TY - JOUR
T1 - A Phase I, dose-escalation trial in adults of three recombinant attenuated Salmonella Typhi vaccine vectors producing Streptococcus pneumoniae surface protein antigen PspA
AU - Frey, Sharon E.
AU - Lottenbach, Kathleen R.
AU - Hill, Heather
AU - Blevins, Tamara P.
AU - Yu, Yinyi
AU - Zhang, Ying
AU - Brenneman, Karen E.
AU - Kelly-Aehle, Sandra M.
AU - McDonald, Caitlin
AU - Jansen, Angela
AU - Curtiss, Roy
PY - 2013/10/1
Y1 - 2013/10/1
N2 - Background: Live, attenuated, orally-administered Salmonella strains are excellent vectors for vaccine antigens and are attractive as vaccines based on previous use of S. Typhimurium in animals. A Phase I dose escalation trial was conducted to evaluate the safety and immunogenicity of three newly constructed recombinant attenuated Salmonella enterica serovar Typhi vaccine (RASV) vectors synthesizing Streptococcus pneumoniae surface protein A (PspA). Methods: The 3 S. Typhi strains used as vectors to deliver PspA were S. Typhi ISP1820; S. Typhi Ty2 RpoS-; and S. Typhi Ty2 RpoS+. Sixty healthy adults (median age 25.2 years) were enrolled into 4 Arms (total 15 subjects per Arm); within each Arm, subjects were randomized 1:1:1 into 3 Groups of 5. All subjects in the same Group received the same vaccine vector, and all subjects in the same Arm received the same titer of vaccine (107, 108, 109 or 1010CFU). Adverse events, safety, shedding, and IgG and IgA titers against Salmonella outer membrane proteins (OMPs), lipopolysaccharide (LPS) and PspA were evaluated. Results: In the highest dose group, no subject experienced severe reactions or serious adverse events. Most adverse events were mild; one subject had a positive blood culture. No subject shed vaccine in stool. No statistically significant differences for post vaccination ELISA or ELISPOT results between Groups were detected. However, a limited number of ≥4 fold increases from baseline for IgA anti-OMPs, IgA and IgG anti-LPS, and IgA anti-PspA occurred for a few individuals as measured by ELISA, and IgA anti-OMPs as measured by ELISPOT assay. Conclusions: All three S. Typhi vectored pneumococcal vaccines were safe and well-tolerated. Immunogenicity was limited possibly due to pre-existing high antibody titers prior to vaccination. Increases in IgA were most often observed.
AB - Background: Live, attenuated, orally-administered Salmonella strains are excellent vectors for vaccine antigens and are attractive as vaccines based on previous use of S. Typhimurium in animals. A Phase I dose escalation trial was conducted to evaluate the safety and immunogenicity of three newly constructed recombinant attenuated Salmonella enterica serovar Typhi vaccine (RASV) vectors synthesizing Streptococcus pneumoniae surface protein A (PspA). Methods: The 3 S. Typhi strains used as vectors to deliver PspA were S. Typhi ISP1820; S. Typhi Ty2 RpoS-; and S. Typhi Ty2 RpoS+. Sixty healthy adults (median age 25.2 years) were enrolled into 4 Arms (total 15 subjects per Arm); within each Arm, subjects were randomized 1:1:1 into 3 Groups of 5. All subjects in the same Group received the same vaccine vector, and all subjects in the same Arm received the same titer of vaccine (107, 108, 109 or 1010CFU). Adverse events, safety, shedding, and IgG and IgA titers against Salmonella outer membrane proteins (OMPs), lipopolysaccharide (LPS) and PspA were evaluated. Results: In the highest dose group, no subject experienced severe reactions or serious adverse events. Most adverse events were mild; one subject had a positive blood culture. No subject shed vaccine in stool. No statistically significant differences for post vaccination ELISA or ELISPOT results between Groups were detected. However, a limited number of ≥4 fold increases from baseline for IgA anti-OMPs, IgA and IgG anti-LPS, and IgA anti-PspA occurred for a few individuals as measured by ELISA, and IgA anti-OMPs as measured by ELISPOT assay. Conclusions: All three S. Typhi vectored pneumococcal vaccines were safe and well-tolerated. Immunogenicity was limited possibly due to pre-existing high antibody titers prior to vaccination. Increases in IgA were most often observed.
KW - ELISA
KW - ELISPOT
KW - Pneumococcal surface protein A
KW - Salmonella Typhi vaccine vector
KW - Streptococcus pneumoniae
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U2 - 10.1016/j.vaccine.2013.07.049
DO - 10.1016/j.vaccine.2013.07.049
M3 - Article
C2 - 23916987
AN - SCOPUS:84884209157
SN - 0264-410X
VL - 31
SP - 4874
EP - 4880
JO - Vaccine
JF - Vaccine
IS - 42
ER -