pneumonia

pneumoniajourn

Vol7SpecialIssueforweb

EuroPneumo Special Issue / pneumonia 2015 Oct 21;7:I–72

observed clinical course until hospital discharge. Twenty-five patients were recruited and 23 had blood samples tested.

Treatment with P4 peptide resulted in significantly increased bacterial killing by neutrophils in 15/23 (65%) of patients

(mean killing index 31.4% vs. 20.3%, p = 0.0024). Clinical measures of disease severity (SOFA and APACHE II) did not

correlate with P4 peptide activity. Serum levels of IL-10 (GM 12.4 vs. 1.9, p = 0.0061) and IL-8 (GM 59.1 vs. 8.5, p = 0.015)

were significantly higher in blood samples that did not respond to P4 stimulation. Treatment with P4 peptide significantly

enhanced neutrophil phagocytic activity in the majority of patients with severe community-acquired pneumonia. This

study supports the rationale for P4 immunotherapy as a therapeutic strategy in severe community-acquired pneumonia.

P2.33

Recombinant expression of Streptococcus pneumoniae capsular

polysaccharides in Escherichia coli

Emily Kay 1 , Laura Yates 1, 2 , Vanessa Terra 1 , Jon Cuccui 1 , Brendan Wren 1

1

London School of Hygiene & Tropical Medicine, London, UK; 2 University of Alberta, Edmonton, Canada

Currently, Streptococcus pneumoniae is responsible for over 14 million cases of pneumonia worldwide annually, and

more than 1 million deaths, the majority of them children. In the UK 2 vaccines are recommended: the pneumococcal

polysaccharide vaccine (PPV23), containing purified capsular polysaccharide from 23 serotypes; and the pneumococcal

conjugate vaccine (PCV13), containing 13 common serotypes conjugated to CRM197 (mutant diphtheria toxin). Vaccine

production costs of pneumococcal conjugate vaccines can be prohibitively high, limiting accessibility of the vaccine in lowincome

countries. Protein glycan coupling technology (PGCT) can be used to produce recombinant vaccines by expressing

the glycan of interest, acceptor protein. and glycosyltransferase enzyme (PglB) within Escherichia coli. This approach is

flexible and can be exploited to produce an unlimited and purified supply of vaccine at low cost. In order to optimise

glycoconjugate yield each of the components must be optimised individually and in concert. Recombinantly expressing

a polysaccharide-encoding locus from a Gram-positive bacterium in a Gram-negative bacterium is challenging, not least

because transcriptional levels may not be maintained, all the necessary substrates and precursors may not be available,

and the resultant components may not be trafficked and assembled in the same way. Our aims were to recombinantly

express S. pneumoniae capsular polysaccharides, from several different capsule types, within E. coli; to find out the

minimum set of genes necessary to reliably and efficiently express these polysaccharides heterologously; and finally, to

assess the suitability of these polysaccharides to be used with PGCT, coupling them to a variety of immunogenic carrier

proteins, to produce an inexpensive and flexible conjugate vaccine. To date, 7 polysaccharides have been recombinantly

expressed and detected using a serotype-specific antiserum; of these, 4 have been coupled to a protein using PGCT.

P2.34

A novel cross-protective whole-cell inactivated pneumococcal vaccine

Rachelle Babb 1 , Austen Chen 1 , Abiodun D Ogunniyi 1 , Tim Hirst 2 , Mohammed Alsharifi 1 , James

Paton 1

1

School of Biological Sciences, University of Adelaide, Adelaide, South Australia, Australia; 2 Gamma Vaccines Pty Ltd, Canberra, Australian Capital

Territory, Australia

Generating a pneumococcal vaccine that is serotype-independent and cost effective remains a global challenge. Gammairradiation

has recently been employed as an inactivation technique for the generation of whole cell bacterial and viral vaccines

due to its ability to conserve pathogen structure without disruption of antigenic determinants. In the present study, we

utilised gamma irradiation to inactivate an unencapsulated Streptococcus pneumoniae strain Rx1 with an unmarked deletion

of the autolysin gene lytA, and with the pneumolysin gene ply replaced with an allele encoding a non-toxic pneumolysoid

(PdT) (designated γ-PN vaccine). Intranasal γ-PN vaccination of C57BL/6 mice was shown to be protective in lethal challenge

models of pneumococcal bacteraemia, pneumonia and meningitis. Vaccine efficacy was shown to be reliant on B cells,

IFN-γ and IL-17A responses. These data are the first to demonstrate the use of gamma-irradiation as a means of generating

an effective serotype-independent pneumococcal vaccine that is dependent on both humoral and cellular immunity.

pneumonia 2015 Volume 7

41

Similar magazines