Long-Term Immunological Memory Induced by Recombinant Oral Salmonella Vaccine Vectors

Abstract

We have previously shown that Salmonella enterica serovar Typhimurium expressing the hagB hemagglutinin gene from Porphyromonas gingivalis can induce primary and recall immune responses in serum and secretions in mice; however, the longevity of memory induced by oral Salmonella carriers has not been adequately demonstrated. In this study, we examined the capacity of mice to mount a recall response 52 weeks after primary immunization. Recall responses were seen in serum immunoglobulin G (IgG) and IgA following boosting at week 52, and in most cases, they were equal to or greater than the primary responses. Significant mucosal IgA recall responses in saliva and vaginal wash were also detected following boosting at week 52. In addition, there was a considerable residual response in secretions at week 51, prior to boosting. These results indicate that oral Salmonella vectors can induce long-term memory to recombinant HagB and are particularly effective at inducing long-lasting mucosal responses as well as at inducing the capacity for mucosal recall responses.

Oral Immunization with RecombinantLactobacillus plantarumInduces a Protective Immune Response in Mice with Lyme Disease

“…Throughout the immunization regimen, stool samples were collected on days 0, 2,4,7,9,11,14,28,30,32,34,49,51,53, and 55 to determine the viability of L. plantarum and its ability to colonize the digestive tract. Suspensions of stools collected from mice immunized with LpA or LpA␣ contained on average 10 6 cells/g of luminal contents, in contrast to the control.…”

“…There have been a number of reports of oral vaccine candidates established from genetically modified pathogenic bacteria, such as Salmonella and Listeria species (1,2,30,45,52), or commensal bacteria, such as Lactococcus lactis and Lactobacillus species (27,31,32,60). The latter are food-grade bacteria that have GRAS status (generally regarded as safe).…”

Human α- and β-Defensins Bind to Immobilized Adhesins fromPorphyromonas gingivalis

“…rHagB was prepared as previously described (33,50). Briefly, rHagB (1.4 kb) was cloned into the vector pQE31 (Qiagen Inc., Valencia, CA), designated pQE31-TX1, and expressed in Escherichia coli M15(pREP4)pQE31-TX1.…”

Hemagglutinin B Is Involved in the Adherence of Porphyromonas gingivalis to Human Coronary Artery Endothelial Cells

“…The purified rHagB migrated as a 49-kDa protein during electrophoresis, as described previously (49), even though the predicted molecular mass of P. gingivalis HagB is 39.4 kDa. This differential migration could be due to the high pI of the protein and thus aberrant migration during electrophoresis, as has been described for other similar proteins (32), or possibly to posttranslational modifications. Using serum from a rabbit immunized with a whole preparation of P. gingivalis 381, we observed a reaction in Western blotting with the purified His 6 -rHagB protein, demonstrating that at least some epitopes of rHagB are in the same conformation as when present in whole P. gingivalis cells (M. Bélanger, unpublished data).…”

“…The hagB gene of P. gingivalis (1.4 kb) was cloned into the vector pQE-31 (QIAGEN), and the construct was designated pQE-31-TX1 (32). The histidine-tagged HagB was purified on a nickel-nitrilotriacetic acid affinity column by fast protein liquid chromatography (FPLC) (Bio-Rad Laboratories, Hercules, CA) from E. coli M15[pREP4]pQE-31-TX1, as described previously (32). The eluted protein was dialyzed against 500 mM sodium chloride (NaCl) and 10 mM Tris, pH 7.4, and was concentrated using polyethylene glycol (PEG) 8000 (Fisher Scientific, Fair Lawn, NJ).…”