Glycosylation-enhancing factor (GEF) and
IgE-potentiating factor were detected in culture supernatants of rat mesenteric lymph nodes (MLN) cells obtained 14 days after
infection with Nippostrongylus brasiliensis (Nb), but not in supernatants of MLN cells of 8-day Nb-infected rats. Both factors were also released from T cells upon antigenic stimulation of KLH +
alum-primed spleen cells. The GEF from the Nb-infected rats and KLH +
alum-primed spleen cells had affinity for
p-aminobenzamidine agarose and were inactivated by phenylmethylsulfonylfluoride, an inhibitor of
serine proteases. These results indicate that the GEF obtained in the two systems is a
serine protease and is identical to that obtained by stimulation of normal T cells with
lymphocytosis-promoting factor (LPF) from Bordetella pertussis. The concomitant formation of
IgE-potentiating factor and GEF by Nb
infection, by antigenic simulation of KLH +
alum-primed spleen cells, and by treatment of rats with Bordetella pertussis
vaccine suggests that the
serine protease is involved in a common pathway leading to the selective formation of
IgE-potentiating factor. In contrast,
glycosylation-inhibiting factor (GIF) is always found during the selective formation of
IgE-suppressive factor.
IgE-suppressive factor and GIF were formed by MLN cells of 8-day Nb-infected rats and KLH-CFA-primed spleen cells. GIF was detected in culture supernatants of T cell hybridomas 23A4 and 23B6, which form unglycosylated
IgE-binding factors upon incubation with
IgE. GIF obtained from all of these sources bound to monoclonal anti-
lipomodulin. These findings indicate that GIF or
lipomodulin is involved in all systems, which leads to the selective formation of
IgE-suppressive factor. However, the formation of GIF was not restricted to those conditions in which
IgE-suppressive factor was selectively formed. The culture supernatants of MLN cells of 14-day Nb-infected rats and
antigen-stimulated KLH +
alum-primed spleen cells contained a small amount of GIF, which could be detected after inactivation of GEF. It appears that T cells from these sources formed GEF and GIF, but that GEF overcame the effect of GIF on glycosylation of
IgE-binding factors. The results indicate that the nature and
biologic activities of
IgE-binding factors are decided by the balance between GEF and GIF formed by T cells.