A longitudinal study was performed with sera and urine of patients with acquired immune deficiency syndrome (AIDS), taken before, during and after clinically Toxoplasma infection. The tested patients were followed for an average of two years. The titres of the specific IgG and IgM antibodies were measured by an indirect fluorescent antibody test (IFAT), and the appearance of circulating antigens of T. gondii was determined in 36 urine samples of 13 patients with neurotoxoplasmosis by means of the coagglutination test. The presence of T. gondii antigens in the urine of AIDS patients by this test was correlated with the immunoblot technique, with clinical symptoms and also with pathological findings. Our results indicate that the detection of T. gondii antigens in the urine of AIDS patients can be regarded as a rapid and efficient method for the diagnosis of acute toxoplasmosis

The utilization of a coagglutination technique for the identification of a human source for feeding mosquitoes is described. The dilution of ingested blood samples in filter paper was performed in 2 mL of a sodium chloride solution at 0.85 %. It was used a suspension of sensibilized Staphylococcus aureus with rabbit's serum, human plasmatic anti-proteins, and human anti-IgG rabbit's serum discriminated well between human and non human blood. No agglutination was observed with the negative control. This technique proved to be sensitive to identify 100 % of the human blood samples taken to the paper 24 hours after the mosquitoes completed their feeding at a temperature of 26 to 28 °C. Among mosquitoes fed and collected in the fields the test had a satisfactory result. Therefore, it may be used in routine work in the fields. The results showed the sensitivity and specificity of this method for identifying human blood ingested by mosquitoses.

Se describe la utilización de la técnica de coaglutinación para la identificación de una fuente humana de alimentación de mosquitos. La dilución de las muestras de sangre ingerida en papel de filtro se hizo en 2 mL de una solución de cloruro de sodio al 0,85 %. Se utilizó una suspensión de estafilococos sensibilizados con un suero normal de conejo como control negativo. La suspensión de Staphylococcus aureus sensibilizados con suero de conejo anti-proteínas plasmáticas humanas y suero de conejo anti-IgG humana discriminó bien entre sangre humana y no humana. No se observó aglutinación con el control negativo. Esta técnica resultó ser sensible para identificar el 100 % de las muestras de sangre humana llevadas al papel 24 h después de que los mosquitos completaron su alimentación a una temperatura de 26 a 28 °C. En mosquitos alimentados y colectados en el campo, la prueba se comportó de forma satisfactoria, en consecuencia puede ser utilizada en trabajos de rutina en el campo. Los resultados mostraron la sensibilidad y especificidad de este método para la identificación de sangre humana ingerida por mosquitos.

A specific monoclonal antibody was characterized to Toxoplasma gondii. The hybridoma produced IgG immunoglobulins. The Western Blot analysis showed that the monoclonal antibody was specific for the antigen of an apparent mollecular mass of 30 kd, which was present on the antigen surface. The monoclonal antibody was purified starting from mouse´s ascitic fluid and it was matched with Sepharose 4B. This immunoabsorbent was used to purify the specific parasitary antigen. The monoclonal antibody studied may be useful for those tecniques contributing to the toxoplasmosis diagnosis.

Se caracterizó un anticuerpo monoclonal específico a Toxoplasma gondii. El hibridoma produjo inmunoglobulinas IgG. El análisis por Western Blot demostró que el anticuerpo monoclonal fue específico para el antígeno de masa molecular aparente de 30 kd, presente en la superficie del parásito. El anticuerpo monoclonal se purificó a partir de fluido ascítico de ratón y se acopló a Sefarosa 4B. Este inmunoabsorbente fue utilizado con el fin de purificar el antígeno parasitario específico. El anticuerpo monoclonal estudiado puede ser de utilidad para las técnicas que contribuyan con el diagnóstico de la toxoplasmosis.

Toxoplasmic encephalitis (TE) is a mayor cause of central nervous system infection in patients with acquired immunodeficiency syndrome (AIDS). Toxoplasma antibodies were detected in 56 of 79 patients with AIDS (71%), in the present study. Fourteen out of 57 seropositive patients developed TF (25%) and had Toxoplasma gondii antigen detected in their urine. For this, most of them received an effective therapy, with the subsequent disappearance of the symptoms and discontinuity of excretion of the T. gondii antigens. Our results suggest that the monitoring of T. gondii antigen in the urine of AIDS patients may be useful to decide on the proper time for therapy, as well as to avoid the beginning of neurologic signs in these patients.

La Encefalitis Toxoplásmica (ET) es la más importante complicación infecciosa del Sistema Nervioso Central en pacientes de SIDA. Anticuerpos anti-Toxoplasma gondii fueron detectados en 57 de 79 pacientes de SIDA (71%). De estos seropositivos, desarrollaron la enfermedad (ET) 14 (25%), en los que coincidentemente se detectó la presencia de antígeno del parásito en orina y por tanto fueron objeto de una terapia efectiva, con la subsecuente desaparición de los sintomas y de los antígenos excretados. Por los resultados del presente trabajo, consideramos lo útil de monitorear en estos pacientes la presencia de antígenos de T. gondii con el objetivo de aplicar oportunamente métodos quimoprofilácticos que eviten el surgimiento de manifestaciones neurológicas en estos pacientes.

A simple and rapid staphylococcal coagglutination test for the detection of Toxoplasma gondii antigens in mice urine is described. A suspension of protein-A containing Staphylococcus aureus coated with rabbit hyperimmune serum was used as reagent. The sensitivity of the antigen assay was found to be at least 118 ng of the antigen protein per ml. No coagglutination was observed when the reagent was challenged against antigenic solutions of other parasites. The suitability of the method for detecting antigens of T. gondii in urine samples was studied by experimental toxoplasma infection in mice. Before the staphylococcal test, the urine samples were double serially diluted in 0.1 M PBS. From the second day on all samples from infected mice were positive at 1/16 dilution. At this dilution, all samples from non infected mice were negative or did not produce coagglutination. This method might be used in the rapid etiological diagnosis also in human cases of acute toxoplasmosis.