Next Article in Journal / Special Issue
Immunization with the H5N1 Recombinant Vaccine Candidate Induces High Protection in Chickens against Vietnamese Highly Pathogenic Avian Influenza Virus Strains
Previous Article in Journal
Histone Methyltransferase DOT1L Is Involved in Larval Molting and Second Stage Nymphal Feeding in Ornithodoros moubata
Previous Article in Special Issue
Progress and Prospects on Vaccine Development against SARS-CoV-2
Open AccessArticle

Identification of Toxoplasma Gondii Tyrosine Hydroxylase (TH) Activity and Molecular Immunoprotection against Toxoplasmosis

1
Xinxiang Key Laboratory of Pathogenic Biology, School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang 453003, China
2
MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China
*
Authors to whom correspondence should be addressed.
Vaccines 2020, 8(2), 158; https://doi.org/10.3390/vaccines8020158
Received: 29 February 2020 / Revised: 22 March 2020 / Accepted: 24 March 2020 / Published: 1 April 2020
The neurotropic parasite Toxoplasma gondii (T. gondii) infection can change the behavior of rodents and cause neuropsychological symptoms in humans, which may be related to the change in neurotransmitter dopamine in the host brain caused by T. gondii infection. T. gondii tyrosine hydroxylase (TgTH) is an important factor in increasing the neurotransmitter dopamine in the host brain. In this study, the enzyme activity of TgTH catalytic substrate for dopamine production and the molecular characteristics of TgTH were identified. In order to amplify the open reading frame (ORF), the designing of the specific primers for polymerase chain reaction (PCR) was on the basis of the TgTH sequence (GenBank Accession No. EU481510.1), which was inserted into pET-32a (+) for the expression of recombined TgTH (rTgTH). The sequence analysis indicated that the gene of TgTH directed the encoding of a 62.4-kDa protein consisting of 565 amino acid residues, which was predicted to have a high antigen index. The enzyme activity test showed that rTgTH and the soluble proteins extracted separately from T. gondii RH strain and PRU strain could catalyze the substrate to produce dopamine in a dose-dependent manner, and the optimum catalytic temperature was 37 °C. The result of the Western Blotting assay revealed that the rTgTH and the native TgTH extracted from somatic of T. gondii RH tachyzoite were successfully detected by the sera of mice infected with T. gondii and the rat serum after rTgTH immune, respectively. Immunofluorescence analysis using antibody against rTgTH demonstrated that the protein was expressed and located on the surface of T. gondii RH tachyzoite. Freund’s adjuvant was used to emulsify the rTgTH, which was subsequently applied to BALB/c mouse immune thrice on week 0, week 2, and week 4, respectively. The result of the animal challenge experiments showed an integral increase in IgG, IgG2a, IgG1, and IFN-γ, IL-4, and IL17 were as well significantly increased, and that the rTgTH vaccinated animals apparently had a prolonged survival time (14.30 ± 2.41) after infection with the RH strain of T. gondii compared with that of the non-vaccinated control animals, which died within 11 days. Additionally, in the rTgTH vaccination group, the number of brain cysts (1275 ± 224) significantly decreased (p < 0.05) compared to the blank control group (2375 ± 883), and the size of the brain cysts in the animals immunized with rTgTH vaccination was remarkably smaller than that of the control mice. All the findings prove that TgTH played an important role in increasing the neurotransmitter dopamine in the host brain and could be used as a vaccine candidate antigen to mediate cell-mediated and humoral immunity. View Full-Text
Keywords: T. gondii; tyrosine hydroxylase; catalytic activity; animal challenge; protective immunity T. gondii; tyrosine hydroxylase; catalytic activity; animal challenge; protective immunity
Show Figures

Figure 1

MDPI and ACS Style

Zhang, Z.; Li, Y.; Li, H.; Song, X.; Ma, Z.; Lu, H.; Liu, S.; Zhao, Y.; Tan, M.; Wang, S.; Li, X. Identification of Toxoplasma Gondii Tyrosine Hydroxylase (TH) Activity and Molecular Immunoprotection against Toxoplasmosis. Vaccines 2020, 8, 158.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Search more from Scilit
 
Search
Back to TopTop