NERVE GROWTH-FACTOR ENHANCES SURVIVAL AND CYTOTOXIC ACTIVITY OF HUMANEOSINOPHILS

Phenotypic change of blood-type eosinophils to tissue-type eosinophils is induced by various cytokines. We examined the effect of nerve grow th factor (NGF) as a candidate for a constitutive cytokine which is ab le to induce the phenotypic change of eosinophils, The viability of hu man peripheral blood eosinophils cultured for 4 d was increased from a mean of 26% to a mean of 50% (P < 0.001) by the addition of NGF (50 n g/ml). Cytotoxic activity of eosinophils determined by larvicidal acti vity was increased 2-3-fold by the addition of NGF (50 ng/ml) (P < 0.0 5), Furthermore, eosinophil chemotactic activity of NGF was demonstrat ed by the blind well chamber method. Since NGF is produced constitutiv ely from various kinds of cells in local tissues, it is suggested that NGF might be a cytokine responsible for phenotypic change to tissue t ype eosinophils in conditions without immune stimuli.