SOUTHEAST ASIAN J TROP MED PUBLIC HEALTH Vol 31 No. 2 June 2000 252 INTRODUCTION Lymphatic filariasis has been identified as the second leading cause of long-term and permanent disability (Ottesen et al, 1997). Although it causes little direct mortality, it results in profound debili- tating morbidity, which has immense socio-eco- nomic impact especially in the developing coun- tries. Wuchereria bancrofti and Brugia malayi are responsible for the majority of cases of lymphatic filariasis. An estimated 128 million people world- wide are diseased with lymphatic filarial species of which 115.12 million are caused by W. bancrofti (Michael and Bundy, 1997). The intermediate vector for W. bancrofti is the mosquito species Culex quinquefasciatus. The microfilarial (mF) stage of the parasite is infective to the mosquito where it undergoes moulting to give rise to the second and the third stage larvae (L3). This stage is infective to humans where it matures into the adult parasite which resides in the lymphatics. The mF show nocturnal periodicity. Although filariasis has been identified as one of only six infectious diseases that are currently considered to be “eradicable” or “potentially eradi- cable” (Ottesen et al, 1997), the control of this disease is curtailed by the lack of easy diagnostic and suitable prophylactic measures. Vast advances have been made in the area of diagnosis of filari- asis. These are based on immunodiagnosis and species-specific DNA techniques. Immunodiagnosis is based either on antibody detection (Kumari et al, 1994; Chenthamarakshan et al, 1996) or an- tigen detection (Chanteau et al, 1994; Ramzy et al, 1994; Dhas and Raj, 1995). Recently two antigen detection test kits have been described, one based on the monoclonal antibody Og4C3 and the other on the monoclonal antibody AD12 (Weil et al, 1997). In immunodiagnosis of filariasis antigen detection assays offer the best scope, while the antibody detection assays provide sensitivity but lack in specificity since they cannot distinguish active from past infection and gastro-intestinal parasitic infections. In DNA based techniques, many studies have described the use of PCR in the diagnosis of filariasis (Siridewa et al, 1996; McCarthy et al, 1996; Zhong et al, 1996; Furtado et al, 1997). Although these techniques are valuable in research, their use in field conditions is limited by the constraints of cost and the need for trained personnel for their implementation and interpreta- tion. So, despite the development of many sophis- ticated diagnostic techniques, microscopy remains the conventional method in the rural areas of many developing countries. Therefore the need still remains to find diagnostic techniques which can be easily applied under field conditions. Although filariasis has been identified as a potentially eradicable disease, there has been slow progress in its achievement. Mass chemotherapy remains the corner stone in the area of control and A PRELIMINARY ANALYSIS OF WUCHERERIA BANCROFTI MICROFILARIAL ANTIGENS FOR POTENTIAL USE IN DIAGNOSIS JK Casinader Saverimuttu 1 , K Berzins 2 , P Perlmann 2 , EH Karunanayake 1 , MM Ismail 3 1 Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Colombo, Sri Lanka; 2 Department of Immunology, Stockholm University, Sweden; 3 Department of Parasitology, Faculty of Medicine, University of Colombo, Sri Lanka Abstract. Several antigens from the microfilarial stage of Wuchereria bancrofti have been identified using immunoblots of microfilarial antigens and screening with immune sera and tropical pulmonary eosinophilia (TPE) sera. This analysis revealed an array of antigens with apparent molecular weights of 14kDa, 35kDa, 42kDa, 63kDa, 88kDa, 97kDa and 200kDa. Among these only the 14kDa and 42kDa antigens were consis- tently recognized by most of the immune sera. A 132kDa antigen was recognized only by TPE sera. Analysis of rabbit immune sera revealed that the 42kDa antigen was shared by two developmental stages of W. bancrofti, namely L3 and mF. This antigen could become a potential vaccine candidate. The 14kDa antigen seems specific for the microfilarial stage and therefore could be a diagnostic marker for active infection. The 132kDa antigen could aid in the diagnosis of TPE. Correspondence: Prof Eric H Karunanayake, Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Colombo, PO Box 271, Sri Lanka. Fax: (94-1) 689181; E-mail: Biochem@eureka.lk