Involvement of the stage-specific 82-kilodalton adhesion molecule of Trypanosoma cruzi metacyclic trypomastigotes in host cell invasion

Abstract

This study provides several pieces of evidence indicating that 3F6-Ag, identified by monoclonal antibody (MAb) 3F6 as a stage-specific glycoprotein of approximately 82 kDa on the surface of metacyclic trypomastigotes of different Trypanosoma cruzi strains, promotes the entry of parasites into host cells through a ligand-receptor type interaction. First, invasion of Vero cells by metacyclic trypomastigotes of both CL and Tulahuen strains was significantly inhibited by MAb 3F6 or its Fab fragments. Second, purified 3F6-Ag bound to Vero cells in a dose-dependent and saturable fashion. Third, soluble 3F6-Ag reduced the infection of Vero cells by metacyclic forms of CL and Tulahuen strains by 90 to 97 and 50%Yo, respectively. Unrelated proteins, as well as extracellular matrix components, such as heparan sulfate and collagen, had no effect. Our studies also show that in the Tulahuen strain, 10D8-Ag, a 35/50-kDa glycoprotein identified by MAb 10D8, participates in target cell invasion, confirming previous observations, but the variant form of 10D8-Ag expressed by highly invasive CL strain metacyclic trypomastigotes appears to be irrelevant. Overall, our results indicate that the

Heterologous Expression of A Trypanosoma Cruzi Surface Glycoprotein (Gp82) In Mammalian Cells Indicates the Existence of Different Signal Sequence Requirements and Processing

“…Instead of the 75 kDa polypeptide, Vero cells transfected with pc-gp82+SP and treated with tunicamycin expressed a 70 kDa species that may correspond to the 70 kDa polypeptide obtained by digestion of gp82 with either PNGase F or endo H (not shown). This result is similar to that obtained with metacyclic trypomastigotes treated with tunicamycin (Ramirez et al 1993). In the same manner as the cells treated with PNGase F, no change was detected in the profile of polypeptides synthesized by Vero cells transfected with pc-gp82 after treatment with tunicamycin.…”

“…gp82 is a surface glycoprotein which contains N-linked oligosaccharide side chains and anchored to the mem-brane through a glycosylphosphatidylinositol moiety (Araya et al 1994;Cardoso de Almeida, and Heise 1993;Ramirez et al 1998). The cDNA clone 518 encodes a polypeptide of 516 amino acids with a molecular mass of 55.6 kDa, which may correspond to the precursor of gp82 devoid of N-linked oligosaccharides (Araya et al 1994;Ramirez et al 1993). The structure of gp82 predicted from the deduced amino acid sequence is very unusual for a membrane protein.…”

“…Metacyclic trypomastigotes, the insect-transmitted infective form of T. cruzi, synthesize a developmentally regulated 82 kDa surface glycoprotein (gp82) that has been implicated in parasite entry into host cells (Ramirez et al 1993;Santori et al 1996). gp82 is a cell adhesion molecule that triggers an increase in intracellular Ca2+, an event required for T. cruzi invasion (Ramirez et al 1993;Dorta et al 1995). The complete primary structure of gp82 has recently been deduced (Araya et al 1994) and analysis of the amino acid sequenc:e suggests the existence of several post-translational modifications, such as N-glycosyl-ation and addition of a glycosylphosphatidylinositol (GPI) anchor.…”

Dynamic flux of microvesicles modulate parasite-host cell interaction ofTrypanosoma cruziin eukaryotic cells

“…This is a multifactorial process where plasma membrane components from the parasite and host cell seem to be involved in ligand-receptor interactions. Some authors have suggested that the TCT and META invasion processes are different, because each stage uses their own set of molecules to adhere and invade the host cell (Ramirez, Ruiz Rde, Araya, Da Silveira, & Yoshida, 1993). We have described that MVs from META-THP-1 interaction avoid complement lysis and increase the invasion of eukaryotic cells by META forms (Cestari et al, 2012).…”

Identificação do(s) receptor(es) da célula hospedeira para a família de glicoproteínas Tc85 presentes na superfície do <i>Trypanosoma cruzi</i>

“…A clonagem de um membro dessa família (Tc85-ll) revelou sua capacidade de adesão a células de mamíferos e a laminina (Giordano et al, 1994(Giordano et al, e 1999. Outros laboratórios também implicaram moléculas de aproximadamente 85 kDa na interação do parasita com a célula do hospedeiro (Boschetti et al, 1987;Lima et al, 1989;Ramirez et al, 1993e Araguth et al, 1988 incluindo uma proteína de 85 kDa, provavelmente da mesma superfamília, mas diferente da Tc85-l l, descrita como receptor de fibronectina ( Ouaissi et al, 1986). Anticorpos contra moléculas de mesma massa molecular inibiram a internação do parasita (Araguth et al, 1988).…”