efecto no se observ6 en Ios leucocitos de controles no infectados. Este hecho ... Moudgil, G. C.; Allan, R. B.; Russell, R. J. & P. C. Wilkinson (1977). Inhibition.
CA/CET, Pub/. Cient. N° 3, 1985, 147-150
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Effects on leucocyte locomotion Onchocerca volvulus antigen and \immune serum ~
ROBERT B. ALLAN, ELlS ALDANA & LUIS YARZABAL Centra Amaz6nico para Investigaci6n y Control de Enjermedades Tropicales «Sim6n Bolivar» (CAICET), Apartado 59, Puerto Ayacucho 7101, Territorio Federal Amazonas, Venezuela. Summary In leucocyte locomotion tests, polymorphonuclear leucocytes from onchocerciasis patients, but not from uninfected controls, were stimulated by onchocerciasis serum. This suggests a specific interaction between a component of onchocerciasis serum and the surface of leucocytes from infected patients which may be important for the accumulation of leucocytes around parasites in vivo. In addition, mixtures of 0. volvulus antigen and onchocerciasis serum were found to be inhibitory to the locomotion of polymorphonuclear leucocytes from uninfected controls . Introduction The observation of efficient killing of micro filariae of Onchoc~rca volvulus by polymorphonuclear leucocyte in in vitro systems (Mackenzie, 1980; Greene et al., 1981; Allan et al., this Symposium) is in conflict with the apparent lack of such a reaction in vivo (Mackenzie, 1980). Microfilariae are able to activate the classical pathway of t9e complement system of serum in the presence of anti-0. volvulus antibody (Greene et al., 1981) and the subsequent generation of chemotactic factors leads to the attraction of leucocytes towards the micro filariae in vitro (King et al. , 1983); this system seems to be inoperative in vivo. Perez-Rojas et al. (1983) found that serum from onchocerciasis patients contained factors wich could block the blastogenic response in mixed lymphocyte cultures and Arango et al. (1984) have shown a correlation between the presence of 0. volvulus antigen in the serum of infected patients and a depression of delayed cutaneous hypersensitivity. In this study we have examined the possibility of inhibitory effects of 0 . volvulus antigen and immune serum on the locomotion of polymorphonuclear leucocytes. Materials and methods Blood for serum and leucocytes was collected from 0 . volvulus infected Yanomami Amerindians in the Sierra Parima of Venezuela, from non-infected eosinophilic patients and from normal controls. Polymorphonuclear cells were isolated by dextran sedimentation of heparinized blood followed by Ficoll-Hypaque density gradient centrifugation of the leuc:_ocyte-enriched plasma (Moudgil et al., 1977) .1 0. volvulus antigen was a crude, soluble extract of adult worms isolated from collagenase-digested subcutaneous nodules removed surgically from patients in the Sierra Parima. The initial antigen concentration used in the experiments was 1 mg/ml. The assay for leucocyte locomotion used was a modified Boyden chamber system (Wilkinson, 1982) where the distance migrated by cells into a 3 urn pore-size micropore filter was measured towards gradients of a standard chemotactic factor (alkali-denatured human serum albumin) and mixtures of the substances under test.
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TABLE 1 The migration of polymorphonuclear leucocytes isolated from 0. volvulus-infected patients towards autologous serum and alkali-denatured HSA (A-d HSA) Measurements in urn.
Buffer
A-d HSA 1 mg/ml
Autologous serum 2007o
Patient I
47
57
100
Patient 2
30
64
109
Control
29
62
69
Cells
A-d HSA
A-d HSA
+ serum I
+ serum 2
62
52
TABLE 2
The migration of polymorphonuclear leucocytes in filters towards alkali-denatured HSA (1 mg/ml) following treatment with 0. YOIYulus antigen and serum from an infected patient. Cells were preincubated for 60 minutes at 37°C in the appropriate mixture before testing. Measurements expressed as OJo of control migration
