INVESTIGADORES
JACOBSEN Monica Ofelia
artículos
Título:
Bovipain-2, the falcipain-2 ortholog, is expressed in intraerythrocytic stages of the tick-transmitted hemoparasite Babesia bovis
Autor/es:
MESPLET, M.; ECHAIDE, I.; DOMINGUEZ, M.; MOSQUEDA, J.; SUAREZ, C.E.; SCHNITTGER, L.; JACOBSEN FLORIN-CHRISTENSEN, M.
Revista:
PARASITES AND VECTORS
Editorial:
BIOMED CENTRAL LTD
Referencias:
Año: 2010 vol. 3 p. 1 - 12
ISSN:
1756-3305
Resumen:
ABSTRACT:
BACKGROUND:
Cysteine proteases have been
shown to be highly relevant for Apicomplexan parasites. In the case of Babesia
bovis, a tick-transmitted hemoparasite of cattle, inhibitors of these enzymes
were shown to hamper intraerythrocytic replication of the parasite,
underscoring their importance for survival.
RESULTS:
Four papain-like cysteine
proteases were found to be encoded by the B. bovis genome using the MEROPS
database. One of them, the ortholog of Plasmodium falciparum falcipain-2, here
named bovipain-2, was further characterized. Bovipain-2 is encoded in B. bovis
chromosome 4 by an ORF of 1.3 kb, has a predicted molecular weight of 42 kDa,
and is hydrophilic with the exception of a transmembrane region. It has
orthologs in several other apicomplexans, and its predicted amino acid sequence
shows a high degree of conservation among several B. bovis isolates from North
and South America. Synteny studies
demonstrated that the bovipain-2 gene has expanded in the genomes of two
related piroplasmids, Theileria parva and T. annulata, into families of 6 and 7
clustered genes respectively. The bovipain-2 gene is transcribed in in vitro
cultured intra-erythrocyte forms of a virulent and an attenuated B. bovis
strain from Argentina,
and has no introns, as shown by RT-PCR followed by sequencing. Antibodies
against a recombinant form of bovipain-2 recognized two parasite protein bands
of 34 and 26 kDa, which coincide with the predicted sizes of the pro-peptidase
and mature peptidase, respectively. Immunofluorescence studies showed an
intracellular localization of bovipain-2 in the middle-rear region of in vitro
cultured merozoites, as well as diffused in the cytoplasm of infected
erythrocytes. Anti-bovipain-2 antibodies also reacted with B. bigemina-infected
erythrocytes giving a similar pattern, which suggests cross-reactivity among
these species. Antibodies in sera of two out of six B. bovis-experimentally
infected bovines tested, reacted specifically with recombinant bovipain-2 in immunoblots, thus
demonstrating expression and immunogenicity during bovine-infecting stages.
CONCLUSIONS:
Overall, we present the
characterization of bovipain-2 and demonstrate its in vitro and in vivo
expression in virulent and attenuated strains. Given the involvement of
apicomplexan cysteine proteases in essential parasite functions, bovipain-2
constitutes a new vaccine candidate and potential drug target for bovine
babesiosis.