Thirty patients with advanced colorectal carcinoma (CRC) were treated with alum-precipitated polyclonal goat anti-idiotypic antibodies (Ab2) to monoclonal anti-CRC antibody C017-4A (Abl) in doses between 0.5 and 4 mg per injection. All patients developed anti-anti-idiotypic antibodies (Ab3) with binding specificities on the surfaces of cultured tumor cells similar to the specificity of Abl.

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Selective inhibition of proinflammatory chemokines such as IL-8 is an important approach to combat inflammatory and infection diseases. Previous studies suggested that interaction of transcription factors NFκB repressing factor (NRF) and NFκB play a crucial role in activation of IL-8 gene expression. In a search for a specific inhibitor of IL-8 expression, we applied tandem affinity purification to investigate interaction of NRF and NFκB p65 in cells. We identified a synthetic peptide corresponding to aa 223–238 of NRF interfering with binding of endogenous p65 to NRF. Furthermore, nucleofection experiments were established to introduce this inhibitory peptide into the nucleus of IL-1 stimulated human cervical and Helicobacter pylori infected gastric epithelial cells. Our data clearly show that the specific peptide disturbing NRF/NFκB interaction is able to significantly decrease endogenous IL-8 gene transcription in response to IL-1 or Helicobacter pylori infection. Thus, our study provides novel insights into NRF and NFκB interaction in vivo and may facilitate the design of new anti-IL-8 drugs based on novel strategies.

Human immunodeficiency virus type 1 (HIV-1) is able to establish a latent infection during which the integrated provirus remains transcriptionally silent. In response to specific stimuli, the HIV-1 long terminal repeat (LTR) is highly activated, enhancing both transcriptional initiation and elongation. Here, we have identified a specific binding sequence of the nuclear NF-B-repressing factor (NRF) within the HIV-1 LTR. The aim of this work was to define the role of NRF in regulating the LTR. Our data show that the endogenous NRF is required for transcriptional activation of the HIV-1 LTR in stimulated cells. In unstimulated cells, however, NRF inhibits HIV-1 LTR activity at the level of transcription elongation. Binding of NRF to the LTR in unstimulated cells prevents recruitment of elongation factor DRB sensitivity-inducing factor and formation of processive elongation complexes by hyperphosphorylated RNA polymerase II. Our data suggest that NRF interrupts the regulatory coupling of LTR binding factors and transcription elongation events. This inhibitory mechanism might contribute to transcriptional quiescence of integrated HIV-1 provirus.

The aim of this study was to investigate the influence of protein kinase C (PKC) alpha and beta on the TCR-CD28-stimulated protein kinase cascades participating in regulation of IL-2 gene transcription and secretion. Inhibition of the synthesis of PKCalpha and beta by specific phosphorothioate-modified antisense oligonucleotides (ODN) resulted in suppression of phosphorylation and activation of Raf-1, mitogen-activated extracellular-regulated kinase kinases and extracellular-regulated kinases in stimulated Jurkat T cells. Furthermore, a marked reduction of IkappaB kinase-alpha-catalyzed IkappaBalpha phosphorylation was observed in both PKCalpha- and beta-specific antisense oligonucleotide-treated cells. In sharp contrast, TCR-CD28-stimulated phosphorylation and activation of the Jun-N-terminal kinase (JNK) cascade was specifically suppressed upon treatment with PKCbeta-specific antisense ODN, suggesting that PKCbeta was a specific upstream regulator of the JNK protein kinase cascade. Significant inhibition of high-affinity NF-AT binding and transactivation, IL-2 gene expression, reduction of IL-2 mRNA synthesis, and, most impressively, a complete suppression of IL-2 secretion were observed in PKCbeta antisense ODN-treated cells. The data indicate a highly specific function of PKCbeta for regulation of TCR-CD28 induced-signaling, IL-2 gene expression and secretion in Jurkat T cells.

Co-stimulation of murine EL-4 thymoma cells-carrying high numbers of TCR and type I IL-1 receptors (IL-1R)-with anti-CD3 antibodies and IL-1 resulted in synergistic enhancement of IL-2 synthesis. While the extracellular signal-regulated kinase (ERK) cascade was activated by both receptors, IL-1 preferentially stimulated Jun-N-terminal kinases (JNK) and p38 mitogen-activated kinase or microtubule-associated protein kinase (MAPK). Interruption of TCR- or IL-1R-stimulated ERK cascade by PD-98059, a specific inhibitor of MAP/ERK kinase (MEK), resulted in partial suppression of nuclear factor of activated T cells activation and in complete inhibition of IL-1-stimulated NFkappaB activation. Suppression of activation of both MEK and p38 MAPK resulted in significant inhibition of IL-2 gene expression. The results show that maximal activation of the IL-2 gene requires activation of at least two different protein kinase cascades, i.e. of the ERK and p38 pathways but presumably also that of JNK which converge at the level of the IL-2 promoter resulting in enhancement of its transcriptional activity.

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