cis-Acting Element at the 5' Noncoding Region of Tacaribe Virus S RNA Modulates Genome Replication.

Tacaribe virus (TCRV) is the prototype of New World mammarenaviruses, a group that includes several members that cause hemorrhagic fevers in humans. The TCRV genome comprises two RNA segments, named S (small) and L (large). Both genomic segments contain noncoding regions (NCRs) at their 5' and 3' ends. While the 5'- and 3'-terminal 19-nucleotide sequences are known to be essential for promoter function, the role of their neighboring internal noncoding region (iNCR) sequences remains poorly understood. To analyze the relevance of the 5' and 3' iNCRs in TCRV S RNA synthesis, mutant S-like minigenomes and miniantigenomes were generated. Using a minireplicon assay, Northern blotting, and reverse transcription-quantitative PCR, we demonstrated that the genomic 5' iNCR is specifically engaged in minigenome replication yet is not directly involved in minigenome transcription, and we showed that the S genome 3' iNCR is barely engaged in this process. Analysis of partial deletions and point mutations, as well as total or partial substitution of the 5' iNCR sequence, led us to conclude that the integrity of the whole genomic 5' iNCR is essential and that a local predicted secondary structure or RNA-RNA interactions between the 5' and 3' iNCRs are not strictly required for viral S RNA synthesis. Furthermore, we employed a TCRV reverse genetic approach to ask whether manipulation of the S genomic 5' iNCR sequence may be suitable for viral attenuation. We found that mutagenesis of the 5' promoter-proximal subregion slightly impacted recombinant TCRV virulence in vivo. IMPORTANCE The Mammarenavirus genus of the Arenaviridae family includes several members that cause severe hemorrhagic fevers associated with high morbidity and mortality rates, for which no FDA-approved vaccines and limited therapeutic resources are available. We provide evidence demonstrating the specific involvement of the TCRV S 5' noncoding sequence adjacent to the viral promoter in replication. In addition, we examined the relevance of this region in the context of an in vivo infection. Our findings provide insight into the mechanism through which this 5' viral RNA noncoding region assists the L polymerase for efficient viral S RNA synthesis. Also, these findings expand our understanding of the effect of genetic manipulation of New World mammarenavirus sequences aimed at the rational design of attenuated recombinant virus vaccine platforms.

Development and Validation of Waste Decontamination Cycle in a Biosafety Level 3 Laboratory.

Introduction: Steam sterilization has been used for decades to effectively kill microbial contaminants in a variety of medical and commercial settings. One of the most critical aspects of safe operations in biosafety level 3 biocontainment laboratories (BSL-3) is the effective inactivation of biological select agents in the waste generated in these environments. The Instituto Nacional de Enfermedades Virales Humanas "Dr. Julio I. Maiztegui" (INEVH, Pergamino, Argentina) is an institute that offers epidemiological surveillance, production of biological reagents, and production of biologicals for human use and studies of reservoirs and vectors. Some of the activities need to be done in a BSL-3 that provides biocontainment, ensuring that the materials are decontaminated before they leave the facility. The objective of this study was to design and validate a decontamination procedure for biological waste from the BSL-3 facility that guarantees steam sterilization processes. Methods: The amount and the distribution of biological waste into the autoclave and other physical parameters were defined and evaluated by calculating lethalities. Results: We evaluated autoclave basic factory programmed cycles, and it was concluded that the sterilization autoclave cycle was not efficient for decontamination of waste. A new simulated load distribution had to be defined. Discussion: The results demonstrated that autoclave factory default settings can be inadequate for sterilizing highly infectious waste, depending of types of waste, such as animal carcass and animal bed waste. Conclusion: These results of the validation process can set the standard to the design of waste management protocols to ensure effective treatment of highly infectious biological waste.

Author Correction: Potential damaging mutation in LRP5 from genome sequencing of the first reported chimpanzee with the Chiari malformation.

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.

Potential damaging mutation in LRP5 from genome sequencing of the first reported chimpanzee with the Chiari malformation.

The genus Pan is the closest related to humans (Homo sapiens) and it includes two species: Pan troglodytes (chimpanzees) and Pan paniscus (bonobos). Different characteristics, some of biomedical aspect, separate them from us. For instance, some common human medical conditions are rare in chimpanzees (menopause, Alzheimer disease) although it is unclear to which extent longevity plays an active role in these differences. However, both humans and chimpanzees present similar pathologies, thus, understanding traits in chimpanzees can help unravel the molecular basis of human conditions. Here, we sequenced the genome of Nico, a central chimpanzee diagnosed with a particular biomedical condition, the Chiari malformation. We performed a variant calling analysis comparing his genome to 25 whole genomes from healthy individuals (bonobos and chimpanzees), and after predicting the effects of the genetic variants, we looked for genes within the OMIM database. We found a novel, private, predicted as damaging mutation in Nico in LRP5, a gene related to bone density alteration pathologies, and we suggest a link between this mutation and his Chiari malformation as previously shown in humans. Our results reinforce the idea that a comparison between humans and chimpanzees can be established in this genetic frame of common diseases.

[Stability of Candid#1 vaccine to prevent Argentine Hemorrhagic Fever]. / Estabilidad de la vacuna CANDID#1 para prevenir la Fiebre Hemorrágica Argentina.

Candid#1 is the first live attenuated vaccine produced and registered in Argentina. Produced since 2003 at the INEVH to prevent Argentine hemorrhagic fever, it is obtained by harvesting supernatants of diploid cells infected with an attenuated strain of Junin virus and subsequent lyophilization. The stability of this vaccine is crucial to ensure its effectiveness. This study was aimed to evaluate the stability of Candid#1 by exposing it to different time and temperature conditions. Three vaccine batches produced in 2003 were analysed according to the following storage scheme: (a) reconstituted vaccine at 2 °C to 8 °C for 8 days; (b) lyophilized vaccine at 2 °C to 8 °C for 6 months; (c) lyophilized vaccine at -18 °C to -20 °C for 10 years. The potency was assessed in Vero cell monolayers under agar. The results were: (a) reconstituted vaccine was stable between 2 °C and 8 °C for 8 days, (b) lyophilized vaccine was stable between 2 °C and 8 °C for 2 months, and (c) lyophilized vaccine was stable 9 years between -18 °C and -20 °C, keeping all its properties. These results allowed us to establish the following storage conditions and expiration times for Candid#1: (a) reconstituted: 12 hours between 2 °C and 8 °C, (b) lyophilized: 30 days between 2 °C and 8 °C and (c) lyophilized: 9 years between -18 °C and -20 °C. Based on our results, favorable changes were made in the conditions of transport, storage and distribution of the vaccine. Domestic freezers in strategically located centers were installed, allowing the preservation of vaccine stocks for distribution to secondary vaccination centers.

Estabilidad de la vacuna Candid#1 para prevenir la fiebre hemorrágica Argentina / Stability of Candid#1 vaccine to prevent Argentine Hemorrhagic Fever

Candid#1 es la primera vacuna a virus vivo atenuado producida y registrada en Argentina. Se produce en el INEVH desde 2003 para prevenir la fiebre hemorrágica argentina y se obtiene mediante cosecha de sobrenadantes de cultivos de células diploides infectadas con una cepa atenuada del virus Junín, formulación y posterior liofilización. Su estabilidad es crucial para asegurar su efectividad. El objetivo de este trabajo fue evaluar la estabilidad de Candid#1 exponiéndola a distintas condiciones de temperatura y tiempo. Tres lotes producidos en 2003 fueron sometidos al siguiente esquema de almacenamiento: (a) vacuna reconstituida conservada entre 2 °C y 8 °C durante 8 días, (b) vacuna liofilizada conservada entre 2 °C y 8 °C durante 6 meses, y (c) vacuna liofilizada conservada entre -18 °C y -20 °C durante 10 años. La potencia fue evaluada en monocapa de células Vero bajo agar. Los resultados fueron: (a) Candid#1 reconstituida fue estable 8 días entre 2 °C y 8 °C, (b) Candid#1 liofilizada fue estable 2 meses entre 2 °C y 8 °C y (c) Candid#1 liofilizada fue estable 9 años entre -18 °C y -20 °C manteniendo todos sus atributos. Estos resultados permitieron establecer las siguientes condiciones de almacenamiento: reconstituida 12 horas entre 2 °C y 8 °C, liofilizada 30 días entre 2 °C y 8 °C y 9 años entre -18 °C y -20 °C. A la luz de estos resultados, se generaron cambios favorables en las condiciones de transporte, almacenamiento y distribución de la vacuna. Se implementó la instalación de freezers domésticos en centros estratégicamente distribuidos, permitiendo preservar stocks de vacuna y distribuir las dosis necesarias a vacunatorios.

Candid#1 is the first live attenuated vaccine produced and registered in Argentina. Produced since 2003 at the INEVH to prevent Argentine hemorrhagic fever, it is obtained by harvesting supernatants of diploid cells infected with an attenuated strain of Junin virus and subsequent lyophilization. The stability of this vaccine is crucial to ensure its effectiveness. This study was aimed to evaluate the stability of Candid#1 by exposing it to different time and temperature conditions. Three vaccine batches produced in 2003 were analysed according to the following storage scheme: (a) reconstituted vaccine at 2 °C to 8°C for 8 days; (b) lyophilized vaccine at 2 °C to 8 °C for 6 months; (c) lyophilized vaccine at -18 °C to -20 °C for 10 years. The potency was assessed in Vero cell monolayers under agar. The results were: (a) reconstituted vaccine was stable between 2 °C and 8 °C for 8 days, (b) lyophilized vaccine was stable between 2 °C and 8 °C for 2 months, and (c) lyophilized vaccine was stable 9 years between -18 °C and -20 °C, keeping all its properties. These results allowed us to establish the following storage conditions and expiration times for Candid#1: (a) reconstituted: 12 hours between 2 °C and 8 °C, (b) lyophilized: 30 days between 2 °C and 8 °C and (c) lyophilized: 9 years between -18 °C and -20 °C. Based on our results, favorable changes were made in the conditions of transport, storage and distribution of the vaccine. Domestic freezers in strategically located centers were installed, allowing the preservation of vaccine stocks for distribution to secondary vaccination centers.

Establecimiento de límites microbiológicos internos para áreas clasificadas Grado D / Establishing internal microbiological limits for D grade-classified areas

Objetivo: contribuir al aseguramiento de la calidad microbiológica de una planta de producción de vacunas, a través del establecimiento de límites internos de alerta y de acción para sus áreas clasificadas Grado D. Métodos: se estudió la microbiota residente de cada área clasificada Grado D. Se analizaron muestras de aire tomadas por el método volumétrico. Las superficies e indumentaria del personal fueron evaluadas por el método de contacto. Los recuentos de microorganismos fueron analizados estadísticamente para la determinación de los límites de alerta y de acción. Resultados: se establecieron los límites de alerta y de acción microbiológicos para cada área clasificada Grado D de la planta de producción del Instituto Nacional de Enfermedades Virales Humanas basados en la determinación de los rangos habituales de trabajo. Se establecieron límites, como en el caso de guantes pos trabajo para un área Grado D, donde la norma no los define. Conclusiones: se mostró concordancia con los límites recomendados por la autoridad regulatoria nacional ANMAT y proporcionó información sobre la carga microbiológica de los ambientes clasificados Grado D, que será de utilidad tanto para la comprensión del ingreso y circulación de microorganismos como para la implementación de medidas para prevenir la contaminación microbiana, aspectos críticos en la fabricación de vacunas seguras, puras y eficaces(AU)

Objective: to contribute to ensuring the microbiological quality of a vaccine manufacturing plant through the establishment of internal microbiological alert and action limits for their grade D classified areas. Methods: the resident microbiota of each grade D classified area was studied. Air samples taken by the volumetric method were analyzed. The surfaces and the staff's gowning were evaluated by the contact method. The microorganism counts were statistically analyzed to determine the alert and action limits. Results: the microbiological alert and action limits have been established for each Grade D classified area of the production plant of the National Institute of Human Viral Diseases, based on the determination of the usual working ranges. Limits were set, as in the case of gloves after work for a Grade D area, where the standard does not define them. Conclusions: the results generally agreed with the limits recommended by the national regulatory authority ANMAT, and additionally, this study provided information on the microbiological flora of grade D classified environments, which will be useful for both understanding the entrance and circulation of microorganisms and implementing measures to prevent biocontamination, which are critical aspects in the manufacture of effective, pure and safe vaccines(AU)

Evaluación de la carga microbiológica ambiental en áreas destinadas a producción y control de vacunas / Evaluation of the environmental microbiological burden in vaccine production and control areas

Objetivo: el objetivo del presente trabajo fue contribuir al aseguramiento de la calidad microbiológica de una planta de producción de vacunas, a través de la identificación de la carga microbiológica ambiental y su comportamiento frente a los desinfectantes utilizados de rutina. Método: Se estudió la flora residente de cada área clasificada. Se analizaron muestras de aire tomadas por los métodos volumétricos y sedimentación en placa. Las superficies y vestimenta del personal fueron evaluadas por el método de contacto. Se realizaron identificaciones en género y especie estableciéndose para cada área un Grupo de Microorganismos Indicador formado por microorganismos aislados con una frecuencia superior al 5 por ciento. Resultados: Bioterio: Staphylococcus spp (50 por ciento), Aerococcus spp (21 por ciento), Micrococcus spp (10 por ciento),Bacillus spp y Géneros Relacionados (6 por ciento); Cultivos Celulares Normales: Staphylococcus spp (48 por ciento), Micrococcus spp (34 por ciento),Bacillus spp y Géneros Relacionados (13 por ciento); Control de Calidad: Staphylococcus spp (50 por ciento), Micrococcus spp (27 por ciento), Kocuria spp (9 por ciento), Bacillus spp y Géneros Relacionados (7 por ciento); Producción: Staphylococcus spp (50 por ciento), Micrococcus spp (17 por ciento), Kocuria spp (11 por ciento), Leuconostoc spp (8 por ciento), Bacillus spp y Géneros Relacionados (6 por ciento). El grupo indicador para la Unidad de Producción se identificó como Staphylococcus spp (49,5 por ciento), Micrococcus spp. (23,0 por ciento), Bacillus spp y Géneros Relacionados (8,1 por ciento). El desafío de los desinfectantes en uso con cepas del grupo de microorganismos indicadores evidenció en general una acción microbicida alta. Conclusión: los resultados proporcionan información sobre la carga microbiológica del ambiente que será de utilidad tanto para la comprensión del ingreso y circulación de microorganismos como para la implementación de medidas para prevenir la contaminación microbiana, aspectos críticos en la fabricación de vacunas seguras, puras y eficaces(AU)

Objectives: the objective of this study was to support microbiological quality assurance in a vaccine production plant through identification of environmental microbiological charge and its behavior with routine disinfectants. Methods: the existing flora of each classified area was studied. Air samples taken by volumetric and plate sedimentation methods were analyzed. Surfaces and the gown of the staff were assessed by contact method. Genera and species were identified, thus setting a Group of Indicator Microorganisms made up of microorganisms that were isolated at a rate greater than 5 percent for each facility. Results: animal Facility: Staphylococcus spp (50 percent), Aerococcus spp (21 percent), Micrococcus spp (10 percent), Bacillus spp and related genera (6 percent); Normal Tissue Culture Laboratory: Staphylococcus spp (48 percent), Micrococcus spp (34 percent), Bacillus spp and related genera (13 percent); Quality Control Laboratory: Staphylococcus spp (50 %), Micrococcus spp (27 percent), Kocuria spp (9 percent), Bacillus spp and related genera (7 percent); Production: Staphylococcus spp (50 percent), Micrococcus spp (17 percent), Kocuria spp (11 percent), Leuconostoc spp (8 percent), Bacillus spp and related genera (6 percent). The Group of Indicator Microorganisms for the Production Unit was identified as Staphylococcus spp (49.5 percent), Micrococcus spp (23 percent) and Bacillus spp and related genera (8.1 percent). The regularly used disinfectants for strains from the Group of Indicator Microorganisms showed a high microbicidal efficacy. Conclusion: the results provide information about the environmental bioburden, which will be useful for the understanding of the microbial entry points and spreading and the implementation of measures to prevent microbial contamination, so critical for manufacture of safe, pure and effective vaccines(AU)

Evaluación de de la eficacia de los procesos de esterilización de consultorios odontológicos del distrito VI de la provincia de buenos aires, argentina 2006 - 2007, mediante la utilización de indicadores biológicos

En un consultorio odontológico, diversas fuentes de posible infección, como saliva, sangre, instrumentos contaminados, etc., pueden ser transmisores de microorganismos tanto a pacientes como al personal odontológico. El objetivo del presente trabajo fue evaluar la eficacia de los procesos de esterilización de los consultorios odontológicos del Distrito VI de la Provincia de Buenos Aires mediante la utilización de Indicadores Biológicos. Participaron del estudio 283 odontólogos que llevaron a cabo un total de 320 procesos de esterilización por calor seco y 19 por calor húmedo. En base a los resultados obtenidos se observó que el 35 % (112/320) de los procesos de esterilización por calor seco controlados no cumplieron con los requisitos, de los cuales 63 repitieron el control y, 55/63 (87%) resolvieron el problema mediante distintas acciones correctivas. Con respecto a la esterilización por calor húmedo, el 32 % (6/19) de los procesos no cumplieron con los requisitos, en 3 de los 6 positivos se efectuaron correcciones simples obteniéndose resultados satisfactorios. El presente trabajo muestra la importancia para la comunidad, de la implementación de rutina de un sistema de control que permita garantizar la esterilidad de los materiales utilizados en los consultorios odontológicos.

In a dental office, several infectious sources, such as saliva, blood, contaminated dental instruments, may be vehicles for microorganisms to reach patients and dental proffesionals. In this work the efficacy of the sterilization process performed at dental offices belonging to the VI district of Buenos Aires Province from Argentina was evaluated through the use of Biological Indicators. Two hundred and eigthy three dentists participated of the study performing a total of 320 dry heat sterilization process and 19 wet heat ones. It was observed that the 35 % (112/320) of the dry heat sterilization process controlled didn't meet the requirements, 63 of which repeated the control and 55 (87%) solved the problem through the adoption of several corrective actions. In relation to wet heat sterilization, the 32 % (6/19) of the process didn't meet the requirements, 3 out of 6 positives overcame the problem after the implementation of corrective actions. These results show the importance for the whole community of a control program implementation in order to guarantee the sterility of the instruments used in the dental practice.

[Behavior of Argentine lymphocytic choriomeningitis virus strains in rodents]. / Comportamiento de cepas argentinas del virus de la coriomeningitis linfocitaria en roedores.

The activity of LCM virus was first reported in Argentina at the beginning of the seventies and only five strains have been isolated from rodents Mus domesticus and two from humans. The objective of this paper was to find differential biological characteristics of Argentine strains of LCM virus comparing them in relation to the historical strains WE and Armstrong. Regarding the results obtained in tissue culture, when L 929 cells were used, plaque forming units (PFU) were obtained with human and mouse strains, whilst on Vero cells only human strains developed PFU. Differentials characteristics of historical and Argentine strain's plates were not found, neither differences related to the strain's origin. Neither historical nor Argentine strains were lethal to new-born mice giving a persistent infection, that was demonstrated when we inoculated new-born mouse by intracranial route with different strains of LCM virus and virus was isolated from brains harvested at different days post inoculation. The only exception was Cba An 13065 strain that exhibited virulence in new-born mice, only with 0.026 PFU was obtained 1 DL50. All the strains resulted lethal to adult mice. The mouse strains were more virulent than human strains, being Cba An 13065 the most virulent. These results demonstrate a different behavior in tissue culture between human and mouse strains and allow the identification of virulence markers by intracranial inoculation into new-born or adult mice.

Comportamiento de cepas argentinas del virus de la Coriomeningitis Linfocitaria en roedores / Behavior of Argentine lymphocytic choriomeningitis virus strains in rodents

La actividad del virus LCM fue informada en Argentina a comienzos de la década del 70 y sólo han sido aisladas cinco cepas a partir del roedor Mus domesticus y dos de humanos. El objetivo de este trabajo consistió en investigar características biológicas de las cepas argentinas de virus LCM para compararlas entre sí y respecto a las cepas históricas WE y Armstrong. En células L 929 se obtuvieron placas bajo agarosa tanto con las cepas humanas como con las cepas de ratón, pero en células Vero sólo se obtuvieron placas con las cepas humanas. No se observó ninguna característica morfométrica de las placas que distinguiera nítidamente a las cepas históricas de las cepas argentinas, ni se observaron diferencias que se relacionen con las especies de origen de las cepas. Las cepas históricas y las cepas argentinas no fueron letales para ratón recién nacido (rrn) generando una infección persistente, según se comprobó al inocular ratones recién nacidos (rrn) por vía intracerebral con cepas de virus LCM y detectarse virus en los cerebros cosechados a diferentes días post inoculación. La única excepción fue la cepa Cba An 13065 que resultó virulenta para rrn ya que con sólo 0.026 UFP se logró 1 DL50. Todas las cepas resultaron letales en ratón adulto (rad), siendo las cepas de ratón más virulentas que las cepas de humanos. Estos resultados permitieron evidenciar el diferente comportamiento en cultivos celulares de las cepas de ratón con respecto a las cepas humanas, e identificar marcadores de virulencia mediante la respuesta a la inoculación por vía intracerebral del rad y del rrn.

The activity of LCM virus was first reported in Argentina at the beginning of the seventies and only five strains have been isolated from rodents Mus domesticus and two from humans. The objective of this paper was to find differential biological characteristics of Argentine strains of LCM virus comparing them in relation to the historical strains WE and Armstrong. Regarding the results obtained in tissue culture, when L 929 cells were used, plaque forming units (PFU) were obtained with human and mouse strains, whilst on Vero cells only human strains developed PFU. Differentials characteristics of historical and Argentine strain's plates were not found, neither differences related to the strain's origin. Neither historical nor Argentine strains were lethal to new-born mice giving a persistent infection, that was demonstrated when we inoculated new-born mouse by intracranial route with different strains of LCM virus and virus was isolated from brains harvested at different days post inoculation. The only exception was Cba An 13065 strain that exhibited virulence in new-born mice, only with 0.026 PFU was obtained 1 DL50. All the strains resulted lethal to adult mice. The mouse strains were more virulent than human strains, being Cba An 13065 the most virulent. These results demonstrate a different behavior in tissue culture between human and mouse strains and allow the identification of virulence markers by intracranial inoculation into new-born or adult mice.

Immune response to vaccination against Argentine hemorrhagic Fever in an area where different arenaviruses coexist.

Neutralizing antibody (NT Ab) titers to Candid #1 (C#1) vaccine against Argentine hemorrhagic fever were studied for 2 years post-vaccination in 330 volunteers, to assess whether the kinetics and/or magnitude of this immune response is modified by previous infection with the arena viruses Junin (JUN) and lymphocytic choriomeningitis (LCM). A total of 160 volunteers received C#1, distributed as follows: without detectable pre-infection with arenaviruses (n = 54); with pre-existing antibodies to JUN (n = 55); with pre-existing antibodies to LCM (n = 51). The remaining 170 individuals received placebo. Levels of anti-JUN NT Ab displayed a trend in which titers increased with the virulence of the infecting strain, from C#1 (X = 49), through subclinical JUN infection (X = 229), vaccination following subclinical infection (X = 367) to JUN clinical infection (X =773). It was also found that the mean titer of NT Ab to C#1 did not vary significantly during 2 years of study and was: a) significantly lower than that elicited by wild strains of JUN, both clinical and subclinical infections (p < 0.01); b) significantly increased the titers of pre-existing anti-JUN Ab (p < 0.01); and c) was not modified by pre-existing anti-LCM Ab (p > 0.05). These data indicate that the immune response to C#1 boosts pre-existing immunity to JUN virus and is not changed by previous experience with LCM virus.

La producción nacional de vacuna a virus Junin vivo atenuado (Candid #1)anti-fiebre hemorrágica argentina / The national vaccine production to alive Junin virus attenuated (Candid #1) Argentine haemorrhagic anti-fever

La emergencia de la fiebre hemorrágica argentina(FHA) a comienzos de la década del ´50 representó para los científicos argentinos un desafío excepcional: una patología humana de alta letalidad, nueva para el mundo, se presentaba solamente en una región ( de gran importancia económica) del territorio argentino. El afrontar ese desafío con dedicación y, sin duda, con más recursos intelectuales que financieros, permitió que a los tres años de la descripción clínica de la enfermedad se demostrara que el virus Junin era el agente etiológico de la FHA, siendo éste el segundo arenavirus descripto luego del virus de la Coriomeningitis Linfocitaria, prototipo del grupo, aislado en 1993. En las décadas de los ´60 y los ´70 se realizaron avances fundamentales con la detección del reservorio natural del virus Junin y el conocimiento de múltiples aspectos de la fisiopatología y la epidemiología de la enfermedad. Esto permitió conocer que se trataba de una enfermedad controlable pero no erradicable. Fue en este mismo período en que se encontró un tratamiento para la FHA que disminuyó drásticamente su mortalidad y se iniciaron diversas líneas de investigación para desarrollar una vacuna eficaz que permitiera controlar la enfermedad. Este trabajo es un relato no exhaustivo de los acontecimientos que condujeron a la elaboración en Argentina de una vacuna (Candid#1) para prevenir la FHA, y fue realizado para rendir homenaje al gran inmunólogo argentino Dr. Ricardo Margni mostrando cómo los principios de la inmunología, difundidos por el Dr. Margni durante su extensa trayectoria como científico y docente contribuyeron, por este camino, a mejorar la calidad de vida de la sociedad.

[Preclinical assay of candid #1 vaccine against Argentine Hemorrhagic Fever made in Argentina]. / Ensayo preclínico de la vacuna Candid #1 producida en Argentina contra la Fiebre Hemorrágica Argentina.

Candid #1 vaccine against Argentine Hemorrhagic Fever produced in USA versus lots of the same vaccine made in Argentina were compared in guinea pigs regarding safety, immunogenicity and protective efficacy against a challenge with pathogenic Junin virus. Lots No Exp 3, 7A and 8A of Argentine origin as well as lot TSI 5-1-92 from USA were inoculated in guinea pigs of 250-400 g in two consecutive assays. Ten animals inoculated with saline performed as normal controls in each experiment. Parameters studied were: a) temperature; b) body weight; c) neutralizing antibodies to Junin virus; d) response to viral challenge. Animals gained weight and remained normothermic up to the challenge. Guinea pigs that received Candid #1 from any manufacturer elicited neutralizing antibodies to Junin virus (titles from 40 to 81920) and survived to challenge whilst 8/10 animals died in each control group. Data presented demonstrated that Candid #1 vaccines from USA or Argentine manufacturers were equally safe, immunogenic and protective in guinea pigs.

Serological study of the lymphochoriomeningitis virus (LCMV) in an inner city of Argentina.

Lymphocytic choriomeningitis virus (LCMV) is the prototype of the family Arenaviridae and is associated with the natural reservoir, Mus domesticus (Md). It causes meningitis and a flu-like illness characterized by malaise, myalgia, retrorbital headache, and photophobia. This study presents the data obtained in a rodent and human serological study during 6 years (1998-2003) in the city of Rio Cuarto, Argentina. Antibodies anti-LCMV were sought by ELISA in rodents and humans. LCMV was found only in Md species in 9.4% of animals. The results also show some seasonal, no significant variations in the prevalence of the infection. Distribution of positive mice was not modified significantly by trapping sites, sex, or age of the animals. The prevalence of LCMV positive urban residents was found to be consistently low (1-3.6%) along the study period, with overage prevalence of 3.3% and values in males (4.6%) significantly higher than in females (2.6%) (P < 0.05). Seven of 432 pregnant women were found to be LCMV positive, but the absence of LCMV antibodies in the newborns demonstrated that the mothers were infected before pregnancy. This study is the first evidence on endemic LCMV in an Argentine city located outside the endemic area of Argentine hemorrhagic fever (AHF) and described the need to study other areas and increase awareness of this viral infection.

Ensayo preclínico de la vacuna Candid #1 producida en Argentina contra la Fiebre Hemorrágica Argentina. / [Preclinical assay of candid #1 vaccine against Argentine Hemorrhagic Fever made in Argentina]

Candid #1 vaccine against Argentine Hemorrhagic Fever produced in USA versus lots of the same vaccine made in Argentina were compared in guinea pigs regarding safety, immunogenicity and protective efficacy against a challenge with pathogenic Junin virus. Lots No Exp 3, 7A and 8A of Argentine origin as well as lot TSI 5-1-92 from USA were inoculated in guinea pigs of 250-400 g in two consecutive assays. Ten animals inoculated with saline performed as normal controls in each experiment. Parameters studied were: a) temperature; b) body weight; c) neutralizing antibodies to Junin virus; d) response to viral challenge. Animals gained weight and remained normothermic up to the challenge. Guinea pigs that received Candid #1 from any manufacturer elicited neutralizing antibodies to Junin virus (titles from 40 to 81920) and survived to challenge whilst 8/10 animals died in each control group. Data presented demonstrated that Candid #1 vaccines from USA or Argentine manufacturers were equally safe, immunogenic and protective in guinea pigs.

IgG subclasses in human immune response to wild and attenuated (vaccine) Junin virus infection.

Different proportions of IgG subclasses have previously been reported to distinguish the immune response elicited by primary and recurrent viral infections, as well as viral vaccines. The goal of this study was to study the IgG subclasses composition in the immune response of patients with Argentine hemorrhagic fever, and vaccinees with Candid #1 strain of Junin virus. Twenty-four individuals inoculated with Candid #1 vaccine and 67 patients with Argentine hemorrhagic fever were studied. Blood samples were drawn at 30, 60, and/or 180 days post-inoculation with Candid #1 and 30, 60, and 90 days after clinical onset of the disease. Specific anti-Junin virus IgG subclasses were titrated with specific human monoclonal antibody fluorescence isothiocyanate conjugate (FITC) by immunofluorescent assay (IFA). IgG(1) anti-Junin virus was found in every subject studied and IgG(3) was also detected in some patients with a severe form of Argentine hemorrhagic fever. IgG(2) and IgG(4) were not detected in any serum sample studied. The mean titer of specific IgG(1) in vaccinees was significantly lower than in patients with Argentine hemorrhagic fever (P < 0.05), but no difference was found between mild and severe cases of the disease (P > 0.05). The results of this study demonstrated a central role of IgG(1) in human recovery from infection with every strain of Junin virus, an observation stressed by the immune response to Candid #1 vaccine, which resulted in no difference in IgG subclasses composition from that found in mild cases of Argentine hemorrhagic fever.

Evaluation of an enzyme-linked immunosorbent assay for detection of antibodies to Junin virus in rodents.

Junin virus is the etiological agent of Argentine hemorrhagic fever, a serious rodent-borne disease. An enzyme-linked immunosorbent assay (ELISA) to detect Junin virus IgG antibodies in rodents was evaluated using sera from 27 Calomys musculinus and five Calomys laucha, inoculated experimentally with a live attenuated strain of this arenavirus. The test performance was compared against an indirect immunofluorescence assay (IFA). The ELISA had a sensitivity and specificity of 100% and a reproducibility of 87.9% for samples with titers above the selected cut-off value. IFA had lower sensitivity (53%) with the same specificity. The ELISA results were similar, whether carried out on whole blood or serum samples, thus eliminating the need for serum separation. A high correlation (K=0.86) between ELISA and IFA results was obtained from 1011 wild sigmodontine and murine rodents collected within and outside of the Argentine hemorrhagic fever endemic area. These results indicate that Junin virus IgG ELISA is the most suitable assay for detection of Junin virus antibodies in rodent samples.

Aislamiento del virus de la coriomeningitis linfocitaria de seres humanos / Isolation of lymphocytic choriomeningitis virus from human individuals

The activity of lymphocytic choriomeningitis virus (LCMv) in Argentina has been previously reported on the basis of serological evidence in rodents and humans and the isolation of only one strain of LCMv from a Mus domesticus captured in the province of Cordoba. The aim of this paper was to register patients with serological diagnosis of LCM, to isolate and to identify human strains of LCMv in Argentina. During the last 19 years, 15 cases were diagnosed as LCM by immunoflourescent indirect assay (IFI) and enzyme-linked immunosorbent assay (ELISA) but when neutralizing assay (NT) was incorporated, eight cases were classified as confirmed, three as probable and four as negative. The geographic distribution of the cases included three provinces: Cordoba, Buenos Aires and Santa Fe. Viral isolation was attempted in five patients classified as confirmed and only two resulted positive (P5226 and P8573). They were identified as LCMv by IFI and NT. The coexistence of LCMv with other arenaviruses, such as Junin and Oliveros viruses, in the same area, raises the probability of interactions between them, which could modify the virulence and/or pathogenicity for humans associated to genomic changes. Future studies of antigenic, genomic and virulence variability of different Argentine strains of LCMv, as well as the systematic search for human infection, will contribute to define the importance of this viral agent in our country and to implement control measures.

Aislamiento del virus de la coriomeningitis linfocitaria de seres humanos / Isolation of lymphocytic choriomeningitis virus from human individuals

The activity of lymphocytic choriomeningitis virus (LCMv) in Argentina has been previously reported on the basis of serological evidence in rodents and humans and the isolation of only one strain of LCMv from a Mus domesticus captured in the province of Cordoba. The aim of this paper was to register patients with serological diagnosis of LCM, to isolate and to identify human strains of LCMv in Argentina. During the last 19 years, 15 cases were diagnosed as LCM by immunoflourescent indirect assay (IFI) and enzyme-linked immunosorbent assay (ELISA) but when neutralizing assay (NT) was incorporated, eight cases were classified as confirmed, three as probable and four as negative. The geographic distribution of the cases included three provinces: Cordoba, Buenos Aires and Santa Fe. Viral isolation was attempted in five patients classified as confirmed and only two resulted positive (P5226 and P8573). They were identified as LCMv by IFI and NT. The coexistence of LCMv with other arenaviruses, such as Junin and Oliveros viruses, in the same area, raises the probability of interactions between them, which could modify the virulence and/or pathogenicity for humans associated to genomic changes. Future studies of antigenic, genomic and virulence variability of different Argentine strains of LCMv, as well as the systematic search for human infection, will contribute to define the importance of this viral agent in our country and to implement control measures. (Au)