Screening of 71 P. multocida Proteins for Protective Efficacy in a Fowl Cholera Infection Model and Characterization of the Protective Antigen PlpE

Abstract

Background There is a strong need for a recombinant subunit vaccine against fowl cholera. We used a reverse vaccinology approach to identify putative secreted or cell surface associated P. multocida proteins that may represent potential vaccine candidate antigens. Principal Findings A high-throughput cloning and expression protocol was used to express and purify 71 recombinant proteins for vaccine trials. Of the 71 proteins tested, only one, PlpE in denatured insoluble form, protected chickens against fowl cholera challenge. PlpE also elicited comparable levels of protection in mice. PlpE was localized by immunofluorescence to the bacterial cell surface, consistent with its ability to elicit a protective immune response. To explore the role of PlpE during infection and immunity, a plpE mutant was generated. The plpE mutant strain retained full virulence for mice. Conclusion These studies show that PlpE is a surface exposed protein and was the only protein of 71 tested that was able to elicit a protective immune response. However, PlpE is not an essential virulence factor. This is the first report of a denatured recombinant protein stimulating protection against fowl cholera.

Pasteurella multocida: from Zoonosis to Cellular Microbiology

“…Only one protein, lipoprotein E (PlpE), was found to protect against P. multocida challenge in chickens and mice, which confirmed previously reported results using the PlpE cloned from the avian serotype A:1 strain X-73 (446). However, a plpE knockout mutant strain retained full virulence (416). Conjugated vaccines comprised of multiple antigens, such as OmpH plus PlpE peptides, have also shown promise (445,565).…”

“…Many iron acquisition-related genes have been predicted to be part of the outer membrane proteome (415). Although iron-dependent expression profiling of the outer membrane proteome still needs to be investigated, most of these membrane proteins were shown to be protective antigens (416).…”

“…OmpH is a major outer membrane porin that forms a homotrimeric channel and has shown some potential as a protective antigen (444). OmpH and Pasteurella lipoprotein E (PlpE) are protective surface antigens associated with P. multocida serotype A:1, A:3, and A:4 strains isolated from cattle with shipping fever (445,446) and from birds with fowl cholera (416). OmpA and OmpH proteins show considerable heterogeneity, and at least among avian P. multocida strains, a number of different variants appear to be associated with certain capsular serotypes (B, D, or F) (200,227).…”

Virulence gene profiles of Pasteurella multocida strains isolated from cattle and buffalo

“…Oma87 is an 87-kDa outer membrane protein of all P. multocida strains that is expressed in vivo (rUFFOLO and aDLer, 1996). Omph and Pasteurella lipoprotein e (Plpe) are protective surface antigens associated with P. multocida serotype a: 1, a: 3, and a: 4 strains isolated from cattle with shipping fever (WU et al, 2007;OkaY et al, 2012), and from birds with fowl cholera (hatFaLUDI et al, 2012). Porins such as Omph are candidates for heterologous vaccine development because they are generally conserved among species, and are highly immunogenic (Lee et al, 2007).…”

Occurrence of Pasteurella multocida among pigs with respiratory disease in China between 2011 and 2015

“…Pasteurella multocida ( P. multocida ), a Gram-negative, non-motile, facultative coccobacillus, belonging to the Pasteurellaceae family [1], is an opportunistic pathogen and common inhabitant of the upper respiratory tract of many animal species, and a causative agent of numerous economically important diseases worldwide, including atrophic rhinitis (AR) in swine, fowl cholera in birds, pneumonia and shipping fever in cattle, snuffles in rabbits [2–4], and occasional zoonotic infections in humans [5]. …”