The course of L. monocytogenes infection was followed in mice treated
with pentoxifylline (POF), a known inhibitor of endogenous tumor necro
sis factor (TNF) formation. Administration of POF caused a delay in L.
monocytogenes elimination which was probably related to a reduction t
he listericidal activity of macrophages and to an attenuation of delay
ed type hypersensitivity (DTH) to Listeria antigens. In spite of this,
some POP-treated mice were protected from lethal effects of virulent
L. monocytogenes bacteria.