Biologia

Experimental Parasitology 114 (2006) 220–227 www.elsevier.com/locate/yexpr

Toxoplasma gondii: An evaluation of diagnostic value of recombinant antigens in a murine model
Justyna Gatkowska a,¤, Elzbieta Hiszczynska-Sawicka b, Jozef Kur b, Lucyna Holec b, Henryka Dlugonska a
b a Department of Immunoparasitology, University of Lodz, 90-237 Lodz, Banacha 12/16 Str., Poland Department ofMicrobiology, Gdansk University of Technology, 80-952 Gdansk, Narutowicza 11/12 Str., Poland

Received 10 January 2006; received in revised form 15 March 2006; accepted 25 March 2006 Available onilne 16 May 2006

Abstract Laboratory diagnostics of toxoplasmosis depends primarily on serological methods detecting speciWc antibodies. Since these methods do not always enable speciWc and sensitiverecognition of the infection and phase of toxoplasmosis, the search for new diagnostic tools continues. Recombinant antigens promise a new alternative in diagnostics of Toxoplasma gondii infections. In this work the usefulness of six recombinant T. gondii antigens: GRA1, GRA6, GRA7, p35, SAG1, and SAG2 in the detection of primary murine toxoplasmosis was evaluated. Sera obtained from infected micediVering in their natural susceptibility to T. gondii infection, BALB/c (relatively resistant) and C57BL/6 (relatively susceptible), were tested using ELISA. During acute infection high response to GRA7, GRA6, and p35 antigens was noticed, whereas a strong reactivity with surface antigens SAG1 and SAG2 was characteristic for chronic toxoplasmosis. Our results show that the recombinant antigens are usefulin distinguishing between acute and chronic toxoplasmosis regardless of the genetically determined susceptibility of the host. © 2006 Elsevier Inc. All rights reserved.
Index Descriptors and Abbreviations: Toxoplasma gondii; Murine experimental toxoplasmosis; Serodiagnostics; Recombinant antigens; Protozoa; Apicomplexa; Toxoplasma gondii BK and DX strains; BALB/c and C57BL/6 inbred mice;Experimental toxoplasmosis; Recombinant antigens; GRA, dense granule antigen; SAG, surface antigen; TLA, toxoplasma lysate antigen; PHA, phytohemagglutinin; ELISA, enzyme-linked immunosorbent assay; [3H]thymidine incorporation; PBS, phosphate-buVered saline; POX, horseradish peroxidase; ABTS, 2,2 -azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)diammonium salt

1. Introduction Toxoplasma gondii is aprotozoan parasite capable of invading any nucleated cell of warm blooded vertebrates including humans. The parasite causes antropozoonotic disease—toxoplasmosis, which in immunocompetent individuals occurs usually asymptomatically. On the other hand, an infection in immunocompromised patients may be serious or even fatal. Primary invasion during pregnancy may endanger life of the fetus (Petersenand Dubey, 2001). Diagnostics of T. gondii infection relies mainly on serological
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Corresponding author. Fax: +48 42 665 58 18. E-mail address: gatjus@biol.uni.lodz.pl (J. Gatkowska).

tests enabling the detection of speciWc anti-Toxoplasma antibodies produced in the infected host. SpeciWcity and sensitivity of these methods depend mostly on diagnostic antigen(s), and often the earlyrecognition of the infection or precise distinction between phases of toxoplasma invasion is diYcult (Joynson and Guy, 2001). Whole T. gondii tachyzoite lysates used as diagnostic antigens in conventional serological tests show batch-to-batch variations and can be contaminated with host proteins. Highly eYcient systems of recombinant antigen production oVer the possibility to develop standardized antigenpreparations at reduced costs (Aubert et al., 2000; Lecordier et al., 2000; Hiszczyjska-Sawicka et al., 2003, 2005). The present trend is to replace native antigens with recombinant antigens

0014-4894/$ - see front matter © 2006 Elsevier Inc. All rights reserved. doi:10.1016/j.exppara.2006.03.011

J. Gatkowska et al. / Experimental Parasitology 114 (2006) 220–227

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