季节性流感裂解疫苗在小鼠中针对同型与异型流感病毒的免疫保护效力

Immune Protective Effectiveness of Seasonal Influenza Spilt Vaccine against Homologous and Heterogonous Subtypes of Influenza Virus in Mice

为了研究季节性流感裂解疫苗在小鼠中针对甲型流感病毒同型同株、同型异株、异型异株攻击的免疫保护效力及其与诱发的血凝抑制（HI）抗体滴度的关系,本研究使用我国2008~2009年度季节性流感裂解疫苗中不同剂量的甲1型流感病毒H1N1（疫苗株病毒A/Brisbane/59/2007（H1N1）-like）和甲3型流感病毒的H3N2（疫苗株病毒A/Brisbane/10/2007（H3N2）-like）疫苗组分免疫BALB/c小鼠,首先确定了能在小鼠中诱发血HI抗体滴度达到40的疫苗免疫剂量;然后以此剂量免疫小鼠,分别使用同型同株流感病毒（鼠肺适应株A/Brisbane/59/2007（H1N1）-like virus（MA））（简称A1）和同型异株流感病毒（鼠肺适应株A/Purto Rico/8/34（H1N1））（简称PR8）攻击H1N1疫苗免疫小鼠,使用异型异株流感病毒A1攻击H3N2疫苗免疫小鼠,通过体重变化和存活率情况,探讨季节性流感疫苗在小鼠中针对甲型流感病毒同型同株、同型异株、异型异株攻击的保护效力。结果显示,季节性流感裂解疫苗H1N1和H3N2组分按照HA不同剂量0.15μg、0.5μg、1.5μg、5μg和15μg免疫小鼠后,所诱发的HI抗体滴度随免疫剂量的增加而增强,1.5μgHA即可以诱发免疫小鼠HI抗体滴度达到40;以此剂量免疫小鼠,分别使用3LD50、10LD50、30LD50、100LD50、300LD50、1 000LD50和3 000LD50的同型同株流感病毒A1进行攻击,1.5μgH1N1疫苗可以100%保护小鼠抵御高至1000LD50同型同株流感病毒A1的攻击,15μg甚至可以100%保护3 000LD50同型同株流感病毒A1的攻击,但是这两个剂量免疫的小鼠在低至3LD50同型异株流感病毒PR8的攻击后都全部死亡;使用可以诱发HI抗体滴度达到140的15μg H3N2疫苗免疫小鼠,在低至3LD50异型异株流感病毒A1的攻击后亦全部死亡。以上结果表明,季节性流感疫苗可使小鼠HI抗体滴度达到40的疫苗免疫剂量为1.5μg,该免疫剂量可以有效保护小鼠抵御同型同株流感病毒的攻击,但是难以保护小鼠抵御同型异株与异型异株流感病毒的攻击,这一结果为建立以季节性流感疫苗为参考的免疫保护评价体系提供了实验依据。

To investigate the seasonal influenza split vaccine＇s immune protective effectiveness against the homologous and heterogonous subtypes of influenza A virus challenge and the relationship between the protective effectiveness and hemagglutination inhibition（HI） antibody titer in mice.Two components of H1N1 and H3N2 in Chinese 2008-2009 seasonal influenza spilt vaccine,were derived from vaccine strain A/Brisbane/59/2007（H1N1）-like virus and A/Brisbane/10/2007（H3N2）-like virus respectively,and were used to immune BALB/c mice.Firstly,different doses of the vaccines were used to immunize mice and the HA immunization dosage that can induce the HI antibody titer of 40 in mice was identified;Secondly,H1N1 vaccine immunized mice were challenged with different doses of influenza virus mouse adaptation strains of A/Brisbane/59/2007（H1N1）-like virus（MA）（referred to as A1 virus,well matched-strain in the homologous subtype） and A/Purto Rico/8/34（H1N1）（referred to as PR8 virus,poor matched-strain in the homologous subtype） respectively,and H3N2 vaccine immunized mice were challenged with H1N1 influenza virus of A1 strain（Heterogonous subtype）,body weight changes and survival rates were observed to explore the immune protective effectiveness of influenza split vaccine against the homologous and heterogonous subtypes of influenza A virus in mice.Results indicated that HI antibody titers were elevated as the HA protein immunization dosages increased from 0.15μg,0.5μg,1.5μg,5μg to 15μg in mice,and 1.5μg HA of the seasonal influenza split vaccine could induced HI antibody titer of 40 in mice;3LD50,10LD50,30LD50,100LD50,300LD50,1000LD50 and 3000LD50 of influenza virus strain A1 were used to challenge the H1N1 immunization mice,1.5μg HA of H1N1 vaccine could 100% protect mice against challenge with 1000LD50 of matched and homologous subtype of influenza virus strains A1,mice immunized with 15μg HA of H1N1 vaccine even could 100% protect mice against challenge with 3000LD50 of influenza virus strains A1;but mice immunized with both the 1.5μg and 15μg HA of H1N1 vaccine were all sacrificed when challenged with 3LD50 of the mismatched and homologous subtype of influenza virus strain PR8,and mice immunized with the high dosage of 15μg HA of H3N2 vaccine also were all sacrificed when challenged with 3LD50 of the heterogonous subtype of influenza virus strain A1.These results suggest that 1.5μg HA of seasonal influenza split vaccine could induced HI antibody titer of 40 after one dose in mice,this dosage of HA can effectively protect mice against matched homologous subtype of influenza virus strain,but hardly to protect mice against mismatched homologous or heterogonous subtype of influenza virus strain.These results provide materials for the establishment of influenza vaccine evaluation system based on seasonal influenza vaccine.