The loading of labeled antibody engineered nanoparticles with Indinavir increases its in vitro efficacy against Cryptosporidium parvum

Introduction: There are evidences indicating the Indinavir (IND) ability to reduce C. parvum infection in both in vitro and in vivo models. However, there are limitations to administrate IND as it, such as its renal toxicity and the high grade of metabolism and degradation. We aimed to encapsulate IND in biodegradable Poly (D,L-lactide-co-glycolide) nanoparticles (Np) and to engineer their surface by the conjugation with an anti-Cryptosporidium IgG polyclonal antibody (Ab).Methods: Tetramethylrhodamine labelled Np were loaded with IND and modified by conjugation with an Ab. The IND loaded modified Np (Ab-TMR-IND-Np) did not show any change, as shown by chemical analysis studies. Results: The treatment with 50µM of the Ab-TMR-IND-Np added to the culture at the same time with excysted oocysts, resulted in a complete inhibition of the infection. In C. parvum infected cells, the extent to which the infection decreased was found to have depended on the duration of treatment with the Ab-TMR-IND-Np. Discussion: The antibody engineered Np loaded with IND are able to target C. parvum oocysts in infected cells, could represent a novel therapeutic strategy against Cryptosporidium sp. infection. Moreover, the Np as IND delivery devices, allow the development of a more appropriate dose formulation reducing the IND side effects.