The ability of interleukin-4 (IL-4) to mediate an antitumor response t
o human gliomas was studied in vivo in nude mice. To allow the effect
of IL-4 to be exerted over a relatively short distance and at an optim
al concentration, a transfected tumor cell line expressing a high leve
l of IL-4 was used in mixed tumor transplantation assays. There was a
significant inhibition of growth of the U87 human glioma line when the
IL-4-secreting cell line, LT-1, was implanted s.c. with the glioma in
5 nude mice when compared to contralateral control tumors consisting
of the U87 glioma and IL-4-negative control cells. In addition, there
was a prolongation of survival when U87 along with IL-4-secreting cell
s were implanted intracerebrally in 12 nude mice compared to 12 contro
l nude mice implanted with U87 and IL-4-negative control cells and 11
control animals receiving U87 alone. Histological analysis 4 days afte
r i.c. inoculation revealed the presence of a dramatic eosinophil infi
ltrate and tumor necrosis. The absence of viable glioma cells as well
as resolution of inflammation 19 days after treatment suggests the pot
ential for complete tumor regression without ongoing inflammatory sequ
elae resulting from cytokine treatment.