Rossi, Omar (2014) MODULATION OF REACTOGENICITY OF GENERALIZED MODULES FOR MEMBRANE ANTIGENS (GMMA)BY GENETIC LIPID A MODIFICATION. [Tesi di dottorato]
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Item Type: | Tesi di dottorato |
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Resource language: | English |
Title: | MODULATION OF REACTOGENICITY OF GENERALIZED MODULES FOR MEMBRANE ANTIGENS (GMMA)BY GENETIC LIPID A MODIFICATION |
Creators: | Creators Email Rossi, Omar omar_rossi@hotmail.it |
Date: | 26 March 2014 |
Number of Pages: | 118 |
Institution: | Università degli Studi di Napoli Federico II |
Department: | Scienze Chimiche |
Scuola di dottorato: | Biotecnologie |
Dottorato: | Scienze biotecnologiche |
Ciclo di dottorato: | 26 |
Coordinatore del Corso di dottorato: | nome email Sannia, Giovanni giovanni.sannia@unina.it |
Tutor: | nome email Sannia, Giovanni UNSPECIFIED Gerke, Christiane UNSPECIFIED |
Date: | 26 March 2014 |
Number of Pages: | 118 |
Keywords: | Shigella, Vaccine, Endotoxin |
Settori scientifico-disciplinari del MIUR: | Area 05 - Scienze biologiche > BIO/11 - Biologia molecolare |
Aree tematiche (7° programma Quadro): | SALUTE e TUTELA DEL CONSUMATORE > Biotecnologie, strumenti e tecnologie generiche per la salute umana |
Date Deposited: | 08 Apr 2014 11:06 |
Last Modified: | 11 Apr 2017 01:00 |
URI: | http://www.fedoa.unina.it/id/eprint/9677 |
Collection description
Outer membrane particles from Gram-negative bacteria are attractive vaccine candidates as they present surface antigens in their natural environment and orientation. We previously developed a high yield production process for genetically derived particles, called Generalized Modules for Membrane Antigens (GMMA), from Shigella. As GMMA are derived from the outer membrane and contain immune-stimulatory components, especially lipopoly-saccharide (LPS), we examined ways of reducing their reactogenicity by modifying lipid A, the endotoxic part of LPS, through deletion of late acyltransferase genes msbB or htrB in GMMA-producing S. sonnei and S. flexneri strains. GMMA with resulting penta-acylated lipid A from the msbB mutants showed a 600-fold reduction, GMMA from the S. sonnei ΔhtrB mutant a 60,000-fold reduced ability compared to GMMA with wild-type lipid A to stimulated human Toll-like receptor 4 (TLR4) in a reporter cell line. In contrast, in the S. flexneri ΔhtrB mutant, a compensatory palmitoleoylation occurs resulting in hexa-acylated lipid A with approximately 10-fold higher activity than the penta-acylated lipid A. In human PBMC, GMMA with penta-acylated lipid A showed a marked reduction in induction of inflammatory cytokines (800-fold for S. sonnei ΔhtrB, 300-fold for the msbB mutants) compared to a 50-fold reduction observed for GMMA with palmitoleoylated lipid A from the S. flexneri ΔhtrB strain. We demonstrated that the residual activity of GMMA with penta-acylated lipid A is largely due to non-lipid A related TLR2 activation whereas GMMA with palmitoleoylated hexa-acylated lipid A predominantly activate TLR4. These results identify the relative activation of TLR4 and TLR2 pathways by GMMA.
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