scholarly journals Plasmodium falciparum Parasites Expressing Pregnancy-Specific Variant Surface Antigens Adhere Strongly to the Choriocarcinoma Cell Line BeWo

2006 ◽  
Vol 74 (5) ◽  
pp. 3035-3038 ◽  
Author(s):  
Rikke N. Haase ◽  
Rosette Megnekou ◽  
Maja Lundquist ◽  
Michael F. Ofori ◽  
Lars Hviid ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Cell Line ◽  
Surface Antigens ◽  
Variant Surface Antigens ◽  
Choriocarcinoma Cell Line

ABSTRACT Placenta-sequestering Plasmodium falciparum parasites causing pregnancy-associated malaria express pregnancy-specific variant surface antigens (VSAPAM). We report here that VSAPAM-expressing patient isolates adhere strongly to the choriocarcinoma cell line BeWo and that the BeWo line can be used to efficiently select for VSAPAM expression in vitro.

In vitro selection of Plasmodium falciparum 3D7 for expression of variant surface antigens associated with severe malaria in African children

2003 ◽  
Vol 25 (8-9) ◽  
pp. 421-427 ◽  
Author(s):  
Trine Staalsoe ◽  
Morten A. Nielsen ◽  
Lasse S. Vestergaard ◽  
Anja T. R. Jensen ◽  
Thor G. Theander ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Severe Malaria ◽  
In Vitro Selection ◽  
Surface Antigens ◽  
Variant Surface Antigens ◽  
African Children ◽  
Selection Of

scholarly journals Selective Expression of Variant Surface Antigens Enables Plasmodium falciparum to Evade Immune Clearance in vivo

2020 ◽  
Author(s):  
Marvin Chew ◽  
Weijian Ye ◽  
Radoslaw Igor Omelianczyk ◽  
Charisse Flerida Pasaje ◽  
Regina Hoo ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Immune Evasion ◽  
Immune Escape ◽  
Killer Cell ◽  
Surface Antigens ◽  
Variant Surface Antigens ◽  
Immune Clearance ◽  
Macrophage Phagocytosis

AbstractPlasmodium falciparum has developed extensive mechanisms to evade host immune clearance. Currently, most of our understanding is based on in vitro studies of individual parasite variant surface antigens and how this relates to the processes in vivo is not well-understood. Here, we have used a humanized mouse model to identify parasite factors important for in vivo growth. We show that upregulation of the specific PfEMP1, VAR2CSA and the RIFIN PF3D7_1254800 provides the parasite with protection from macrophage phagocytosis and natural killer cell mediated killing. Taken together, these findings reveal new insights on the molecular and cellular mechanisms that coordinate the immune escape process the parasite utilizes in vivo. As immune evasion may be particularly important during the establishment of the blood stage infection when parasite numbers are still relatively small, identification of specific parasite variant surface antigens provides targets for developing more effective vaccines by targeting parasite immune evasion.

Chromosomes of a Human Choriocarcinoma Cell Line in Vitro

2008 ◽  
Vol 14 (5) ◽  
pp. 312-312
Author(s):  
H. Soma ◽  
T. Miyashita ◽  
A. Nakamura
Keyword(s):  
Cell Line ◽  
Choriocarcinoma Cell Line

scholarly journals Immunoglobulin G Isotype Responses to Variant Surface Antigens of Plasmodium falciparum in Healthy Gabonese Adults and Children during and after Successive Malaria Attacks

2004 ◽  
Vol 72 (1) ◽  
pp. 284-294 ◽  
Author(s):  
Gerardo Cabrera ◽  
Clarisse Yone ◽  
Anne E. Tebo ◽  
Jan van Aaken ◽  
Bertrand Lell ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Immunoglobulin G ◽  
Surface Antigens ◽  
Healthy Adults ◽  
Healthy Children ◽  
Variant Surface Antigens ◽  
Age Related ◽  
Adults And Children ◽  
The Individual ◽  
Malaria Episodes

ABSTRACT We assessed immunoglobulin G (IgG) isotype responses with specificity for the variant surface antigens (VSA) of heterologous Plasmodium falciparum isolates by using flow cytometry and plasma from healthy Gabonese adults and from children during and after two consecutive malaria episodes. The individual isolate-specific antibody profiles differed markedly in terms of their isotype content but were similar for healthy adults and healthy uninfected children. In healthy adults, IgG3 and IgG2 responses were the highest, while in healthy children, IgG3 and IgG4 predominated. A transiently elevated IgG1 response was observed during the second of two successive malaria episodes in children, signaling P. falciparum infection-induced cross-reactive anti-VSA responses. Our findings highlight the prominence of IgG3 in the overall profile of these responses but also indicate a marked age-related increase in the prevalence of anti-VSA antibodies of the classically noncytophilic IgG2 isotype, possibly reflecting the high frequency of the histidine-131 variant of FcγRIIA in the Gabonese population.

scholarly journals Temporal Expression and Localization Patterns of Variant Surface Antigens in Clinical Plasmodium falciparum Isolates during Erythrocyte Schizogony

PLoS ONE ◽  
2012 ◽  
Vol 7 (11) ◽  
pp. e49540 ◽  
Author(s):  
Anna Bachmann ◽  
Michaela Petter ◽  
Ann-Kathrin Tilly ◽  
Laura Biller ◽  
Karin A. Uliczka ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Surface Antigens ◽  
Temporal Expression ◽  
Variant Surface Antigens

scholarly journals Placental Malaria Induces Variant-Specific Antibodies of the Cytophilic Subtypes Immunoglobulin G1 (IgG1) and IgG3 That Correlate with Adhesion Inhibitory Activity

2005 ◽  
Vol 73 (9) ◽  
pp. 5903-5907 ◽  
Author(s):  
Salenna R. Elliott ◽  
Amy K. Brennan ◽  
James G. Beeson ◽  
Eyob Tadesse ◽  
Malcolm E. Molyneux ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Inhibitory Activity ◽  
Placental Malaria ◽  
Surface Antigens ◽  
Phagocytic Cells ◽  
Specific Antibodies ◽  
Variant Surface Antigens ◽  
And Control ◽  
Chondroitin Sulfate A ◽  
In Pregnancy

ABSTRACT Antibodies targeting variant antigens on the surfaces of chondroitin sulfate A (CSA)-binding malaria-infected erythrocytes have been linked to protection against the complications of malaria in pregnancy. We examined the isotype/subtype profiles of antibodies that bound to variant surface antigens expressed by CSA-adherent Plasmodium falciparum in pregnant Malawian women with and without histologically defined placental malaria. Women in their first pregnancy with placental malaria produced significantly greater amounts of immunoglobulin G1 (IgG1) and IgG3 reactive with surface antigens of malaria-infected erythrocytes than uninfected women of the same gravidity. IgG1 and IgG3 levels in infected and control women in later pregnancies were similar to those in infected women in their first pregnancy. Levels of IgG2 and IgG4 were similarly low in infected and uninfected women of all gravidities. IgM that bound to the surface of CSA-adherent P. falciparum occurred in all groups of women and malaria-naïve controls. There was a significant correlation between IgG1 and IgG3 levels, indicating that women usually produced both subtypes. Levels of IgG1 and IgG3 correlated with the ability of serum or plasma to inhibit parasite adhesion to CSA. Taken together, these data suggest that IgG1 and IgG3 dominate the IgG response to placental-type variant surface antigens. They may function by blocking parasite adhesion to placental CSA, but given their cytophilic nature, they might also opsonize malaria-infected erythrocytes for interaction with Fc receptors on phagocytic cells.

scholarly journals Effects of Pregnancy and Intensity of Plasmodium falciparum Transmission on Immunoglobulin G Subclass Responses to Variant Surface Antigens

2005 ◽  
Vol 73 (7) ◽  
pp. 4112-4118 ◽  
Author(s):  
Rosette Megnekou ◽  
Trine Staalsoe ◽  
Diane W Taylor ◽  
Rose Leke ◽  
Lars Hviid
Keyword(s):  
Plasmodium Falciparum ◽  
Gestational Age ◽  
Immunoglobulin G ◽  
Surface Antigens ◽  
Transmission Intensity ◽  
Parasite Transmission ◽  
Variant Surface Antigens ◽  
Pregnancy Status ◽  
Immunoglobulin G Subclass ◽  
Very High

ABSTRACT Placenta-sequestering Plasmodium falciparum involved in the pathogenesis of pregnancy-associated malaria (PAM) in otherwise clinically immune women expresses particular variant surface antigens (VSAPAM) on the surface of infected erythrocytes that differ from VSA found in parasitized nonpregnant individuals (non-PAM type VSA). We studied levels of immunoglobulin G (IgG) and IgG subclasses with specificity for VSAPAM and for non-PAM type VSA in pregnant and nonpregnant women from two sites with different endemicities in Cameroon. We found that VSAPAM-specific responses depended on the pregnancy status, parity, gestational age, and parasite transmission intensity, whereas only the parasite transmission intensity influenced the levels of IgG specific for non-PAM type VSA. For both types of VSA, the responses were dominated by the cytophilic subclass IgG1, followed by IgG3. In pregnant women, the levels of VSAPAM-specific antibodies either were very low or negative or were very high, whereas the levels of the antibodies specific for non-PAM type VSA were uniformly high. Interestingly, the levels of VSAPAM-specific IgG1 increased with increasing gestational age, while the levels of the corresponding IgG3 tended to decrease with increasing gestational age. The IgG subclass responses with specificity for non-PAM type VSA did not vary significantly with gestational age. Taken together, our data indicate that IgG1 and to a lesser extent IgG3 are the main subclasses involved in acquired VSAPAM-specific immunity to pregnancy-associated malaria.

scholarly journals The Association of High Prevalence of Trophozoites in Peripheral Blood with Lower Antibody Response toP. falciparumInfected Erythrocytes among Asymptomatic Children in Sudan

2016 ◽  
Vol 2016 ◽  
pp. 1-4
Author(s):  
Sara N. Mohamed ◽  
Dina A. Hassan ◽  
Abdelrahim M. El Hussein ◽  
Ihssan M. Osman ◽  
Muntasir E. Ibrahim ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Plasmodium Falciparum ◽  
Peripheral Blood ◽  
Surface Antigens ◽  
Igg Antibodies ◽  
Autologous Plasma ◽  
Variant Surface Antigens ◽  
Asymptomatic Children ◽  
Infected Rbcs ◽  
The Mean

Background. The most prominent variant surface antigens (VSAs) ofPlasmodium falciparumare the var gene-encodedPlasmodium falciparumerythrocyte membrane protein 1 (PfEMP1) family, which serves as a parasite-sequestering ligand to endothelial cells. In this study we have examined the antibody reactivity of autologous plasma from symptomatic and asymptomatic malaria infected children against the infected erythrocytes’ surface antigens using flow cytometry.Methods. Ethidium-bromide-labelled erythrocytic mature forms ofP. falciparumparasites obtained from symptomatic and asymptomatic children were sequentially incubated with autologous plasma and fluorescein isothiocyanate-conjugated (FITC) antihuman IgG. Plasma antibody reactivity was detected by flow cytometry.Results. Asymptomatic children had more prevalence of trophozoites in peripheral blood (66%) compared to symptomatic children (16%),p=0.002. The mean percentage of infected RBCs reacting with autologous sera was 89.78 among symptomatic children compared to 79.62 among asymptomatic children (p=0.09). Moreover, the mean fluorescence intensity (MFI) in the asymptomatic was significantly higher compared to symptomatic children (pvalue = 0.040).Conclusion. Variant surface antigens onPlasmodium falciparuminfected RBCs from symptomatic malaria children tend to be better recognized by IgG antibodies. This may suggest a role of some IgG antibodies in severity of malaria.

Sign in / Sign up

Export Citation Format

Share Document