Theileria Survival Strategies and Host Cell Transformation

The effect of the HMGB1/RAGE/TLR4/NF-κB signalling pathway in patients with idiopathic epilepsy and its relationship with toxoplasmosis

This study aims to investigate the relationship between toxoplasmosis and this pathway, which may be effective in the formation of epilepsy by acting through the HMGB1/RAGE/TLR4/NF-κB signalling pathway in patients with idiopathic epilepsy. In the study, four different experimental groups were formed by selecting Toxoplasma gondii IgG positive and negative patients with idiopathic epilepsy and healthy controls. Experimental groups were as follows: Group 1: Epilepsy+/Toxo- (E+, T-) (n = 10), Group 2: Epilepsy-/Toxo- (E-, T-) (n = 10), Group 3: Epilepsy-/Toxo+ (E-, T+) (n = 10), Group 4: Epilepsy+/Toxo+ (E+, T+) (n = 10). HMGB1, RAGE, TLR4, TLR1, TLR2, TLR3, IRAK1, IRAK2, IKBKB, IKBKG, BCL3, IL1β, IL10, 1 L8 and TNFα mRNA expression levels in the HMGB/RAGE/TLR4/NF-κB signalling pathway were determined by quantitative simultaneous PCR (qRT-PCR) after collecting blood samples from all patients in the groups. Statistical analysis was performed by one-way ANOVA followed by LSD post-hoc tests, and p < 0.05 was considered to denote statistical significance. The gene expression levels of HMGB1, TLR4, IL10, IL1B, IL8, and TLR2 were significantly higher in the G1 group than in the other groups (p < 0.05). In the G3 group, RAGE and BCL3 gene expression levels were significantly higher than in the other groups (p < 0.05). In the G4 group, however, IRAK2, IKBKB, and IKBKG gene expression levels were significantly higher than in the other groups (p < 0.05). HMGB1, TLR4, IRAK2, IKBKB, IL10, IL1B, IL1B, and IL8 in this signalling pathway are highly expressed in epilepsy patients in G1 and seizures occur with the stimulation of excitatory mechanisms by acting through this pathway. The signalling pathway in epilepsy may be activated by HMGB1, TLR4, and TLR2, which are considered to increase the level of proinflammatory cytokines. In T. gondii, this pathway is activated by RAGE and BCL3.

From molecule to diagnostic tool: Theileria annulata surface protein TaSP

Isolation and characterization of the Theileria annulata macroshizont stage protein TaSP showed that this parasite surface membrane protein is a highly antigenic protein suitable for the development of diagnostic tools for tropical theileriosis. An enzyme-linked immunosorbent assay (ELISA) for the detection of circulating antibodies against Theileria annulata was established and validated using the recombinantly expressed TaSP protein. The ELISA has subsequently been applied for cross-sectional surveys to determine the distribution and prevalence of tropical theileriosis in Sudan.

Identification, molecular characterization and subcellular localization of a Theileria annulata parasite protein secreted into the host cell cytoplasm

Intracellular leucoproliferative Theileria are unique as eukaryotic organisms that transform the immune cells of their ruminant host. Theileria utilize the uncontrolled proliferation for rapid multiplication and distribution into host daughter cells. The equal distribution of the schizont into the daughter cells is thought to be accomplished by a tight association with the host cell mitotic apparatus. In this study, we describe a highly conserved novel 37 kD Theileria annulata protein (TaSE). TaSE was found to be localized inside the parasite, the parasite membrane and within the host cell cytoplasm. Moreover, it co-localized at distinct points with host cell microtubules, which was especially apparent during mitosis, where co-localization was found with the centromere, the mitotic spindle and the midbody. Association of TaSE with the host cell tubulin network was corroborated by coimmunoprecipitation and transient transfection experiments. This is the first description of a theilerial protein co-localizing and potentially interacting with a host cell protein. The distribution of TaSE during mitosis makes it a protein to consider as playing a potential role for parasite distribution into daughter host cells.

Theileria: intracellular protozoan parasites of wild and domestic ruminants transmitted by ixodid ticks

Theileria are economically important, intra-cellular protozoa, transmitted by ixodid ticks, which infect wild and domestic ruminants. In the mammalian host, parasites infect leukocytes and erythrocytes. In the arthropod vector they develop in gut epithelial cells and salivary glands. All four intra-cellular stages of Theileria survive free in the cytoplasm. The schizont stages of certain Theileria species induce a unique, cancer-like, phenotype in infected host leukocytes. Theileria undergoes an obligate sexual cycle, involving fusion of gametes in the tick gut, to produce a transiently diploid zygote. The existence of sexual recombination in T. parva has been confirmed in the laboratory, and is presumed to contribute to the extensive polymorphism observed in field isolates. Key parameters in T. parva population dynamics are the relative importance of asymptomatic carrier cattle and animals undergoing severe disease, in transmission of the parasite to ticks, and the extent of transmission by nymphs as compared to adult ticks. Tick populations differ in vector competence for specific T. parva stocks. Recombinant forms of T. parva and T. annulata sporozoite surface antigens induce protection against parasite challenge in cattle. In future, vaccines might be improved by inclusion of tick peptides in multivalent vaccines.