Gene Expression of virulence factors ROP1 and ROP2 in women infected with Toxoplasma gondii mixed with Herpes Simplex Virus

Abstract

 Toxoplasma gondii (T. gondii) is a pervasive protozoan parasite associated with serious pregnancy complications, such as spontaneous abortion. Rhoptry Protein1 (ROP1) and Rhoptry Protein2 (ROP2) are a major virulence factor which is used in the host cell invasion and formation of parasitophorous vacuoles. The purpose of this research was to examine the relation between T. gondii infection and the intensity of the ROP1 and ROP2 gene expression and the frequency of adverse pregnancy outcomes. The present research was carried out on 250 women, 100 of whom were pregnant women (Group 1), 100 of whom had a history of spontaneous abortion (Group 2), and 50 of whom were controls (Group 3). Initial screening for toxoplasmosis was performed using a rapid IgG antibody test. Confirmation of active infection and detection of Herpes Simplex Virus (HSV) co-infection was carried out using Real-Time PCR targeting the T. gondii B1 gene and HSV DNA, respectively. ROP1 and ROP 2gene expression was quantified via RT-qPCR in T. gondii-positive samples and compared across groups. The rapid IgG test showed seropositivity in 23.0% (23/100) of pregnant women and 21.0% (21/100) of aborted women, while all controls were seronegative (0/50), a statistically significant difference (p=0.001). Real-Time PCR confirmed active T. gondii infection in 19.0% (19/100) of pregnant women and 16.0% (16/100) of aborted women, with all controls testing negative (p=0.005). HSV was detected in 7.0% (7/100) of pregnant women and 17.0% (17/100) of aborted women (p=0.002). ROP1 gene expression was significantly higher (p=0.053) in pregnant women with T. gondii infection (Mean ± SD: 8.15 ± 1.33) and those with mixed T. gondii/HSV infection (7.76 ± 1.02) compared to aborted women with T. gondii infection only (6.12 ± 1.41) and aborted women with mixed infection (5.65 ± 1.4), while Mean of ROP2 Gene expression were (Mean ± SD: 7.30 ± 1.16) in pregnant women with T. gondii infection only and those with mixed T. gondii/HSV infection (6.38 ± 1.2) compared to aborted women with T. gondii infection only (6.75 ± 0.68) and aborted women with mixed (T. gondii and Herpes) infection (5.90 ± 1.3), the mean levels was non-significant higher (p-value=0.24) in both group (pregnant women with T. gondii infection only, pregnant women with mixed (T. gondii and Herpes) infection) in compared to both (aborted women with T. gondii infection only and aborted women with mixed (T. gondii and Herpes) infection, as determined by Duncan's post-hoc test. Finally, the high increase in the ROP1 expression level may also be used as a possible molecular marker in predicting the risk of abortion in pregnant women infected with T. gondii.