Homotypic antibodies target novel E glycoprotein domains after natural DENV 3 infection/vaccination.

The envelope (E) glycoprotein is the primary target of type-specific (TS) neutralizing antibodies (nAbs) after infection with any of the four distinct dengue virus serotypes (DENV1-4). nAbs can be elicited to distinct structural E domains (EDs) I, II, or III. However, the relative contribution of these domain-specific antibodies is unclear. To identify the primary DENV3 nAb targets in sera after natural infection or vaccination, chimeric DENV1 recombinant encoding DENV3 EDI, EDII, or EDIII were generated. DENV3 EDII is the principal target of TS polyclonal nAb responses and encodes two or more neutralizing epitopes. In contrast, some were individuals vaccinated with a DENV3 monovalent vaccine-elicited serum TS nAbs targeting each ED in a subject-dependent fashion, with an emphasis on EDI and EDIII. Vaccine responses were also sensitive to DENV3 genotypic variation. This DENV1/3 panel allows the measurement of serum ED TS nAbs, revealing differences in TS nAb immunity after natural infection or vaccination.

Identification of Anti-Premembrane Antibody as a Serocomplex-Specific Marker To Discriminate Zika, Dengue, and West Nile Virus Infections.

Although transmission of Zika virus (ZIKV) in the Americas has greatly declined since late 2017, recent reports of reduced risks of symptomatic Zika by prior dengue virus (DENV) infection and increased risks of severe dengue disease by previous ZIKV or DENV infection underscore a critical need for serological tests that can discriminate past ZIKV, DENV, and/or other flavivirus infections and improve our understanding of the immune interactions between these viruses and vaccine strategy in endemic regions. As serological tests for ZIKV primarily focus on envelope (E) and nonstructural protein 1 (NS1), antibodies to other ZIKV proteins have not been explored. Here, we employed Western blot analysis using antigens of 6 flaviviruses from 3 serocomplexes to investigate antibody responses following reverse transcription-PCR (RT-PCR)-confirmed ZIKV infection. Panels of 20 primary ZIKV and 20 ZIKV with previous DENV infection recognized E proteins of all 6 flaviviruses and the NS1 protein of ZIKV with some cross-reactivity to DENV. While the primary ZIKV panel recognized only the premembrane (prM) protein of ZIKV, the ZIKV with previous DENV panel recognized both ZIKV and DENV prM proteins. Analysis of antibody responses following 42 DENV and 18 West Nile virus infections revealed similar patterns of recognition by anti-E and anti-NS1 antibodies, whereas both panels recognized the prM protein of the homologous serocomplex but not others. The specificity was further supported by analysis of sequential samples. Together, these findings suggest that anti-prM antibody is a flavivirus serocomplex-specific marker and can be used to delineate current and past flavivirus infections in endemic areas. IMPORTANCE Despite a decline in Zika virus (ZIKV) transmission since late 2017, questions regarding its surveillance, potential reemergence, and interactions with other flaviviruses in regions where it is endemic remain unanswered. Recent studies have reported reduced risks of symptomatic Zika by prior dengue virus (DENV) infection and increased risks of severe dengue disease by previous ZIKV or DENV infection, highlighting a need for better serological tests to discriminate past ZIKV, DENV, and/or other flavivirus infections and improved understanding of the immune interactions and vaccine strategy for these viruses. As most serological tests for ZIKV focused on envelope and nonstructural protein 1, antibodies to other ZIKV proteins, including potentially specific antibodies, remain understudied. We employed Western blot analysis using antigens of 6 flaviviruses to study antibody responses following well-documented ZIKV, DENV, and West Nile virus infections and identified anti-premembrane antibody as a flavivirus serocomplex-specific marker to delineate current and past flavivirus infections in areas where flaviviruses are endemic.

Pre-existing T Cell Memory against Zika Virus.

The mosquito-borne Zika virus (ZIKV) has spread rapidly into regions where dengue virus (DENV) is endemic, and flavivirus cross-reactive T cell responses have been observed repeatedly in animal models and in humans. Preexisting cellular immunity to DENV is thought to contribute to protection in subsequent ZIKV infection, but the epitope targets of cross-reactive T cell responses have not been comprehensively identified. Using human blood samples from the regions of Nicaragua and Sri Lanka where DENV is endemic that were collected before the global spread of ZIKV in 2016, we employed an in vitro expansion strategy to map ZIKV T cell epitopes in ZIKV-unexposed, DENV-seropositive donors. We identified 93 epitopes across the ZIKV proteome, and we observed patterns of immunodominance that were dependent on antigen size and sequence identity to DENV. We confirmed the immunogenicity of these epitopes through a computational HLA binding analysis, and we showed that cross-reactive T cells specifically recognize ZIKV peptides homologous to DENV sequences. We also found that these CD4 responses were derived from the memory T cell compartment. These data have implications for understanding the dynamics of flavivirus-specific T cell immunity in areas of endemicity.IMPORTANCE Multiple flaviviruses, including Zika virus (ZIKV) and the four serotypes of dengue virus (DENV), are prevalent in the same large tropical and equatorial areas, which are inhabited by hundreds of millions of people. The interplay of DENV and ZIKV infection is especially relevant, as these two viruses are endemic in largely overlapping regions, have significant sequence similarity, and share the same arthropod vector. Here, we define the targets of preexisting immunity to ZIKV in unexposed subjects in areas where dengue is endemic. We demonstrate that preexisting immunity to DENV could shape ZIKV-specific responses, and DENV-ZIKV cross-reactive T cell populations can be expanded by stimulation with ZIKV peptides. The issue of potential ZIKV and DENV cross-reactivity is of relevance for understanding patterns of natural immunity, as well as for the development of diagnostic tests and vaccines.

Identification of Dengue Virus Serotype 3 Specific Antigenic Sites Targeted by Neutralizing Human Antibodies.

The rational design of dengue virus (DENV) vaccines requires a detailed understanding of the molecular basis for antibody-mediated immunity. The durably protective antibody response to DENV after primary infection is serotype specific. However, there is an incomplete understanding of the antigenic determinants for DENV type-specific (TS) antibodies, especially for DENV serotype 3, which has only one well-studied, strongly neutralizing human monoclonal antibody (mAb). Here, we investigated the human B cell response in children after natural DENV infection in the endemic area of Nicaragua and isolated 15 DENV3 TS mAbs recognizing the envelope (E) glycoprotein. Functional epitope mapping of these mAbs and small animal prophylaxis studies revealed a complex landscape with protective epitopes clustering in at least 6-7 antigenic sites. Potently neutralizing TS mAbs recognized sites principally in E glycoprotein domains I and II, and patterns suggest frequent recognition of quaternary structures on the surface of viral particles.

Molecular Signatures of Dengue Virus-Specific IL-10/IFN-γ Co-producing CD4 T Cells and Their Association with Dengue Disease.

Dengue virus (DENV) can cause diseases ranging from dengue fever (DF) to more severe dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS). Whether antiviral T cells contribute to the protection against or pathogenesis of severe disease is not well defined. Here, we identified antigen-specific IL-10+IFN-γ+ double-positive (DP) CD4 T cells during acute DENV infection. While the transcriptomic signatures of DP cells partially overlapped with those of cytotoxic and type 1 regulatory CD4 T cells, the majority of them were non-cytotoxic/Tr1 and included IL21, IL22, CD109, and CCR1. Although we observed a higher frequency of DP cells in DHF, the transcriptomic profile of DP cells was similar in DF and DHF, suggesting that DHF is not associated with the altered phenotypic or functional attributes of DP cells. Overall, this study revealed a DENV-specific DP cell subset in patients with acute dengue disease and argues against altered DP cells as a determinant of DHF.

The respiratory microbiota: associations with influenza symptomatology and viral shedding.

PURPOSE: Manifestations of infection and the degree of influenza virus vary. We hypothesized that the nose/throat microbiota modifies the duration of influenza symptoms and viral shedding. Exploring these relationships may help identify additional methods for reducing influenza severity and transmission. METHODS: Using a household transmission study in Nicaragua, we identified secondary cases of influenza virus infection, defined as contacts with detectable virus or a greater than 4-fold change in hemagglutinin inhibition antibody titer. We characterized the nose/throat microbiota of secondary cases before infection and explored whether the duration of symptoms and shedding differed by bacterial community characteristics. RESULTS: Among 124 secondary cases of influenza, higher bacterial community diversity before infection was associated with longer shedding duration (Shannon acceleration factor [AF]: 1.61, 95% confidence interval [CI]: 1.24, 2.10) and earlier time to infection (Shannon AF: 0.72, 95% CI: 0.53, 0.97; Chao1 AF: 0.992, 95% CI: 0.986, 0.998). Neisseria and multiple other oligotypes were significantly associated with symptom and shedding durations and time to infection. CONCLUSIONS: The nose/throat microbiota before influenza virus infection was associated with influenza symptoms and shedding durations. Further studies are needed to determine if the nose/throat microbiota is a viable target for reducing influenza symptoms and transmission.

Development of Envelope Protein Antigens To Serologically Differentiate Zika Virus Infection from Dengue Virus Infection.

Zika virus (ZIKV) is an emerging flavivirus that can cause birth defects and neurologic complications. Molecular tests are effective for diagnosing acute ZIKV infection, although the majority of infections produce no symptoms at all or present after the narrow window in which molecular diagnostics are dependable. Serology is a reliable method for detecting infections after the viremic period; however, most serological assays have limited specificity due to cross-reactive antibodies elicited by flavivirus infections. Since ZIKV and dengue virus (DENV) widely cocirculate, distinguishing ZIKV infection from DENV infection is particularly important for diagnosing individual cases or for surveillance to coordinate public health responses. Flaviviruses also elicit type-specific antibodies directed to non-cross-reactive epitopes of the infecting virus; such epitopes are attractive targets for the design of antigens for development of serological tests with greater specificity. Guided by comparative epitope modeling of the ZIKV envelope protein, we designed two recombinant antigens displaying unique antigenic regions on domain I (Z-EDI) and domain III (Z-EDIII) of the ZIKV envelope protein. Both the Z-EDI and Z-EDIII antigens consistently detected ZIKV-specific IgG in ZIKV-immune sera but not cross-reactive IgG in DENV-immune sera in late convalescence (>12 weeks postinfection). In contrast, during early convalescence (2 to 12 weeks postinfection), secondary DENV-immune sera and some primary DENV-immune sera cross-reacted with the Z-EDI and Z-EDIII antigens. Analysis of sequential samples from DENV-immune individuals demonstrated that Z-EDIII cross-reactivity peaked in early convalescence and declined steeply over time. The Z-EDIII antigen has much potential as a diagnostic antigen for population-level surveillance and for detecting past infections in patients.

CD14+CD16+ monocytes are the main target of Zika virus infection in peripheral blood mononuclear cells in a paediatric study in Nicaragua.

The recent Zika pandemic in the Americas is linked to congenital birth defects and Guillain-Barré syndrome. White blood cells (WBCs) play an important role in host immune responses early in arboviral infection. Infected WBCs can also function as 'Trojan horses' and carry viruses into immune-sheltered spaces, including the placenta, testes and brain. Therefore, defining which WBCs are permissive to Zika virus (ZIKV) is critical. Here, we analyse ZIKV infectivity of peripheral blood mononuclear cells (PBMCs) in vitro and from Nicaraguan Zika patients and show CD14+CD16+ monocytes are the main target of infection, with ZIKV replication detected in some dendritic cells. The frequency of CD14+ monocytes was significantly decreased, while the CD14+CD16+ monocyte population was significantly expanded during ZIKV infection compared to uninfected controls. Viral RNA was detected in PBMCs from all patients, but in serum from only a subset, suggesting PBMCs may be a reservoir for ZIKV. In Zika patients, the frequency of infected cells was lower but the percentage of infected CD14+CD16+ monocytes was significantly higher compared to dengue cases. The gene expression profile in monocytes isolated from ZIKV- and dengue virus-infected patients was comparable, except for significant differences in interferon-γ, CXCL12, XCL1, interleukin-6 and interleukin-10 levels. Thus, our study provides a detailed picture of the innate immune profile of ZIKV infection and highlights the important role of monocytes, and CD14+CD16+ monocytes in particular.

Intrahost Selection Pressures Drive Rapid Dengue Virus Microevolution in Acute Human Infections.

Dengue, caused by four dengue virus serotypes (DENV-1 to DENV-4), is a highly prevalent mosquito-borne viral disease in humans. Yet, selection pressures driving DENV microevolution within human hosts (intrahost) remain unknown. We employed a whole-genome segmented amplification approach coupled with deep sequencing to profile DENV-3 intrahost diversity in peripheral blood mononuclear cell (PBMC) and plasma samples from 77 dengue patients. DENV-3 intrahost diversity appears to be driven by immune pressures as well as replicative success in PBMCs and potentially other replication sites. Hotspots for intrahost variation were detected in 59%-78% of patients in the viral Envelope and pre-Membrane/Membrane proteins, which together form the virion surface. Dominant variants at the hotspots arose via convergent microevolution, appear to be immune-escape variants, and were evolutionarily constrained at the macro level due to viral replication defects. Dengue is thus an example of an acute infection in which selection pressures within infected individuals drive rapid intrahost virus microevolution.

Development of in-house serological methods for diagnosis and surveillance of chikungunya / Desarrollo de métodos serológicos propios para el diagnóstico y la vigilancia del chikungunya

ABSTRACT Objective To develop and evaluate serological methods for chikungunya diagnosis and research in Nicaragua. Methods Two IgM ELISA capture systems (MAC-ELISA) for diagnosis of acute chikungunya virus (CHIKV) infections, and two Inhibition ELISA Methods (IEM) to measure total antibodies against CHIKV were developed using monoclonal antibodies (mAbs) and hyperimmune serum at the National Virology Laboratory of Nicaragua in 2014-2015. The sensitivity, specificity, predictive values, and agreement of the MAC-ELISAs were obtained by comparing the results of 198 samples (116 positive; 82 negative) with the Centers for Disease Control and Prevention's IgM ELISA (Atlanta, Georgia, United States; CDC-MAC-ELISA). For clinical evaluation of the four serological techniques, 260 paired acute and convalescent phase serum samples of suspected chikungunya cases were used. Results All four assays were standardized by determining the optimal concentrations of the different reagents. Processing times were substantially reduced compared to the CDC-MAC-ELISA. For the MAC-ELISA systems, a sensitivity of 96.6% and 97.4%, and a specificity of 98.8% and 91.5% were obtained using mAb and hyperimmune serum, respectively, compared with the CDC method. Clinical evaluation of the four serological techniques versus the CDC real-time RT-PCR assay resulted in a sensitivity of 95.7% and a specificity of 88.8%-95.9%. Conclusion Two MAC-ELISA and two IEM systems were standardized, demonstrating very good quality for chikungunya diagnosis and research demands. This will achieve more efficient epidemiological surveillance in Nicaragua, the first country in Central America to produce its own reagents for serological diagnosis of CHIKV. The methods evaluated here can be applied in other countries and will contribute to sustainable diagnostic systems to combat the disease.

RESUMEN Objetivo Elaborar y evaluar métodos serológicos para el diagnóstico y la investigación del chikungunya. Métodos Se elaboraron dos sistemas de ELISA de captura de IgM (MAC-ELISA por sus siglas en inglés) para el diagnóstico de la infección aguda por el virus de (CHIKV) y dos métodos de ELISA de inhibición (MEI) para determinar el valor cuantitativo de los anticuerpos totales contra el CHIKV, en el Laboratorio Nacional de Virología de Nicaragua en 2014-2015, para lo cual se utilizaron anticuerpos monoclonales (AcMo) y sueros hiperinmunes. Se determinó la sensibilidad, la especificidad y los valores predictivos, así como la concordancia de los MAC-ELISA, comparando los resultados de 198 muestras (116 positivas y 82 negativas) con el ELISA de los Centros para el Control y la Prevención de Enfermedades de los Estados Unidos (Atlanta; MAC-ELISA-CDC). Para la evaluación clínica de las cuatro técnicas serológicas, se emplearon 260 muestras de suero obtenidas en la fase aguda y en la fase de convalecencia de presuntos casos de chikungunya. Resultados Se estandarizaron los cuatro métodos analíticos determinando las concentraciones óptimas de los diferentes reactivos. La duración del procesamiento se redujo sustancialmente en comparación con el MAC-ELISA-CDC. Con los sistemas de MAC-ELISA, se obtuvo una sensibilidad del 96,6% y del 97,4% y una especificidad del 98,8% y del 91,5% al utilizar AcMo y suero hiperinmune, respectivamente, en comparación con el método de los CDC. La evaluación clínica de las cuatro técnicas serológicas, en comparación con la PCR en tiempo real de los CDC, arrojó una sensibilidad del 95,7% y una especificidad del 88,8%-95,9%. Conclusiones Se estandarizaron dos sistemas de ELISA-MAC y dos de MEI y se comprobó que poseen la calidad adecuada para el diagnóstico y las investigaciones del chikungunya, con lo cual mejorará la eficiencia de la vigilancia epidemiológica en Nicaragua, el primer país centroamericano que produce sus propios reactivos para el diagnóstico serológico del CHIKV. Los métodos estudiados en este trabajo pueden aplicarse en otros países y contribuyen al desarrollo de sistemas de diagnóstico sostenibles para combatir la enfermedad.

Immunodominant Dengue Virus-Specific CD8+ T Cell Responses Are Associated with a Memory PD-1+ Phenotype.

UNLABELLED: Dengue disease is a large public health problem that mainly afflicts tropical and subtropical regions. Understanding of the correlates of protection against dengue virus (DENV) is poor and hinders the development of a successful human vaccine. The present study aims to define DENV-specific CD8(+)T cell responses in general and those of HLA alleles associated with dominant responses in particular. In human blood donors in Nicaragua, we observed a striking dominance of HLA B-restricted responses in general and of the allele B*35:01 in particular. Comparing these patterns to those in the general population of Sri Lanka, we found a strong correlation between restriction of the HLA allele and the breadth and magnitude of CD8(+)T cell responses, suggesting that HLA genes profoundly influence the nature of responses. The majority of gamma interferon (IFN-γ) responses were associated with effector memory phenotypes, which were also detected in non-B*35:01-expressing T cells. However, only the B*35:01 DENV-specific T cells were associated with marked expression of the programmed death 1 protein (PD-1). These cells did not coexpress other inhibitory receptors and were able to proliferate in response to DENV-specific stimulation. Thus, the expression of particular HLA class I alleles is a defining characteristic influencing the magnitude and breadth of CD8 responses, and a distinct, highly differentiated phenotype is specifically associated with dominant CD8(+)T cells. These results are of relevance for both vaccine design and the identification of robust correlates of protection in natural immunity. IMPORTANCE: Dengue is an increasingly significant public health problem as its mosquito vectors spread over greater areas; no vaccines against the virus have yet been approved. An important step toward vaccine development is defining protective immune responses; toward that end, we here characterize the phenotype of the immunodominant T cell responses. These DENV-reactive T cells express high levels of the receptor programmed death 1 protein (PD-1), while those from disease-susceptible alleles do not. Not only does this represent a possible correlate of immunodominance, but it raises the hypothesis that PD-1 might be a regulator that prevents excessive damage while preserving antiviral function. Further, as this study employs distinct populations (Nicaraguan and Sri Lankan donors), we also confirmed that this pattern holds despite geographic and ethnic differences. This finding indicates that HLA type is the major determinant in shaping T cell responses.

Analysis of cross-reactive antibodies recognizing the fusion loop of envelope protein and correlation with neutralizing antibody titers in Nicaraguan dengue cases.

Dengue virus (DENV) is the leading cause of arboviral diseases in humans worldwide. The envelope (E) protein of DENV is the major target of neutralizing antibodies (Abs). Previous studies have shown that a significant proportion of anti-E Abs in human serum after DENV infection recognize the highly conserved fusion loop (FL) of E protein. The role of anti-FL Abs in protection against subsequent DENV infection versus pathogenesis remains unclear. A human anti-E monoclonal Ab was used as a standard in a virion-capture ELISA to measure the concentration of anti-E Abs, [anti-E Abs], in dengue-immune sera from Nicaraguan patients collected 3, 6, 12 and 18 months post-infection. The proportion of anti-FL Abs was determined by capture ELISA using virus-like particles containing mutations in FL, and the concentration of anti-FL Abs, [anti-FL Abs], was calculated. Neutralization titers (NT50) were determined using a previously described flow cytometry-based assay. Analysis of sequential samples from 10 dengue patients revealed [anti-E Abs] and [anti-FL Abs] were higher in secondary than in primary DENV infections. While [anti-FL Abs] did not correlate with NT50 against the current infecting serotype, it correlated with NT50 against the serotypes to which patients had likely not yet been exposed ("non-exposed" serotypes) in 14 secondary DENV3 and 15 secondary DENV2 cases. These findings demonstrate the kinetics of anti-FL Abs and provide evidence that anti-FL Abs play a protective role against "non-exposed" serotypes after secondary DENV infection.

Diagnostic accuracy of a rapid influenza test for pandemic influenza A H1N1.

BACKGROUND: With the current influenza A H1N1 pandemic (H1N1pdm), it is extremely important that clinicians can quickly and accurately identify influenza cases. METHODOLOGY/PRINCIPAL FINDINGS: To investigate the performance of the QuickVue Influenza A+B rapid test, we conducted a prospective study of the diagnostic accuracy of the QuickVue Influenza A+B test compared to real-time reverse transcriptase-polymerase chain reaction (RT-PCR) for influenza A H1N1pdm in Nicaraguan children aged 2 to 14 years. Rapid test sensitivity and specificity compared to real-time RT-PCR were 64.1% (95% CI 53.5, 73.9) and 98.3% (95.0, 99.6), respectively. Agreement between the two tests was 86.4% (95% CI 81.7, 90.3), and kappa was calculated to be 0.67 (95% CI 0.56, 0.76). Performance of the rapid test varied by day of presentation, with a sensitivity of 41.7% (95% CI 22.1, 63.4) for samples from children presenting on the day of symptom onset and a sensitivity of 72.1% (95% CI 59.9, 82.3) for samples from children presenting one or more days post-symptom onset. CONCLUSIONS/SIGNIFICANCE: We found that the rapid test performed with moderate sensitivity and high specificity. Test performance varied by day of onset, with lower sensitivity on the day of symptom onset.

Immunoglobulin M enzyme-linked immunosorbent assay using recombinant polypeptides for diagnosis of dengue.

We demonstrate that a mixture of four recombinant dengue virus E polypeptides corresponding to the N-terminal region of the envelope protein from all serotypes substitutes for standard antigens in two immunoglobulin M enzyme-linked immunosorbent assay formats with 100% concordance, making these polypeptides a useful and accessible reagent for serological diagnosis of dengue in endemic countries.

Prevalence and factors associated to the epidemic neuropathy in a population assisted by a familiar doctor in Cuba

With the outbreak of an epidemic neuropathy (EN) of unknown ethiology, a study of the prevalence and factors associated to the disease was carried out in the Zamora community, municipality of Marianao, Havana City. There were 11 patients identified with EN for a prevalence rate of 1.7/100. The major risk group was the one between 45 and 64 years of age, female sex, black skin. In the univaried analysis, a high prevalence ratio (PR) was found linked to bevarage intake (PR=5.32 95 per cent; confidence intervals (CI) = 1.2-24.4), frequent drugs intake (PR=6.59; CI=1.8-24.6), consumption of edible of non certified fats (PR=4.48; CI=1.2-16.7) and the smoking habit (PR=3.6; CI=1.1-12.2). More than 73/100 (CI=68.7-78.3) of the people under serologic study were infected with Coxsakie virus A-9 (strain 47) isolated from a patient still under research. It seems there are many factors like linder intake, antecedents of hemorrhagic conjuntivitis, nutritional aspects and others that, with the virus isolated were associated with this epidemiologic situation.

Validacion de un ultramicroELISA de deteccion de anticuerpos contra el antigeno de superficie de la hepatitis B / Validation of an ultramicroELISA for the detection of antibodies against the hepatitis B surface antigen

Se presentan los resultados del estudio de validacion del ensayo ultramicroanalitico de deteccion de anticuerpos contra el antigeno de superficie de la hepatitis B (UMELISA anti HBsAg), que se realizo comparando los resultados obtenidos, con el juego diagnostico comercial Hepanostika anti-HBsAg. Se utilizaron para ello sueros procedentes de los ensayos clinicos de la vacuna recombinante cubana contra la hepatitis B. Con el primer panel de sueros (n = 300) se obtuvo el 93,1 por ciento de sensibilidad, el 98,5 por ciento de especificidad y una concordancia del 94,3 por ciento. El coeficiente de correlacion indico una tendencia similar de los resultados (p < 0,01) y no se encontraron diferencias significativas en el titulo promedio geometrico (TPG) entre ambos ensayos (P > 0,05). Con el segundo panel (n = 100), realizado en el Instituto de Medicina Tropical "Pedro Kouri" (IPK) y el Centro de Inmunoensayo (CIE) simulataneamente, se obtuvo una sensibilidad del 96,25 por ciento en ambos centros, una especificidad del 75 por ciento en el IPK y del 90 por ciento en el CIE y una coincidencia del 92 y 95 por ciento, respectivamente. El coeficiente de correlacion mostro valores similares y no hubo diferencias significativas entre las TPG alcanzadas por los 2 metodos (P > 0,05). Los resultados obtenidos en general muestran la validez del nuevo ensayo y la factibilidad de su utilizacion en la practica, ya sea para el seguimiento de la infeccion o para la realizacion de ensayos clinicos de evaluacion de vacunas

Neuropatia epidemica cubana. Parte III. Anticuerpos neutralizantes a cepas aisladas y otros Enterovirus en pacientes y personas sanas / Cuban epidemic neuropathy. Part III. Neutralizing antibodies to isolated strains and to other enteroviruses in patients and healthy subjects

Se realizaron determinaciones de anticuerpos neutralizantes en sueros de pacientes con neuropatia epidemica y de grupos de personas aparentemente sanas, a la cepa 47/93 IPK (CA9) y la 590 productora de efecto citopatico ligero (ECP-L), asi como a las cepas de referencia de CA9 y CB1-6, por la tecnica de microneutralizacion. Los enfermos y sus contactos mostraron porcentajes significativamente superiores de anticuerpos neutralizantes a la cepa 47-93 que el grupo considerado control y los residentes en municipios de baja tasa de la enfermedad. Esta diferencia tambien se comprobo en los titulos promedio geometrico (TPG) con las cepas de referencia de CA9 y CB2-4. Se comprobo un incremento de la circulacion de la cepa 47/93 en la poblacion infantil desde 1981 a 1993. Los enfermos mostraron porcentajes y TPG significativamente menores de anticuerpos neutralizantes a la cepa 590 que el grupo control, a pesar de que en 25/28 se habian aislados agentes con ECP-L. Se plantea la posibilidad de 2 mecanismos de neutralizacion y se formula una hipotesis sobre el mecanismo por el cual estos virus puedan participar en la fisiopatologia de la enfermedad

Utilizacion del ELISA y el ultramicroELISA en la identificacion de una cepa de Coxsackie A) aislada durante la epidemia de neuropatia en Cuba / Utilization of ELISA and ultramicroELISA techniques in the identification of a Coxackie straim A9 isolation during the outbreak of epidemic neuropathy in Cuba

Durante 1993, nuestro pais se vio afectado por un brote de neuropatia epidemica (NE) caracterizado por 2 formas clinicas fundamentales: optica y periferica. Aunque la causa de la enfermedad fue considerada multifactorial (fundamentalmente agentes neurotoxicos y deficiencia nutricional), fue aislado un Enterovirus del liquido cefalorraquideo de un paciente (cepa 47/93, IPK), el cual fue posteriormente clasificado como Coxsackie A9 (Cox A9) mediante la prueba de neutralizacion (Nt) utilizando los pools de suero de Lim Benyesh Melnick (LBM). Se presentan los resultados obtenidos durante la aplicacion del ELISA y del ultramicroELISA en la identificacion de este agente a partir del sobrenadante de cultivo de celulas infectadas, asi como en la deteccion de anticuerpos a la cepa en poblaciones con baja y alta incidencias de la enfermedad

Comparacion de los resultados obtenidos en la serologia de IgM y la neutralizacion anti-Coxsackie A9 (cepa 47) en casos de neuropatia epidemica y sus contactos / Comparison of the results obtained in IgM serology and the neutralization of anti-Coxsackie A9 (strain 47) in cases presenting with epidemic with epidemic neuropathy and their contacts

Se estudio un total de 213 monosueros de pacientes con el diagnostico de neuropatia epidemica y sus contactos, por las tecnicas de inmunofluorescencia indirecta y neutralizacion, con el fin de demostrar la presencia de anticuerpos IgM y neutralizantes en los sueros frente a la cepa 47 IPK/93 identificada como Coxsackie A9. La edad promedio de estos pacientes oscilo entre 20 y 50 anos y la positividad a ambas tecnicas no predomino. No hubo diferencia significativa en los resultados obtenidos entre pacientes y contactos en las tecnicas empleadas