Immunoassay Tested for Recombinant Nematode Antigen

Scientists at Anna University (Chennai, India) have determined the specificity and sensitivity and an immunoassay to diagnose, monitor, and evaluate human lymphatic filariasis. High-affinity monoclonal antibodies (mAbs) were developed that specifically binds to both Wucheria bancrofti and Brugia malayi microfilaria antigens. Blood samples were collected from different clinical groups: 25 from individuals that lived in as endemic region, but were normal; 23 with microfilareamia; and 10 with chronic pathology.

Two of the mAbs of subclass immunoglobulins IgG2a and IgM showed high affinity, avidity, and reactivity to recombinant and microfilaria native antigen. Both the mAbs were used in combination as capture antibodies and polyclonal as detection antibody to develop the assay. The assay showed very high sensitivity towards W. bancrofti microfilaria positive samples compared to endemic normal samples. The microscopy based parasitological examination of blood smear is the simplest detection method for microfilaria, which is most widely used in the field. However, it poses problems like night blood collection, labor-intensive technique, low sensitivity and variations based on blood volume and parasite load.

Lymphatic filariasis is a painful and profoundly disfiguring disease. Infection is usually acquired in childhood but its visible manifestations occur later in life, causing temporary or permanent disability. The importance of developing effective assays to diagnose, monitor, and evaluate human lymphatic filariasis has been emphasized by the World Health Organization (WHO; Geneva, Switzerland). In the present study, monoclonal antibodies against the filarial microfilaria specific antigen, WbSXP-1 have been used to develop a sandwich ELISA successfully detecting circulating antigen in infected positive individuals. The study was published online on June 30, 2011, in Clinica Chimica Acta.

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Anna University
World Health Organization