ldl receptor deficient mice , transgenic mice developed essentially as described in ishibashi et al ., “ massive xanthomatosis and atherosclerosis in cholesterol fed low density lipoprotein receptor - negative mice ”, j . clin . invest ., 93 : 1885 - 1893 ( 1994 ), incorporated herein by reference , were used in these examples . the ldl deficient mice are currently used as a model for the development of atherosclerosis ( see von der thüsen et al ., circulation ( 2001 ) supra ). male ldl receptor deficient mice were put on a cholesterol rich diet ( type w diet containing 0 . 25 % cholesterol , 15 % cocoa butter ). after 14 days , collars were placed around the left and the right carotid artery ( as described in von der thüsen circulation 2001 , supra ). the mice were then treated with il - 9 with daily intraperitoneal injection with 1 μg baculovirus recombinant il - 9 ( druez , et al ., j . immunol ., 145 : 2494 - 2499 ( 1990 ) incorporated herein by reference ) per mouse per day from day 21 to day 56 . control animals received daily injections with vehicle alone ( pbs containing 1 % autologous mouse serum ). body weight , cholesterol levels and lipoprotein profile were monitored throughout the experiment . at the end of the experiment ( day 56 after the last dose of il - 9 ), animals were anesthetized and exsanguinated by femoral artery transection . in situ perfusion fixation through the left cardiac ventricle was performed by pbs instillation for 15 minutes , followed by constant - pressure infusion ( at 80 mm hg ) of 10 % neutral buffered formalin for 30 minutes . subsequently , both carotid bifurcations and common carotid arteries were removed . no differences were observed between the body weight of il - 9 - treated and vehicle - treated mice . in addition , il - 9 treatment did not affect the cholesterol levels as compared to the control mice . throughout the experiments the mice , regardless of treatment , maintained a level of approximately 3000 mg cholesterol / dl . il - 9 treatment did not alter the lipoprotein profile of the treated mice as compared to the control mice ( 80 % of the total cholesterol is recovered in both groups in the vldl fraction ). the collar - induced atherosclerosis in treated and untreated mice was assayed by determining plaque size ( surface area at the point where the size / area of the plaque is maximal ) media size ( between the intima ( plaque ) and the smooth muscle layer ), intima / media ratio and intima / lumen ratio ( fig1 a - d ) essentially as described in von der thüsen ( circulation 2001 supra ). briefly , hematoxylin and eosin - stained sections were assessed in cross - section at 3 levels : 0 . 5 mm proximal , in the mid - section and 0 . 5 mm distal to the collar . the intimal surface area was calculated by subtracting the patent lumen area from the area circumscribed by the internal elastic lamina . the medial surface area was defined as the area between the internal elastic lamina and the external elastic lamina . the intima / media ratio and the intima / lumen ratio were determined by dividing the intimal area by the medial area and the total area confined by the internal elastic lamina , respectively . the results are set forth in fig1 a through 1d and indicate that il - 9 significantly reduced plaque size without effect on the size of the media . these results clearly demonstrate that daily treatment of mice with il - 9 significantly reduces the initiation of atherosclerosis . example 1 was repeated in female ldl receptor deficient mice and the effects of il - 9 on atherosclerotic plaque formation was evaluated . on day 1 , two groups of mice ( group a ( il - 9 treated , n = 9 ) and group b ( control , n = 8 )) were put on a western type diet containing 0 . 25 % cholesterol and 15 % cocoa butter . at day 15 collars were placed around the left and right carotid artery ( as described by von der thüsen et al ., circulation ( 2001 ) supra ). from day 16 through day 42 the group a mice were injected daily ( intra - peritoneal ) with 1 μg baculovirus produced il - 9 dissolved in 100 μl of pbs ( containing 1 % normal autologous mouse serum ). the group b control mice received a daily intra - peritoneal injection of 100 μl of pbs ( containing 1 % normal autologous mouse serum ). at day 42 , both groups of mice were anaesthetized and exsanguinated by femoral artery transection , and in situ perfusion fixation through the left cardiac ventricle was performed by pbs instillation for 15 minutes , followed by constant - pressure infusion ( at 80 mm hg ) of 10 % neutral buffered formalin for 30 minutes . subsequently , both carotid bifurcations and common carotid arteries were removed . formalin fixation was omitted for arteries that were to be stained for von willebrand factor “ vwf ”; these were immediately snap - frozen in liquid nitrogen after having been embedded in oct compound ( tissue - tek ; sakura finetek ), whereas the remaining arteries were left in 10 % formalin overnight before freezing . the specimens were stored at − 20 ° c . until further use . transverse 5 - mm cryosections were prepared in a proximal direction from the carotid bifurcation and mounted in order on a parallel series of slides . [ 0035 ] fig2 depicts the effects of baculovirus - produced il - 9 on the development of atherosclerotic plaques . the mice of group a , which were treated with il - 9 , showed a clear diminishment in the extent of atherosclerosis . the significant reduction in the extent of atherosclerosis was 58 . 6 % in comparison to the control group ( p & lt ; 0 . 05 ). the effect of il - 9 on tnf - a production by blood monocytes in response to lps was determined in a whole blood assay . mice ( group a : il - 9 treated , n = 9 )) received a daily intra - peritoneal injection of recombinant il - 9 dissolved in 100 μl of pbs ( containing 1 % normal autologous mouse serum ) for five days . control mice ( group b , n = 8 ) received a daily i . p . injection of 100 μl of pbs ( containing 1 % normal autologous mouse serum ) for five days . at day 5 blood was collected from the tail vein of all mice . whole blood was obtained by tail vein transection and diluted 25 fold in dulbecco &# 39 ; s modified eagle &# 39 ; s medium supplemented with l - glutamine , penicillin and streptomycin , which contained varying concentration so lipopolysaccharide ( re 595 , list biological laboratories , campbell , calif .). following incubation overnight at 37 ° c ., 50 μl of the supernatent was analyzed for tnf - α content by elisa . the results are depicted in fig3 . the tnf - α production in the whole blood assay after lps stimulation was not significantly different in the il - 9 treated animals as compared to the control treated animals . the effect of endogenous interleukin 9 on atherosclerosis was also assayed by vaccinating mice with il - 9 ovalbumin conjugates ( il - 9 - ova ) prior to placing the mice on a diet containing 0 . 25 % cholesterol and 15 % cocoa butter . on day 1 , 10 female ldl receptor mice ( group a ) were vaccinated in both footpads using 1 μg of il - 9 - ovalbumin conjugate in the presence of complete freund &# 39 ; s adjuvant as described by richard et al ., (“ anti - il - 9 vaccination prevents worm expulsion and blood eosinophilia in trichuris muris - infected mice ”, pnas 97 767 - 772 ( 2000 ) incorporated herein by reference ). control mice were 10 female ldl receptor mice vaccinated with ovalbumin in the presence of complete freund &# 39 ; s adjuvant ( group b ). on days 15 , 29 and 43 , the group a mice were vaccinated with 1 μg of il - 9 - ovalbumin conjugate in the presence of incomplete freund &# 39 ; s adjuvant . on days 15 , 29 and 43 , the control group b mice were vaccinated with ovalbumin in the presence of incomplete freund &# 39 ; s adjuvant . on day 57 the two groups of mice were put on a western type diet ( 0 . 25 % cholesterol , 15 % cocoa butter ) and assayed for the production of il - 9 specific antibodies . anti - il - 9 titers of the vaccinated mice were tested in a ts1 assay . the titers are the reciprocal dilutions of the sera that produce 50 % inhibition of il - 9 ( 50 pg / ml ). the only group a mice that were included in the experiment were those that had a significant level of anti - il - 9 antibodies ( 6 / 10 mice ). the control mice vaccinated with ova did not produce il - 9 antibodies . two weeks later ( day 71 ) collars were placed around the left and right carotid artery ( as described by von der thüsen et al . 2001 supra ) of the control mice and the mice with the significant levels of anti - il - 9 antibody . on day 113 , both groups of mice were anaesthetized , and in situ perfusion fixation through the left cardiac ventricle was performed by pbs instillation for 15 minutes , followed by constant - pressure infusion ( at 80 mm hg ) of 10 % neutral buffered formalin for 30 minutes . subsequently , both carotid bifurcations and common carotid arteries were removed . formalin fixation was omitted for arteries that were to be stained for vwf ; these were immediately snap - frozen in liquid nitrogen after having been embedded in oct compound ( tissue - tek ; sakura finetek ), whereas the remaining arteries were left in 10 % formalin overnight before freezing . the specimens were stored at − 20 ° c . until further use . transverse 5 - mm cryosections were prepared in a proximal direction from the carotid bifurcation and mounted in order on a parallel series of slides . [ 0045 ] fig4 demonstrates that the group a mice , which were vaccinated with il - 9 - ova conjugates and had significant levels of il - 9 specific antibodies , had a clear increase in the extent of atherosclerosis . the level of atherosclerosis was more than double ( 2 . 05 fold ) the level in control mice which were vaccinated ovalbumin ( p & lt ; 0 . 05 ). the results set forth herein demonstrate that administration of il - 9 to a subject inhibits formation and progression of atherosclerotic plaques . the increase in atherosclerosis as a result of il - 9 - ova immunization demonstrates that endogenous il - 9 plays a role in inhibiting atherosclerosis and that il - 9 does not prevent the subsequent production of tnf by blood monocytes in response to lps in vitro . the terms and expressions which have been employed are used as terms of description and not of limitation , and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or any portions thereof , it being recognized that various modifications are possible within the scope of the invention .
this invention relates to methods for inhibiting the initiation or progression of a pathologic disorder associated with atherosclerotic plaque formation comprising administering to a subject an amount of il - 9 sufficient to inhibit plaque formation and / or plaque progression and / or to promote plaque regression . the methods of this invention also relate to inhibiting the proliferation of smooth muscle cells in one or more arteries and to inhibiting the deposition and accumulation of fat and proteins in one or more arteries .