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
Lingua: English
Title: MODULATION OF REACTOGENICITY OF GENERALIZED MODULES FOR MEMBRANE ANTIGENS (GMMA)BY GENETIC LIPID A MODIFICATION
Creators:
CreatorsEmail
Rossi, Omaromar_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:
nomeemail
Sannia, Giovannigiovanni.sannia@unina.it
Tutor:
nomeemail
Sannia, GiovanniUNSPECIFIED
Gerke, ChristianeUNSPECIFIED
Date: 26 March 2014
Number of Pages: 118
Uncontrolled 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

Abstract

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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