[Attempt to isolate from Ascaris suum an antigenic fraction for use in the immunologic diagnosis of onchocerciasis].

For the purpose of immunological diagnosis of onchocerciasis, the authors attempted to isolate an antigenic fraction from Ascaris suum which would only detect anti-Onchocerca volvulus antibodies. Chromatofocusing was done on a crude antigenic preparation from the ascaris. Immunoelectrophoresis showed that the fraction eluted between pH 5.6 and pH 4.9 contained antigens which reveal anti-Onchocerca antibodies; anti-Loa loa antibodies are revealed by the fraction eluted at pH less than 4. From the fraction which reveal anti-Onchocerca antibodies, affinity chromatography isolated a system in which three components were detected by electrofocusing at a Pi of about pH 5.5. The specificity and sensitivity of this system are being studied.