Present address: Wellcome Trust Centre for the Epidemiology of Infectious Disease, Department of Zoology, University of Oxford, Oxford OX1 3PS, UK.
Activation of human dendritic cells by the PorA protein of Neisseria meningitidis
Article first published online: 1 APR 2004
Volume 6, Issue 7, pages 651–662, July 2004
How to Cite
Al-Bader, T., Jolley, K. A., Humphries, H. E., Holloway, J., Heckels, J. E., Semper, A. E., Friedmann, P. S. and Christodoulides, M. (2004), Activation of human dendritic cells by the PorA protein of Neisseria meningitidis. Cellular Microbiology, 6: 651–662. doi: 10.1111/j.1462-5822.2004.00392.x
- Issue published online: 1 APR 2004
- Article first published online: 1 APR 2004
- Received 10 November, 2003; revised 23 January, 2004; accepted 26 January, 2004.
The major porin proteins present in the outer membrane of Neisseria meningitidis, the causative agent of life-threatening meningitis and septicaemia, are believed to have potent immunostimulatory effects. In this study, the interactions between human monocyte-derived dendritic cells (mo-DC) and the PorA porin were investigated, in order to reveal the role of this protein in promoting innate and adaptive immune responses. Recombinant (r)PorA induced mo-DC maturation, as reflected by reduced receptor-mediated endocytosis, increased production of the chemokines IL-8, RANTES, MIP-1α and MIP-1β and augmented expression of the surface markers CD40, CD54, CD80, CD86 and major histocompatibility complex class II molecules. However, rPorA induced either low level or no significant secretion of pro-inflammatory cytokines from mo-DC. The protein potently augmented the capacity of mo-DC to activate both allogeneic CD4+ memory T-cells and CD4+RA+ naïve T-cells. In addition, rPorA appeared to inhibit the production of IL-12p70 that follows from the interaction between CD40 on the mo-DC and CD40-ligand on T-cells, thereby directing T-cell differentiation towards a Th2 type response. These data demonstrate that PorA is involved in DC activation and in influencing the nature of the T-helper immune response, which are important properties for generating antibody responses required for protective immunity against meningococci and for determining the immuno-adjuvant effects of this protein.