Inflammation is accompanied by changes in the plasma concentrations of "
acute phase reactants" including the C-reactive
proteins of man and other species. Previous results in our laboratory showed that CRP in rabbit acute phase serum may circulate in association with
very low density lipoproteins (VLDL), which influence both the apparent m.w. and electrophoretic mobility of CRP. We now show that the ability of VLDL to interact with CRP varies with time during the
acute phase response. Before the induction of
inflammation, the factor(s) responsible for the beta-mobility of CRP is present at low levels in the VLDL. During the first 24 hr of the
acute phase response, the activity can no longer be demonstrated in the VLDL fraction. By 36 to 48 hr after inflammatory stimulation, a significantly increased level of this factor(s) is measurable in VLDL. Furthermore, during the
acute phase response, the
alpha-lipoproteins decrease, and the beta- and
pre-beta lipoproteins increase. The increase in beta- and
pre-beta-lipoproteins is due to an accumulation of VLDL isolated at d less than 1.006 g/ml. These changes are accompanied by marked
hypertriglyceridemia and a significant increase in
phosphocholine-containing
phospholipids. A non-CRP
apoprotein present in low amounts in VLDL from normal rabbit plasma appears to increase in VLDL as
inflammation progresses. This VLDL
apoprotein increases in response to multiple acute phase stimuli and may be a newly recognized
acute phase reactant in the rabbit.