Cell adherence to microfilariae of Onchocerca volvulus: a comparative study

Area of Science:

• Immunology
• Parasitology
• Molecular Biology

Background:

• Antibody-mediated cellular responses are crucial in parasitic infections.
• Understanding immune interactions with microfilariae is key to Onchocerca volvulus and Dirofilaria immitis pathogenesis.

Purpose of the Study:

• To investigate in vitro antibody-mediated adherence of granulocytes to Onchocerca volvulus and Dirofilaria immitis microfilariae.
• To characterize the cellular and molecular mechanisms involved in these interactions.
• To explore potential diagnostic or prognostic applications.

Main Methods:

• In vitro assays measuring granulocyte adherence to microfilariae using human and canine sera.
• Testing the effects of various inhibitors (indomethacin, nordihydroguaiaretic acid, nifedipine, lidocaine, chloroquine) and drugs (ivermectin, diethylcarbamazine) on adherence.
• Assessing antibody stability and absorption with microfilarial antigens.

Main Results:

• Human sera showed specific reactivity to O. volvulus, with eosinophils as the primary adhering cells, and the reaction was sensitive to indomethacin and motility inhibitors.
• D. immitis microfilariae induced neutrophil adherence, with stable antibody activity, absorbable by antigens, and inhibited by motility reducers.
• Adherence-mediating antibodies were detected in a minority of amicrofilaraemic dogs with occult infections; in humans, positive sera correlated with punctate keratitis.

Conclusions:

• The study delineates distinct in vitro cellular adherence mechanisms for O. volvulus and D. immitis microfilariae.
• The findings suggest potential roles for these immune interactions in parasitic disease pathogenesis and highlight possible clinical correlations.
• Further characterization of the molecular mechanisms underlying these antibody-mediated responses is warranted.