[Monoclonal antibodies to dengue virus 4: the spectrum of the reactivity to 4 serotypes of dengue]. / Anticuerpos monoclonales al virus dengue 4: espectro de reactividad a los 4 serotipos del dengue.

These types of monoclonal antibodies 8E8, 3F7 and 1E9 to dengue 4 virus H-241 strain. These monoclonal antibodies show various patterns of reactivity to the four dengue serotypes and different antigen preparations of serotype 4 when they were tested in various serological methods. The monoclonal antibody 8E8 exhibited a specificity of serotype (D-2; by hemagglutination inhibition); subcomplex (D-2 and D-4 by immunofluorescence) and complex (by immunoperoxidase technique). It was able to neutralize by 80% homologous virus and it turned out to be the only reactive monoclonal antibody in the complement fixation test. The monoclonal 3F7 did not react to by hemagglutination inhibition, recognized serotypes D-1, D-2, D-3 and D-4 by immunofluorescence and only serotypes D1 and D4 by immunoperoxidase technique but it was unable to neutralize the homologous virus. The 1E9 antibody was reactive to serotypes D1, D-2, D-3 and D-4 only by hemagglutination inhibition and neutralized serotype D-4. All the monoclonal antibodies were able to react to various dengue antigens through an ELISA of double antibody and showed fluorescent activity against 38th pass in Beagle dog kidney culture; however, they could not react to a D-4 recombinant antigen.

[Fast detection and characterization of influenza A and B viruses in nasopharyngeal secretions by the immunoperoxidase method]. / Detección y caracterización rápida de los virus de influenza A y B en secreciones nasofaríngeas mediante el método de la inmunoperoxidasa.

One hundred and fourty eight samples from patients with a symptomatology compatible with the influenza virus were studied aimed at identifying in a fast way these viruses. A rapid MDCK-L cell culture was developed on 96 well plates, where nasopharingeal exudates or gargarisms were inoculated and incubated all night long at 37 degrees C. The medium was removed and cells were washed with PBS and fixed with methanol. Viral antigens were detected through the immunoperoxidase staining by using two monoclonal antibody pools for the identification of influenza A and influenza B viruses. The HA1-71 monoclonal antibody, specific for influenza A (H3N2) and the HA2-76, which react with both A (H3N2) and A (H1N1) were used for subtyping. Of all the positive samples (136), 72% corresponded to type A while 34.6% and 37.5% corresponded to subtypes H1 and H3, respectively. Influenza B was detected in 27.9% of the 148 samples studied. Only 12 were negative (8.1%). The use of this technique is recommended as a rapid, convenient and sensitive method that is easy to carry put and to interpretate for the detection and characterization in type and subtype of the influenza viruses starting from the nasopharyngeal exudates or gargarisms.

[The standardization of the plaque reduction technic for differentiating a dengue infection from a yellow fever infection]. / Normalización de la técnica de reducción de placas para diferenciar una infección por dengue de una infección por fiebre amarilla.

The plaque reduction neutralization assay was standardized to differentiate an infection caused by dengue from another infection produced by yellow fever. Serum samples from Cuban donors were used to this end. Information on previous vaccination against yellow fever was available. Samples from Costa Rican patients with a clinical picture of dengue and with no antecedents of vaccination against yellow fever were also utilized. The optimal plaque staining day was the fifth day and the smallest serum dilution capable of differentiating an infection resulting from dengue from another infection caused by yellow fever was of 1/5. According to the high specificity of the standardized technique, risk factor studies of dengue hemorrhagic fever could be made among individuals vaccinated against yellow fever, which is a present and important topic.

[Monoclonal antibodies which recognize herpes simplex virus and their possible diagnostic application]. / Anticuerpos monoclonales (AcM) que reconocen el virus herpes simple (HSV) y su posible aplicación al diagnóstico.

It is reported the obtention of monoclonal antibodies, which are capable of recognizing HSV-1 and HSV-2 viruses, by the conventional technology of cellular fusion. The monoclonal antibodies of highest positivity according to the indirect immunofluorescence technique were partially characterized. It was determined the neutralizing capacity of 2 of them (278-F7 and 70-G10), which were used to identify isolations of clinical specimens by indirect immunofluorescence. These monoclonal antibodies recognized HSV-1 up to a dilution of 1:2 560.

[The characterization of influenza viruses by the immunoperoxidase method using monoclonal antibodies. Its setup and validation]. / Caracterización de los virus de influenza por el método de la inmunoperoxidasa utilizando anticuerpos monoclonales. Montaje y validación.

The immunoperoxidase method for the rapid classification of influenza viruses in type and subtype was applied and validated for the first time in Cuba. The method is based on a rapid culture in MDCK-L cells and on the use of monoclonal antibodies for the classification in type and subtype. A pool of antibodies against influenza A and another against influenza B and HA1-71 and HA2-76 monoclonal antibodies are used for the subtyping in H1 and H3. The validation was carried out by applying this method to 21 international reference strains and to 23 human influenza virus strains that were isolated and previously classified by hemagglutination inhibition. All the strains reacted to the monoclonal antibodies according to their hemagglutinin type and subtype. 6 reference strains and 9 isolations were characterized within the H1N1 subtype: 9 reference strains and 10 isolations in the H3N2 subtype; and 6 reference strains and 4 isolations in type B. There were neither unspecific nor crossed reactions among the controls established. There was 100% of sensitivity, specificity and coincidence. The technique used proved to be fast and convenient for the characterization in type and subtype of the isolated influenza virus strains. It may substitute the classic hemagglutination inhibition method when it is required the rapid characterization of outbreaks or epidemics of acute respiratory infections, which is very important due to the high morbidity they cause mainly in risk groups and to their economic repercussion.

[Inhibition of the multiplication of a Coxsackie A9 strain isolated from a patient with epidemic neuropathy by the interferons alfa and gamma]. / Inhibición de la multiplicación de la cepa de Coxsackie A9 aislada de un paciente con neuropatía epidémica frente a los interferones alfa y gamma.

We present the results of the in vitro action of alpha and gamma interferons and of Intacglobin and Igegam against the 47/93/IPK (Coxsackie A9) strain isolated from the cerebrospinal fluid of a patient with epidemic neuropathy. The in vitro studies showed that the two interferons inhibited the replication of this agent; they also showed the presence of antibodies to it in the Intacglobin and Igegam. The results attained demonstrated that the use of these compounds could be effective for the treatment of this entity.

[Establishment of a subline of C6/36 adapted to growing in a serum-free medium and its usefulness for studies on the dengue virus]. / Obtención de una sublínea de C6/36 adaptada a crecer en medío libre de suero y su utilización para estudios sobre virus del dengue.

Using the C6/36 clone of the Aedes albopictus cell line, a derived cell line was obtained capable of growing in a commercial serum-free medium facilitating this line to keep its morphologic characteristics and adhesion capacity. The growth speed rate reduction of the adapted cell line was compensated by its low maintenance cost. Its usefulness in the multiplication of dengue viruses 1 and 2 was tested; the reported line showed the same susceptibility for the 2 agents than the original cell line when the indirect fluorescence technique was applied.

[Normalization of an ultramicroELISA for the detection of antibodies against human Parvovirus B19]. / Normalización de un ultramicroELISA para la detección de anticuerpos a Parvovirus humano B19.

An ultramicroELISA (UME) method was normalized for the detection of antibodies to serum human parvovirus B19. The optimum antigen concentration determined was 400 ng/ml, serum dilution was of 1:100; and the conjugate work dilution was of 1:2,000. 11 paired serum samples were also evaluated and antibodies were detected. The usefulness of the analyzed system is discussed.

[Obtaining a clone of the AP-61 cell line. Its usefulness in the multiplication of dengue viruses 1 and 2]. / Obtención de un clono de la línea celular AP-61. Su utilidad para la multiplicación de los virus dengue 1 y 2.

The obtention of a clone of the cell line AP-61 (Aedes pseudoscutellaris) is reported. Details of the cloning and culture media employed are discussed. Usefulness of the clone for the multiplication of dengue 1 and 2 viruses is proved in comparison with the original line using the indirect immunofluorescence technique.

[Establishment of a diploid cell line of human lung (PHuE-1)]. / Obtención de una línea celular diploide de pulmón humano (PHuE-1).

The obtention of a diploid cell line from human lung of great concern for the virological diagnosis and research is reported. Certain aspects about its application and characterization are discussed.

[Use of goat serum as a substitute for calf serum for growing various primary cultures from vertebrates]. / Utilización del suero caprino como sustituto del suero de ternera donante en el crecimiento de algunos cultivos primarios de vertebrados.

Goat's serum was used to prepare primary cultures of fibroblast from chicken embryo and hamster kidney. Later they were inoculated the East equine encephalomyelitis virus, being compared with culture from calf's serum. The choice of goat's serum is of great interest for the development of scientific research and national economy.

[Preliminary study of AP-64 cell line (Aedes pseudoscutellaris) for dengue-1 and -2 virus multiplication]. / Estudio preliminar de la línea celular AP-64 (Aedes pseudoscutellaris) para la multiplicación de los virus dengue-1 y 2.

We study a new arthropod cell line, AP-64, which was obtained from Aedes pseudoscutellaris larvae. The best growth and maintenance media are defined, testing the adequacy of dengue 1 and 2 viruses which become manifest by the appearance of the cytopathogenic effect as syncytiums. The immunofluorescence technique is applied to detect early multiplication of those viruses.

Aislamiento del virus del dengue 2 en sueros de pacientes utilizando el raton lactante y cultivo de celulas LLCMK2. / Isolation of dengue virus type 2 in serum of patients using suckling mice and LLCMK2 cell cultures

El virus del dengue 2 fue aislado en 22 de 40 sueros de pacientes clinicamente diagnosticados como dengue durante la epidemia de dengue hemorragico de Cuba 1981.Se utilizaron como sistemas de aislamientos el raton lactante y las celulas LLCMK2 demostrandose la mayor sensibilidad de estas al obtener 13 aislamientos mas que en raton lactante. Todas las cepas fueron identificadas como dengue tipo 2