comprise a range of compounds varying only in length of their lipophilic sidechain. The most abundant species were extracted from the cells and purified by silica and C18 chromatography. Members of the more stable class were shown to be potent and selective competitive inhibitors of LpPLA2.

High avidity melanoma-reactive cytotoxic T lymphocytes are efficiently induced from peripheral blood lymphocytes on stimulation by peptide-pulsed melanoma cells

To design an efficient procedure to expand high avidity melanoma reactive T cells and to perform immunotherapies, we compared conditions of peripheral blood lymphocyte (PBL) stimulation by Melan-A/MART-1 peptides. Avidity of induced CTLs was evaluated by measuring their lysis and cytokine secretion to peptide-pulsed transporter-associated protein-deficient cells and to melanoma cells. In side-by-side experiments, we show that melanoma cells, either allogeneic or autologous, induced the growth of high avidity Melan-A-reactive CTLs from all donors, whereas essentially low avidity T cells were induced by peptide-pulsed PBLs. We also show that at least two cytokines, interleukin-6 and interleukin-2, were required to promote the growth of high avidity CTLs. Once sorted by tetramer labeling or cloning, the specificity and reactivity to tumor cells of peptide-specific T cells induced by allogeneic melanoma cells were confirmed. We then describe a relatively simple and efficient procedure that allowed us to obtain systematically high amounts (in the range of billion) of high avidity Melan-A/ MART-1-specific T cells from the PBLs of HLA-A2 melanoma patients and healthy donors in 3 months. Because this antigen is expressed by most melanoma tumors, this procedure should be useful for checking the efficiency of adoptive immunotherapy of melanoma tumors and using functionally well-defined Melan-A/MART-1-specific CTLs in a large group of patients.

The neuronal apoptosis inhibitory protein (Naip) is expressed in macrophages and is modulated after phagocytosis and during intracellular infection with Legionella pneumophila

Legionella pneumophila is an intracellular pathogen that causes Legionnaires' disease in humans. Inbred mouse strains are uniformly resistant to L. pneumophila infection with the notable exception of A/J, where the chromosome 13 locus Lgn1 renders A/J macrophages permissive to L. pneumophila replication. The mouse Lgn1 region is syntenic with the spinal muscular atrophy (SMA) locus on human chromosome 5 and includes several copies of the neuronal apoptosis inhibitory protein (Naip) gene. We have analyzed a possible link among Lgn1, Naip, and macrophage function. RNA expression studies show that Naip (mostly copy 2) mRNA transcripts are expressed in macrophage-rich tissues, such as spleen, lung, and liver and are abundant in primary macrophages. Immunoblotting and immunoprecipitation analyses identify Naip protein expression in mouse macrophages and in macrophage cell lines RAW 264.7 and J774A. Interestingly, macrophages from permissive A/J mice express significantly less Naip protein than their nonpermissive C57BL/6J counterpart. Naip protein expression is increased after phagocytic events. Naip protein levels during infection with either virulent or avirulent strains of L. pneumophila increase during the first 6 h postinfection and remain elevated during the 48-h observation period. This enhanced expression is also observed in macrophages infected with Salmonella typhimurium. Likewise, an increase in Naip protein levels in macrophages is observed 24 h after phagocytosis of Latex beads. The cosegregation of Lgn1 and Naip together with the detected Naip protein expression in host macrophages as well as its modulation after phagocytic events and during intracellular infection make it an attractive candidate for the Lgn1 locus.

Changes in the alcohol consumption pattern among schoolchildren in Barcelona

Alcohol consumption is a major health problem in most developed countries. In Mediterranean countries, experimentation with alcoholic beverages typically occurs during the early adolescent years within the family context. In this study we analysed alcohol consumption and its determinants in a survey of a sample of schoolchildren in 1994. The results were compared to those obtained in a previous study in 1987. In 1994 a random, stratified sample of all 8th grade classrooms of a city, public, private or subsidised school was, obtained. Some 759 13 and 14 year old pupils responded to a self-administered questionnaire on health-related habits. Overall, there was a high awareness of alcohol in the environment, as 20.7% of the pupils reported their father was a regular or occasional drinker and 41.6% declared some of their friends were drinking. Compared with the results of the 1987 survey, there was a marked decline in the proportion of schoolchildren reporting alcohol consumption by their father or their siblings. Regarding the pupils' consumption, 66.7% of them had tried drinking alcohol in 1994, 54.7% declared they were allowed to drink in family celebrations, and 17.2% had experienced being drunk. Most of these indicators showed a significant decrease compared with the 1987 data, with the exception of drunken episodes where there appears to be no changes. The results suggest that there are some changes in the Spanish context, where regular drinking among adolescents may be declining.

Ambient pH signal transduction in Aspergillus: completion of gene characterization

Completing the molecular analysis of the six pal genes of the ambient pH signal transduction pathway in Aspergillus nidulans, we report the characterization of palC and palH. The derived translation product of palH contains 760 amino acids with prediction of seven transmembrane domains in its N-terminal moiety. Remarkably, a palH frameshift mutant lacking just over half the PalH protein, including almost all of the long hydrophilic region C-terminal to the transmembrane domains, retains some PalH function. The palC-derived translation product contains 507 amino acids, and the null phenotype of a frameshift mutation indicates that at least one of the C-terminal 142 residues is essential for function. Uniquely among the A. nidulans pH-signalling pal genes, palC appears to have no Saccharomyces cerevisiae homologue, although it does have a Neurospora crassa expressed sequence tag homologue. In agreement with findings for the palA, palB and palI genes of this signalling pathway, levels of the palC and palH mRNAs do not appear to be pH regulated.

Recognition of leukemic blasts by HLA-DPB1-specific cytotoxic T cell clones: a perspective for adjuvant immunotherapy post-bone marrow transplantation

There is increasing evidence that the immune response plays a role in the prevention of leukemic relapses after allogeneic bone marrow transplantation (BMT). Producing this effect (referred to as the graft-versus-leukemia reaction or GVL) is a current goal of clinical transplantation. At present, all protocols rely on the injection of donor T cells with unknown specificities. In keeping with this approach, we recently proposed the use of a single allogeneic T cell clone transfected with the HSv-tk gene to target an HLA-DPB1 mismatch in the GVH direction. For this strategy to be successful, HLA-DP antigens must be expressed on leukemic cells, which should be recognised by the HLA-DP-specific T cell clone and subsequently destroyed. In the present study, differential expression of HLA-DR, -DQ and -DP was tested by fluorescence using monoclonal antibodies on a panel of 46 acute myeloid leukemias (AML), 28 acute lymphoblastic leukemias (ALL) and 31 chronic lymphocytic leukemias of B cell origin (B-CLL). The vast majority of leukemic cells expressed HLA-DP antigens although with considerable variability. HLA-DPB1 genotyped leukemic cells were used as target cells for an HLA-DPB1*0401-specific T cell clone. Specific recognition of leukemic blasts was demonstrated for 11 out of 11 B-CLL, 11 out of 19 AML and nine out of 16 ALL. These data show that most leukemic blasts are accessible to direct lysis by allogeneic HLA-DP-specific T cells.

Specificity determinants of proteolytic processing of Aspergillus PacC transcription factor are remote from the processing site, and processing occurs in yeast if pH signalling is bypassed

The Aspergillus nidulans transcription factor PacC, which mediates pH regulation, is proteolytically processed to a functional form in response to ambient alkaline pH. The full-length PacC form is unstable in the presence of an operational pH signal transduction pathway, due to processing to the relatively stable short functional form. We have characterized and used an extensive collection of pacC mutations, including a novel class of "neutrality-mimicking" pacC mutations having aspects of both acidity- and alkalinity-mimicking phenotypes, to investigate a number of important features of PacC processing. Analysis of mutant proteins lacking the major translation initiation residue or truncated at various distances from the C terminus showed that PacC processing does not remove N-terminal residues, indicated that processing yields slightly heterogeneous products, and delimited the most upstream processing site to residues approximately 252 to 254. Faithful processing of three mutant proteins having deletions of a region including the predicted processing site(s) and of a fourth having 55 frameshifted residues following residue 238 indicated that specificity determinants reside at sequences or structural features located upstream of residue 235. Thus, the PacC protease cuts a peptide bond(s) remote from these determinants, possibly thereby resembling type I endonucleases. Downstream of the cleavage site, residues 407 to 678 are not essential for processing, but truncation at or before residue 333 largely prevents it. Ambient pH apparently regulates the accessibility of PacC to proteolytic processing. Alkalinity-mimicking mutations L259R, L266F, and L340S favor the protease-accessible conformation, whereas a protein with residues 465 to 540 deleted retains a protease-inaccessible conformation, leading to acidity mimicry. Finally, not only does processing constitute a crucial form of modulation for PacC, but there is evidence for its conservation during fungal evolution. Transgenic expression of a truncated PacC protein, which was processed in a pH-independent manner, showed that appropriate processing can occur in Saccharomyces cerevisiae.

Frequency and relative fraction of tumor antigen-specific T cells among lymphocytes from melanoma-invaded lymph nodes

Several tumor antigens have been described as candidates for immunotherapy. Our study compared HLA-A2-restricted epitopes from 5 antigens commonly expressed by melanomas, i.e., Melan-A/MART-1 peptides (26-35 and 27-35), tyrosinase (368-376), gp-100 (280-288), MAGE-3 (271-279) and NA17-A (1-10), for their relative capacity to promote the development of cytotoxic and cytokine-producing specific CD8+ lymphocytes within melanoma-invaded lymph nodes. We used short-term cultured melanoma-invaded lymph node lymphocytes (MILLs) and tested responses developed by these cells to peptide-pulsed TAP-deficient T2 cells. We measured both the lytic response developed by MILLs and the fraction of these cells that secreted interferon-gamma (IFN-gamma), as deduced from intracellular cytokine labeling. Reverse transcription-polymerase chain reaction (RT-PCR) was used to analyze the expression of the 5 antigens within melanoma-invaded lymph nodes. Melan-A/MART-1, tyrosinase and gp-100 peptides were recognized by MILLs derived, respectively, from 8 of 20, 5 of 19 and 4 of 20 melanoma-invaded lymph nodes expressing these antigens. Most MILLs specific for Melan-A/MART-1 and tyrosinase exhibited both lysis and IFN-gamma responses, whereas most of those specific for gp-100 developed only lysis. Weak lysis without IFN-gamma secretion was developed against NA17-A and MAGE-3 peptides by MILLs from, respectively, 3 of 9 and 2 of 14 lymph nodes expressing these antigens. Our data show a prevalence of both cytotoxic and IFN-gamma-secreting effector T cells specific for differentiation antigens within HLA-A2 melanoma-invaded lymph nodes, which makes these antigens attractive targets for specific immunotherapy.

Vicinal fluorine-proton coupling constants

The angular dependence and the effect of individual substituents upon the NMR vicinal fluorine-proton couplings 3JFH have been studied using data sets of experimental and calculated couplings. Coupling constants for a series of fluoroethane derivatives, CHXF-CH3 and CH2F-CH2X (X = CH3, NH2, OH, and F), were calculated by means of the SCF ab initio and semiempirical INDO/FPT methods. The calculated couplings reproduce correctly the main experimental trends in spite of the limitation in the calculation because of lack of electronic correlation and the use of medium size basis set. The individual substituent effects DeltaKXi<INF POS="STACK">ni are described by quadratic expressions on the relative electronegativities of substituents DeltachiXi (DeltaKXi<INF POS="STACK">ni = k0<INF POS="STACK">ni + kniDeltachiXi + kniiDeltachi2<INF POS="STACK">Xi). A selected data set of 58 experimental couplings, ranging from 1.9 to 44.4 Hz, has been collected from the literature. An extended Karplus equation with 16 coefficients that includes the electronegativity substituent effects has been derived from the experimental data set with a root-mean-square deviation of 1.2 Hz. Copyright 1998 Academic Press.

LFA-3 co-stimulates cytokine secretion by cytotoxic T lymphocytes by providing a TCR-independent activation signal

T cell activation is known to depend not only on efficient antigen recognition and subsequent signaling through TCR, but also on interactions involving multiple adhesion and accessory molecules such as CD28/B7, LFA-1/ICAM-1 and LFA-3/CD2. The present study dissects the role of LFA-3/CD2 interactions in the activation of melanoma-specific CD8+ T cell clones. To this end we analyzed the influence of LFA-3 density on melanoma cells on lysis and cytokine production (TNF, IL-2, IFN-gamma) by T cells following activation by various amounts of antigenic peptides. Our results indicate that increasing LFA-3 density on melanoma cells variably affects their lysis susceptibility, but systematically and considerably enhances cytokine production by melanoma-specific cytotoxic T lymphocyte (CTL) clones. At any stimulatory antigen density, LFA-3 increased the fraction of responding cells and/or cytokine amounts produced by individual cells, without affecting TCR down-regulation. These results show that CD2 engagement increases cytokine gene activation essentially by providing to T cells a TCR-independent co-activation signal. From a practical point of view, our data demonstrate that the level of LFA-3 expressed on tumors critically affects cytokine production by specific CTL and thus the efficiency of specific immune reactions mediated by these cells.

LFA-3 co-stimulates cytokine secretion by cytotoxic T lymphocytes by providing a TCR-independent activation signal

T cell activation is known to depend not only on efficient antigen recognition and subsequent signaling through TCR, but also on interactions involving multiple adhesion and accessory molecules such as CD28/B7, LFA-1/ICAM-1 and LFA-3/CD2. The present study dissects the role of LFA-3/CD2 interactions in the activation of melanoma-specific CD8+ T cell clones. To this end we analyzed the influence of LFA-3 density on melanoma cells on lysis and cytokine production (TNF, IL-2, IFN-gamma) by T cells following activation by various amounts of antigenic peptides. Our results indicate that increasing LFA-3 density on melanoma cells variably affects their lysis susceptibility, but systematically and considerably enhances cytokine production by melanoma-specific cytotoxic T lymphocyte (CTL) clones. At any stimulatory antigen density, LFA-3 increased the fraction of responding cells and/or cytokine amounts produced by individual cells, without affecting TCR down-regulation. These results show that CD2 engagement increases cytokine gene activation essentially by providing to T cells a TCR-independent co-activation signal. From a practical point of view, our data demonstrate that the level of LFA-3 expressed on tumors critically affects cytokine production by specific CTL and thus the efficiency of specific immune reactions mediated by these cells.

[Multiple carpometacarpal dislocations. Five cases]

The authors report 5 cases treated and reviewed in their centre, together with the clinical and radiological results. Multiple carpometacarpal dislocations of all of the triphalangeal fingers are rare lesions induced by high-energy trauma, in which the therapeutic strategy is controversial.

Identification and characterization of a new oncogene derived from the regulatory subunit of phosphoinositide 3-kinase

p85/p110 phosphoinositide 3-kinase (PI3K) is a heterodimer composed of a p85-regulatory and a p110-catalytic subunit, which is involved in a variety of cellular responses including cytoskeletal organization, cell survival and proliferation. We describe here the cloning and characterization of p65-PI3K, a mutant of the regulatory subunit of PI3K, which includes the initial 571 residues of the wild type p85alpha-protein linked to a region conserved in the eph tyrosine kinase receptor family. We demonstrate that this mutation, obtained from a transformed cell, unlike previously engineered mutations of the regulatory subunit, induces the constitutive activation of PI3K and contributes to cellular transformation. This report links the PI3K enzyme to mammalian tumor development for the first time.

Endogenous LH surge versus hCG as ovulation trigger after low-dose highly purified FSH in IUI: a comparison of 761 cycles

PURPOSE

The results obtained with a protocol consisting of ovarian stimulation with low doses of highly purified FSH (FSH HP), administration of a GnRH analogue to induce an endogenous surge of gonadotropins, and IUI were evaluated. These results were compared with those seen with similar FSH stimulation and hCG administration followed by IUI.

METHODS

Three hundred sixty-four patients scheduled for IUI, after inclusion in a total of 345 FSH HP/GnRH-stimulated cycles and 416 FSH HP/HCG-stimulated cycles, were studied. The stimulation protocol consisted of daily subcutaneous injection of 75 IU of FSH HP from day 3 or 5 of the cycle, depending on the duration of the spontaneous cycle. hCG was administered on days 0, +2, and +5 to support the luteal phase. Monitoring was conducted using circulating estradiol levels and vaginal ultrasonography. Administration of two s.c. doses of leuprolide acetate (LA) or 7500 IU of i.m. hCG when at least one 18-mm-diameter follicle was seen and estradiol levels reached 120 pg/ml per follicle with a diameter > or = 16 mm. Intrauterine insemination was with semen capacitated by swim-up, thawed at room temperature if previously frozen.

RESULTS

The ovulation rate was 99.28 after hCG and 99.23 with LA. No significant differences were seen between the estradiol and progesterone levels of both groups or in the estradiol/progesterone ratio. The duration of the luteal phase was similar in both groups. Pregnancy rates per cycle were 17.31% (hCG) and 27.25% (LA), respectively (P = 0.0007), and abortion rates 22.22% (hCG) and 24.47% (LA), respectively. No cases of ovarian hyperstimulation were seen.

CONCLUSIONS

After FSH HP administration according to a low-dose protocol, the use of LA to trigger a gonadotropin surge as a means of inducing ovulation in FSH-stimulated women could be a good alternative to improve the results and prevent ovarian hyperstimulation in IUI cycles.

Heterogeneity of biologic responses of melanoma-specific CTL

To better understand how Ag density influences the various biologic responses of CTL, we analyzed lysis and, at the single cell level, cytokine production by a panel of melanoma-specific CTL clones. Titration experiments done with peptide-pulsed TAP-deficient T2 cells indicated that: 1) Ag density affects both the fraction of responding cells and the amount of cytokine secreted by each cell. 2) Different responses have a relative Ag requirement that may vary between clones. Lysis and secretion of IFN-gamma, and for most clones' secretion of TNF-alpha, required lower Ag densities, by one or two logs, than IL-2 and granulocyte-macrophage CSF secretion. 3) In a significant fraction of IFN-gamma-secreting cells, IL-2 production is not induced. 4) A large fraction of cloned cells is refractory to lymphokine gene activation for about 2 wk after previous stimulation. Together these data indicate that CTL biologic responses are controlled by variable Ag thresholds and by additional parameters affecting activation requirements of each cell. A similar heterogeneity of cytokine responses was observed to Ag endogenously presented by melanoma cells. As a consequence, most melanoma lines, including those with the highest Ag expression, could trigger only low CTL fractions to secrete IL-2 and, also for most clones, granulocyte-macrophage CSF. This may be an important component of the inefficiency of specific CTL in cancer patients.

Heterogeneity of biologic responses of melanoma-specific CTL

To better understand how Ag density influences the various biologic responses of CTL, we analyzed lysis and, at the single cell level, cytokine production by a panel of melanoma-specific CTL clones. Titration experiments done with peptide-pulsed TAP-deficient T2 cells indicated that: 1) Ag density affects both the fraction of responding cells and the amount of cytokine secreted by each cell. 2) Different responses have a relative Ag requirement that may vary between clones. Lysis and secretion of IFN-gamma, and for most clones' secretion of TNF-alpha, required lower Ag densities, by one or two logs, than IL-2 and granulocyte-macrophage CSF secretion. 3) In a significant fraction of IFN-gamma-secreting cells, IL-2 production is not induced. 4) A large fraction of cloned cells is refractory to lymphokine gene activation for about 2 wk after previous stimulation. Together these data indicate that CTL biologic responses are controlled by variable Ag thresholds and by additional parameters affecting activation requirements of each cell. A similar heterogeneity of cytokine responses was observed to Ag endogenously presented by melanoma cells. As a consequence, most melanoma lines, including those with the highest Ag expression, could trigger only low CTL fractions to secrete IL-2 and, also for most clones, granulocyte-macrophage CSF. This may be an important component of the inefficiency of specific CTL in cancer patients.

Human monocyte-derived macrophages and dendritic cells are comparably effective in vitro in presenting HLA class I-restricted exogenous peptides

Recent experimental data have shown that mice could be immunized efficiently, in particular against cancer, by the injection of antigen-loaded dendritic cells (DC) or macrophages (MPH). In the present work, these two antigen-presenting cells (APC) were prepared in humans from circulating mononuclear cells (MNC). MPH were obtained from MNC that were cultured in hydrophobic plastic bags and purified by elutriation. DC were from the culture of adherent elutriation-purified monocytes in the presence of granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-4 (IL-4). The two APC were prepared in parallel from the same donors and their phenotype and antigen-presenting capacity were compared. DC differed from MPH by a higher expression of HLA-DR and CD23 and a lower expression of CD14, CD64 and of adhesion molecules. DC and MPH were comparably effective in (a) enhancing the mitotic response of autologous lymphocytes to immobilized anti-CD3 (accessory function); (b) presenting melanoma peptides to specific cytotoxic T lymphocyte (CTL) clones; and (c) stimulating the generation of CTL directed against a myxovirus influenza peptide. However, DC were more effective than MPH in inducing the mitotic response of allogeneic peripheral blood leucocytes (PBL), possibly because of their higher expression of HLA class II molecules. In conclusion, DC and MPH prepared from blood MNC did not differ substantially in their ability to activate HLA class I-restricted T-cell responses by exogenous peptide presentation.