Immunocharacterization of the mucin-type proteins from the intracellular stage of Trypanosoma cruzi.

VANINA A. CAMPO; CARLOS A. BUSCAGLIA; JAVIER M. DI NOIA; ALBERTO CARLOS C. FRASCH

Mendoza, Argentina

Congreso; VII Congreso de Protozoología y Enfermedades Parasitarias; 2005

Sociedad Argentina de Protozoología (SAP)

@font-face { font-family: "Times New Roman"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0in 0in 0.0001pt; font-size: 12pt; font-family: Times; }p.MsoBodyText, li.MsoBodyText, div.MsoBodyText { margin: 0in 0in 0.0001pt; text-align: justify; line-height: 150%; font-size: 12pt; font-family: Times; font-style: italic; }table.MsoNormalTable { font-size: 10pt; font-family: "Times New Roman"; }div.Section1 { page: Section1; } The surface of Trypanosoma cruzi is covered by different groups of mucins that are differentially expressed during the parasite life cycle. We have previously identified the major mucins from the bloodstream trypomastigote stage. Here, we present additional evidence that together with our previous observations allows for the identification of a second mucin group also expressed in the mammal-dwelling stages, but predominant in the intracellular amastigote. These mucins are encoded by many genes, are mostly composed by tandem repeats and are highly conserved except for an exposed hypervariable (HV) N-terminal peptide. Antibodies against HV peptides are restricted to ~50% of the chronically infected human population, are monospecific (i.e. directed towards a single HV), and display low-avidity. In contrast, immunization with a single HV peptide triggers high-avidity, cross-reacting humoral responses against multiple HV sequences, but not against other T. cruzi surface antigens. The diversity present in the HV regions and the characteristics of the antibody response against them suggest a role of these molecules in eluding and/or modulating the mammalian host immune system.