[Protective immune mechanisms induced by cellular vaccine made of the erythrocytic Plasmodium yoelii].
OBJECTIVE
To explore the characteristics of protective immunity against Plasmodium yoelii (P.y.) infection by asexual blood-stages cellular vaccine.


METHODS
The particulate vaccines were constructed by saponin or double-distilled-water lysed parasitic red blood cells and inoculated into BALB/c mice by intraperitoneal injection (i.p.). Each group was challenged by the lethal erythrocytic P.y. parasites, and then their parasitemia and survival rates were detected. Expressions of interleukin-4 (IL-4) and interferon-gamma (IFN-gamma) were detected by RT-PCR. ELISA showed the serum antibodies against the malaria challenge and their-subclasses. Special membrane protein was recognized by immunofluorescence assay.


RESULTS
The vaccination with saponified erythrocytic parasites protected the immunized mice against P.y. challenge, while double-distilled-water lysed vaccine did not (P < 0.01). This protection was characterized by the increase of both IFN-gamma/IgG2a and IL-4/IgG1. Meanwhile, MHC class I alpha chain molecule was recognized on the membrane of infected-erthythrocyte.


CONCLUSIONS
Saponified P.y. asexual blood-stage cellular vaccine has a significantly high protective immunity against this lethal P.y. malaria, and the immunity may be associated with the expression levels of IgG2a and IFN-gamma. MHC class I alpha chain on infected erythrocytes may play an important role in the successful immunization.
Yuan
Jie
J
Department of Etiology, Institute of Basic Medical Sciences, CAMS and PUMC, Beijing 100005, China.
Xu
Bei
B
Liu
Bao-feng
BF
D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D015395:Histocompatibility Antigens Class I / Q000097:blood; D007074:Immunoglobulin G / Q000097:blood; D008288:Malaria / Q000517:prevention & control*; D017780:Malaria Vaccines / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D010967:Plasmodium yoelii / Q000276:immunology*; D011897:Random Allocation; D014611:Vaccination
D000913:Antibodies, Protozoan; D015395:Histocompatibility Antigens Class I; D007074:Immunoglobulin G; C099187:MHC class I-related chain A; D017780:Malaria Vaccines