ABSTRACT
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
Subject(s)
Humans , Intestinal Diseases, Parasitic/diagnosis , Schistosomiasis mansoni/diagnosis , Leukocyte Adherence Inhibition Test/methods , Cell Adhesion , Colorimetry , Leukocytes/physiologyABSTRACT
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