Title:A New Vaccine Delivery Vehicle and Adjuvant Candidate: Bordetella pertussis Inactivated Whole Cells Entrapped in Alginate Microspheres
VOLUME: 23 ISSUE: 18
Author(s):Naser Mohammadpour Dounighi, Fereshteh Shahcheraghi*, Mehdi Razzaghi-Abyaneh*, Mojtaba Nofeli and Hossein Zolfagharian
Affiliation:Department of Microbiology, Pasteur Institute of Iran, Tehran, Departments of Microbiology and Mycology, Pasteur Institute of Iran, P. O. Box 13164, Tehran, Departments of Microbiology and Mycology, Pasteur Institute of Iran, P. O. Box 13164, Tehran, Department of Human Vaccine and Serum, Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization, Karaj, Department of Human Vaccine and Serum, Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization, Karaj
Keywords:Bordetella pertussis, bacteria, microparticle, whole cell vaccine, potency, immunogenicity.
Abstract:There is no doubt about the whole cell pertussis vaccine efficacy, but it is necessary to improve the
vaccine quality specially to decrease its toxicity by obtaining good immunogenicity with low bacterial content. In
this work, under optimum condition inactivated B. pertussis bacteria cells entrapped with alginate microparticles
were fabricated and in vivo immunogenicity and ptency of new microparticle based vaccine were evaluated in
mice.
Microspheres loaded with inactive B. pertussis bacterium cells were prepared via an emulsification method and
analyzed for morphology, size, polydispersity index, loading efficiency, loading capacity, release profile and in
vivo potency.
The inactivated bacterial suspension mixture prepared in this work was nontoxic and showed potent ED50 (1:333
of human dose) and preserved agglutinins 1, 2, 3. The optimum conditions for the preparation of microparticles
were achieved at alginate concentration 3.8% (w/v), CaCl2 8% (w/v), PLL 0.1% (w/v), lipophilic surfactant 0.22
(%w/v), hydrophilic surfactant 3.6 (%w/v), cross linking time 3min, homogenization rate 600 rpm, and alginate to
CaCl2 solution ratio 4. Both empty and B. pertussis loaded microparticles exhibited smooth surface texture and
relatively spherical shape. The B. pertussis encapsulated microspheres fabricated under optimized conditions
showed mean particle size 151.1 μm, polydispersity index 0.43, loading efficiency 89.6%, loading capacity
36.3%, and relatively constant release rate lasted to 15 days. In vivo immunogenicity and protection study against
wild type challenge showed strongly higher potency (approximately 2.5 fold) of encapsulated B. pertussis organisms
than non-encapsulated conventional aluminum hydroxide adsorbed vaccine.
It can be concluded that microencapsulation of inactive B. pertussis cells appears to be a suitable approach for
improving the wP vaccine quality, specially by obtaining good immunogenicity with low bacterial content.
