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

Abstract

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.

Cutting Edge: Antibody-Mediated Cessation of Hemotropic Infection by the Intraerythrocytic Mouse PathogenBartonella grahamii

“…For example, specific Abs bind to Plasmodium spp. Ag exposed on the surface of infected erythrocytes (29). Such binding may cause complement-mediated host cell lysis and opsonization.…”

Applications of Flow Cytometry to Clinical Microbiology

“…Thus, if the parasite is inside the cell, its DNA can be stained with specific fluorochromes and detected by FCM. The multiparameter analysis permitted by FCM can be used to study other characteristics, such as parasite antigens expressed by the erythrocyte (which can be detected by antibodies conjugated with fluorochromes) (54,153) or the viability state of the parasitised cell. Furthermore, the technique can be used with either fresh or fixed cells (241,242).…”

Strain-specific recognition of live Leishmania donovani promastigotes by homologous antiserum raised against a crude membrane fraction of infected macrophages

“…Parasites and animals L. donovani strains RMRI68 (Sodhi et al 1992;Choudhury et al 1997), AG83 (MHOM/IN/83/AG83), and DD8 (MHOM/IN/80/ DD8) were isolates from Indian patients with kala azar. Parasites were maintained in vitro in NNN medium with a few mass cultivations in RPMI 1640 (Gibco, Grand Island, N.Y.) supplemented with 10% (v/v) fetal calf serum (FCS, Sera Lab) (RPMI complete medium).…”

“…The method followed was essentially that described in our earlier paper (Choudhury et al 1997). The infection load obtained, using 2 h infection followed by a 4-h post-infection period, with strain RMRI68 and strain AG83, was 3±4 parasites/cell with a 60% level of infection and 1±2 parasites/cell with a 90% level of infection, respectively.…”

“…We recently demonstrated that the polyclonal antiserum or monoclonal antibodies (MAbs) generated by homologous immunization with parasite-infected cell membranes eectively react with neo-antigenic determinants on the infected cell surface (Owais et al 1995;Choudhury et al 1997). Based on this, in this paper we have checked if such an immunization strategy is useful in diverting the immune response towards`minor' antigenic determinant(s) in the absence of major parasite immunogenic components.…”