Incidencia de potyvirus y caracterización molecular de PVY en regiones productoras de papa (Solanum tuberosum L) de Colombia / Incidence of potyvirus and molecular characterization of PVY in potato (Solanum tuberosum L) growing regions of Colombia

Los problemas virales reducen los rendimientos y la calidad del tubérculo semilla en cultivos de papa de todo el mundo. Esta investigación se planteó con el fin de evaluar los niveles de incidencia de potyvirus en diez de las principales regiones cultivadoras de papa de los departamentos de Antioquia, Boyacá, Cundinamarca y Nariño (Colombia), y las características genotípicas del virus Y de la papa (Potato virus Y, PVY), seleccionado por ser el potyvirus más limitante de este cultivo. Para la evaluación de la incidencia se utilizaron pruebas de Elisa con anticuerpos que reconocen epítopes comunes a los potyvirus, mientras que las pruebas moleculares incluyeron el análisis filogenético de secuencias parciales del gen de la cápside viral de 33 aislamientos, así como la secuenciación de una porción de los extremos 5´ y 3´del genoma de dos cepas colombianas de este virus. Los resultados confirmaron la presencia de potyvirus en los cultivos de los cuatro departamentos evaluados, con una incidencia promedio del 72%, siendo este nivel superior al 56% en todas las zonas evaluadas. Los análisis moleculares del PVY, permitieron asociar las cepas colombianas estudiadas con las razas PVYN y la variante PVYNTN, esta última responsable de la enfermedad conocida en el mundo como PTNRD (Potato tuber necrotic ringspot disease).

Potato viruses are responsible for significant reductions in seed quality and crop yields around the world. In this study, we evaluate the levels of incidence of potyvirus in ten potato growing regions of Colombia from the provinces of Antioquia, Boyacá, Cundinamarca and Nariño. As PVY is the most limiting potyvirus in potato farming, a molecular characterization of Colombian PVY strains was also performed. Incidence was evaluated by ELISA using general potyvirus antibodies. Phylogenetic analysis were made on the partial sequence of the capsid gene from 33 isolates. A portion of the 5´ and 3' genome ends was obtained from two Colombian strains. Results confirmed the presence of potyvirus in the four provinces with an average incidence of 72%. The lowest incidence value was 56%. Molecular analysis clustered all Colombian isolates with strains PVYN and PVYNTN, the latter responsible for the disease known as PTNRD (Potato tuber necrotic ringspot disease).

Significance of plasma IgA and IgG antibodies to Epstein-Barr virus early and viral capsid antigens in Thai nasopharyngeal carcinoma.

Epstein-Barr virus (EBV) is an important causal factor of human nasopharyngeal carcinoma (NPC). High levels of serum IgA and IgG antibodies to EBV early and viral capsid antigens (IgA/EA, IgA/VCA, IgG/EA and IgG/VCA) have been reported in NPC patients. Since specific serum IgA/EA, IgA/VCA and IgG/EA are claimed to be useful serological markers for NPC. In order to evaluate whether plasma IgA/EA, IgA/VCA, IgG/EA and IgG/VCA antibody levels are useful markers for diagnosis and prognosis of Thai NPC, we examined the prevalence of these antibodies in 79 NPC patients, and 127 age-matched controls (47 healthy subjects (HS), 32 cases of other disease (OD) and 48 cases of other cancer (OC)) by using an indirect immunofluorescence assay. The prevalence of plasma IgA/EA, IgA/VCA, and IgG/EA in NPC patients (55.7, 68.4 and 68.4%) was significantly higher than in the HS (0.0, 0.0 and 20.5%,), OD (0.0, 0.0 and 3.1%) and OC (0.0, 0.0 and 20.8%) groups (p<0.05). The prevalence of plasma IgG/VCA in NPC patients (93.7%) was significantly different from those for the OD and OC groups (71.9 and 43.8%) but not for the HS group (89.4%). In NPC patients, the geometric mean titers (GMT) of plasma IgA/EA, IgA/VCA and IgG/EA were increased with an advanced clinical stage of disease but not IgG/VCA. In contrast, GMT of IgG/VCA was increased with aggressive type of disease (histological type) but not IgA/EA, IgA/VCA, and IgG/VCA. The results of our study suggest that plasma IgA/EA, IgA/VCA and IgG/EA antibodies may be useful markers for diagnosis and assessing prognosis of Thai NPC.

Anti-VP1 and anti-VP2 antibodies detected by immunofluorescence assays in patients with acute human parvovirus B19 infection

Acute human parvovirus B19 infection is followed by an antibody response to the structural proteins of the viral capsid (VP1 and VP2). We used 80 sera collected from 58 erythema infectiosum and 6 transient aplastic crisis patients to test IgM and IgG antibodies against these two proteins in an immunofluorescence assay (IFA) using Sf9 cells infected with recombinant baculovirus expressing either VP1 or VP2 antigen. Although less sensitive than IgM capture enzyme immunoassay using native antigen (MACEIA), we could detect anti-VP1 or anti-VP2 IgM antibodies by IFA in 49 patients with acute infection (76.6 percent). Detection of IgG anti-VP1 and anti-VP2 by IFA, however, was as sensitive as IgG detection by indirect enzyme immunoassay. By applying IgG avidity IFA to sera of the 15 IgM IFA negative patients we were able to confirm acute infection in further 12 cases by IFA. Overall, acute infection was confirmed by IFA in 61 (95.3 percent) of the 64 patients

Perspectivas para el desarrollo de vacunas e inmunoterapia contra cáncer cervicouterino / Perspectives for vaccines and immunotherapy againts cervical cancer

El cáncer cervicouterino representa un grave problema de salud pública, debido a la asociación de la neoplasia con el virus del papiloma humano; actualmente se realizan estudios usados estrategias dirigidas a combatir este patógeno, mediante vacunas, que podrían ser de gran utilidad para el control de la progresión de la enfermedad. El estudio tanto de la inmunología humoral como celular ha servido para el desarrollo de vcunas. Así, la utilización de partículas virales sintéticas para el estudio de anticuerpos neutralizantes y el uso de proteínas tempranas virales, entre otras, para la inducción de inmunidad mediada por células, han sido la pauta para realizar estudios que dirijan la respuesta inmune para prevenir la infección celular tanto hacia células infectadas no transformadas como hacia células transformadas viralmente con resultados favorables

Prevalence of IgA specific antibodies to Epstein-Barr virus capsid and early antigens in nasopharyngeal carcinoma.

Ninety-one patients with nasopharyngeal carcinoma (NPC), and 164 age-matched healthy controls were tested for presence of IgA antibodies to Epstein-Barr virus capsid antigen (VCA) and early antigen (EA) in their sera by indirect ELISA using "EBViral DETECT" commercial test kit. IgA anti-VCA was found in 76 (83.5%) of NPC patients and 16 (9.8%) of the controls. Meanwhile, IgA anti-EA was found in 72 (79.1%) of NPC patients and 21 (12.8%) of the controls. In a parallel study by indirect immunofluorescence test (IIF), IgA anti-VCA was found in 77 of 91 (84.6%) NPC patients and 22 of 142 (15.5%) controls. The prevalence rates of anti-VCA as screened by ELISA and IIF were very similar suggesting that neither one of the two tests can be used alternatively depending on the purpose and facilities in each individual laboratory. IgA antibodies to VCA and EA were more prevalence in NPC patients than those in the controls, the finding which again supported the association between EBV and NPC as was suggested in many other reports.

Expression of the VP3-VP1 sequence of foot-and-mouth disease virus in Escherichia coli

1. cDNA recombinants containing the VP3 and VP1 sequences of foot-and-mouth disease virus were isolated and the VP3-VP1 sequence was reconstructed. 2. The reconstructed VP3-VP1 sequence was subcloned into expression vector pEX31b and a fusion protein of about 62,000 Da was expressed. 3. When injected into mice, the fusion protein was able to elicit the production of antibodies that recognized viral VP1 and VP3. 4. Antibodies present in sera from mice immunized with VP3-VP1 protein did not neutralize the foot-and-mouth disease virus in vitro

Caracterización de tipos antigenícos de rotavirus circulantes en Mendoza, Argentina, en base a tipificación de la proteína de la capside externa VP7 / Characterization of antigenic types of circulating rotavirus in Mendoza, Argentina with base to typing of external VP7 capsid protein

El rotavirus es uno de los agentes etiológicos más comunes de la diarrea aguda de la infancia. La compresión de los mecanismos inmunológicos involucrados en las enfermedades por rotavirus incluso el conocimiento de las variaciones antigénicas, estacionales y geográficas pueden ser cruciales para el desarrollo de la vacuna. Un anticuerpo monoclonal, basado en ELISA, específico para el dominio antigénico sobre la cápside exterior proteica VP7, ha sido desarrollado y usado ampliamente durante los últimos años. Estudiamos la epidemiología del rotavirus VP7, causante de diarrea en niños que consultaron en los dos hospitales principales de Mendoza, Argentina, durante un período de 20 meses. Fueron identificados 227 casos de diarrea, 45 de los cuales (20 por ciento) fueron rotavirus positivas. Pudimos determinar el serotipo de 43 virus (96 por ciento), 42 tipo VP7 y 1 tipo VP7-3. Este último fue detectado hacia el final del segundo año representando posiblemente un tipo VP7 nuevo, que llegaba. Se identificaron 3 patrones electroforéticos, dos correspondientes a la epidemia de tipo VP7 en Mendoza, parecían caracterizados por un patrón relativamente homogéneo de circulación con fuerte predominancia del virus VP7-tipo 1,por lo menos durante el período estudiado de 20 meses, en contraste con lo que se ha informado en ciudades más grandes y cosmopolitas, tales como Buenos Aires

Comparison of the immune response against polio peptides covalently-surface-linked to and internally-entrapped in liposomes.

The adjuvanticity of liposomes on two different modes of presentation of polio virus subunit peptides was demonstrated by incorporating the poorly immunogenic synthetic polio peptides, W1 and W2, into the internal space of and covalently-linked to the surface of dehydration-rehydration vesicles (DRV). It was found that for both peptides, liposome association in either mode boosted the primary and secondary IgG1 responses against 5 micrograms peptide as compared to controls in which free peptide was administered. Surface-linkage of peptides (both W1 and W2) exhibited an initially more rapid rise in antibody levels, as compared to internal entrapment of the peptides, but elicited no observable secondary response. However, although encapsulated W1 showed a milder primary response when compared to the surface-linked formulation, it later elicited a strong secondary response. These results suggested that it may be advantageous to administer liposomal virus subunit vaccines in both surface-linked and internally entrapped formulations to achieve adequate initial antibody levels followed by an anamnestic response.

Evaluación diagnóstica de infecciones de cuello uterino asociadas a infección por virus papiloma humano / Diagnostic evaluation of cervix uteri infections associated with infection caused by human papilloma virus

El objetivo de este trabajo es demostrar la presencia de proteínas de virus papilomas humano (HPV) en biopsias de cuello uterino diagnosticadas histológicamente como cervicopatías de origen viral. Se escogieron 38 biopsias cervicales que cumplían con los criterios mencionados por Toki y Yajima para diagnóstico de HPV. Las biopsias provienen de archivos de placas del programa de detección de cáncer cérvico-uterino de las áreas Norte y Oriente de Santiago. Se empleó la técnica de inmunoperoxidasa usando el método ABC (complejo avidina-biotina-peroxidasa), utilizando como anticuerpo primario, uno policlonal diluido a 1:200, que reacciona con todas las variedades de virus papiloma. Veinte de las 38 biopsias (52,9%) presentan antígenos virales en núcleo de las capas superficiales del epitelio escamoso, en cantidad suficiente como para ser reconocidos por la sensibilidad del método. Este porcentaje es comparable a lo descrito en la literatura y que varía entre un 40% y un 62%

Malaria antibody levels in patients with nasopharyngeal carcinoma.

The antibody titres to P. falciparum and Epstein-Barr Virus-associated antigens were assayed in 22 patients with NPC and 43 controls. All, but one patient had antimalarial titres; 14 had titres greater than 80 and 4 patients greater than 640. Compared to controls the mean anti-malarial titre for most age groups were higher in the patients. Those patients with high anti-malarial titres also had high IgA anti-VCA titre, an antibody which has been demonstrated to be diagnostic for NPC. The peak anti-VCA (IgG) and anti-EA (IgG) antibody titres were associated with anti-falciparum titres of 320-640 and 80-160, respectively. The results are discussed in relation to the possible association between malarial infection and etiology of NPC.