Panupong Sahaisook. Analysis of crude and excretory-secretory antigens of Dirofilaria immitis adult worms against antibody of brugian filariasis by elisa and immunoblot . Master's Degree(Tropical Medicine). Mahidol University. : Mahidol University, 2007.
Analysis of crude and excretory-secretory antigens of Dirofilaria immitis adult worms against antibody of brugian filariasis by elisa and immunoblot
Abstract:
Serodiagnosis of Brugian filariasis is not available in Thailand and a good test
has not been demonstrated in the literature. Therefore, this study evaluated excretorysecretory
antigens, either non-delipidized (NDLP) or delipidized (DLP) crude extracts
from Dirofilaria immitis fresh and post-RPMI 1640 cultured adult worms, from which
NDLP-fresh male and ether-DLP-fresh female crude extracts were subsequently
selected by immunoblot test using pooled Brugian and negative sera to discriminate
the unsatisfied extracts. IgG-ELISA analyzed male ES antigen (0.5 μg/ml), 1:800-
diluted sera of Brugian filariasis (36 cases), other parasitic infections (181) and
negative controls (54), and 1:8,000 dilution of IgG-conjugate. The test gave 100%
sensitivity and 96.17% specificity at cut-off value 0.587. Only 8 cases of six parasitic
infections (4.42%) and 1 negative control (1.85%) were false-positive. Under the
above conditions, ES female antigen produced 100% sensitivity and 81.12%
specificity at cut-off value 0.616. False positives were found in 37 cases of twenty
parasitic infections (20.11%) and 8 negative controls (14.81%). For NDLP-fresh male
antigen (2 μg/ml), serum dilution (1:1,600), and IgG-conjugate dilution (1:8,000),
gave 88.89% sensitivity and 81.28% specificity, at cut-off value 0.233. The DLPfresh
female antigen used the same conditions as the male crude antigen, except for
IgG-conjugate at 1:16,000, resulting in 94.44% sensitivity and 76.17% specificity at
cut-off value 0.164. Twenty parasitic infections showed false positives, 24.31%
(44/181) and 30.94% (56/181) for crude male and female antigens, respectively. By
immunoblot, only fresh male crude antigen showed an interesting glycoprotein band of
20.62 kDa, but it was inconsistent with Brugian filariasis sera and also cross-reacted
with Bancroftian filariasis (5/5), gnathostomiasis (1/3), and angiostrongyliasis (1/3).
It was concluded that ES male antigen can probably be used in the serodiagnosis of
Brugian filariasis by IgG-ELISA, and male crude antigen may be used in detecting
lymphatic filariasis by IgG-immunoblot. However, a purified antigen is needed for
further study.