Evaluation of C-reactive protein as an inflammatory biomarker in rabbits for vaccine nonclinical safety studies.

INTRODUCTION: Inflammatory reactions are one of the potential safety concerns that are evaluated in the framework of vaccine safety testing. In nonclinical studies, the assessment of the inflammation relies notably on the measurement of biomarkers. C-reactive protein (CRP) is an acute-phase plasma protein of hepatic origin that could be used for that purpose in toxicity studies with rabbits. METHODS: To evaluate the utility of CRP as an additional inflammatory biomarker in adjuvant or vaccine toxicity studies, rabbits were injected on Day 0 with saline, aluminium phosphate, aluminium hydroxide, Adjuvant System (AS)01, AS03, AS15, or diphtheria-tetanus-whole cell pertussis-hepatitis B vaccine (DTPw-HB). Body weights, haematology parameters, CRP and fibrinogen levels were measured daily up to Day 7. Macroscopic changes at the injection site were also evaluated up to Day 7. At Day 7, a histopathological examination of the injection site was performed. RESULTS: Like fibrinogen, CRP levels rapidly increased after the injection of Adjuvant Systems or DTPw-HB, peaking at Day 1, and returning to baseline in less than a week. The magnitude of the CRP increase was consistently higher than that of fibrinogen with a larger fold increase from background, providing a more sensitive evaluation. The number of circulating heterophils was also increased on Day 1 after the injection of Adjuvant Systems or DTPw-HB. The highest increases in CRP levels were observed after the injection of DTPw-HB or AS03, and were also associated with the persistence of mixed inflammatory cell infiltrates (including heterophils) at the injection sites on Day 7. No increases in CRP levels and in circulating heterophils were observed after injection of the aluminium salt adjuvants. DISCUSSION: Our study supports the use of CRP as an accurate biomarker of acute inflammation in rabbits for vaccine toxicity studies and highlights an association between increased CRP levels and the recruitment of heterophils.

Evaluation of the intramuscular administration of Cervarix™ vaccine on fertility, pre- and post-natal development in rats.

Cervarix™ is a prophylactic human papillomavirus (HPV)-16/18 vaccine for the prevention of cervical cancer. It contains GSK Biologicals' proprietary Adjuvant System AS04. The objective of this study was to investigate the effects of Cervarix™ and of AS04 on female fertility and pre- and post-natal development in Sprague Dawley rats. Female rats were injected with vaccine, AS04, or saline 30 days before mating and on Gestation Days 6, 8, 11 and 15. Each dose of vaccine was one-fifth the human dose volume. Treatment of rats with vaccine or AS04 was not associated with any systemic toxicity and had no impact on female fertility. There were no adverse effects on pre- or post-natal development of litters from treated rats, as judged by fetal evaluation at Gestation Day 20, and growth and survival of pups to postnatal Day 25. These results support the use of the vaccine in the targeted human population.