A CD8+ T cell heptaepitope minigene vaccine induces protective immunity against Chlamydia pneumoniae.
An intact T cell compartment and IFN-gamma signaling are required for protective immunity against Chlamydia. In the mouse model of Chlamydia pneumoniae (Cpn) infection, this immunity is critically dependent on CD8(+) T cells. Recently we reported that Cpn-infected mice generate an MHC class I-restricted CD8(+) Tc1 response against various Cpn Ags, and that CD8(+) CTL to multiple epitopes inhibit Cpn growth in vitro. Here, we engineered a DNA minigene encoding seven H-2(b)-restricted Cpn CTL epitopes, the universal pan-DR epitope Th epitope, and an endoplasmic reticulum-translocating signal sequence. Immunization of C57BL/6 mice with this construct primed IFN-gamma-producing CD8(+) CTL against all seven CTL epitopes. CD8(+) T cell lines generated to minigene-encoded CTL epitopes secreted IFN-gamma and TNF-alpha and exhibited CTL activity upon recognition of Cpn-infected macrophages. Following intranasal challenge with Cpn, a 3.6 log reduction in mean lung bacterial numbers compared with control animals was obtained. Using a 20-fold increase in the Cpn challenging dose, minigene-vaccinated mice had a 60-fold reduction in lung bacterial loads, compared with controls. Immunization and challenge studies with beta(2)-microglobulin(-/-) mice indicated that the reduction of lung Cpn burdens was mediated by the MHC class I-dependent CD8(+) T cells to minigene-included Cpn CTL epitopes, rather than by pan-DR epitope-specific CD4(+) T cells. This constitutes the first demonstration of significant protection achieved by immunization with a CD8(+) T cell epitope-based DNA construct in a bacterial system and provides the basis for the optimal design of multicomponent anti-Cpn vaccines for humans.
Pinchuk
Irina
I
Center for Pulmonary and Infectious Disease Control, Department of Microbiology and Immunology, University of Texas Health Center, Tyler, TX 75708, USA.
Starcher
Barry C
BC
Livingston
Brian
B
Tvninnereim
Amy
A
Wu
Shiping
S
Appella
Ettore
E
Sidney
John
J
Sette
Alessandro
A
Wizel
Benjamin
B
D000595:Amino Acid Sequence; D000818:Animals; D017951:Antigen Presentation / Q000235:genetics; D001428:Bacterial Vaccines / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D001483:Base Sequence; D002460:Cell Line; D023521:Chlamydophila Infections / Q000276:immunology* / Q000517:prevention & control*; D016993:Chlamydophila pneumoniae / Q000235:genetics / Q000276:immunology*; D003602:Cytotoxicity, Immunologic / Q000235:genetics; D018984:Epitopes, T-Lymphocyte / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D005260:Female; D005822:Genetic Vectors; D015395:Histocompatibility Antigens Class I / Q000502:physiology; D007371:Interferon-gamma / Q000096:biosynthesis; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D012720:Severity of Illness Index; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology* / Q000378:metabolism; D014162:Transfection; D019444:Vaccines, DNA / Q000008:administration & dosage* / Q000235:genetics / Q000276:immunology*; D022223:Vaccines, Subunit / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology; D001613:beta 2-Microglobulin / Q000502:physiology
D001428:Bacterial Vaccines; D018984:Epitopes, T-Lymphocyte; D015395:Histocompatibility Antigens Class I; D019444:Vaccines, DNA; D022223:Vaccines, Subunit; D001613:beta 2-Microglobulin; D007371:Interferon-gamma