Serological differentiation of acute and chronic schistosomiasis mansoni by antibody responses to keyhole limpet hemocyanin.
The existence of a shared epitope between the hemocyanin of the marine mollusk Megathura crenulata, better known as the keyhole limpet, and schistosomula has been reported. This epitope has been shown to be a major immunogen in human infection. In this study, keyhole limpet hemocyanin (KLH) was used to measure antibodies recognizing the cross-reacting epitopes in sera from patients with acute and chronic schistosomiasis using an enzyme-linked immunosorbent assay (ELISA). Marked differences in IgG and IgM antibody response were noted between acutely and chronically infected patients at a reciprocal serum dilution of up to 2,560. The acute sera had a mean +/- SD OD490 nm values for IgG and IgM of 1.0 +/- 0.44 and 1.34 +/- 0.6 compared to mean +/- SD IgG and IgM absorbance for the chronic sera of 0.22 +/- 0.10 and 0.22 +/- 0.11 respectively. Setting our lowest positive limit at greater than 2 SD above the mean of the chronic sera, 28 of the 30 patients previously diagnosed as having acute schistosomiasis were correctly identified by their IgG and IgM response. Of 5 patients studied longitudinally, IgG persisted at the same levels 10-13 weeks after treatment. IgM levels, on the other hand, showed a tendency to decrease but remained above the established cut-off level. This study provides further evidence for the association of schistosomulum surface carbohydrate antibody with acute infection and demonstrates the ability of a simple non-competitive ELISA using microtiter plates coated with minute quantities of KLH to differentiate serologically between cases of acute and chronic schistosomiasis.
Mansour
M M
MM
U.S. Naval Medical Research Unit No. 3, Cairo, Egypt.
Ali
P O
PO
Farid
Z
Z
Simpson
A J
AJ
Woody
J W
JW
D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000818:Animals; D000909:Antibodies, Helminth / Q000096:biosynthesis*; D000941:Antigens / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D002908:Chronic Disease; D003429:Cross Reactions; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000276:immunology; D006433:Hemocyanins / Q000276:immunology*; D006737:Horseshoe Crabs; D006801:Humans; D007074:Immunoglobulin G / Q000096:biosynthesis; D007075:Immunoglobulin M / Q000096:biosynthesis; D011233:Precipitin Tests; D011237:Predictive Value of Tests; D012550:Schistosoma mansoni / Q000276:immunology*; D012555:Schistosomiasis mansoni / Q000175:diagnosis* / Q000276:immunology
D000909:Antibodies, Helminth; D000941:Antigens; D000939:Epitopes; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D006433:Hemocyanins; C032808:keyhole-limpet hemocyanin