Induction of cellular and humoral responses by autoclaved and heat-killed antigen of Leishmania donovani in experimental visceral leishmaniasis.
The potential of autoclaved and heat-killed antigen of Leishmania donovani to induce cell-mediated and humoral response has been evaluated in the present study. The vaccines were delivered thrice subcutaneously at an interval of 2 weeks. Two weeks after second booster, BALB/c mice were challenged with 10(7) stationary phase promastigotes of L. donovani. Significant protection was achieved in immunized mice against L. donovani challenge with 69% to 76% and 59% to 64% reduction in parasite load in the liver and spleen respectively. Immunization induced significantly higher level of delayed type hypersensitivity (DTH) response in mice immunized with heat-killed antigen followed by autoclaved antigen. The immune response was assessed by quantifying Leishmania-specific antibodies and cytokine production. The antibody response was predominantly of IgG type with increased IgG2a production and lesser amount of IgM. The immunization preferentially stimulates the production of IFN-gamma and IL-2 in splenocytes which suggests a Th1 type response with a concomitant down-regulation of IL-10 and IL-4. These results indicate a potential for the heat-killed and autoclaved antigen as a vaccine which could trigger cell-mediated immune response.
Nagill
Rajeev
R
Parasitology Laboratory, Department of Zoology, Panjab University, Chandigarh-160014, India.
Mahajan
Raman
R
Sharma
Meenakshi
M
Kaur
Sukhbir
S
D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood*; D000953:Antigens, Protozoan / Q000008:administration & dosage / Q000276:immunology*; D016207:Cytokines / Q000378:metabolism; D007114:Immunization; D007893:Leishmania donovani / Q000276:immunology*; D054332:Leishmaniasis Vaccines / Q000008:administration & dosage / Q000276:immunology*; D007898:Leishmaniasis, Visceral / Q000276:immunology* / Q000469:parasitology / Q000517:prevention & control; D051379:Mice; D008807:Mice, Inbred BALB C; D013242:Sterilization / Q000295:instrumentation / Q000379:methods; D018417:Th1 Cells / Q000276:immunology*; D015164:Vaccines, Inactivated / Q000008:administration & dosage / Q000276:immunology*
D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D016207:Cytokines; D054332:Leishmaniasis Vaccines; D015164:Vaccines, Inactivated