Detection of Circulating Antigen in Bancroftian Filariasis by using a Monoclonal Antibody

Abstract

A monoclonal antibody designated Gib 13-5-2 (Gib 13) and directed against the cattle parasite Onchocerca gibsoni was used in a two-site immunoradiometric assay (IRMA) for detection of circulating antigen in the sera of Wuchereria bancrofti-infected individuals from Sri Lanka and Papua New Guinea. The microfilaremic patients were, in general, serum antigen positive by the Gib 13 IRMA. Among the amicrofilaremic patients, 47% of those with lymphedema, lymphangitis, hydrocele, etc., and 25% of those with elephantiasis had circulating antigen. Correlation of the presence of serum antigen with clinical status indicated that the Gib 13 target antigen in serum is probably an indicator of either active or early infection, or of both. The antigen was also detected in the urine of some patients. By sodium dodecyl sulphate polyacrylamide gel electrophoresis immunoblotting, Gib 13 target antigens of molecular weights 67,000 and 52,000 were identified.

Differential recognition of a protective filarial antigen by antibodies from humans with bancroftian filariasis.

“…The Gib 13 antibody is directed against an epitope contained in egg antigens of the filarial parasite Onchocerca gibsoni (26). Increased amounts of cross-reacting antigens are present in the sera of W. bancrofti-infected subjects (27,28). In the current study, the mean Gib 13 level was significantly higher (P < 0.05) in microfilaremic subjects than in age-and disease-matched amicrofilaremic individuals.…”

“…The level of microfilaremia was determined by the nuclepore filtration technique from a 4-ml sample of blood drawn between 2,200 and 2,400 h (25). The level of circulating Gib 13 antigen was used to estimate the relative load of adult worms in the two study groups (26)(27)(28). Immulon I wells (Dynatech Laboratories) were coated with 50 Ml (10 mg/ml) of a 50% NH4S04 precipitate of Gib 13 ascites fluid (kindly provided by Dr. G. Mitchell, Walter and Eliza Hall Institute, Melbourne, Australia), redissolved in PBS, and the assay was performed with a 1:2 dilution of serum as described by Forsyth et al (28).…”

Identification and specificity of a 38�kDa Loa loa antigenic fraction in sera from high-microfilaraemic Gabonese patients

“…Several research groups have found antigenic fractions with M r of 35-200 kDa in the sera of wuchererian patients (Dissanayake et al 1984;Lal et al 1987). Chandrashekar et al (1990) also found a 23 kDa antigen in the sera of onchocercian patients.…”

Cytochemical characterization of the third-stage larva of Wuchereria bancrofti (Nematoda: Filarioidea)

“…These structures may be involved in processes of immune evasion (Klonisch et al 1991) and nutrient intake (Howells and Chen 1983;Kennedy 1991) and also may present important antigens that elicit the immunological response (Araujo et al 1993). Previous studies have shown that important filarial antigens contain carbohydrates, mainly as glycoproteins (Dissanayake et al 1984;Ottesen 1984), and lectins have been widely used as probes for localization of carbohydrates residues in different biological systems (Araujo et al 1993(Araujo et al , 1994a(Araujo et al ,b, 1995.…”