Variable numbers of calreticulin genes in Trypanosoma cruzi correlate with atypical morphology and protein expression.

Trypanosoma cruzi calreticulin (TcCalr, formerly known as TcCRT), upon binding to Complement (C) C1 and ficolins, inhibits the classical and lectin pathways and promotes infectivity. This virulence correlates with the expression of TcCalr. The TcCalr C inhibitory capacity was shown in a previous work using a clonal epimastigote cell line from the TCC T. cruzi strain, lacking one TcCalr allele (TcCalr+/-) or over expressing it (TcCalr+). In this work, we detected atypical morphology in TcCalr+/- and in TcCalr+ parasites, as compared to the wild-type (WT) strain. Polyclonal anti-TcCalr antibodies detected TcCalr presence mainly in the parasite nucleus. The number of TcCalr indicator gold particles, detected in electron microscopy and quantified in silico, correlated with the number of TcCalr coding genes. Both TcCalr+ and TcCalr +/- epimastigotes presented morphological alterations.