the present invention provides a polysaccharide composition and use thereof , which can be achieved by appropriately improving the process parameters by those skilled in the art in light of the present disclosure . particularly , it is to be noted that all the similar substitutions and alterations are obvious for those skilled in the art , and are all deemed to be within the present invention . the method and use of the present invention have been described through preferred examples , and related personnel obviously can make alteration or appropriately change and combine the method and use herein to achieve and apply the technology of the present invention without departing from the content , spirit and scope of the present invention . the reagents , medicaments , animals or instruments are all commonly commercial available , and can be commercially purchased . the present invention is further illustrated in conjunction with the following examples : lentinan 10 g , pachymaran 10 g and tremellan 10 g were mixed to obtain polysaccharide composition 1 . lentinan 10 g , pachymaran 30 g and tremellan 30 g were mixed to obtain polysaccharide composition 2 . lentinan 30 g , pachymaran 10 g and tremellan 10 g were mixed to obtain polysaccharide composition 3 . lentinan 10 g , pachymaran 30 g and tremellan 10 g were mixed to obtain polysaccharide composition 4 . lentinan 10 g , pachymaran 20 g and tremellan 30 g were mixed to obtain polysaccharide composition 5 . lentinan 20 g , pachymaran 10 g and tremellan 30 g were mixed to obtain polysaccharide composition 6 . lentinan 30 g , pachymaran 20 g and tremellan 10 g were mixed to obtain polysaccharide composition 7 . balb / c mice ( female , 6 ˜ 8 weeks old , body weight 18 ˜ 22 g ) were provided by beijing hfk bioscience co . ltd ., with license number : sock ( jing ) 2014 - 0004 . they were housed in the state key laboratory of agricultural microbiology , huazhong agricultural university . the license number for using experimental animals is : hzaumu2015 - 0006 . mice lung adapted strain of influenza virus : a / pr / 8 ( h1n1 ), concentration : 10 4 pfu / ml . mexican pandemic flu h1n1 , concentration : 10 4 pfu / ml . influenza virus vaccine contains 10 4 pfu / ml inactivated virus and mixed mf59 adjuvant at equal amount . influenza virus and vaccine were both provided by the state key laboratory of agricultural microbiology , huazhong agricultural university . lentinan , pachymaran , tremellan and polysaccharide compositions prepared in examples 1 ˜ 7 were respectively formulated into 20 mg / ml polysaccharide solutions . the dosage for intragastrical administration is 200 mg / kg ( 100 μl / 10 g based on the body weight of the mouse ). the function of random number of excel software was employed to randomly divide balb / c mice into blank group , vaccine group , lentinan group , pachymaran group , tremellan group , polysaccharide composition 1 ( prepared in example 1 ), polysaccharide composition 2 ( prepared in example 2 ), polysaccharide composition 3 ( prepared in example 3 ), polysaccharide composition 4 ( prepared in example 4 ), polysaccharide composition 5 ( prepared in example 5 ), polysaccharide composition 6 ( prepared in example 6 ), and polysaccharide composition 7 ( prepared in example 7 ); with 17 mice in each group . they were respectively operated according to the following processes : vaccine group : intragastrically administrated with normal saline for 30 days , and 100 μl of influenza virus vaccine was intramuscularly injected on day 10 and day 25 , respectively . lentinan group , pachymaran group , tremellan group , polysaccharide composition groups 1 ˜ 7 : intragastrically administrated with 200 mg / kg polysaccharide for 30 days , and 100 μl influenza virus vaccine ( containing 10 4 pfu / ml of inactivated virus and mixed adjuvant at equal amount ) was intramuscularly injected on day 10 and day 25 , respectively . on day 31 ( day 0 ), 3 mice were taken from each group , from which blood and lungs were collected . on day 32 , each group was infected by 50 μl h1n1 influenza virus through nasal dropping . from day 33 to day 46 ( within 2 weeks after infection ), the change in body weight of test mice was weighed everyday ( table 1 ), the survival state of mice was observed , and statistical analysis was conducted for mortality ( table 2 ). on day 46 ( day 14 after infection ), the experiment was completed . as was shown in table 1 and table 2 , after infection by a / pr / 8 ( h1n1 ) virus , the mice in blank group did not show obvious abnormal symptoms within 2 days . on day 3 , they started to exhibit tachypnea , beslowinmovement , dull hair , reduced diet , emaciation , etc . on day 7 , deaths occurred . 5 mice in total died within 2 weeks . the mice in vaccine group did not show obvious morbid symptoms . they had normal diet and slightly less shiny hair color . their body weights slightly decreased in fluctuation . on day 10 , one mouse died . mice in all the polysaccharide groups were in good mental state . they had agile action , shiny hair , normal breath , normal diet , naturally increasing body weights , and no death in all the seven groups . compared to the vaccine group , the polysaccharide composition 1 had a significant better efficacy on weight gain of mice ( p & lt ; 0 . 05 ). as was shown in table 3 and table 4 , after infection by mexican pandemic flu h1n1 virus , the mice in blank group started to exhibit tachypnea , beslowinmovement , dull hair , reduced diet , emaciation , etc . on day 4 , deaths occurred . 6 mice in total died within 2 weeks . the mice in vaccine group did not show obvious morbid symptoms . they had normal diet and slightly less shiny hair color . their body weights slightly decreased in fluctuation . on day 10 , one mouse died , and a total of 2 mice died within 2 weeks . mice in each polysaccharide group were in good mental state . they had agile action , shiny hair , normal breath , normal diet , and naturally increasing body weights . one mouse in the pachymaran group died on day 13 , and no mouse died in all the other groups . compared to the vaccine group , polysaccharide compositions 1 , 3 and 7 had significantly better efficacy on weight gain of mice ( p & lt ; 0 . 05 ). test mice in experimental example 1 were infected by influenza virus via nose - dripping . on day 35 ( day 3 after infection ), 3 mice were taken from each group , from which blood and lungs were collected . on day 38 ( day 6 after infection ), 3 mice were taken from each group , from which blood and lungs were collected . on day 46 ( day 14 after infection ), the mice were weighed and sacrificed , from which blood and lungs were collected . blood was collected by enucleating eyeballs of the mice to allow the blood dripping freely into a 1 . 5 ml centrifuge tube . the blood was left stand for 2 hours before centrifugation at 3500 rpm for 10 min to obtain the serum , which was divided into aliquots in 200 μl pcr tube and frozen at − 20 ° c . for later use . antibody titers in the serum were detected by elisa ( the results are as shown in table 5 and table 6 ). mice were weighed and sacrificed . the lungs were collected aseptically , weighed and frozen . the lung index was calculated ( the results are as shown in table 7 and table 8 ) with the formula lung index = lung weight ( mg )/ body weight ( g ). an amount of pbs was added . the lung tissues were adequately homogenized manually or using a homogenizer . virus titers in the tissues were detected by dilution method of counting ( table 9 and table 10 ). the homogenate of lung tissues was centrifuged for about 20 min . the supernatant was collected . the contents of il - 2 and il - 5 in the homogenate of lung tissues were detected respectively according to the procedure in the instructions of the elisa kit for mice cytokines il - 2 and il - 5 ( table 11 and table 12 ). as was shown in table 5 , before the a / pr / 8 ( h1n1 ) virus infection , no specific antibodies were present in the serum of the blank group as negative control . there was no significant difference regarding the levels of specific antibodies in the serum amongst all of the vaccination groups ( pure vaccine group and polysaccharide groups ). from day 3 after the virus infection , specific antibodies increased in all the groups except the blank group , wherein the level thereof in the polysaccharide composition 1 group was significantly higher than that in the pure vaccine group ( p & lt ; 0 . 05 ), and the antibodies in the blank group were always at lower levels . on day 6 after infection , as compared to the vaccine group , there were significant differences in the pachymaran group and the 7 groups of polysaccharide compositions ( p & lt ; 0 . 05 ). as compared to the lentinan group , tremellan group and pachymaran group , there were significant differences in the polysaccharide compositions 1 , 3 , 6 and 7 ( p & lt ; 0 . 05 ). on day 14 after infection , as compared to the vaccine group , the pachymaran group and the 7 groups of polysaccharide compositions were capable of significantly increasing the contents of specific antibodies in mice serum ( p & lt ; 0 . 05 ). as compared to the lentinan group and tremellan group , all the 7 groups of polysaccharide compositions had significant effects on increase of specific antibodies in mice serum . as compared to the pachymaran group , there were significant increases in specific antibodies in serum of mice administered with polysaccharide compositions 1 , 3 and 7 ( p & lt ; 0 . 05 ). the above results suggested that the polysaccharide compositions had significant better efficacies on improvement of decrease in level of antibody induced by infection of a / pr / 8 ( h1n1 ) virus than the single polysaccharide groups , wherein the polysaccharide compositions 1 , 3 and 7 had better effects . as was shown in table 6 , before the mexican pandemic flu h1n1 virus infection , no specific antibodies were present in the serum of the blank group as negative control . there was no significant difference regarding the levels of specific antibodies in the serum amongst all of the vaccination groups ( pure vaccine group and polysaccharide groups ). from day 3 after the virus infection , specific antibodies significantly increased in all the groups . the levels of specific antibodies in all the groups except the lentinan group were significantly higher than that in the pure vaccine group ( p & lt ; 0 . 05 ). the antibodies in the blank group were always at lower levels . as compared to the single polysaccharide groups , the levels of antibodies for the polysaccharide compositions 1 , 2 , 5 and 6 were significantly higher ( p & lt ; 0 . 05 ). on day 6 and day 14 after infection , as compared to the vaccine group , the levels of antibodies for all the groups of polysaccharide compositions significantly increased ( p & lt ; 0 . 05 ). as compared to the single polysaccharide groups , the levels of antibodies for all the groups of polysaccharide compositions significantly increased ( p & lt ; 0 . 05 ) the above results suggested that all the polysaccharide compositions had significant better efficacies on improvement of decrease in level of antibody induced by infection of mexican pandemic flu h1n1 virus than the single polysaccharide groups . it was observed morphologically that , in the infected mice in blank group , lung volumes significantly increased . large areas of lung consolidation showing dark red appearance were observed throughout the lung . in the mice in vaccine group , the entire lung appeared reddish , and the lesion degree was obviously slighter than that of the blank group , with some dark red lesions of lung consolidation observed . in the infected mice in polysaccharide groups , the surface of lung appeared reddish with no ecchymosis or petechiae , had no obvious areas of lung consolidation , and very few lung lobes exhibited the phenomena of congestion . the results of lung index were as shown in table 7 . starting from day 3 , the lung indexes of the mice in the blank group significantly increased . the lung indexes of the mice in other groups were relatively stable . as compared to the vaccine group , the polysaccharide compositions 2 , 5 and 6 showed the effects of significantly improving lung indexes ( p & lt ; 0 . 05 ). on day 6 after infection , as compared to the vaccine group , all the polysaccharide groups showed effects of significantly improving the lung indexes ( p & lt ; 0 . 05 ). as compared to the lentinan group and tremellan group , all the polysaccharide compositions had significantly better improving effects on mice lung index than lentinan and tremellan ( p & lt ; 0 . 05 ). as compared to pachymaran , the lung indexes of mice in polysaccharide compositions 1 , 3 , 6 and 7 significantly decreased ( p & lt ; 0 . 05 ). on day 14 after infection , as compared to the vaccine group , all the polysaccharide groups showed effects of significantly improving the lung indexes ( p & lt ; 0 . 05 ). as compared to the single polysaccharide groups , all the 7 groups of polysaccharide compositions can reduce the lung index of mice ( p & lt ; 0 . 05 ). the above results suggested that polysaccharide compositions with different ratios had significantly better efficacies on improving lung damage induced by infection of a / pr / 8 ( h1n1 ) virus than the single polysaccharides . it was observed morphologically that , in the infected mice in blank group , lung volumes significantly increased . large areas of lung consolidation showing dark red appearance were observed throughout the lung . in the mice in vaccine group , the entire lung appeared reddish , and the lesion degree was obviously slighter than that of the blank group , with some dark red lesions of lung consolidation observed . in the infected mice in polysaccharide groups , the surface of lung appeared reddish with no ecchymosis or petechiae , had no obvious areas of lung consolidation , and very few lung lobes exhibited the phenomena of congestion . the results of lung index were as shown in table 8 . starting from day 3 , the lung indexes of the mice in the blank group significantly increased . the lung indexes of the mice in other groups were relatively stable . on day 6 and day 14 , as compared to the vaccine group , all the polysaccharide groups showed effects of significantly reducing the lung index ( p & lt ; 0 . 05 ). as compared to the single polysaccharide groups , the lung indexes of mice for all polysaccharide composition groups with 7 ratios were significantly lower ( p & lt ; 0 . 05 ). the above results suggested that polysaccharide compositions with different ratios had significantly better efficacies on improving lung damage induced by infection of mexican pandemic flu h1n1 virus than single polysaccharides . as was shown in table 9 , starting from day 3 after the infection of a / pr / 8 ( h1n1 ) virus , the a / pr / 8 ( h1n1 ) viral titer of the lung of the mice in the blank group reached very high level , while the a / pr / 8 ( h1n1 ) viral titers of the lung of the mice in the vaccine group and polysaccharide groups were significantly lower than that in the blank group ( p & lt ; 0 . 05 ), wherein the a / pr / 8 ( h1n1 ) viral titers of the lung of the mice in the groups of polysaccharide compositions 1 , 3 and 7 were lower than that of the vaccine group ( p & lt ; 0 . 05 ). on day 6 after infection , the contents of a / pr / 8 ( h1n1 ) virus in the lung of all the groups of polysaccharide compositions was significantly lower than that of the vaccine group ( p & lt ; 0 . 05 ); as compared to the single polysaccharide group , all the 7 groups of polysaccharide composition can reduce the content of a / pr / 8 ( h1n1 ) virus in the lung of mice ( p & lt ; 0 . 05 ). on day 14 after infection , the contents of a / pr / 8 ( h1n1 ) virus in the lung of mice in all of the polysaccharide groups were significantly lower than that of the vaccine group ( p & lt ; 0 . 05 ). there was no difference between the effects of the polysaccharide compositions and the single polysaccharides . as was shown in table 10 , starting from day 3 after the infection of mexican pandemic flu h1n1 virus , the mexican pandemic flu h1n1 viral titer in the blank group reached very high level , while the mexican pandemic flu h1n1 viral titers in the vaccine group and polysaccharide groups were significantly lower than that in the blank group ( p & lt ; 0 . 05 ), wherein the mexican pandemic flu h1n1 viral titers in the groups of polysaccharide compositions 1 and 5 were lower than that in the vaccine group ( p & lt ; 0 . 05 ). as compared to the single polysaccharide group , the polysaccharide composition 1 showed the effects of significantly reducing the viral titer ( p & lt ; 0 . 05 ). on day 6 after infection , the mexican pandemic flu h1n1 viral titers in the lungs of the mice in all groups of the polysaccharide compositions were significantly lower than that in the vaccine group ( p & lt ; 0 . 05 ). as compared to the single polysaccharide groups , the contents of mexican pandemic flu h1n1 virus in the lung of mice of all the groups of the polysaccharide compositions were significantly reduced ( p & lt ; 0 . 05 ). on day 14 after infection , the contents of mexican pandemic flu h1n1 virus in the lung of all the groups were in relatively normal levels . the mexican pandemic flu h1n1 viral titers of mice in all the polysaccharide groups were significantly lower than that in the vaccine group ( p & lt ; 0 . 05 ). after the mice were infected by a / pr / 8 ( h1n1 ) virus , the levels of cytokines in the homogenate of lung significantly changed . the il - 2 gradually increased as the time of infection increased . as can be known from table 11 , with respect to improvement of the level of il - 2 in the homogenate of lung , the effects of the groups of polysaccharide compositions 3 and 7 were significantly better than those of the vaccine group and tremellan group ( p & lt ; 0 . 05 ), suggesting that the polysaccharide compositions 3 and 7 can play an anti - virus role by improving the il - 2 level in the homogenate of lung , and the effects were significantly better than those of the single polysaccharide groups . after the mice were infected by a / pr / 8 ( h1n1 ) virus , the cytokine il - 5 in the lung gradually increased as the time of infection increased . on day 3 and day 6 of the virus infection , the il - 5 level in the lung of mice of the groups of polysaccharide compositions 1 , 3 and 7 significantly increased as compared to the vaccine group . on day 14 , the il - 5 level in the lung of mice in the lentinan group and all the groups of the polysaccharide compositions significantly increased as compared to the vaccine group . starting from day 6 , the effects of polysaccharide compositions 3 and 7 were significantly better than that of the pachymaran . the above results suggested that the lentinan and the polysaccharide compositions can play an anti - virus role by improving the il - 5 level in the homogenate of lung , wherein some polysaccharide compositions had better efficacies than the single polysaccharides . after the mice were infected by mexican pandemic flu h1n1 virus , the levels of cytokines in the homogenate of lung significantly changed , and the il - 2 gradually increased as the time of infection increased . as can be known from table 12 , with respect to improvement to the level of il - 2 in the homogenate of lung , the effects of all of the polysaccharide groups were significantly better than that of the vaccine group ( p & lt ; 0 . 05 ). as compared to the lentinan group , the effects of polysaccharide compositions 6 and 7 were all significantly better than that of the lentinan . this suggested that , with respect of improving the il - 2 level in the homogenate of lung , the effects of the polysaccharide compositions were better than that of single polysaccharide . after the mice were infected by mexican pandemic flu h1n1 virus , the cytokine il - 5 in the lung gradually increased as the time of infection increased . on day 3 of the virus infection , there was no significant difference amongst all of the groups . on day 6 and day 14 , the il - 5 level in the lung of mice in the tremellan group , the groups of polysaccharide compositions 6 and 7 significantly increased as compared to the vaccine group . as compared to the lentinan and pachymaran , the polysaccharide compositions 6 and 7 were significantly better . this suggested that , with respect to improving the il - 5 level in the homogenate of lung , the effects of the polysaccharide compositions were better than that of single polysaccharide . the above are merely preferred embodiments of the present invention . it should be noted that , for an ordinary skilled in the art , several improvements and modifications may also be made without departing from the principle of the present invention , and these improvements and modifications should also be deemed to be within the protection scope of the present invention .