pneumonia

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Vol7SpecialIssueforweb

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

individual-based modelling of pneumococcal vaccine effects is possible for applications in public health.

P2.41

Evaluation of the efficacy of the immunisation with PspA in a

co-colonisation model in mice

Rafaella Tostes, Maria Leonor Oliveira, Paulo Ho, Eliane Miyaji

Instituto Butantan, São Paulo/SP, Brazil

Pneumococcal surface protein A (PspA) is one of the leading candidates for a protein vaccine against pneumococcal

infections. PspA shows variability and the great majority of strains express PspA from family 1 (clades 1 and 2) or family

2 (clades 3, 4, and 5). The aim of this study is to evaluate the protection elicited by nasal immunisation with recombinant

PspAs from different clades in a mouse model of co-colonisation of the nasopharynx with two strains, one expressing PspA

from family 1 and another expressing PspA from family 2. BALB/c mice were immunised intranasally with recombinant

PspAs from clades 1 to 4 (rPspA1, rPspA2, rPspA3 and rPspA4) using the whole-cell pertussis vaccine as adjuvant.

Immunisation with rPspA1 elicited an increase in anti-rPspA1 and anti-rPspA4 IgG titres measured by ELISA, whereas

immunisation with rPspA4 elicited an increase only in anti-rPspA4 IgG titres. Mice were then challenged with a mixture

of the strains 491/00 (serotype 6B, PspA1) and 472/96 (serotype 6B, PspA4, trimethoprim resistant) and bacteria were

recovered from nasal washes 5 days after challenge. Only mice immunised with rPspA1 showed statistically significant

reduction in colonisation with both strains when compared to the control saline group. Animals immunised with rPspA3

and rPspA4 showed statistically significant reduction only in the PspA4 expressing strain when compared to saline. Our

preliminary results indicate that rPspA1 and possibly a mixture of rPspA1 and rPspA4 would be suitable for attaining

protection against colonisation with strains expressing different PspAs.

Supported by FAPESP, Fundação Butantan, CAPES and CNPq (Brazil).

P2.42

New protein vaccines against pneumococcal pneumonia using

experimentally induced immunity

Jessica Owugha 1 , Angela Wright 1 , Andrea Collins 1 , Cintia Vadesilho 2 , Eliane Miyaji 2 , Kondwani

Jambo 3 , Stephen Gordon 1 , Daniela Ferreira 1

1

Liverpool School of Tropical Medicine, Liverpool, UK; 2 Biotechnology Centre, Instituto Butantan, São Paulo, Brazil; 3 Malawi-Liverpool Wellcome Trust

Clinical Research Programme, Blantyre, Malawi

Our experimental human pneumococcal carriage (EHPC) model provides an ethical measurement of vaccine efficacy

where colonisation is a surrogate for disease. Factors associated with prevention of colonisation include T-helper 17

cell (Th-17) and humoral immune responses. The conserved yet heterogeneous virulence factor pneumococcal surface

protein (PspA) is a promising vaccine candidate, immunogenic and protective in murine disease models. Identification

of a region eliciting beneficial Th-17 and humoral responses may inform development of a vaccine conferring protection

against pneumonia. Four recombinant PspA fragments (approximately 100 amino acids) were expressed in Escherichia

coli BL21 and used in ex vivo stimulation. Volunteers were inoculated with pneumococcus and mononuclear cells isolated

from peripheral blood (PBMCs) and bronchoalveolar lavage (BAL). Th-17 cells were stained for surface phenotyping and

intracellular cytokine production. Assay optimisation revealed Th-17 responses were best detected 5 days post-antigen

stimulation. Preliminary analysis of PBMC stimulations demonstrates an increase in Th-17 response post-pneumococcal

inoculation in all antigens, with elevated responses in one of four fragments. PBMCs of volunteers inoculated with

pneumococcus demonstrate an increased Th-17 response on stimulation with all candidate antigens. The PspA

fragment inducing the highest Th-17 response in blood and BAL will be used to purify antibodies from plasma of healthy

adults susceptible to or protected from colonisation. Resultant antibodies will be employed in functional binding and

complement deposition assays to compare ability to bind and potentially clear pneumococci of differing strains.

Acknowledgements Study volunteers, LSTM PhD Studentship body, MRC/FAPESP, NIHR clinical staff

pneumonia 2015 Volume 7

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