Poliomielitis paralitica en Guatemala / Paralytic poliomielytis in Guatemala

Durante la epidemia de poliomielitis paralítica que afectó a Guatemala entre 1982 y 1983, se llevó a cabo un estudio longitudinal de las características clínicas y virológicas de 133 niños con este diagnóstico ingresados en un hospital de la capital. La edad de los pacientes fluctuó entre los cuatro meses y los cinco años. El 68% no habían recibido ninguna dosis de la vacuna oral de poliovirus, mientras que al 6% se les habían administrado tres dosis. En 102 niños se aislaron poliovirus; en 92 de estos casos los virus excretados eran solo del tipo 1; en siete, del tipo 2; en uno, del tipo 3, y en dos niños, de los tipos 1 y 2. Se tomaron 66 cepas círicas para establecer la diferenciación intratípica y se halló que 55 de los 56 virus aislados del tipo 1 y el único del tipo 3 eran virus no análogos al de Sabin, mientras que las nueve cepas del tipo 2 eran análogas al virus de Sabin. Estas observaciones confirman la necesidad de la vacunación durante el primer semestre de vida y que el establecimiento de medidas adecuadas para controlar la transmisión de poliovirus del tipo salvaje produciría una notable disminución de la morbilidad causada por la poliomielitis

Poliomielitis paralitica en Guatemala / Paralytic poliomielytis in Guatemala

During the epidemic of paralytic polio that struck in Guatemala in 1982 and 1983 a longitudinal study was carried out of the clinical and virological characteristics of 133 children admitted with this diagnosis to a hospital in the capital city. The age of the patients ranged between four months and five years; 68 percent of them had not received any dose of oral polio vaccine and 6 percent had received three doses. Poliovirus was isolated from 102 children; in 92 of these cases the virus excreted was only of type 1, in seven it was of type 2, in one of type 3, and in two of types 1 and 2. Sixty-six virus strains were taken for intratypical differentiation and it was found that 55 of the 56 strains of type 1 virus and the sole strain of type 3 were viruses not analogous to the Sabin virus, and the nine of type 2 were analogous to it. These findings confirm the need to vaccinate during the first six months of life and that adequate measures to control the transmission of wild poliovirus would greatly reduce morbidity from the disease

Strain differentiation of polioviruses with monoclonal antibodies.

Panels of monoclonal antibodies raised against different poliovirus type 1, 2 and 3 strains, were tested in a micro-neutralization test and in a micro-enzyme linked immunosorbent assay against a large number of poliovirus strains. The results were compared with those obtained with the classical system of serodifferentiation using strain specific cross-absorbed antisera. For this purpose a theoretical pattern fitting computer program was developed, in which each strain could be compared with all the other strains of which the serological data had been stored in the memory of the computer. The results obtained with the panels of monoclonal antibodies coincided well with those obtained with the cross-absorbed antisera. Especially for the identification of virus isolates related to the Sabin vaccine strains, these panels of monoclonal antibodies proved to be valuable tools.

Production and potential use of monoclonal antibodies against polio viruses.

Lymphocyte hybridomas secreting monoclonal antibodies against different strains of polio virus type 1, 2, or 3 have been produced. For this purpose Balb/C mice were immunized with purified and inactivated virus suspensions and their splenocytes were fused with P3X63Ag8 mouse myeloma cells. Screening for antibody production was performed in an enzyme-linked immunosorbent assay (ELISA). Antibodies were produced either in cell culture or in Balb/C mice by passaging the hybridomas as solid or ascitic tumors, after they had been cloned at least three times by limiting dilutions in microtiter plates. Specificities of a number of these monoclonal antibodies were determined in the ELISA and in a neutralization test using different polio virus subtypes. The results indicate that for epidemiological studies monoclonal antibodies may prove to be very useful tools. Also the use of monoclonal antibodies for vaccine production (affinity chromatography; characterization of viral substructures) and routine vaccine control purpose (antigen quantification; neutralization of vaccine virus) seems attractive. Two of the neutralizing monoclonal antibodies against polio virus type 1, showed a selective immunoprecipitation with VP1, which suggests that VP1 is an important polypeptide for the induction of neutralizing antibody in vivo.

D-antigen determination in polio vaccine production: comparison of gel diffusion and ELISA methods.

Up to now gel diffusion is widely used for in vitro determination of polio D-antigen. This method has several disadvantages, its relatively low sensitivity being the main one. Generally samples have to be concentrated, which requires fairly large amounts of material and often results in some loss of antigen due to adsorption. Two ELISA methods have been developed for determination of polio D-antigen. These tests have a high sensitivity, approximately 1 DU/ml, and require very small amounts of sample and antisera. Using the indirect method only one HRPO conjugated antiserum is needed for quantitation of type 1, 2 and 3 D-antigen. Comparison of D-antigen values obtained by ELISA and gel diffusion for a number of vaccines revealed a good correlation between the different methods. The indirect ELISA method has also been applied successfully for D-antigen quantitation of A1PO4 adsorbed DT-and DPT-polio vaccines.

Epidemiological implications of the isolations and intratypic serodifferentiation of poliovirus strains in the Netherlands.

From the results of virus isolation and serological studies it can be concluded that poliovirus does not occur endemically in the Netherlands. On the other hand continual importation of poliovirus is demonstrated among children of foreign workers, refugees and adoptive children. A certain part of these imported poliovirus strains appear to be wild type as shown by intratypic serodifferentiation with monospecific antisera. These strains are a continuous danger to non-immunized persons lacking neutralizing antibodies. The intratypic serodifferentiation with monospecific antisera also appears to be applicable for the differentiation of wild poliovirus strains and may therefore be a useful tool in epidemiological studies.

Direct enzyme linked immunosorbent assay (ELISA) for quantification of poliomyelitis virus D-antigen.

The proposed micro-ELISA assay by means of the double antibody method involves three steps: adsorption of type specific antiserum on micro-wells; simultaneous incubation of antigen and Horse Radish Peroxydase (HRPO) conjugated antiserum; substrate incubation followed by photometric measurement of absorbance at 403 nm. Preliminary results seem generally in good agreement with those obtained by other tests such as gel diffusion and indirect ELISA.

Concentration and purification of poliovirus by immune adsorption on immobilized antibodies.

Antibodies to poliovirus type 1, 2 and 3 have been coupled to Sepharose 4 B. The immune sorbentia have high binding capacities for both live and inactivated virus. Bound antigen is eluted with a high concentration of ammoniumisothiocyanate. Immediately after elution the chaotropic salt is removed by gelfiltration. The antigen recovery with inactivated virus was low; however, with live virus a good recovery was obtained. Therefore, immune adsorption seems to be applicable for concentration and purification of large amounts of live poliovirus.

Intratypic serodifferentiation of poliomyelitis virus strains by strain-specific antisera.

Strain-specific antisera against non-Sabin-like and Sabin-like poliovirus strains were prepared by cross-absorption of the antisera with the heterologous strain. Isolates from different parts of the world were differentiated intratypically as non-Sabin-like and Sabin-like strains with the aid of these sera in the immunodiffusion test and neutralization test. In comparison with other marker tests, intratypic differentiation can be performed more easily. Further, fewer intermediate strains were found and, in our opinion, the results are more reliable.