Penetration of Erythrocytes by Merozoites of Mammalian and Avian Malarial Parasites

Ladda, Roger L.; Aikawa, Masamichi; Sprinz, Helmuth

doi:10.2307/3277308

Cited by 136 publications

(49 citation statements)

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“…That antigens are released during schizont development and rupture or merozoite invasion has been reported (12,40,41). The antigens responsible for the E surface IF described by us may be part of the merozoite coat that is peeled off at invasion or may be released from the merozoite rhoptries (14,(42)(43)(44). Our findings further imply that they have affinity for receptor structures in the E membrane (45)(46)(47).…”

Section: Discussionsupporting

confidence: 58%

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

Perlmann¹,

Berzins²,

Wahlgren³

et al. 1984

The Journal of Experimental Medicine

255

159

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

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Section: Discussionsupporting

confidence: 58%

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

Perlmann¹,

Berzins²,

Wahlgren³

et al. 1984

The Journal of Experimental Medicine

255

159

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“…Several investigators (9)(10)(11)29) have proposed that during invasion, material within the rhoptry is incorporated into the host membrane, facilitating PVM formation. Stewart et al (10) localized membranous whorls in the rhoptry-microneme complex of the merozoite but not in trophozoites or immature schizonts.…”

Section: Methodsmentioning

confidence: 99%

“…More recent studies show the initial interaction between Plasmodium falciparum (Pf) merozoite and erythrocyte to be mediated by specific receptors on both cells (4)(5)(6)(7)(8). The requirement for the merozoite to attach with its apical end before successful invasion (2,9) and the observation that the rhoptry-microneme complex of the merozoite extends to the apical end (2,9,10) suggest the rhoptries contain material released by the parasite upon invasion. Recently, fixation of merozoites with tannic acid has permitted EM visualization of membranous whorls associated with the rhoptries near the apical end of Pf merozoites.…”

mentioning

confidence: 99%

The role of lipids in Plasmodium falciparum invasion of erythrocytes: a coordinated biochemical and microscopic analysis.

Mikkelsen

Kamber

Wadwa

et al. 1988

Proc. Natl. Acad. Sci. U.S.A.

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The role of lipids in Plasmodium falciparum invasion of erythrocytes was investigated by biochemical and fluorescent microscopic analysis. Metabolic incorporation of radioactive oleate or palmitate and fractionation of radiolabeled phospholipids by thin-layer chromatography revealed no difference in the major phospholipid classes of schizonts and early ring forms after merozoite invasion. Fluorescent anthroyloxy derivatives of oleate and palmitate were also metabolically incorporated into parasite phospholipids. By microscopic analysis, the fluorescent phospholipids were seen localized in the plasma membrane and, within the merozoite, concentrated near the apical end. During invasion fluorescent phospholipid appeared to be injected from the apical end of the merozoite into the host membrane, both within and outside the parasite-host membrane junctions. After invasion fluorescent lipid was only found in the parasite plasma membrane and/or parasitophorous vacuole membrane. Parallel experiments with a fluorescent cholesterol derivative, incorporated into parasite membranes by exchange, revealed neither heterogeneous distribution of label within the parasite nor evidence for cholesterol transfer from merozoite to host cell membrane. Results suggest that during invasion no major covalent alteration of parasite lipids, such as lysophospholipid formation, occurs. However, invasion and formation of the parasitophorous vacuolar membrane apparently involves insertion of parasite phospholipids into the host membrane.

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“…The processes by which the invasive forms of the parasite recognize and penetrate a host cell are still not completely understood and most of our current knowledge is based on studies of the merozoite (Ladda et al, 1969;Bannister et al, 1975;Dvorak et al, 1975;Aikawa et al, 1978;Miller et al, 1979;Mitchell and Bannister, 1988;Sherman, 1999). The main steps in the invasion process are: (i) initial merozoite binding, reorientation and deformation of erythrocyte, (ii) formation of a junction (the irreversible commitment of the parasite to invasion) and (iii) parasite entry.…”

Section: Introductionmentioning

confidence: 99%

Invasion of host cells by malaria parasites: a tale of two protein families

Iyer

Grüner

Rénia

et al. 2007

Molecular Microbiology

129

124

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SummaryMalaria parasites are obligate intracellular parasites whose invasive stages select and invade the unique host cell in which they can develop with exquisite specificity and efficacy. Most studies aimed at elucidating the molecules and the mechanisms implicated in the selection and invasion processes have been conducted on the merozoite, the stage that invades erythrocytes to perpetuate the pathological cycles of parasite multiplication in the blood. Bioinformatic analysis has helped identify the members of two parasite protein families, the reticulocyte-binding protein homologues (RBL) and erythrocyte binding like (EBL), in recently sequenced genomes of different Plasmodium species. In this article we review data from classical studies and gene disruption experiments that are helping to illuminate the role of these proteins in the selection-invasion processes. The manner in which subsets of proteins from each of the families act in concert suggests a model to explain the ability of the parasites to use alternate pathways of invasion. Future perspectives and implications are discussed.

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Penetration of Erythrocytes by Merozoites of Mammalian and Avian Malarial Parasites

Cited by 136 publications

References 0 publications

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

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

The role of lipids in Plasmodium falciparum invasion of erythrocytes: a coordinated biochemical and microscopic analysis.

Invasion of host cells by malaria parasites: a tale of two protein families

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