1. Identification of Chlamydia pneumoniae- specific CD8+ T-cell epitopes that elicit a CTL response, for two mouse and two human MHC Class I types (Objective 1;
2. Immunization of mice with DNA vaccines coding for specific Chlamydia pneumoniae proteins resulted in partial protection against challenge (Objective 2);
3. Several Chlamydia pneumoniae proteins, produced in Bacillus, for use as immunological reagents (Objective 3).
PROPOSAL SUMMARY Objectives The overall objective of the proposed research is the establishment of a rationale for the design and development of vaccines to prevent infections by intracellular parasitic agents. To do so will require the identification of mechanisms that optimize the induction of cell-mediated immunity through the targeted activation of specific immune system cells (CD8+), especially cytotoxic T-lymphocytes (CTLs), with as little as possible activation of other immune system cells that may exacerbate the pathology of the infection. The model disease for this study will be infection by the bacterium Chlamydia pneumonia (Cpn), which produces both an acute infection associated with marked inflammatory reactions, and a long-term latent infection in which Cpn persists as an obligatory intracellular parasite, to be studied in a mouse infection model.
The separate approaches summarised below, utilising the Cpn mouse infection, are intended to develop a general methodology to both identify and characterize the important CD8+ T-cell epitopes required to induce protective cell-mediated immunity against specific infectious agents, and to optimize this response while minimising harmful immune reactions in the design and construction of effective vaccines heretofore unavailable.
Specific Aims and Work Plan The general objective state above will be pursued through seven work packages, each directed toward a specific goal, but all contributing in a synergistic manner to the attainment of the primary objective:
- The identification of pathogen-specific epitopes that stimulate CD8+ T-cells.
. WP1 Identification of such CD8+ epitopes within known sequences of major Cpn proteins
. WP2 Identification of such Cpn epitopes, on the basis of their MHC Class-I presentation.
- The design, formulation, and testing of prototype vaccines.
. WP3 DNA vaccines, coding for specially constructed fusion proteins containing the T-cell epitopes,
. WP4 T-cell epitopes incorporated into a recombinant protein expressed by a live Salmonella carrier.
. WP5 The introduction of T-cell epitopes as peptides in a liposome formulation,
. WP6 Testing the candidate vaccines in genetically defined inbred strains of mice
- The production of immunological reagents for the characterization of Cpn- specific immunity.
. WP7 Production of selected Cpn proteins in the gram- positive host Bacillus subtilis.
Funding SchemeCSC - Cost-sharing contracts
171 77 Stockholm
NE2 4HH Newcastle - Upon Tyne