Latex?protein complexes from an acute phase recombinant antigen ofToxoplasma gondii for the diagnosis of recently acquired toxoplasmosis

PERETTI LEANDRO; GONZALEA VERÓNICA; MARCIPAR IVÁN; GUGLIOTA LUIS

COLLOIDS AND SURFACES B-BIOINTERFACES

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2014 vol. 120 p. 88 - 96

0927-7765

tThe synthesis and characterization of latex?protein complexes (LPC), from the acute phase recombinantantigen P35 (P35Ag) of Toxoplasma gondii and ?core?shell? carboxylated or polystyrene (PS) latexes (ofdifferent sizes and charge densities) are considered, with the aim of producing immunoagglutinationreagents able to detect recently acquired toxoplasmosis. Physical adsorption (PA) and chemical coupling(CC) of P35Ag onto latex particles at different pH were investigated. Greater amounts of adsorbed proteinwere obtained on PS latexes than on carboxylated latexes, indicating that hydrophobic forces govern theinteractions between the protein and the particle surface. In the CC experiments, the highest amountof bound protein was obtained at pH 6, near the isoelectric point of the protein (IP = 6.27). At this pH, itdecreased both the repulsion between particle surface and protein, and the repulsion between neigh-boring molecules. The LPC were characterized and the antigenicity of the P35Ag protein coupled on theparticles surface was evaluated by Enzyme-Linked ImmunoSorbent Assay (ELISA). Results from ELISAshowed that the P35Ag coupled to the latex particles surface was not affected during the particles sensi-tization by PA and CC and the produced LPC were able to recognize specific anti-P35Ag antibodies presentin the acute phase of the disease.