Recognition of the parasite infected cell surface determinants by homologous antiserum raised against infected cell membranes.

Identification of neo-antigenic determinant(s) on parasite infected cell surface is important to control intracellular infections. Such determinant(s) on the surface of intact Plasmodium berghei infected erythrocytes have not been conclusively demonstrated. To generate polyclonal antiserum selectively recognizing the parasite infected cell surface determinant(s), in natural state, we have examined the efficacy of the homologous immunizations, in BALB/c mice, with the membrane rich preparation of: i) erythrocytes in vivo infected with Plasmodium berghei and, ii) macrophages in vitro infected with Leishmania donovani. Anti-infected erythrocyte membrane antiserum specifically recognized, albeit at low level, the infected cell surface as determined by flow cytometry and immunoelectron microscopy. Immunoprecipitation of radiolabeled antigens revealed at least three parasite proteins of > 205 kDa, 160 kDa and 100 kDa specifically present on infected erythrocyte surface. Normal uninfected erythrocytes did not react with the antiserum. Anti-L. donovani-infected macrophage membrane antiserum also recognized only infected macrophage surface and not the normal macrophages. Thus, the approach may find wide application in delineating disease specific determinant(s) on the infected cell surface, particularly to those where animal models are available.