Selective blockade of NF-kappa B by novel mutated I kappa B alpha suppresses CD3/CD28-induced activation of memory CD4(+) T cells in asthma

Background:Nuclear factor kappa B(NF-kappa B) overactivation plays a crucial role in T-helper 2 (Th2)-biased allergic airway inflammation by increased activation and decreased apoptosis of CD4(+) T cells. We have shown that targeted NF-kappa B suppression in dendritic cells by adenoviral gene transfer of a novel mutated inhibitor of NF-kappa B(I kappa B alpha) (AdI kappa B alpha M) contributes to T-cell tolerance, but the immunosuppressive action of AdI kappa B alpha M on memory(CD45RO(+)) CD4(+) T cells remains enigmatic. Methods:CD45RO(+) T cells from Dermatophagoides farinaei-sensitized asthmatic patients, untransfected or transfected with AdI kappa B alpha M or AdLacZ(beta-galactosidase) for 24 h, were stimulated with anti-CD3(1.0 mu g/ml) plus anti-CD28(0.5 mu g/ml) monoclonal antibody for an additional 24 h. I kappa B alpha M transgene expression and NF-kappa B activation were detected by polymerase chain reaction(PCR), reverse transcription-PCR(RT-PCR), Western blot analysis, and electrophoretic mobility shift assay. Phenotype and apoptosis were measured by flow cytometry, annexin V binding, and terminal deoxyribonucleotidyl transferase-mediated dUTP nick end labeling analyses. Cytokine production and cell proliferation were determined using enzyme-linked immunosorbent assay andH-3 thymidine incorporation. Results:A unique 801-bp I kappa B alpha M cDNA and a dose-dependent increase in I kappa B alpha M transgene expression were observed in AdI kappa B alpha M-transfected CD45RO(+) T cells. Significantly, AdI kappa B alpha M inhibited CD3/CD28-mediated NF-kappa B activation in CD45RO(+) T cells, leading to evident apoptosis, reduction of eotaxin, RANTES, Th1 interferon (IFN)-gamma and interleukin (IL)-2, and Th2 (IL-4, IL-5, and IL-13 despite a slight decrease in IL-10) cytokines and secondary proliferative response. AdI kappa B alpha M also upregulated cytotoxic T lymphocyte-associated antigen 4(CTLA-4) and downregulated CD69 besides no change in CD28. Conclusion:I kappa B alpha M might be beneficial to augment memory CD4(+) T-cell tolerance through modulating B7-CD28/CTLA-4 co-stimulatory pathways and NF-kappa B-dependent cytokine profiles in allergic inflammatory diseases including asthma.