Antibodies Detection Employing Sol-gel Immobilized Parasites

G. J. COPELLO; M. DE MARZI; M. F. DESIMONE; E. MALCHIODI; L. E. DÍAZ

JOURNAL OF IMMUNOLOGICAL METHODS

Elsevier

Año: 2008 vol. 335 p. 65 - 70

0022-1759

Immunoflourescence assay (IFA) and Immunoperoxidase assay (IPA) are useful diagnosis techniques for specific antibodies detection in different diseases.  Both involve several fixation alternatives for immobilization of cells such as solvent or heat fixation. The non-covalent immobilization implies rigorous storage condition at -20ºC to preserve the slides, and usually numerous cells are detached during washing steps, which can lead to inconsistencies of the results. Sol-gel chemistry is usually used for coating different materials because of the mild condition of the polymerization reaction and the capability of introducing functional groups to a wide surface variety. Here, we developed a novel procedure for the attachment of Trypanosoma cruzi epimastigotes and Leishmania guyanensis promastigotes over a silicon oxide polymer covered glass surface. The film was prepared using standard microscope slides with tetraethoxysilane and 3-aminopropyl triethoxysilane as polymeric precursors.  When acetone was used as major coating solvent,  IFA showed the fluorescence of attached parasites without matrix background interference.  Similar results were observed when IPA was evaluated.  Sensibility and specificity of sol-gel immobilized parasites slides were comparable with heat fixation technique.  Coated slides performances were maintained for at least 2 months at 4ºC storing temperature.  This immobilization method does not affect molecular epitopes of attached cells. Thus, homogeneous, ready to use and long lasting coated slides were obtained, which are appropriate for field conditions.