Quantification of the population and phagocytary activity of hemocytes of resistant and susceptible strains of Biomphalaria glabrata and Biomphalaria tenagophila infected with Schistosoma mansoni

Entre os fatores determinantes na resistencia e suscetibilidade da Biomphalaria ao Schistosoma mansoni, os hemocitos desempenharam importante papel. Com o objetivo de estudar as interacoes S. mansoni/Biomphalaria relativas aos hemocitos o primeiro passo e certamente relacionado a padronizacao desta populacao de celulas em Biomphalaria nao infectada. Desta forma a quantificacao desta populacao de celulas na hemolinfa bem como sua capacidade fagocitaria foi determinada pela primeira vez. Alem disso, usando cepas de B. glabrata e B. tenagophila suscetiveis e resistentes, o hemocitograma e a capacidade fagocitaria dos hemocitos, apos infeccao com S. mansoni, foram tambem determinados. Cepas de B. glabrata (BA e BH respectivamente) resistentes e suscetiveis bem como cepas de B. tenagophila (TAIM e CF respectivamente) foram infectadas com 10 miracidios das cepas LE e SJ de S. mansoni, respectivamente. Estes caramujos infectados e respectivos controles nao infectados foram avaliados em relacao ao numero de hemocitos circulantes e alteracao da capacidade fagocitaria, usando Zimozan e MTT...

Colorimetric leukocyte adherence inhibition assay: a new auxiliary technique for the diagnosis of Schistosomiasis

We describe a modification of the leukocyte adherence inhibition assay (LAI) in which we propose the use of 3-(4,5-dimethylthiazole-2-yl)-2-5-diphenyltetrazolium bromide (MTT) dye which is taken up and reduced by mitochondria. The method was tested by screening peripheral blood leukocytes from Schistosoma mansoni-infected patients. Peripheral blood leuckocytes from patients (N=2) but not from the blood of normal subjects (N=10) failed to adhere to glass in the presence od soluble adult worm antigenic preparation (SWAP). The non-adherence index (NAI) values for schistosomiasis patients were in the range of 11.0 to 72.3 (mean ñ SEM = 29.3 ñ 4.3), whereas the values for normal subjects were -56.0 to +2.0(-25.9 ñ 7.6) and those for treated patients -59.6 to +4.0 (-19.3 ñ 5.8). Our results show that the colorimetric LAI assay can be used as an auxiliary test for the diagnosis of schistosomiasis

A microcalorimetric assay to measure the reactivity of antigen-stimulated mononuclear cells from Schistosoma mansoni infected patients

The reactivity of mononuclear cells (2 x 10**6/ml minimum Eagle's medium, MEM) from normal subjects and from Schistosoma mansoni-infected patients was evaluated by microcalorimetry. The results which are reported as heat production (mcal for 2 x 10**6 cells in 3600s), were 2,087 ñ 21.2 and 2,497.0 ñ 21.3 for mononuclear cells from infected patients (N = 8) under stimulation with S. mansoni soluble egg antigen (SEA) and soluble adult worm antigenic preparation (SWAP), respectively. The values for cells from normal subjects (N = 8) were 13.7 ñ 1.1 and 29.3 ñ 3.2 in the presence of the same antigens. Pre-treatment of mononuclear cells from patients with 1 mM aminophylline (a cAMP phospphodiesterase inhibitor) totally abolished heat production. Cell viability (> 95%) was not changed after the measurement. The microcalorimetric assay described here measures the cellular metabolic activity and we feed justified in suggesting this techinique as an auxiliary diagnosis of schistosomiasis. Given the sensitivity, precision and accuracy of this microcalorimetric assay, we feel it can be used for the diagnosis of disease conditions for which a reliable diagnostic method is required

Correlation between the lack of mononuclear cell cytotoxicity against schistosomula in vitro with schistosomiasis

A comparison was made of the reactivity of mononuclear cells from subjects and from S. mansoni-infected patients. The following parameters were evaluated: 1) ability of mononuclear cells to kill schistosoma in the presence of complement; 2) [3H]-inositol incorporation into phosphatidylinositol (PI) and the rate of inositolphosphates (IPx) released. Cells from normal subjects, but not from S. mansoni infected patients, were able to kill schistosomula in vitro. A decrease in inositolpolyphosphates (IPx) was observed for phytohemagglutinin (PHA)-stimulated mononuclear cells from infected patients when compared with mononuclear cells from normal subjects after 24 h of incubation. The results suggest that the reactivity of mononuclear cells from infected patients is altered under conditions of nonspecific stimulation with PHA when compared with normal cells