“Human and rabbit antibodies against Toxoplasma Hsp20 are able to block parasite invasion and gliding motility”

COCERES VM, CORVI MM AND ANGEL SO.

Ascochinga-Córdoba

Congreso; XXIV Reunion Anual de la Sociedad Argentina de Protozoologia; 2010

Sociedad Argentina de Protozoología

Toxoplasma gondii Hsp20 is a pellicle-associated functional chaperone whose biological role is still unknown. Here we demonstrate that Hsp20 is present in different apicomplexan parasites, showing a high degree of conservation between them, with Neosopora caninum Hsp20 presenting an 82% identity. Rabbit anti-T. gondii Hsp20 serum is able to recognize the N. caninum counterpart, which was also localized to the parasite pellicle. Incubation of T. gondii and N. caninum tachyzoites with anti-Hsp20 antibody blocked parasite invasion at rates of 43.5% and 54.7% respectively. This antiserum also blocked T. gondii gliding at rates of 48.7%. Purified anti-Hsp20 antibodies from serum samples of infected individuals also blocked invasion and gliding at rates of 26 and 40%, respectively. A detailed analysis of extracellular parasites by immunolocalization with alpha toxin, glycerol and non-permeabilized parasites, indicated that Hsp20 is localized at both plasma membrane and IMC, being exposed to environmental antibodies. Hsp20 was also detected at the conoid and polar ring. During gliding, Hsp20 relocalizes as a traverse bar along the parasite, near the apical region, being also detected in the trail. Here we demonstrated that Hsp20 could be important for parasite invasion/gliding and also as a target for immunotherapy.