Yoshimi Imoto Yamamoto

Alguns aspectos de imunoensaios aplicados à química analítica

In the last years, the use of antibody-antigen interactions, has earned attention not only for clinical analysis, but also for food industry and environmental control. Since the scope and diversity of immunoassay technology have shown a wide development. Continuous advances in order to analyse complex matrices, to improve reliability, simplicity (nonseparation) and to get multiple simultaneous assays, and extreme sensitivity (lower than zeptomole detection limits) are increasing. Many strategies have been investigated including chemiluminescent enzyme immunoassays, DNA as label and development of flow injection and immunosensors techniques. This subject became very usefull and important in nowadays that are taught in the undergraduate courses of chemistry in the european universities. However in our country are still ignored in the chemistry course.

Active transmission of Leishmania braziliensis braziliensis in the Serra de Mar forest, São Paulo, Brazil

transferred from the forest to the peridomestic environment. None of lhe sentinel hamsters in peridomestic habitats became infected between spring 1982 and winter 1984, again suggesting that in this period peridomestic transmission did not occur. Peridomestic sandfly populations must become infected if transmission is to occur in this environment and lhe source of infection could be a wild animal or a dog that had become infected in the nearby forest. In such a situation the dog would serve as an amp1ifying host, but it is questionable if it can serve as a maintenance reservoir. The disappearance of peridomestic transmission in 1982 in the present study area indicares that, in this particular region, the dog does not serve as a reservoir. Workers in Rio de Janeiro State (COUTINHO et ai., 1985) considered that lhe dog played an important role in the domestic transmission cycle of cutaneous leishmaniasis in that area. The present observations show conclusively that there is an enzootic L. b. braziliensis cycle in the Serra de Mar forest, adding further weight to the idea that lhe primary reservoir of this particular parasite in southem Brazil is a wild mammal. Although dogs have been found infected in this region it still remains to be seen what role they play as reservoirs in any peridomestic cycle. I Short Report I

Evaluation of an enzyme immunoassay (IgM cap dot EIA) using a peroxidase-labelled Toxoplasma gondii antigen (Alk-Toxo) for the diagnosis of acute toxoplasmosis

Abstract An IgM capture enzyme immunoassay (IgM cap dot EIA) using a peroxidase-labelled Toxoplasma gondii antigen was standardized and assessed for the diagnosis of acute toxoplasmosis. This assay appeared to detect mostly IgM antibodies to Toxoplasma antigenic bands of 30, 27, 24, 22 and 18-17 kDa. In the study of serum samples (416) from patients with acute and chronic toxoplasmosis, from patients with unrelated diseases and from clinically healthy individuals, the IgM cap dot EIA showed diagnostic features similar to those of IgM capture enzyme-linked immunosorbent assay (ELISA) and IgM immunofluorescence test. Nevertheless, only this assay gave clear-cut results.

Identification of Toxoplasma gondii antigens involved in the IgM AND IgG indirect hemagglutination tests for the diagnosis of toxoplasmosis

Crude Toxoplasma gondii antigens represent raw material used to prepare reagents to be employed in different serologic tests for the diagnosis of toxoplasmosis, including the IgM and IgG indirect hemagglutination (IgG-HA and IgM-HA) tests. So far, the actual antigenic molecules of the parasite involved in the interaction with agglutinating anti-T. gondii antibodies in these tests are unknown. The absorption process of serum samples from toxoplasmosis patients with the IgG-HA reagent (G-toxo-HA) demonstrated that red cells from this reagent were coated with T. gondii antigens with Mr of 39, 35, 30, 27, 22 and 14 kDa. The immune-absorption process with the IgM-HA reagent (M-toxo-HA), in turn, provided antibody eluates which recognized antigenic bands of the parasite corresponding to Mr of 54, 35 and 30 kDa, implying that these antigens are coating red cells from this reagent. The identification of most relevant antigens for each type of HA reagent seems to be useful for the inspection of the raw antigenic material, as well as of reagent batches routinely produced. Moreover the present findings can be used to modify these reagents in order to improve the performance of HA tests for the diagnosis of toxoplasmosis.