Safety and Immunogenicity of Recombinant Group B Meningococcal Vaccine in Rats
OBJECTIVE To investigate the non-clinical safety and immunogenicity of recombinant group B meningococcal vac-cine by repeatedly dose to rats,so as to provide reference for designing dose level and monitoring toxicity and side effects in clinical tri-als.METHODS SD rats were used to design 4 main toxicity groups including negative control group,adjuvant control group,low dose vaccine group(1 dose each)and high dose vaccine group(3 doses each)and 3 satellite groups.The vaccine was dosed by intra-muscular injection at weeks 0,3,6,9 and 12 respectively.During the study,all the animals of the main toxicity group were observed for clinical signs,indicators such as body weights,food consumption,body temperature,blood cells counting,coagulation,serum bio-chemistry,ophthalmology,T lymphocyte subsets and cytokines were detected.Serum specific IgG antibody and bactericidal antibody were measured for satellite animals.All the animals were observed anatomically,main organs were weighed to the calculate viscera/body ratio and the viscera/brain ratio,and various tissues and organs were examined pathologically.RESULTS It could produce high-leveled binding antibodies and bactericidal antibodies with strong activity in immune serum that rats injected the low and high do-ses of recombinant group B meningococcal vaccines.Both the low and high dose vaccines caused the increases in neutrophils,mono-cytes and lymphocytes significantly,the decreases in hemoglobin and RBC significantly.Other dose-related changes involved the in-crease in serum globulin and decrease in albumin,with concomitant decrease in A/G,which basically returned to normal after 4 weeks of recovery period.The histopathological findings associated with adjuvant and vaccine were mild or moderate granulomatous inflamma-tion,acute inflammation in injection site,infiltration and proliferation of mononuclear cells/mixed cells in the sciatic membrane,and increased number of myeloid plasma cells and granulocytes in lymph nodes.CONCLUSION Recombinant group B meningococcal vaccine had good immunogenicity and safety profile in SD rats,there is no immune toxicity reaction.It is obvious that adjuvant and vaccine-related changes in indicators of peripheral blood and the inflammation response in injection site.Under the dose levels of this study,there is no adverse effect level on recombinant B group meningococcal vaccine for 3 doses/one rat.
recombinant group B meningococcal vaccineratimmunogenicitysafety
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