scholarly journals Plasmodium falciparum Merozoite Surface Protein 6 Displays Multiple Targets for Naturally Occurring Antibodies That Mediate Monocyte-Dependent Parasite Killing

2005 ◽  
Vol 73 (2) ◽  
pp. 1235-1238 ◽  
Author(s):  
Subhash Singh ◽  
Soe Soe ◽  
Christian Roussilhon ◽  
Giampietro Corradin ◽  
Pierre Druilhe
Keyword(s):  
Plasmodium Falciparum ◽  
Surface Protein ◽  
Merozoite Surface Protein ◽  
Naturally Occurring ◽  
C Terminus ◽  
Sequence Homologies ◽  
Merozoite Surface Antigen ◽  
Falciparum Merozoite ◽  
Erythrocytic Cycle ◽  
Naturally Occurring Antibodies

ABSTRACT Plasmodium falciparum MSP6 is a merozoite surface antigen that shows organization and sequence homologies similar to those of MSP3. Within its C-terminus conserved region, it presents some epitopes that are cross-reactive with MSP3 and others that are not, both being targets of naturally occurring antibodies that block the P. falciparum erythrocytic cycle in cooperation with monocytes.

scholarly journals Fine Specificity of Serum Antibodies to Plasmodium falciparum Merozoite Surface Protein, PfMSP-119, Predicts Protection from Malaria Infection and High-Density Parasitemia

2004 ◽  
Vol 72 (3) ◽  
pp. 1557-1567 ◽  
Author(s):  
Brenda A. Okech ◽  
Patrick H. Corran ◽  
James Todd ◽  
Amy Joynson-Hicks ◽  
Chairat Uthaipibull ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Surface Protein ◽  
Field Studies ◽  
Merozoite Surface Protein ◽  
High Density ◽  
Enzyme Linked Immunosorbent Assay ◽  
Fine Specificity ◽  
Vaccine Trials ◽  
C Terminus ◽  
Falciparum Merozoite

ABSTRACT Antibodies to the C terminus of the Plasmodium falciparum merozoite surface protein, PfMSP-119, may inhibit merozoite invasion or block the effects of inhibitory antibodies. Here, using a competition enzyme-linked immunosorbent assay and antibody binding to wild-type and mutated recombinant proteins, we show that there are marked variations between individuals in the fine specificity of naturally acquired anti-MSP-119 antibodies. Furthermore, although neither the prevalence nor the concentration of total anti-MSP-119 antibodies was associated with resistance to malaria in African children, significant associations were observed between antibody fine specificity and subsequent risk of infection and high-density parasitemia during a follow-up period. Thus, the fine specificity of naturally acquired human anti-MSP-119 antibodies is crucial in determining their function. Future field studies, including the evaluation of PfMSP-1 vaccine trials, should include assays that explore antibody fine specificity as well as titer.

scholarly journals Plasmodium falciparum Merozoite Surface Protein 8 Is a Ring-Stage Membrane Protein That Localizes to the Parasitophorous Vacuole of Infected Erythrocytes

2005 ◽  
Vol 73 (7) ◽  
pp. 3912-3922 ◽  
Author(s):  
Damien R. Drew ◽  
Paul R. Sanders ◽  
Brendan S. Crabb
Keyword(s):  
Plasmodium Falciparum ◽  
Parasitophorous Vacuole ◽  
Surface Protein ◽  
Merozoite Surface Protein ◽  
Food Vacuole ◽  
Ring Stage ◽  
C Terminus ◽  
Falciparum Merozoite ◽  
Merozoite Antigens ◽  
Epidermal Growth

ABSTRACT To date, the following seven glycosylphosphatidylinositol (GPI)-anchored merozoite antigens have been described in Plasmodium falciparum: merozoite-associated surface protein 1 (MSP-1), MSP-2, MSP-4, MSP-5, MSP-8, MSP-10, and the rhoptry-associated membrane antigen. Of these, MSP-1, MSP-8, and MSP-10 possess a double epidermal growth factor (EGF)-like domain at the C terminus, and these modules are considered potential targets of protective immunity. In this study, we found that surprisingly, P. falciparum MSP-8 is transcribed and translated in the ring stage and is absent from the surface of merozoites. MSP-8 is the only GPI-anchored protein known to be expressed at this time. It is synthesized as a mature 80-kDa protein which is rapidly processed to a C-terminal 17-kDa species that contains the double EGF module. As determined by a combination of immunofluorescence and membrane purification approaches, it appears likely that MSP-8 initially localizes to the parasite plasma membrane in the ring stage. Although the C-terminal 17-kDa fragment is present in more mature stages, at these times it is found in the food vacuole. We successfully disrupted the MSP-8 gene in P. falciparum, a process that validated the specificity of the antibodies used in this study and also demonstrated that MSP-8 does not play a role essential to maintenance of the erythrocyte cycle. This finding, together with the observation that MSP-8 is exclusively intracellular, casts doubt over the viability of this antigen as a vaccine. However, it is still possible that MSP-8 is involved in an early parasitophorous vacuole function that is significant for pathogenesis in the human host.

scholarly journals Plasmodium falciparum merozoite surface protein 2 is unstructured and forms amyloid-like fibrils

2009 ◽  
Vol 166 (2) ◽  
pp. 159-171 ◽  
Author(s):  
Christopher G. Adda ◽  
Vince J. Murphy ◽  
Margaret Sunde ◽  
Lynne J. Waddington ◽  
Jesse Schloegel ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Surface Protein ◽  
Merozoite Surface Protein ◽  
Falciparum Merozoite

scholarly journals Comparative Immunogenicities of Full-Length Plasmodium falciparum Merozoite Surface Protein 3 and a 24-Kilodalton N-Terminal Fragment

2011 ◽  
Vol 18 (8) ◽  
pp. 1221-1228 ◽  
Author(s):  
Maryam Imam ◽  
Yengkhom Sangeeta Devi ◽  
Akhilesh K. Verma ◽  
Virander Singh Chauhan
Keyword(s):  
Plasmodium Falciparum ◽  
Surface Protein ◽  
Merozoite Surface Protein ◽  
Terminal Region ◽  
Content Type ◽  
Conserved Domain ◽  
Terminal Fragment ◽  
Falciparum Merozoite ◽  
Form Part ◽  
Parasite Lysate

ABSTRACTRecombinantPlasmodium falciparummerozoite surface protein 3 (PfMSP3F) and a 24-kDa fragment from its N terminus (MSP3N) that includes the essential conserved domain, which elicits the maximum antibody (Ab)-dependent cellular inhibition (ADCI), were expressed as soluble proteins inEscherichia coli. Both proteins were found to be stable in both soluble and lyophilized forms. Immunization with MSP3F and MSP3N formulated separately with two human-compatible adjuvants, aluminum hydroxide (Alhydrogel) and Montanide ISA 720, produced significant antibody responses in mice and rabbits. Polyclonal Abs against both antigens recognized native MSP3 in the parasite lysate. These two Abs also recognized two synthetic peptides, previously characterized to possess B cell epitopes from the N-terminal region. Antibody depletion assay showed that most of the IgG response is directed toward the N-terminal region of the full protein. Anti-MSP3F and anti-MSP3N rabbit antibodies did not inhibit merozoite invasion or intraerythrocytic development but significantly reduced parasitemia in the presence of human monocytes. The ADCI demonstrated by anti-MSP3N antibodies was comparable to that exhibited by anti-MSP3F antibodies (both generated in rabbit). These results suggest that the N-terminal fragment of MSP3 can be considered a vaccine candidate that can form part of a multigenic vaccine against malaria.

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