Evaluation of the potential of excretions-secretions (E-S) of Litomosoides carinii to substitute for human filarial E-S.

The antigenic cross-reactivity of the excretions-secretions (E-S) of Litomosoides carinii was investigated. Immunoprecipitation using pooled sera from a number of human filarial infections in combination with sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis revealed variations in the cross-reactivity of individual molecules. Some were specific to L. carinii, the major examples in this category being two E-S components of 140 and 160 kDa released by day 40- to 42-day-old female worms. Another, a high-molecular-weight product of 26- to 28-day E-S, was broadly cross-reactive. A third group appeared to exhibit reactivity to antibody to some but not all human filarial parasites. The most striking examples of this were two distinct 14-kDa products that bound solely to antibodies in an onchocerciasis serum pool. These results are discussed in relation to the use of cross-reacting molecules in investigating the immunisation potential, defining the function, and evaluating the diagnostic utility of human filarial E-S.