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Multi-epitope chimeric antigen used as a serological marker to estimate Plasmodium falciparum transmission intensity in the border area of China-Myanmar

View Article: PubMed Central - PubMed

ABSTRACT

Background: Following the decline of malaria transmission in many countries and regions, serological parameters have become particularly useful for estimating malaria transmission in low-intensity areas. This study evaluated a novel serological marker, Malaria Random Constructed Antigen-1 (M.RCAg-1), which contains 11 epitopes from eight Plasmodium falciparum antigens, as a tool for assessing malaria transmission intensity along the border area of China-Myanmar.

Method: Serum from Plasmodium falciparum and P. vivax patients was used to detect the properties of M.RCAg-1 and antibody responses. Cross-sectional surveys were conducted at the China-Myanmar border and in Hainan province in 2012 and 2013 using cluster sampling. Filter blood spot papers were collected from all participants. Antibodies against M.RCAg-1 were detected using indirect ELISA. The Mann–Whitney test and Spearman’s rank correlation test were performed to analyze antibody data. P. falciparum malaria transmission intensity was estimated using a catalytic conversion model based on the maximum likelihood of generating a community seroconversion rate (SCR).

Results: M.RCAg-1 was well-recognized by the naturally acquired anti-malaria antibodies in P. falciparum patients and had very limited cross-reactivity with P. vivax infection. The total amount of IgG antibodies was decreased with the decrease in parasitemia after taking medication and lasted several weeks. In a population survey, the antibody levels were higher in residents living close to the China-Myanmar border than those living in non-epidemic areas (P < 0.0001), but no significant difference was observed between residents from Hainan and non-epidemic areas. The calculated SCR was 0.0128 for Jieyangka, 0.004 for Susuzhai, 0.0047 for Qiushan, and 0.043 for Kayahe. The estimated exposure rate obtained from the anti-M.RCAg-1 antibody level correlated with traditional measures of transmission intensity derived from altitude.

Conclusion: Our study demonstrates that M.RCAg-1 is potentially useful as a serological indicator of exposure to P. falciparum malaria, especially for malaria surveillance in low transmission areas.

Electronic supplementary material: The online version of this article (doi:10.1186/s40249-016-0194-x) contains supplementary material, which is available to authorized users.

No MeSH data available.


Anti-M.RCAg-1 antibody levels in different age groups and different study sites. a Grouped by age, to compare antibody levels of individuals from different study sites. b Grouped by study site, to compare antibody levels of individuals with different ages
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Fig4: Anti-M.RCAg-1 antibody levels in different age groups and different study sites. a Grouped by age, to compare antibody levels of individuals from different study sites. b Grouped by study site, to compare antibody levels of individuals with different ages

Mentions: To determine whether M.RCAg-1 can be used to estimate exposure to Pf malaria, especially in low transmission areas, we tested the antibody levels in eluates from blood spots collected from residents living in Hainan province and along the China-Myanmar border. We found no significant differences in the antibody levels of residents from Hainan and participants from Beijing (P = 0.176). However, on the China-Myanmar border, the antibody levels of residents from the four villages were significantly higher than the levels in participants from Beijing (P < 0.0001). In the three villages in Yunnan province, antibody levels decreased with increasing elevation (r = −0.258, P < 0.0001 in 5-14-year-olds; r = −0.492, P < 0.0001 in 15-30-year-olds; r = −0.356, P = 0.001 in 31-45-year-olds; and r = −0.473, P < 0.0001 in >45-year-olds; Fig. 4a). The antibody concentrations increased with increasing age (r = 0.421, P < 0.0001 in Jieyangka; r = 0.435, P < 0.0001 in Susuzhai; r = 0.451, P < 0.0001 in Qiushan; and r = 0.374, P = 0.003 in Kayahe; Fig. 4b). No difference in antibody levels was found between males and females for any of the villages (P > 0.05).Fig. 4


Multi-epitope chimeric antigen used as a serological marker to estimate Plasmodium falciparum transmission intensity in the border area of China-Myanmar
Anti-M.RCAg-1 antibody levels in different age groups and different study sites. a Grouped by age, to compare antibody levels of individuals from different study sites. b Grouped by study site, to compare antibody levels of individuals with different ages
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC5015264&req=5

Fig4: Anti-M.RCAg-1 antibody levels in different age groups and different study sites. a Grouped by age, to compare antibody levels of individuals from different study sites. b Grouped by study site, to compare antibody levels of individuals with different ages
Mentions: To determine whether M.RCAg-1 can be used to estimate exposure to Pf malaria, especially in low transmission areas, we tested the antibody levels in eluates from blood spots collected from residents living in Hainan province and along the China-Myanmar border. We found no significant differences in the antibody levels of residents from Hainan and participants from Beijing (P = 0.176). However, on the China-Myanmar border, the antibody levels of residents from the four villages were significantly higher than the levels in participants from Beijing (P < 0.0001). In the three villages in Yunnan province, antibody levels decreased with increasing elevation (r = −0.258, P < 0.0001 in 5-14-year-olds; r = −0.492, P < 0.0001 in 15-30-year-olds; r = −0.356, P = 0.001 in 31-45-year-olds; and r = −0.473, P < 0.0001 in >45-year-olds; Fig. 4a). The antibody concentrations increased with increasing age (r = 0.421, P < 0.0001 in Jieyangka; r = 0.435, P < 0.0001 in Susuzhai; r = 0.451, P < 0.0001 in Qiushan; and r = 0.374, P = 0.003 in Kayahe; Fig. 4b). No difference in antibody levels was found between males and females for any of the villages (P > 0.05).Fig. 4

View Article: PubMed Central - PubMed

ABSTRACT

Background: Following the decline of malaria transmission in many countries and regions, serological parameters have become particularly useful for estimating malaria transmission in low-intensity areas. This study evaluated a novel serological marker, Malaria Random Constructed Antigen-1 (M.RCAg-1), which contains 11 epitopes from eight Plasmodium falciparum antigens, as a tool for assessing malaria transmission intensity along the border area of China-Myanmar.

Method: Serum from Plasmodium falciparum and P. vivax patients was used to detect the properties of M.RCAg-1 and antibody responses. Cross-sectional surveys were conducted at the China-Myanmar border and in Hainan province in 2012 and 2013 using cluster sampling. Filter blood spot papers were collected from all participants. Antibodies against M.RCAg-1 were detected using indirect ELISA. The Mann&ndash;Whitney test and Spearman&rsquo;s rank correlation test were performed to analyze antibody data. P. falciparum malaria transmission intensity was estimated using a catalytic conversion model based on the maximum likelihood of generating a community seroconversion rate (SCR).

Results: M.RCAg-1 was well-recognized by the naturally acquired anti-malaria antibodies in P. falciparum patients and had very limited cross-reactivity with P. vivax infection. The total amount of IgG antibodies was decreased with the decrease in parasitemia after taking medication and lasted several weeks. In a population survey, the antibody levels were higher in residents living close to the China-Myanmar border than those living in non-epidemic areas (P&thinsp;&lt;&thinsp;0.0001), but no significant difference was observed between residents from Hainan and non-epidemic areas. The calculated SCR was 0.0128 for Jieyangka, 0.004 for Susuzhai, 0.0047 for Qiushan, and 0.043 for Kayahe. The estimated exposure rate obtained from the anti-M.RCAg-1 antibody level correlated with traditional measures of transmission intensity derived from altitude.

Conclusion: Our study demonstrates that M.RCAg-1 is potentially useful as a serological indicator of exposure to P. falciparum malaria, especially for malaria surveillance in low transmission areas.

Electronic supplementary material: The online version of this article (doi:10.1186/s40249-016-0194-x) contains supplementary material, which is available to authorized users.

No MeSH data available.