ABSTRACT
Vaccination is the most effective method for preventing rabies virus (RABV) infection in both humans and animals; however, no satisfactory vaccine has been developed for use worldwide. In the present study, we investigated the immunoadjuvant properties of Salmonella Typhimurium flagellin (FljB, FliC, and FljB'-FliC) to improve immune responses against the rabies vaccine (RV) and the protective efficacy of the whole-killed rabies vaccine (WKRV) with or without flagellins in BALB/c mice. We also compared the differences among the three flagellins in terms of immunoadjuvant properties to RV. FljB can cause the WKRV to induce stronger humoral and cellular immune responses than WKRV alone or WKRV with FliC or FljB'-FliC can. Mice immunized with WKRV and FljB produced higher levels of virus-neutralizing antibody (VNA) against RABV than those in the other groups did. Although mice in all treatment groups survived RABV challenge, the body weight loss in the group immunized with WKRV and FljB was lower than in the other groups. These results indicate that FljB is a promising adjuvant for use in the development of effective rabies vaccines.
Subject(s)
Adjuvants, Immunologic/administration & dosage , Flagellin/administration & dosage , Rabies Vaccines/administration & dosage , Rabies Vaccines/immunology , Rabies/prevention & control , Animals , Antibodies, Neutralizing/blood , Antibodies, Viral/blood , Body Weight , Disease Models, Animal , Flagellin/genetics , Mice, Inbred BALB C , Salmonella typhimurium/genetics , Survival Analysis , Vaccines, Inactivated/administration & dosage , Vaccines, Inactivated/immunologyABSTRACT
Toxoplasmosis, caused by the intracellular protozoon Toxoplasma gondii, is a significant parasitic zoonosis with a world-wide distribution. As a main transmission route, human infection can be acquired by the ingestion of T. gondii oocysts from the environment (e.g., soil, water, fruits and vegetables). Regarding the detection of T. gondii oocysts in environmental samples, the development of a time-saving, cost-effective and highly sensitive technique is crucial for the surveillance, prevention and control of toxoplasmosis. In this study, we developed a new method by combining recombinase-aided amplification (RAA) with CRISPR-Cas12a, designated as the RAA-Cas12a-Tg system. Here, we compared this system targeting the 529 bp repeat element (529 bp-RE) with the routine PCR targeting both 529 bp-RE and ITS-1 gene, respectively, to assess its ability to detect T. gondii oocysts in soil samples. Our results indicated that the 529 bp RE-based RAA-Cas12a-Tg system was able to detect T. gondii successfully in nearly an hour at body temperature and was more sensitive than the routine PCR assay. The sensitivity of this system reached as low as 1 fM with high specificity. Thus, RAA-Cas12a-Tg system provided a rapid, sensitive and easily operable method for point-of-care detection of T. gondii oocysts in soil, which will facilitate the control of T. gondii infection in humans and animals.