Charge-reducing lymphokine activity in Concanavalin A-stimulated lymphocyte supernatants: preliminary biological and...

Supernatants of Concanavalin A stimulated (active) and unstimulated (control) guinea pig lymphocytes were fractionated by gel filtration on Sephadex G-100 into four arbitrary fractions (F1-F4). Fraction F3 from active supernatant (m.w. range 40 000-15000 D) was found to cause significant slowing of guinea pig macrophages in cell electrophoresis at dilutions of 1 : 200 (expressed as aliquots of the unfractionated supernatants). Neither the other fractions of the active supernatant nor the respective fractions of the control supernatant revealed any significant mobility reduction of guinea pig macrophages in cell electrophoresis. This charge-reducing activity could be blocked by alpha-L fucose, but not by other related monosaccharides. It was shown to be lyophilizable, nondialyzable, adsorbable to guinea pig macrophages and stable at 253 K for several months. The possible relationship of the charge-reducing lymphokine(s) to guinea pig macrophage migration inhibitory factor (MMIF) is discussed.