English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Background  In the context of the development of a successful malaria vaccine, understanding the polymorphisms exhibited by malaria antigens in natural parasite populations is crucial for proper vaccine design. Recent observations have indicated that sequence polymorphisms in the C-terminal T-cell epitopes of the  Plasmodium falciparum  circumsporozoite protein (Pf csp ) are rather low and apparently stable in low endemic areas. This study sought to assess the pattern in a malaria endemic setting in Africa, using samples from Freetown, Sierra Leone.    Methods  Filter-paper blood samples were collected from subjects at a teaching hospital in Freetown during September–October 2006 and in April–May 2007. The C-terminal portion of the Pf csp  gene spanning the Th2R and Th3R epitopes was amplified and directly sequenced; sequences were analysed with subject parameters and polymorphism patterns in Freetown were compared to that in other malaria endemic areas.    Results and Discussion  Overall, the genetic diversity in Freetown was high. From a total of 99 sequences, 42 haplotypes were identified with at least three accounting for 44.4% (44/99): the 3D7-type (19.2%), a novel type, P-01 (17.2%), and E12 (8.1%). Interestingly, all were unique to the African sub-region and there appeared to be predilection for certain haplotypes to distribute in certain age-groups: the 3D7 type was detected mainly in hospitalized children under 15 years of age, while the P-01 type was common in adult antenatal females (Pearson Chi-square = 48.750, degrees of freedom = 34,  P  = 0.049). In contrast, the single-haplotype predominance (proportion > 50%) pattern previously identified in Asia was not detected in Freetown.    Conclusion  Haplotype distribution of the T-cell epitopes of Pf csp  in Freetown appeared to vary with age in the study population, and the polymorphism patterns were similar to that observed in neighbouring Gambia, but differed significantly at the sequence level from that observed in Asia. The findings further emphasize the role of local factors in generating polymorphisms in the T-cell epitopes of the  P. falciparum  circumsporozoite protein.

malaria journal

T-cell epitope polymorphisms of the Plasmodium falciparum circumsporozoite protein among field isolates from Sierra Leone: age-dependent haplotype distribution?