An immunogenic antigen of murine Plasmodium yoelii 17X associates with class I MHC glycoproteins.
Reticulocytes infected with the non-lethal variant of Plasmodium yoelii 17X (PY17X-NL) express elevated levels of class I, but not class II, MHC Ag when compared with non-parasitized reticulocytes. In contrast, class I Ag are not detectable on erythrocytes parasitized by the lethal variant PY17X-L. In addition, the responder status of various inbred strains of mice to PY17X-NL has been shown to positively correlate with the levels of class I MHC antigens expressed on PY17X-NL parasitized red blood cells (PRBC). MHC Ag are known to restrict, or guide, immune responses. However, earlier studies have failed to demonstrate H-2 restricted activity in the effector arm of immunity to blood-stage murine malaria. Therefore, we have examined the induction of immunity by irradiated PY17X-NL PRBC. No MHC restriction was observed in the ability of PRBC to immunize recipients. However, using irradiated PRBC bearing low, intermediate or high levels of class I Ag we found that the levels, rather than haplotype, of class I Ag expressed on irradiated PRBC greatly influenced their ability to induce immunity. Furthermore, class I-associated parasite-directed Ag were isolated as an immunogenic complex with anti-class I MHC antibody. Such complexes induced immunity in vivo in the absence of adjuvant suggesting a biologically important mechanism by which non-lethal, reticulocytic forms of malarial parasites may immunize their hosts.
Mogil
R J
RJ
Department of Immunology, University of Alberta, Edmonton, Canada.
Patton
C L
CL
Green
D R
DR
D000818:Animals; D000953:Antigens, Protozoan / Q000276:immunology* / Q000302:isolation & purification; D004910:Erythrocyte Membrane / Q000276:immunology; D004912:Erythrocytes / Q000469:parasitology; D006183:H-2 Antigens / Q000276:immunology*; D007110:Immunity, Active; D007964:Leukocytosis / Q000276:immunology; D008288:Malaria / Q000097:blood / Q000469:parasitology / Q000517:prevention & control; D008562:Membrane Glycoproteins / Q000276:immunology*; D051379:Mice; D008806:Mice, Inbred AKR; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D009000:Monocytes; D010967:Plasmodium yoelii / Q000276:immunology*; D014612:Vaccines / Q000276:immunology
D000953:Antigens, Protozoan; D006183:H-2 Antigens; D008562:Membrane Glycoproteins; D014612:Vaccines