RESUMEN
Plasma samples from St. Lucians were tested for the presence of antibodies which cooperate in vitro with normal human luekocytes in causing cytotoxic damage to schistosomula of Schistosoma mansoni. The in vitro antibody activity, which has been previosly shown to depend on eosinophil effector cells was detected in 56 percent of the individuals with known, current S. mansoni infections and in 14 percent of control subjects from the same endemic area. Quantitatively, eosinophil dependent cytoxic antibody (EDCA) activity, when expressed as the maximum amount of damage to schistosomula induced at high plasma concentration, correlated significantly with the intensity of S.mansoni infection as detemined by fecal egg count, the highest levels of activity occuring in patients with stool counts of 60 eggs/ml or greater. In addition, plasma ECDA activity was found to correlate with the in vitro blastogenic responsiveness of patients' lympjocytes to three different parasite antigen preparations. In contrast, titrations of ECDA activity failed to reveal a relationship between ECDA titer and the most recent egg count performned on each subjects. However, a significant correlation was observed when titers were compared to egg counts averaged over a 3-year period. Neither maximal ECDA activity nor titer was found to correlate with the duration of known schistosome infection (AU)