Rational Design of a Chimeric Derivative of PcrV as a Subunit Vaccine Against Pseudomonas aeruginosa

Abstract

Pseudomonas aeruginosa (PA) is a major cause of nosocomial infections, which remain an unsolved problem in the clinic despite conventional antibiotic treatment. A PA vaccine could be both an effective and economical strategy to address this issue. Many studies have shown that PcrV, a structural protein of the type 3 secretion system (T3SS) from PA, is an ideal target for immune prevention and therapy. However, difficulties in the production of high-quality PcrV likely hinder its further application in the vaccine industry. Thus, we hypothesized that an optimized PcrV derivative with a rational design could be produced. In this study, the full-length PcrV was divided into four domains with the guidance of its structure, and the Nter domain (Met1-Lys127) and H12 domain (Leu251-Ile294) were found to be immunodominant. Subsequently, Nter and H12 were combined with a flexible linker to generate an artificial PcrV derivative (PcrV NH ). PcrV NH was successfully produced in E. coli and behaved as a homogenous monomer. Moreover, immunization with PcrV NH elicited a multifactorial immune response and conferred broad protection in an acute PA pneumonia model and was equally effective to full-length PcrV. In addition, passive immunization with anti-PcrV NH antibodies alone also showed significant protection, at least based on inhibition of the T3SS and mediation of opsonophagocytic killing activities. These results provide an additional example for the rational design of antigens and suggest that PcrV NH is a promising vaccine candidate for the control of PA infection.

Genome-Scale Screening of Vaccine Candidates Against Pseudomonas Aeruginosa

“…These results lead us to combine PcrV NH , a vaccine candidate invented previously to improve protection against PA [13]. As shown in Figure 5A, the levels of anti-reFlgE and anti-PcrV NH were signi cantly elevated after immunization with the two recombinant proteins.…”

“…However, there are twenty major serotypes and various subtypes, and the poor immunogenicity of lipopolysaccharide limits the protection of LPS vaccines, as observed in clinical trials [10]. The genetically engineered components of agella, pilin, the type 3 secretion system (T3SS) and other virulence factors have also been tested [11][12][13]. A phase 2/3 clinical trial for a promising new vaccine, IC43, has been completed in patients in intensive care units [14].…”

Complete Genome Sequence of Pseudomonas aeruginosa XN-1, Isolated from the Sputum of a Severe Pneumonia Patient

“… P. aeruginosa XN-1 (CCTCC M2015730) was isolated from a severe pneumonia patient and deposited in the China Center for Type Culture Collection (CCTCC). According to our previous studies ( 6 – 8 ), strain XN-1 has strong virulence. In a mouse model of acute pneumonia, no mouse survived 36 h after challenge with a lethal dose of bacteria (1.0 × 10 7 CFU) ( 6 , 7 ).…”

<p>Protective Efficacy of the OprF/OprI/PcrV Recombinant Chimeric Protein Against <em>Pseudomonas aeruginosa</em> in the Burned BALB/c Mouse Model</p>

“…of PcrV. 42 PcrV protein as a vaccine could increase the titres of the TNF-α, INF-Ƴ, Cluster of Differentiation 3 (CD 3 ), Cluster of Differentiation 28 (CD 28 ), and Cluster of Differentiation 4 (CD 4 ). 3 Therefore, all the three proteins selected to design the chimeric antigen have both the ability to activate cellular and humoral immunity.…”