Murine Dendritic Cells Pulsed In Vitro withToxoplasma gondiiAntigens Induce Protective Immunity In Vivo

Abstract

The activation of a predominant T-helper-cell subset plays a critical role in disease resolution. In the case of Toxoplasma gondii, the available evidence indicates that CD4+protective cells belong to the Th1 subset. The aim of this study was to determine whether T. gondii antigens (in T. gondii sonicate [TSo]) presented by splenic dendritic cells (DC) were able to induce a specific immune response in vivo and to protect CBA/J mice orally challenged with T. gondiicysts. CBA/J mice immunized with TSo-pulsed DC exhibited significantly fewer cysts in their brains after oral infection with T. gondii 76K than control mice did. Protected mice developed a strong humoral response in vivo, with especially high levels of anti-TSo immunoglobulin G2a antibodies in serum. T. gondii antigens such as SAG1 (surface protein), SAG2 (surface protein), MIC1 (microneme protein), ROP2 through ROP4 (rhoptry proteins), and MIC2 (microneme protein) were recognized predominantly. Furthermore, DC loaded with TSo, which synthesized high levels of interleukin-12 (IL-12), triggered a strong cellular response in vivo, as assessed by the proliferation of lymph node cells in response to TSo restimulation in vitro. Cellular proliferation was associated with gamma interferon and IL-2 production. Taken together, these results indicate that immunization of CBA/J mice with TSo-pulsed DC can induce both humoral and Th1-like cellular immune responses and affords partial resistance against the establishment of chronic toxoplasmosis.

Mycobacterium tuberculosis‐activated dendritic cells induce protective immunityin mice

“…This reinforces the importance of DC in generating protective immune responses against infectious agents. Other groups have shown, for example, that similar strategies can be used to protect against experimental infections with Chlamydia trachomatis 14 and Toxoplasma gondii 15. Recently, BCG‐infected DC were shown to protect mice against an aerosol challenge with M. tuberculosis; 16 however, in these experiments the DC were given intratracheally a route which would favour local presentation to T cells but would not necessarily indicate systemic priming of naı¨ve T cells.…”

Extracellular Vesicles: Role in Inflammatory Responses and Potential Uses in Vaccination in Cancer and Infectious Diseases

“…EVs derived from DC incubated with T. gondii antigens induce an intense immune response, increasing the levels of MHC class II and the specific production of T-cells and cytokines [ 140 ]. Studies of immunization with these DC are promising alternatives in promoting protection against T. gondii [ 141 , 142 ]. Eimeria tenella , Eimeria maxima , and Eimeria acervulina are also coccidian parasite of chickens that also release EVs, which confer protective immune response against the parasite [ 123 , 143 , 144 ].…”

Targeted Delivery of Toxoplasma gondii Antigens to Dendritic Cells Promote Immunogenicity and Protective Efficiency against Toxoplasmosis

“…It has been documented that following loading with pathogenic antigens and adoptive transfer, DCs mediate protection against a wide spectrum of infectious diseases, including toxoplasmosis. We previously showed that DCs pulsed with T. gondii antigen elicit protective immunity against chronic toxoplasmosis in mice ( 19 , 20 ). However, it is not feasible to use ex vivo antigen-loaded DCs for first-line prophylactic vaccination.…”