Evaluation of the inhibition of invasion in vitro of P. yoelii strain with different monoclonal antibodies raised against MSP-119

Objective. Antibodies are glycoproteins that can protect against diseases like malaria by binding and neutralizing parasites. The effect of antibodies on surface proteins is to block invasion. In this work, we developed an assay to evaluate the inhibition of invasion of Plasmodium yoelii mediated by the Merozoite Surface Protein 1 (MSP-1), which is one of the invasive blood stages of the malaria parasite, using several Monoclonal Antibodies (Mabs) raised against a 19 kDa fraction of MSP-1 (MSP-119). Material and Methods. Mabs were previously evaluated in a passive transfer experiment which inhibited the growth of the parasite and were characterized. A panel of five of these Mabs (B10, B6, F5, D3 and D9) raised against the C-terminal fragment of MSP-1 from P yoelii were used to evaluate the inhibition of invasion. An ANOVA test was used to compare the inhibition effect. Results. The protective and partially protective Mabs were evaluated in a growth assay in vitro. The inhibition effect of invasion was determined as significant (p<0.05) for Mab F5. The results suggest that Mab F5, an IgG3 which recognizes the first epidermal growth factor (EGF)-like module of the fragment C-terminal of MSP-119, can interfere with erythrocytes invasion in vitro, in the first 30 minutes of the invasion. Conclusions. This suggests that the first module of MSP-119, which is recognized by Mab F5, is a relevant epitope in the invasion process in vitro by the merozoite. This assay was a useful tool to evaluate in vitro protective Mabs implicated in the inhibition of invasion.Objetivo. Los anticuerpos son glicoproteínas que pueden proteger de enfermedades como la malaria por su capacidad de unión a proteínas y consecuente neutralización de parásitos a través del bloqueo del proceso de invasión. En este trabajo, se ha desarrollado un ensayo para evaluar la inhibición de la invasión de merozoítos de Plasmodium yoelii, una de las etapas invasivas del parasito de la malaria, mediada por la Proteína de Superficie de Merozoíto 1 (MSP- 1), usando Anticuerpos Monoclonales (Mabs) dirigidos contra un fragmento de 19 kDa de MSP-1 (MSP-119). Material y Métodos. Los anticuerpos monoclonales (Mabs) fueron evaluados previamente en un ensayo de transferencia pasiva que inhibía el crecimiento del parásito y también fueron caracterizados. Para evaluar la inhibición de la invasión se utilizó un panel de cinco de estos Mabs (B10, B6, F5, D3 and D9) hechos contra el fragmento Cterminal de la MSP-119 de P yoelii. Para comparar el efecto de la inhibición se realizó una prueba ANOVA. Resultados. Los Mabs protectores y parcialmente protectores fueron evaluados en un ensayo de crecimiento in vitro. El efecto de inhibición de la invasión fue significativo (p