EFFECT OF BOVINE KAPPA-CASEINOGLYCOPEPTIDE ON SECRETION OF INTERLEUKIN-1 FAMILY CYTOKINES BY P388D1 CELLS, A LINE DERIVED FROM MOUSE MONOCYTE MACROPHAGE/

P388D1 cells, a line derived from DBA/2 mouse monocyte/macrophage, pro duced an inhibitory factor, which was neutralized by goat anti-IL-1ra polyclonal antibody, by lipopolysaccharide(LPS)-induced proliferation of mouse spleen cells in the presence of kappa-caseinoglycopeptide (re sidues 106-169 of kappa-casein, CGP) but not in the absence of CGP. Re verse transcription-polymerase chain reaction analysis showed that P38 8D1 cells transcribed IL-1ra mRNA in both the absence and the presence of CGP. These observations indicate that CGP might increase IL-1ra bi osynthesis and/or secretion. On the other hand, CGP did not affect sec retion of IL-1 alpha and IL-1 beta produced from P388D1 cells in eithe r the absence or presence of LPS. Moreover, little IL-1ra was secreted when CGP was added after 1 h cultivation of P388D1 cells with LPS, Th ese results suggest that CGP is not able to induce IL-1ra production f rom previously activated macrophages. CGP may contribute to antiinflam matory response in neonatal intestine by induction of IL-1ra produced from monocytes/macrophages of maternal milk origin.