Preparation of microspheres containing leptospiral antigen using biodegradable alginate polymers/Priprava mikrokuglica s antigenom leptospira od bioloski razgradivih alginatnih polimera

Leptospirosis is a worldwide zoonosis caused by pathogenic Leptospira spp. Although the currently available whole cell leptospiral vaccines can induce protection against Leptospirosis, further study for a new generation of vaccine that can stimulate long-term immunity is needed. Biodegradable microspheres as antigen delivery systems have been extensively investigated for decades, especially those based on hydrophilic polymers, such as alginate and chitosan, which have excellent biocompatibility, non- toxicity and biodegradability. The aim of this study was to prepare and characterize alginate microspheres as an antigen delivery system for immunization against leptospirosis. Alginate microspheres containing Leptospiral antigen (LA) were prepared by an emulsification method and characterized for shape, size distribution, loading efficiency (LE), loading capacity (LC) and release profile. The effects of some parameters (such as concentration of alginate and emulsifiers and stirring rate) on microspheres characteristics were investigated. The optimal condition parameters for the preparation of LA loaded alginate microspheres were estimated. The optimum concentrations were obtained for alginate and emulsifiers, 3.5 % (w/v), span 80 (0.2 % w/v) and tween 80 (3.75 % w/v), respectively. Moreover, appropriate homogenizing rate was obtained at 500 rpm. Our results showed the mean particle size of the microspheres as 200 µm, loading efficiency 97 % and loading capacity 8 %. A suitable release profile was observed for in vitro release test of LA from alginate microspheres over an extended period of time (192 hours). These results make the alginate microspheres particularly interesting for an LA delivery system. Key words : Leptospira spp., leptospiral antigen, alginate, micro spheres, antigen delivery, immunization Leptospiroza je zoonoza prouzrocena patogenim vrstama roda Leptospira, a prosirena je diljem svijeta. Iako danasnja cjepiva protiv leptospiroze, proizvedena od cijelih bakterijskih stanica, mogu pruziti zastitu od leptospiroze, potrebna su daljnja istrazivanja nove generacije cjepiva koja ce moci potaknuti tvorbu dugotrajne imunosti. Bioloski razgradive mikrokuglice istrazuju se desecima godina kao mogucnost sporog otpustanja antigena, a posebice su zanimljive one od hidrofilnih polimera kao sto je alginat i kitosan, koji imaju izvrsnu biolosku kompatibilnost, nisu toksicni, a bioloski su razgradivi. Svrha ovog rada bila je pripraviti alginatne mikrokuglice