Generación de anticuerpos inhibitorios de enzimas. Anticuerpos de dominio único inhiben la actividad transialidasa del Tripanosoma Cruzi

URRUTIA M.

Capital Federal

Exposición; Seminarios del Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y Diagnóstico (CEBBAD).; 2012

Universidad Maimónides/CEBBAD,

SINGLE-DOMAIN LLAMA ANTIBODIES INHIBIT TRANS-SIALIDASE ACTIVITY OF TRYPANOSOMA CRUZI. Urrutia M. Fundación Instituto Leloir. Bs As. Instituto de Investigaciones Biotecnológicas (IIB), UNSAM. Bs As. e-mail: murrutia@leloir.org.ar   Trypanosoma cruzi trans-sialidase (TcTS) constitutes a key molecule in both the establishment of the infection and the development of pathologic abnormalities related with Chagas disease. Llamas produce, additionally to conventional antibodies, unusual immunoglobulins devoid of light chains. Their binding site is formed solely by one variable region (VHH). The binding strategies of these VHH are very particular, their CDR3 region form long extensions that can protrude into cavities on antigens, e.g. the active site crevice of enzymes being suitable for the development of enzyme inhibitors. The cDNA isolated from lymphocytes of llamas immunized with TcTS was used to generate by PCR a VHH library composed of 1x106 clones. Phage display was used for panning and screening of the library. Preliminary TcTS inhibition screening allowed us to identify four strong inhibitors clones (SI), which have the same CDR3Â’s length sharing 16 out of 17 CDRs residues, and few differences along the rest of the sequences. Inhibitory capacity, affinity measurements and native/denature recombinant enzyme recognition assays are shown. We present different evidences suggesting that the SI could be recognizing an epitope probably overlapped to the active site of the enzyme.