Antibodies in malarial sera to parasite antigens in the membrane of erythrocytes infected with early asexual stages of Plasmodium falciparum.

• DOI: 10.1084/jem.159.6.1686
• Publication Date: 2004-06-23T21:00:50Z
• Authors: H Perlmann; K Berzins; M Wahlgren; J Carlsson; A Björkman; M E Patarroyo; P Perlmann
• Keywords: Immunofluorescence; Pronase

Monolayers of human erythrocytes (E) infected with Plasmodium falciparum were briefly fixed 1% glutaraldehyde and air dried. They then exposed to sera from patients P. malaria or donors immune this parasite tested in an indirect immunofluorescence assay (IFA). Parasites E made visible by counterstaining ethidium bromide. Immunofluorescence (IF) was restricted the surface E. No antibody binding detected unless dried, suggesting that relevant antigens not available on outer layers surface. Staining over large parts seen already when merozoite penetrated noninfected cells strong containing early stages (rings, trophozoites). It weak absent schizonts. Antibodies different Africa, Colombia, Sweden reacted similarly a Tanzanian strain kept culture for many years parasitized freshly drawn African, Swedish, Colombian patients. All residents holoendemic area (Liberia) IFA positive. In contrast, some Swedish primary infection gave negative results. The results enzyme-linked immunosorbent which dried targets well-correlated, same antibodies these assays. involved susceptible pronase but trypsin neuraminidase. IF inhibited lysates E, extracts, soluble present supernatants normal ghost extracts. inhibitory heat stable (100 degrees C, 5 min). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed immunoblotting either antigen-enriched preparations extracts showed eluted monolayers consistently predominant polypeptide Mr 155,000 two four minor polypeptides lower molecular weights. Metabolic labeling parasites 75Se-methionine indicated derived. We conclude reactions are released bursting schizonts merozoites deposited membrane course invasion.(ABSTRACT TRUNCATED AT 400 WORDS)