Production and characterization of monoclonal antibodies against Toxoplasma gondii ROP18 with strain-specific reactivity

Abstract

<jats:title>Abstract</jats:title><jats:p>The rhoptry kinase 18 of <jats:italic>Toxoplasma gondii</jats:italic> (TgROP18) has been identified as a key virulence factor that allows the parasite to escape from host immune defences and promotes its proliferation in host cells. Although much research is focused on the interaction between host cells and TgROP18, the development of monoclonal antibodies (mAbs) against TgROP18 has not been reported till date. To produce mAbs targeting TgROP18, two hybridomas secreting mAbs against TgROP18, designated as A1 and T2, were generated using cell fusion technology. The subtypes of the A1 and T2 mAbs were identified as IgG3 <jats:italic>λ</jats:italic> and IgM <jats:italic>κ</jats:italic>, and peptide scanning revealed that the core sequences of the antigenic epitopes were <jats:sup>180</jats:sup>LRAQRRRSELVFE<jats:sup>192</jats:sup> and <jats:sup>351</jats:sup>NYFLLMMRAEADM<jats:sup>363</jats:sup>, respectively. The T2 mAb specifically reacted with both <jats:italic>T. gondii</jats:italic> type I and Chinese I, but not with <jats:italic>T. gondii</jats:italic> type II, <jats:italic>Plasmodium falciparum</jats:italic> or <jats:italic>Schistosoma japonicum</jats:italic>. Finally, the sequences of heavy chain and light chain complementarity-determining regions of T2 were amplified, cloned and characterized, making the modification of the mAb feasible in the future. The development of mAbs against TgROP18 would aid the investigation of the molecular mechanisms underlying the modulation of host cellular functions by TgROP18, and in the development of strategies to diagnose and treat Toxoplasmosis.</jats:p>

Monoclonal Antibodies for Protozoan Infections: A Future Reality or a Utopic Idea?

“…A number of different toxoplasma antigens have been proposed in the last years as candidates for the development of monoclonal antibodies or vaccines, although only preliminary studies have been performed so far. These include rhoptry kinase 18 of Toxoplasma gondii (TgROP18), a key virulence factor that promotes parasite proliferation for which species- and strain-specific mAbs have been obtained ( 113 ), and a synthetic peptide from surface antigen 1 (SAG1) ( 114 ).…”