ABSTRACT
This study evaluated two vaccine candidates for their effectiveness in protecting BALB/c mice against Leishmania chagasiinfection. These immunogenic preparations were composed of Leishmania amazonensisor Leishmania braziliensisantigenic extracts in association with saponin adjuvant. Mice were given three subcutaneous doses of one of these vaccine candidates weekly for three weeks and four weeks later challenged with promastigotes of L. chagasiby intravenous injection. We observed that both vaccine candidates induced a significant reduction in the parasite load of the liver, while the L. amazonensisantigenic extract also stimulated a reduction in spleen parasite load. This protection was associated with a suppression of both interleukin (IL)-10 and IL-4 cytokines by spleen cells in response to L. chagasiantigen. No change was detected in the production of IFN-γ. Our data show that these immunogenic preparations reduce the type 2 immune response leading to the control of parasite replication.
Subject(s)
Animals , Female , Mice , Antigens, Protozoan/immunology , /biosynthesis , /biosynthesis , Leishmaniasis Vaccines/immunology , Leishmaniasis, Cutaneous/immunology , Antigens, Protozoan , /immunology , /immunology , Leishmania braziliensis/immunology , Leishmania infantum/immunology , Leishmania mexicana/immunology , Leishmaniasis, Cutaneous , Leishmaniasis, Cutaneous , Liver , Mice, Inbred BALB C , Saponins , Saponins/immunology , SpleenABSTRACT
PURPOSE: Surface antigen 3 (SAG3) of Toxoplasma gondii is very similar in structure to the major surface antigen 1 (SAG1). Although numerous studies have supported the importance of SAG1 in protection against T. gondii infection, few reports exist on SAG3. MATERIALS AND METHODS: Glutathione-S-transferase (GST)-fused SAG3 of T. gondii (rSAG3) were immunized into BALB/c mice alone or in combination with Quil A (rSAG3/Quil A), and then evaluated the protective immunity in vivo and in vitro against murine toxoplasmosis. RESULTS: Immunization with rSAG3 or rSAG3/Quil A resulted in significantly more survival days and fewer brain cysts after challenge with T. gondii compared to an infected control group. Mice immunized with rSAG3 alone or in combination with Quil A produced significantly more specific IgG2a antibody, whereas specific IgG1 antibody titers did not increase. The percentage of CD8+ T cells, IFN-gamma mRNA expression, and nitric oxide production significantly increased in rSAG3- and rSAG3/Quil A-immunized mice. CONCLUSION: These results indicate that vaccination with Toxoplasma rSAG3 results in partial protective immunity against T. gondii infection through induction of a Th1-type immune response, and that protective immunity is accelerated by the modulating effects of Quil A.
Subject(s)
Animals , Female , Mice , Antigens, Protozoan/genetics , Bacterial Proteins/genetics , Blotting, Western , Enzyme-Linked Immunosorbent Assay , Flow Cytometry , Immunoglobulin G/immunology , Interferon-gamma/metabolism , Mice, Inbred BALB C , Nitric Oxide/metabolism , Protozoan Proteins/genetics , Recombinant Fusion Proteins/genetics , Reverse Transcriptase Polymerase Chain Reaction , Saponins/immunology , Toxoplasma/growth & development , Toxoplasmosis, Animal/immunology , Vaccination/methodsABSTRACT
PURPOSE: Surface antigen 3 (SAG3) of Toxoplasma gondii is very similar in structure to the major surface antigen 1 (SAG1). Although numerous studies have supported the importance of SAG1 in protection against T. gondii infection, few reports exist on SAG3. MATERIALS AND METHODS: Glutathione-S-transferase (GST)-fused SAG3 of T. gondii (rSAG3) were immunized into BALB/c mice alone or in combination with Quil A (rSAG3/Quil A), and then evaluated the protective immunity in vivo and in vitro against murine toxoplasmosis. RESULTS: Immunization with rSAG3 or rSAG3/Quil A resulted in significantly more survival days and fewer brain cysts after challenge with T. gondii compared to an infected control group. Mice immunized with rSAG3 alone or in combination with Quil A produced significantly more specific IgG2a antibody, whereas specific IgG1 antibody titers did not increase. The percentage of CD8+ T cells, IFN-gamma mRNA expression, and nitric oxide production significantly increased in rSAG3- and rSAG3/Quil A-immunized mice. CONCLUSION: These results indicate that vaccination with Toxoplasma rSAG3 results in partial protective immunity against T. gondii infection through induction of a Th1-type immune response, and that protective immunity is accelerated by the modulating effects of Quil A.
Subject(s)
Animals , Female , Mice , Antigens, Protozoan/genetics , Bacterial Proteins/genetics , Blotting, Western , Enzyme-Linked Immunosorbent Assay , Flow Cytometry , Immunoglobulin G/immunology , Interferon-gamma/metabolism , Mice, Inbred BALB C , Nitric Oxide/metabolism , Protozoan Proteins/genetics , Recombinant Fusion Proteins/genetics , Reverse Transcriptase Polymerase Chain Reaction , Saponins/immunology , Toxoplasma/growth & development , Toxoplasmosis, Animal/immunology , Vaccination/methodsABSTRACT
The crude extract and saponins of Indian pseudoginseng and saponins of Korean ginseng have been studied using a battery of biological tests in rats and mice. Indian pseudoginseng saponins were found to exhibit better activity than the Korean ginseng saponins in several tests employed. The results indicate a need for in-depth study of Indian pseudoginseng as an adaptogenic agent, after cultivation of the plant under controlled conditions.