Quantitative determination of sporozoites and circumsporozoite antigen in mosquitoes infected withPlasmodium falciparumorP. vivax

Abstract

It is essential for malariologists and researchers to have simple and accurate means of assessing the threat of Plasmodium parasites. An attempt was therefore made to re-standardize one of the circumsporozoite (CS) ELISA that can be used to detect and quantify the circumsporozoite antigens of P. falciparum and P. vivax. A two-site, 'sandwich' ELISA based on a monoclonal antibody was used to test for the CS antigen and sporozoites of each Plasmodium species simultaneously. Using the resultant optical-density values, standard curves, that permit the number of sporozoites in an infected mosquito to be estimated from the quantification of the CS antigen, were constructed. Using these plots and the CS ELISA, the presence of just 12.5 sporozoites (i.e. 0.8 pg CS antigen) of P. falciparum, four sporozoites (3.2 pg antigen) of P. vivax-210 or 12.5 sporozoites (32.0 pg antigen) of P. vivax-247 could be demonstrated.

Evidence for Transmission of Plasmodium Vivax Among a Duffy Antigen Negative Population in Western Kenya

“…Each ELISA plate contained negative controls and an array of antigen standards required to generate a standard curve and quantitatively estimate the amount of CS antigen present in each sample. 15 Because of low sample volume, the three ELISAs were run consecutively by transferring samples from one assay to the next after the 2-hour sample incubation step. During initial screening, 127 of 4,989 specimens produced results indicating P. vivax antigen (VK 247 only); these were retested under more stringent conditions, yielding 32 specimens containing Ն 1.0 pg P. vivax antigen.…”

Identification of a Novel Gene Encoding a Secreted Antigen 1 of Babesia Gibsoni and Evaluation of Its Use in Serodiagnosis

“…Circulating antigens secreted into plasma by parasites may be used as diagnostic targets to be detected in serological tests to predict the total parasite biomass of infected dogs. In malaria, circulating antigens have been successfully used to develop serological tests to detect antigens, [21][22][23] and several of them have already been used in the development of a model to estimate the total parasite biomass 24 or used in a commercial ELISA kit to test the sensitivity of a drug against Plasmodium in sandwich ELISA. 23 For the purposes of this study, we designed a double-antibody sandwich ELISA to detect BgSA1 in the plasma of dogs infected with B. gibsoni.…”

Plasmodium falciparum infection rates for some Anopheles spp. from Guinea-Bissau, West Africa

“…We followed the Sporozoite ELISA directions provided by the CDC (Sep, 2009 version) with a few modifications (see supplemental document for the modified ELISA protocol). Samples were considered positive if absorbance values were three or more standard deviations from the negative control samples (99% CI) on each ELISA plate ( Beier et al , 1987; De Arruda et al , 2004). …”