两种不同保护剂冻干的仔猪副伤寒活疫苗质量比较

Comparison of swine paratyphoid live vaccines lyophilized with two different stabilizers

摘要:

【目的】系统比较两种不同保护剂冻干的仔猪副伤寒活疫苗(耐热苗和常规苗)质量指标，为科学评价两种疫苗质量提供参考。【方法】制备耐热苗和常规苗各3批，分别进行物理性状、纯粹性、活菌计数、安全性、剩余水分、真空度和保存期等参数测定和比较，同时比较冻干前后的活菌存活率及耐老化性能。任选耐热苗与常规苗1批，按3×109 CFU分别口服与肌肉注射仔猪各5头，设相同条件下不免疫对照5头，30 d后静脉注射致死量猪霍乱沙门氏菌，临床观察30 d后评估疫苗的效力。【结果】耐热苗及常规苗的物理性状、纯粹性、活菌计数、安全性、剩余水分、真空度均符合现行《中国兽药典》的要求。3批耐热苗冻干菌存活率分别为88.2%、83.1%和86.4%，耐老化试验后的活菌存活率为83.6%、82.9%和88.8%；然而3批常规苗冻干菌存活率分别为52.3%、56.2%和61.4%，耐老化活菌存活率分别为58.5%、60.2%和54.7%。经37 °C、7 d耐老化试验结果显示，耐热苗物理性状良好，而常规苗原有团块表面凹陷1/4?1/2。保存期结果表明耐热苗4 °C有效期可达24个月，常规苗仅为9个月。仔猪免疫攻毒结果表明，耐热苗肌肉注射及口服免疫均达100% (5/5)保护；常规苗肌肉注射达80% (4/5)保护，口服达100% (5/5)保护，不免疫对照0保护 (5/5死亡)。【结论】耐热苗具有较高的冻干菌存活率和良好的耐老化性能，4 °C可长期保存且不影响其免疫效力。

Abstract:

[Objective] To systematically compare the physical, chemical and biological properties of the swine paratyphoid thermo-stable live vaccine (TS vaccine) and the traditional swine paratyphoid live vaccine (traditional vaccine), and provide references for evaluation of live vaccine prepared with thermo-tolerant stabilizer. [Methods] Three batches of TS vaccine and traditional vaccine were prepared. The vaccine physical properties, pureness, viable bacterial counts, safety, residual moisture, vacuity and storage period were measured according to the standard methods in Veterinary Pharmacopoeia of the People’s Republic of China. The survival ratio of the vaccines after lyophilization and the thermo-stabilities after storage at 37 °C for 7 days was compared. One batch of TS vaccine and traditional vaccine were selected for further protective efficacy study. Twenty-five piglets were randomly divided into five groups. With the exception of the non-vaccinated control, the other four groups were immunized orally (p.o.) or intramuscularly (i.m.) with 1 dose of TS or traditional vaccine. After thirty days, all piglets were challenged intravenously with 1 minimum lethal dose (MLD) of virulent Salmonella enterica serovar Choleraesuis. The protective efficacy of two vaccines were observed for 30 days post challenge. [Results] The physical properties, pureness, viable bacterial counts, safety, residual moisture and vacuity of two vaccines met the requirements of Veterinary Pharmacopoeia of the People’s Republic of China. The bacterial survival ratio after lyophilization of the TS vaccine was 88.2%, 83.1%, 86.4%, respectively, compared to the 52.3%, 56.2%, 61.4% for the traditional vaccine, respectively. After stored at 37 °C for 7 days, the survival ratio of the TS vaccine was 83.6%, 82.9%, 88.8%, respectively, compared to the 58.5%, 60.2%, 54.7% of the traditional vaccine, respectively. After stored at 37 °C for 7 days, the TS vaccine showed good properties, while the traditional vaccine had surface concave of 1/4?1/2. The storage period at 4 °C of the TS vaccine lasted 24 months, compared to the only 9 months for the traditional vaccine. The protective efficacy of the TS vaccine was 100% for oral or intramuscular immunization route. For the traditional vaccine, the protective efficacy was 100% for oral route and 80% for intramuscular route. [Conclusion] The TS vaccine had higher survival ratio after lyophilization and better thermo-stability. The TS vaccine could be stored at 4 °C for long-term and had good protective efficacy.