This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Cambiaso, C L Articles by Masson, P L Search for Related Content PubMed PubMed Citation Articles by Cambiaso, C L Articles by Masson, P L

Latex agglutination assay of human immunoglobulin M antitoxoplasma antibodies which uses enzymatically treated antigen-coated particles.

Unit of Experimental Medicine, Université Catholique de Louvain, Brussels, Belgium.

ABSTRACT

An assay of immunoglobulin M (IgM) antitoxoplasma antibodies which is rapid (less than 30 min), homogeneous, and reliable (interassay coefficient of variation, less than 11%) is proposed. Its principle is based on the observation that a suspension of latex particles coated with toxoplasma antigens, after treatment with proteinase K, becomes less agglutinable by IgG antibodies but more agglutinable by IgM antibodies. The difference between the activities of the two classes of antibodies is increased by the addition of a monoclonal antibody directed against the Fc region of IgM. Agglutination is measured with a special instrument which optically counts the particles that remain free after the reaction. Turbidimetric reading, although less sensitive, is also suitable. No significant interferences either by IgG antitoxoplasma antibodies or by rheumatoid factor or antinuclear antibodies were observed. The sensitivity was similar to that of the immunosorbent agglutination assay.