Age-dependent association between IgG2 and IgG3 subclasses to Pf332-C231 antigen and protection from malaria, and induction of protective antibodies by sub-patent malaria infections, in Daraweesh

Giha, Hayder A.; Iriemenam, Nnaemeka C.; Balogun, Halima A.; Arnot, David E.; Theander, Thor G.; Berzins, Klavs; ElGhazali, Gehad

doi:10.1016/j.vaccine.2009.12.018

Cited by 21 publications

(15 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…More stable sexual stage immune responses in adults were previously reported in the Gambia [38]. There may be an innate difference between children and adults in how acquired immune systems function [48], [49], resulting in more efficient immune response after recent exposure in adults compared to children [46], [50], [51]. In addition, higher cumulative exposure may have resulted in a more stable immune response in adults [38].…”

Section: Discussionmentioning

confidence: 71%

“…The use of molecular gametocyte detection methods, unavailable at the time, would have improved our study as some of the exposure to gametocyte antigens in our cohort will have been missed due to the limited sensitivity of microscopy for detecting low density gametocytaemia [9], [42], [43], [44], [45]. Submicroscopic infections were previously associated with the boosting of immune responses to schizont [46] and merozoite antigens [47] and it is therefore possible that sub-microscopic gametocyte densities may have had a similar immune-boosting effect in our study. Because only microscopy data were available, we were only able to test the association between exposure to relatively high, i.e.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

The Dynamics of Naturally Acquired Immune Responses to Plasmodium falciparum Sexual Stage Antigens Pfs230 & Pfs48/45 in a Low Endemic Area in Tanzania

et al. 2010

View full text Add to dashboard Cite

BackgroundNaturally acquired immune responses against sexual stages of P. falciparum can reduce the transmission of malaria from humans to mosquitoes. These antigens are candidate transmission-blocking vaccines but little is known about the acquisition of sexual stage immunity after exposure to gametocytes, or their longevity and functionality. We conducted a longitudinal study on functional sexual stage immune responses.Methodology/Principal FindingsParasitaemic individuals (n = 116) were recruited at a health centre in Lower Moshi, Tanzania. Patients presented with gametocytes (n = 16), developed circulating gametocytes by day 7 (n = 69) or between day 7 and 14 (n = 10) after treatment or did not develop gametocytes (n = 21). Serum samples were collected on the first day of gametocytaemia and 28 and 84 days post-enrolment (or d7, 28, 84 after enrolment from gametocyte-negative individuals). Antibody responses to sexual stage antigens Pfs230 and Pfs48/45 were detected in 20.7% (72/348) and 15.2% (53/348) of the samples, respectively, and were less prevalent than antibodies against asexual stage antigens MSP-119 (48.1%; 137/285) and AMA-1 (52.4%; 129/246)(p<0.001). The prevalence of anti-Pfs230 (p = 0.026) and anti-Pfs48/45 antibodies (p = 0.017) increased with longer duration of gametocyte exposure and had an estimated half-life of approximately 3 months. Membrane feeding experiments demonstrated a strong association between the prevalence and concentration of Pfs230 and Pfs48/45 antibodies and transmission reducing activity (TRA, p<0.01).Conclusions/SignificanceIn a longitudinal study, anti-Pfs230 and Pf48/45 antibodies developed rapidly after exposure to gametocytes and were strongly associated with transmission-reducing activity. Our data indicate that the extent of antigen exposure is important in eliciting functional transmission-reducing immune responses.

show abstract

Section: Discussionmentioning

confidence: 71%

Section: Discussionmentioning

confidence: 99%

The Dynamics of Naturally Acquired Immune Responses to Plasmodium falciparum Sexual Stage Antigens Pfs230 & Pfs48/45 in a Low Endemic Area in Tanzania

et al. 2010

View full text Add to dashboard Cite

show abstract

“…Contrary to previous studies, we did not find evidence for a boosting of immune responses by submicroscopic parasite carriage. 43,44 We observed few submicroscopic infections in children 1-5 years of age ( N = 11), which will have affected our power to detect such an immune-boosting effect. These findings confirm previous indications that parasitization status can be an important consideration in longitudinal assessments of the protective role of immune responses.…”

Section: Discussionmentioning

confidence: 96%

Continuing Intense Malaria Transmission in Northern Uganda

Proietti¹,

Pettinato²,

Kanoi³

et al. 2011

The American Society of Tropical Medicine and Hygiene

View full text Add to dashboard Cite

Abstract. Recent reports of reductions in malaria transmission in several African countries have resulted in optimism that malaria can be eliminated in parts of Africa where it is currently endemic. It is not known whether these trends are global or whether they are also present in areas where political instability has hindered effective malaria control. We determined malaria parasite carriage and age-dependent antibody responses to Plasmodium falciparum antigens in cross-sectional surveys in Apac, northern Uganda that was affected by political unrest. Under-five parasite prevalence was 55.8% (115/206) by microscopy and 71.9% (41/57) by polymerase chain reaction. Plasmodium ovale alone, or as a co-infection, was detected in 8.6% (12/139) and Plasmodium malariae in 4.3% (6/139) of the infections. Age seroprevalence curves gave no indication of recent changes in malaria transmission intensity. Malaria control remains a tremendous challenge in areas that have not benefited from large-scale interventions, illustrated here by the district of Apac.

show abstract

“…Alternative approaches such as long-term active and passive case-detection from a spatially representative sample of communities and health facilities and use of polymerase chain reaction (PCR) [39] to detect low level infections and serological markers to assess Plasmodium antibody exposure [40,41] should be explored. One of the best examples of such a detailed investigation is represented by the 11 year longitudinal study of malaria in one village, Daraweesh in Eastern Sudan [42], which provided important observations on the epidemiology [43], seasonality [44], presence of sub-microscopic chronic P. falciparum infections [45]; ethnic and genetic susceptibility [42,46] and immunity [47] to malaria under conditions of very low transmission intensity.…”

Section: Discussionmentioning

confidence: 99%

The spatial-temporal clustering of Plasmodium falciparum infection over eleven years in Gezira State, The Sudan

Mirghani

Nour

Bushra

et al. 2010

Malar J

View full text Add to dashboard Cite

BackgroundMalaria infection and disease exhibit microgeographic heterogeneity which if predictable could have implications for designing small-area intervention. Here, the space-time clustering of Plasmodium falciparum infections using data from repeat cross-sectional surveys in Gezira State, a low transmission area in northern Sudan, is investigated.MethodsData from cross-sectional surveys undertaken in January each year from 1999-2009 in 88 villages in the Gezira state were assembled. During each survey, about a 100 children between the ages two to ten years were sampled to examine the presence of P. falciparum parasites. In 2009, all the villages were mapped using global positioning systems. Cluster level data were analysed for spatial-only and space-time clustering using the Bernoulli model and the significance of clusters were tested using the Kulldorff scan statistic.ResultsOver the study period, 96,022 malaria slide examinations were undertaken and the P. falciparum prevalence was 8.6% in 1999 and by 2009 this had reduced to 1.6%. The cluster analysis showed the presence of one significant spatial-only cluster in each survey year and one significant space-time cluster over the whole study period. The primary spatial-only clusters in 10/11 years were either contained within or overlapped with the primary space-time cluster.ConclusionThe results of the study confirm the generally low malaria transmission in the state of Gezira and the presence of spatial and space-time clusters concentrated around a specific area in the south of the state. Improved surveillance data that allows for the analysis of seasonality, age and other risk factors need to be collected to design effective small area interventions as Gezira state targets malaria elimination.

show abstract

Age-dependent association between IgG2 and IgG3 subclasses to Pf332-C231 antigen and protection from malaria, and induction of protective antibodies by sub-patent malaria infections, in Daraweesh

Cited by 21 publications

References 37 publications

The Dynamics of Naturally Acquired Immune Responses to Plasmodium falciparum Sexual Stage Antigens Pfs230 & Pfs48/45 in a Low Endemic Area in Tanzania

The Dynamics of Naturally Acquired Immune Responses to Plasmodium falciparum Sexual Stage Antigens Pfs230 & Pfs48/45 in a Low Endemic Area in Tanzania

Continuing Intense Malaria Transmission in Northern Uganda

The spatial-temporal clustering of Plasmodium falciparum infection over eleven years in Gezira State, The Sudan

Contact Info

Product

Resources

About