Fig 1.
Field studies and samples tested.
(A) Central Cameroon field study. Because the three FTS positive samples were very weakly positive by FTS and negative by ICT, we chose not to examine them further. (B) East Region study. Participants who were ICT-positive on initial screening were visited the following week for venous blood collection. Nine venous blood samples were FTS-positive. Two of these tested negative for filarial antigen by ELISA; the other seven were tested further by ELISA and/or western blot as indicated. Gray shading indicates the origin of the samples used in the proteomic analysis.
Table 1.
Central Cameroon field study L. loa and W. bancrofti test results by prior ICT status.
Fig 2.
Loiasis patient sera lack antibodies specific to the AD12 carbohydrate epitope.
Serum samples were tested for the ability to block AD12 binding to B. malayi antigens that contain the AD12 epitope. The horizontal line denotes the mean value for each group.
Table 2.
Summary of Mf burden and antigenemia in ICT/FTS cross-reactive L. loa infected individuals from East Region Cameroon mapping study.
Fig 3.
Loiasis sera positive by LF RDT contain multiple AD12 epitope-containing antigens.
(A) AD12 western blot showing reactive bands in pooled sera from 13 individuals with W. bancrofti infection (Wb CFA+) or 12 uninfected individuals (CFA-). (B) Antigens from sample P811355 (355), and pooled cross-reactive sera. Soluble L. loa antigen (Loa Ag, 0.5 μg) served as a positive control. Because the antigen level was much higher in sample P811355 than in the pooled sample, different chemiluminescent exposure times were used for the same blot (45 seconds for soluble L. loa antigen and P811355; 15 minutes for the pooled serum sample).
Table 3.
Proteins identified in cross-reactive L. loa sera.
Table 4.
GO enrichment analysis of mass spectrometry hits.
Fig 4.
L. loa secretes glycoproteins reactive with monoclonal antibody AD12.
Western blot of AD12 glycoproteins immunoaffinity purified from 1mL of culture supernatant (ES products) from L. loa adult worms (L5) or microfilaria (Mf). Soluble L. loa antigen (Loa Ag, 0.5 μg) served as a positive control.
Table 5.
Proteins identified in L5 stage L. loa excretory/secretory products.