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PELA microspheres loaded H. pylori lysates and their mucosal immune response
Jian-Min Ren1, Quan-Ming Zou, Fu-Kun Wang
1Faculty of Medical Laboratory Science, Third Military Medical University, Chongqing 400038, China. renjianmin123@sina.com
Aim:
To prepare poly (D,L-lactide)-polyethylene glycol copolymer (PELA) microspheres loaded H.pylori lysates or Cystografin and observe their targeting in gastrointestinal mucous membrane or analyze the mucosal immune responses by oral administration.
Methods:
PELA microspheres loaded H.pylori lysates or Cystografin were prepared by double emulsion evaporation method. Their distribution in gastrointestinal mucous membrane was observed by CT. Balb/c mice orally immunized in mucosal immune responses, whose antibody production in salivary and gut washing and antibody secreting cells in Peyer's patches (PP) were estimated by ELISA and ELISPOT, respectively. The microspheres physical properties, such as particle size, protein level and morphology were investigated.
Results:
All prepared microspheres were found to have a smooth surface morphology from 3.20-4.05 microm in diameter and high encapsulation efficiency from 74.9-82.2 %. No significant correlation in their physical properties was shown, depending on their molecular weight at the similar composition ratio. Immunization with all types of PELA-Hp microspheres elevated the saliva sIgA level at week 3 by approximately 3-4 times that with soluble antigen, which was greatly enhanced after boosting. At one week after last immunization with all types of PELA-Hp microspheres (week 8), the specific sIgA-ASCs, IgG-ASCs and sIgA in salivary rose obviously. In intestinal Peyer's patches, the specific sIgA-ASCs were 5.92-6.98X10(4)/ml cell and IgG-ASCs were 3.47-4.02X10(4)/ml cell, about 5-9 times higher than those with soluble antigen (P<0.01). ASCs in intestine were more than those in stomach and the majority of the ASCs were sIgA-ASCs. The sIgA in gut washing fluid was 1.62-1.85 OD, about 3-6 times tthat of those with soluble antigen. There were significant differences of the ASCs and sIgA in gut washing fluid as compared with those of PBS and MS-0 (P<0.05). There appeared to be good correlation between sIgA level in gut washing fluid and sIgA-ASCs in intestinal Peyer's patches.
Conclusion:
PELA microspheres may be used as vehicle to delivery antigen and adjuvant in designing oral vaccination.
Insights
Poly (D,L-lactide)-polyethylene glycol copolymer (PELA) microspheres effectively deliver antigens for oral vaccination. These PELA microspheres significantly enhance mucosal immune responses, particularly sIgA production in saliva and gut, making them promising for vaccine development.
Area of Science:
- Biomaterials Science
- Immunology
- Vaccine Technology
Background:
- Oral vaccination strategies are sought for improved patient compliance and reduced healthcare costs.
- Developing effective delivery systems for antigens and adjuvants is crucial for oral vaccine efficacy.
- Poly (D,L-lactide)-polyethylene glycol copolymer (PELA) microspheres offer potential for controlled antigen release and immune stimulation.
Purpose of the Study:
- To prepare PELA microspheres loaded with Helicobacter pylori (H. pylori) lysates or Cystografin.
- To evaluate the targeting and distribution of PELA microspheres in the gastrointestinal mucous membrane.
- To analyze the mucosal immune responses induced by oral administration of PELA microsphere-based vaccines.
Main Methods:
- PELA microspheres were fabricated using the double emulsion evaporation method.
- Microsphere distribution was visualized using computed tomography (CT) in the gastrointestinal tract.
- Mucosal immune responses in Balb/c mice were assessed via ELISA and ELISPOT assays, measuring antibody production and antibody-secreting cells (ASCs) in saliva and Peyer's patches.
Main Results:
- PELA microspheres exhibited smooth morphology (3.20-4.05 µm) and high encapsulation efficiency (74.9-82.2%).
- Oral immunization with PELA-H. pylori microspheres significantly increased salivary sIgA levels (3-4 times) and gut sIgA levels (3-6 times) compared to soluble antigen.
- Intestinal Peyer's patches showed a substantial increase in specific sIgA-ASCs (5.92-6.98X10^4/ml) and IgG-ASCs (3.47-4.02X10^4/ml), indicating robust mucosal immune activation.
Conclusions:
- PELA microspheres serve as effective vehicles for delivering antigens and adjuvants in oral vaccine designs.
- The enhanced mucosal immune responses suggest PELA microspheres are a promising platform for developing oral vaccines against H. pylori and potentially other pathogens.
- Further research can explore optimizing PELA microsphere formulations for specific vaccine applications.