Naturally occurring immunoglobulin Mantibodies toToxoplasma gondiiin Japanese populations

Abstract

Varying degrees of naturally occurring immunoglobulin (Ig) M antibodies to Toxoplasma gondii were observed in almost all of adult Japanese populations negative for IgG antibodies as determined by an enzyme-linked immunosorbent assay (ELISA). The antibody activity was reduced by absorption of sera with Toxoplasma soluble antigen or by 2-mercaptoethanol treatment of the IgM fraction after sucrose density gradient centrifugation. Umbilical cord sera had almost no detectable IgM antibodies, and the ELISA value in infants increased with age until 1 year. Most paired sera collected from adults at a 1-year interval showed constant IgM antibody levels, suggesting retention of natural IgM antibodies throughout their lives without changing ELISA values of greater than or equal to 0.1/year. Polar staining was observed in immunofluorescent studies for 14 serum samples with natural IgM antibody levels of greater than or equal to 0.5, while samples obtained from a pregnant woman with natural IgM antibody levels of greater than or equal to 0.9 reacted to the whole organism as was observed in positive sera of acute patients. Western blotting analysis revealed that natural IgM antibodies were directed to multiple antigen molecules. The band pattern differed slightly from one serum to another, but almost consistent patterns were observed in sera sequentially obtained from an adult over 4 years.

Strategy for Diagnosis of Congenital Toxoplasmosis: Evaluation of Methods Comparing Mothers and Newborns and Standard Methods for Postnatal Detection of Immunoglobulin G, M, and A Antibodies

“…Detection of anti-Toxoplasma IgM is widely used for the diagnosis of CT. We compared an EIA with an ISAGA for IgM and, in our hands, found that the ISAGA for IgM performed better than the EIA for IgM, as reported previously (9,15,26). In-house and commercial EIAs are used to screen adult sera, in which the level of background noise due to natural IgM is high (21), and must be modified and carefully validated before being used with sera from infants (3, 3a). IB for IgM gave better results than ISAGA or EIA.…”

Serodiagnosis of acute toxoplasmosis using a recombinant form of the dense granule antigen GRA6 in an enzyme-linked immunosorbent assay

“…Although they give satisfying results, accurate dierentiation between recently acquired and chronic toxoplasmosis remains problematic. False-positive reactions with antinuclear factors, rheumatoid factors, or naturally occurring human antibodies and false-negative reactivity due to competitive inhibition by high levels of speci®c IgG antibodies have been described (Araujo et al 1971;Camargo et al 1972;Potasman et al 1986;Konishi 1991). The presence of speci®c IgM antibodies is not always indicative of an acute infection with T. gondii, since IgM antibodies can persist for months or years (Fucillo et al 1987).…”

Antibodies to Toxoplasma gondii in Individuals with First-Episode Schizophrenia

“…These antibodies usually belong to the IgM class, but they may belong to the IgG class as well. The source of these "naturally occurring" antibodies is unknown but may be related to exposure to cross-reacting microorganisms [10,11]. Additional studies should attempt to document infection with T. gondii in individuals with first-episode schizophrenia by use of methods such as the measurement of intrathecal antibody production [12] and the direct detection of Toxoplasma DNA by means of PCR analysis [13].…”