BRUGIA-MALAYI - THE DIAGNOSTIC POTENTIAL OF RECOMBINANT EXCRETORY SECRETORY ANTIGENS/

The diagnostic potential of recombinant E/S antigens of the lymphatic filaria Brugia malayi was investigated by Western blot. A cDNA express ion library was constructed using B. malayi male adult worm mRNA, and E/S recombinants were identified with a rabbit antiserum raised agains t E/S products collected in vitro from B. malayi male and female adult worms. Two of these recombinants, Bm12 and Bm14L, were studied after subcloning the cDNA inserts in an Escherichia coli plasmid expression and purification vector, obtaining the inserts' nucleotide sequence, a nd purifying the expressed proteins. By homology of their deduced amin o acid sequence with that of previously identified proteins, Bm12 was identified as the B. malayi gp15/400 antigen, and Bm14 as a member of the hsp90 family df heat shock proteins. The antigenic cross-reactivit y of the purified recombinant proteins was assessed with 28 serum samp les from patients infected with Ascaris, Trichuris, or hookworm, and a lso with a few samples from patients with onchocerciasis and loiasis. For Bm12, the specificity for all of the intestinal helminthiasis toge ther was 75%. Bm14L, on the other hand, crossreacted with all of the a scariasis serum samples with which it was tested. Presence of antibodi es cross-reactive with B. malayi was confirmed in all of these serum s amples by examining their antibody reactivity with Western blots of ex tracts of whole B. malayi adult worms. A semiquantitative (+ or -) ass essment of the sensitivity of Bm12 for antibody detection was performe d using 6 serum samples from patients with chronic filariasis and 24 s amples from patients with microfilaremia. All of these serum samples c ontained anti-Bm12 antibody (sensitivity of 100%). Finally, the abilit y of Bm12 to detect antibody before the onset of patency was establish ed with a longitudinal collection of serum samples obtained from 2 Afr ican green vervets (Cercopithecus aethiops) and 3 rhesus macaques (Mac aca mulatta), all of which were infected with B. malayi. Anti-Bm12 ant ibodies were detectable in all animals between 4 and 11 weeks before p atency. (C) 1991 Academic Press, Inc.