Am J Trop Med Hyg

Am J Trop Med Hyg. occasions of mice after challenge. Our results showed that mice immunized with pDsRed2-GRA8 exhibited specific humoral and cellular responses, induced higher IgG antibody titers with predominant IgG2a production; increased levels of IL-10, IL-12 (p70), IFN-, TNF-, and splenocyte proliferation; and prolonged survival times compared to those of control mice. The present study showed that DNA immunization with pDsRed2-GRA8 induced humoral (Rac)-PT2399 and cellular immune responses, and all immunized mice showed greater Th1-type immune responses and longer survival occasions than those of control mice. These results indicated that GRA8 DNA immunization induces a partial protective effect against acute toxoplasmosis. is usually a ubiquitous intracellular protozoan parasite that can invade and replicate in all nucleated cells. It is prevalent in humans and animals worldwide, and one-third of the worlds populace is usually reportedly infected with [1,2]. Although 80C90% of individuals with primary contamination are asymptomatic, the most affected are immunocompromised individuals (HIV/AIDS, cancer patients, organ and tissue transplant recipients, and congenitally infected children), and in these patients, can lead to encephalitis, ophthalmopathy, or even death [3C5]. infection in domestic animals can cause substantial Rabbit Polyclonal to CG028 economic losses due to abortion and neonatal loss in livestock and represents a source of transmission to humans [6C8]. To date, no safe and effective drug is available to eliminate tissue cysts [9]. Thus, the development of a vaccine is considered to be the most effective way to control toxoplasmosis [10]. Unfortunately, after decades of effort, only one vaccine (Toxovax?) has been licensed for use to prevent abortion in sheep and goats, and no vaccine suitable for use in humans exists [11]. In these circumstances, there is an urgent need to develop new, effective vaccines to reduce the high incidence of toxoplasmosis by preventing and treating this disease in humans and animals [12]. DNA vaccines have become a major focus of research, because they promote the specific expression of an encoded vaccine antigen by host cells and can deliver multivalent vaccines to a host in a single dose. In particular, DNA vaccines can also elicit potent, long-lasting humoral and cell-mediated immunity [13]. has evolved unique secretory organelles to help establish infection in its hosts. Among these secretory organelles, the dense granules (GRA), micronemes (MIC), and rhoptries (ROP) are the best characterized, and these organelles play critical roles in adhesion, motility, host invasion, intracellular replication, manipulation of host signaling and innate immune pathways, and formation of the parasitophorous vacuole (PV) [14,15]. The vaccine candidate antigens involved in protective immunity against include membrane-associated surface antigens (SAGs) and secreted GRAs, MICs and ROPs [16C24]. However, none of these antigens could completely inhibit tissue cyst formation [25]. Dense granules is an important secretory organelle in the cytoplasm, and GRA proteins are potent antigens that trigger strong T and B cell responses upon infection [20,26]. Previous studies have demonstrated that GRA8 is a marker of acute infection, and IgG, IgM or IgA detection with GRA8 by enzyme-linked immunosorbent assay (ELISA) is useful in diagnosing infection and discriminating acute from chronic infection [27C29]. However, no study of the protective efficacy of a DNA vaccine (Rac)-PT2399 expressing GRA8 to induce resistance to acute infection has been published. To evaluate the protective immune responses induced by GRA8, we constructed a GRA8-expressing eukaryotic plasmid, pDsRed2-GRA8, and evaluated its immunogenicity and protective efficacy after vaccination (Rac)-PT2399 of BALB/c mice through challenge with the highly virulent GFP-RH strain. MATERIALS AND METHODS Animals Specific-pathogen-free (SPF) female BALB/c mice of 6 to 8 8 weeks old were purchased from Guangdong Medical Laboratory Animal Center, Guangzhou, Guangdong Province, China. All mice were handled in strict accordance with the Good Animal Practice Requirements of the Animal Ethics Procedures and Guidelines of the Peoples Republic of China. This study was approved by the Committee on the Ethics of Animal Experiments of Guangdong Medical University (Permit Number: SYXK [Guangdong] 2015-0147). strain The tachyzoites of the GFP-RH strain were maintained in human retinal pigment epithelial cells (ARPE-19; ATCC, Rockville, Maryland, USA). Briefly, GFP-RH were infected into ARPE-19 cells (parasite/cell ratio, 5: 1) and incubated at 37?C with 5% CO2 for 2 to 3 3 days. Following host cell rupture, lysed tachyzoites and host cellular debris were centrifuged at.