Computational analysis and in vitro evaluation of TMF 104, for its antioxidant, antimicrobial, and anticancer efficacies.

Benzylidene chromanones are small molecules, structurally similar to active phytochemicals. Herein, we report one novel benzylidene chromanone, TMF 104, for its bio-efficacies. Its computational docking for Vanin-1, antioxidant, free radical scavenging capacities, antimicrobial effects, and anticancer efficacy were analyzed. TMF 104 predicated strong binging to Vanin-1 protein with a docking energy of -8.1 kcal/mol. The compound dose-dependently exhibited free-radical scavenging and antioxidant activities when tested in vitro. The compound also had remarkable activity against Salmonella typhimurium, Enterococcus faecalis, Staphylococcus aureus, and Escherichia coli with minimum inhibitory concentration values of 1.5, 2.0, 12.5, and 13.5 µg/ml, respectively. The compound was also effective against Bacillus cereus and Pseudomonas aeruginosa albeit at higher concentrations. TMF 104 dose-dependently inhibited the proliferation of MCF-7, NCI H460, and Caki-1 cells with respective GI50 values of 24.51, 21.95, and 32.95 µg/ml, whereas the compound was toxic to normal Vero cells at much higher concentration of 264.70 µg/ml. The compound also aided in apoptosis and increased the sub G0 /G1 phase of the cell cycle in all three cancer cells tested. Our study identified a novel, potent benzylidene analogue with potent antioxidant, antimicrobial, and anticancer activities, which drives further attention for further research.

FNF-12, a novel benzylidene-chromanone derivative, attenuates inflammatory response in in vitro and in vivo asthma models mediated by M2-related Th2 cytokines via MAPK and NF-kB signaling.

BACKGROUND AND AIM: This study evaluates a novel benzylidene-chromanone derivative, FNF-12, for efficacy in in vitro and in vivo asthma models. METHODS: Rat basophilic leukemia (RBL-2H3) and acute monocytic leukemia (THP-1)-derived M2 macrophages were used. Human whole blood-derived neutrophils and basophils were employed. Flow cytometry was used for studying key signalling proteins. Platelet activation factor (PAF)-induced asthma model in guinea pigs was used for in vivo studies. RESULTS: The chemical structure of FNF-12 was confirmed with proton-nuclear mass resonance (NMR) and mass spectroscopy. FNF-12 controlled degranulation in RBL-2H3 cells with an IC50 value of 123.7 nM and inhibited TNF-α release from these cells in a dose-responsive way. The compound effectively controlled the migration and elastase release in activated neutrophils. IC50 value in the FcεRI-basophil activation assay was found to be 205 nM. FNF-12 controlled the release of lipopolysaccharide (LPS)-induced interleukin-10, I-309/CCL1 and MDC/CCL22 in THP-1 derived M2 macrophages. The compound suppressed LPS-induced mitogen activated protein kinase (MAPK)-p-p38 and nuclear factor kappa B(NF-kB)-p-p65 expression in these cells. A dose-dependent decrease in the accumulation of total leucocytes, eosinophils, neutrophils and macrophages was observed in PAF-induced animal models. CONCLUSION: FNF-12 was able to control the inflammatory responses in in vitro and in vivo asthma models, which may be driven by controlling M2-related Th2 cytokines via MAPK and NF-kB signaling.

Structure activity evaluation and computational analysis identify potent, novel 3-benzylidene chroman-4-one analogs with anti-fungal, anti-oxidant, and anti-cancer activities.

SIGNIFICANCE: 3-Benzylidene chroman-4-ones share close homology with naturally occurring bioactive compounds. OBJECTIVES: This study evaluated the antifungal, antioxidant, and anticancer activities of novel 3-benzylidene chromanone analogs with respect to their structure-activity relationships. METHODS: Compounds 45e-64e were synthesized inhouse. Aspergillus niger (MTCC 1344) Aspergillus flavus and Botrytis cinerea were the fungal strains tested. Computational docking analysis was carried out for vanin-1, estrogen receptor (ER), and Akt proteins using Auto-dock vina. Free radical scavenging and total antioxidant capacity was analyzed using spectrophotometric methods. MCF-7 (breast cancer) cell line was used for anticancer assays. Flow cytometry was used to detect cell cycle and apoptosis. RESULTS: Out of the twenty compounds screened, compounds 47e, 50e, 52e, 57e, and 61e that possessed either methoxy and ethoxy/methyl/isopropyl group exhibited very good activity against all fungi. Compounds possessing methoxy group alone showed moderate activity and compounds devoid of methoxy, and ethoxy groups did not show any activity. When computationally analyzed against target proteins for antioxidant properties, the compounds exhibited excellent binging efficacy to vanin-1 and ERs. These predictions were translated in the in vitro free-radical scavenging and antioxidant assays. The compounds exhibited anti-proliferative efficacy in breast cancer cell line, increased the sub-G0/G1 cell cycle populations and total apoptosis in MCF-7 cells. Additionally, the compounds also depicted excelling binging energy when computationally analyzed for Akt enzyme binding. CONCLUSION: In summary, our study identified potential analogs of 3-benzylidene chroman-4-one molecules with excellent anti-fungal, anti-oxidant, and anticancer activities which demand further research for drug developments.

Computational and in vitro characterization of ICY-5: A potential candidate promoting mitochondrial apoptosis via the c-MET and STAT3 pathways.

Targeted chemotherapy remains the primary choice in controlling various forms of breast cancer (BC) due to its heterogenous gene expressions in various subtypes. In silico and in vitro evaluation of ICY-5, a novel arylidene analogue against c-MET, was performed. ICY-5 exhibited a docking score of -9.6 kcal/mol in inactive conformation and, - 8.6 kcal/mol in active conformation for c-MET. ICY-5 inhibited c-MET enzyme with an IC50 of 34.34 nM. The compound effectively inhibited MDA-MB 231 and MCF-7 cell proliferation, with GI50 values of 62.61 and 75.31 nM, respectively, and hepatocyte growth factor (HGF)/R c-MET phosphorylation with IC50 s of 71.41 and 83.77 nM, respectively. ICY-5 dose-dependently inhibited HGF-induced transmigration, cell scattering, invasion and altered cell cycle. An increase in apoptotic populations of these cells, with a dose-dependent decease in phosphorylation of STAT3 protein was observed. Furthermore, ICY-5 upregulated the caspase-3, caspase-9, Bcl-2-associated X and survivin, and downregulated Bcl-2, vascular endothelial growth factor, matrix metalloproteinase-2 (MMP-2), and MMP-9 in both BC cell lines. In summary, ICY-5 exhibited excellent efficacy in BC cells, targeting c-MET/SAT-3-mediated mitochondrial apoptosis. Further research will be required to ascertain ICY-5 suitability as a targeted chemotherapeutic against multiple forms of BC.

Anticancer efficacy of 3-(4-isopropyl) benzylidene-8-ethoxy, 6-methyl, chroman-4-one (SBL-060), a novel, dual, estrogen receptor-Akt kinase inhibitor in acute myeloid leukemia cells.

Estrogen receptor (ER) α is expressed in a subset of patient-derived acute myeloid leukemia (AML) cells, whereas Akt is predominantly expressed in most types of AML. Targeting AML with dual inhibitors is a novel approach to combat the disease. Herein, we examined a novel small molecule, 3-(4-isopropyl) benzylidene-8-ethoxy,6-methyl, chroman-4-one (SBL-060), capable of targeting AML cells by inhibiting ERα and Akt kinase. The chemical properties of SBL-060 were identified by proton nuclear magnetic resonance (1H-NMR), 13C-NMR, and mass spectroscopy. In silico docking was performed using an automated protocol with AutoDock-VINA. THP-1 and HL-60 cell lines were differentiated using phorbol 12-myristate 13-acetate. ERα inhibition was assessed using ELISA. The MTT assay assessed cell viability. Flow cytometry was performed for cell cycle, apoptosis, and p-Akt analyses. Chemical analysis identified the compound as 3-(4-isopropyl) benzylidene-8-ethoxy,6-methyl, chroman-4-one, which showed high binding efficacy toward ER, with a ΔGbinding score of -7.4 kcal/mol. SBL-060 inhibited ERα, exhibiting IC50 values of 448 and 374.3 nM in THP-1 and HL-60 cells, respectively. Regarding inhibited cell proliferation, GI50 values of SBL-060 were 244.1 and 189.9 nM for THP-1 and HL-60 cells, respectively. In addition, a dose-dependent increase in sub G0/G1 phase cell cycle arrest and total apoptosis was observed after treatment with SBL-060 in both cell types. SBL-060 also dose-dependently increased the p-Akt-positive populations in both THP-1 and HL-60 cells. Our results indicate that SBL-060 has excellent efficacy against differentiated AML cell types by inhibiting ER and Akt kinase, warranting further preclinical evaluations.

Neurological Disorders Seen During Second Wave of SARS-CoV-2 Pandemic from Two Tertiary Care Centers in Central and Southern Kerala.

Background and Objective: SARS-CoV-2 infections present with predominant respiratory symptoms. Only a few anecdotal reports of neurological involvement have come out from India so far. Adverse neurological events following immunization (AEFI) were also reported. We present the neurological symptoms seen either in association with vaccination or COVID-19 infection during the second wave. Methods: This was a retrospective study that included consecutive COVID-19 patients' admissions during the second wave of COVID-19 pandemic in two tertiary health care centres in Kerala. Neurological symptoms two weeks prior or thirty days after a positive status of antigen or RTPCR was termed as COVID-19-Associated Neurological Disorders (CAND) and those with neurological symptoms within one month of COVID-19 vaccination was termed as Post-Vaccinal Neurological Disorders (PVND). Results: During the study period, 1270 COVID-19 admissions were reported. We identified neurological symptoms in 42 patients (3.3%), of which 35 were CAND and 7 were PVND. Stroke was the most common (50%), followed by seizures and peripheral nervous system disorders (14.2% each). Encephalitis/demyelination (11.9%) and COVID-19-associated infections (9.5%) were also seen. Conclusion: During the SARS-CoV-2 pandemic, CAND and PVND have been emerging. Association of some of these may be fortuitous; however it is worth mentioning as pathogenic mechanisms of COVID-19 affecting various organ systems still remain unclear. Moreover, this may be helpful in future studies designing management options.

Biallelic loss-of-function variants in TBC1D2B cause a neurodevelopmental disorder with seizures and gingival overgrowth.

The family of Tre2-Bub2-Cdc16 (TBC)-domain containing GTPase activating proteins (RABGAPs) is not only known as key regulatorof RAB GTPase activity but also has GAP-independent functions. Rab GTPases are implicated in membrane trafficking pathways, such as vesicular trafficking. We report biallelic loss-of-function variants in TBC1D2B, encoding a member of the TBC/RABGAP family with yet unknown function, as the underlying cause of cognitive impairment, seizures, and/or gingival overgrowth in three individuals from unrelated families. TBC1D2B messenger RNA amount was drastically reduced, and the protein was absent in fibroblasts of two patients. In immunofluorescence analysis, ectopically expressed TBC1D2B colocalized with vesicles positive for RAB5, a small GTPase orchestrating early endocytic vesicle trafficking. In two independent TBC1D2B CRISPR/Cas9 knockout HeLa cell lines that serve as cellular model of TBC1D2B deficiency, epidermal growth factor internalization was significantly reduced compared with the parental HeLa cell line suggesting a role of TBC1D2B in early endocytosis. Serum deprivation of TBC1D2B-deficient HeLa cell lines caused a decrease in cell viability and an increase in apoptosis. Our data reveal that loss of TBC1D2B causes a neurodevelopmental disorder with gingival overgrowth, possibly by deficits in vesicle trafficking and/or cell survival.

Efficacy of oncolytic mutants targeting pRb and p53 pathways is synergistically enhanced when combined with cytotoxic drugs in prostate cancer cells and tumor xenografts.

Replication-selective oncolytic adenoviruses have proven safety records with promising clinical outcomes. However, strategies to improve efficacy are still required. Here we report greatly improved antitumor efficacy for both attenuated (dl1520) and highly potent (dl922­947) oncolytic mutants in combination with the current standard of care for late-stage hormone-independent prostate cancers, mitoxantrone or docetaxel. In agreement with previous reports, dl922­947 had superior potency compared with dl1520 both as a single agent and in combination with cytotoxic drugs. The dl922­947 mutant caused significant synergistic cell killing in both drug-insensitive and -sensitive prostate cancer cell lines, PC3 and DU145, respectively, when combined with docetaxel or mitoxantrone. The magnitude of the synergistic response was greatest for dl1520 whereas overall efficacy was greatest for dl922­947, and the latter was also more efficacious in vivo in prostate cancer models. In DU145 and PC3 cells increased viral uptake (up to 9- and 8-fold, respectively), E1A expression, and altered cell cycle progression contributed to the synergistic cell killing. A similar trend was also detected in LNCaP cells. Potent E1A expression was essential for the response. In murine xenograft models (DU145 and PC3) tumor growth inhibition was improved when suboptimal doses of docetaxel and viral mutants were combined. These findings demonstrate that the efficacy of highly potent oncolytic mutants such as dl922­947 that target the retinoblastoma protein (pRb) pathway could be further enhanced even with low drug doses, and support the deletion of the E1ACR2 region in future candidate adenoviruses for treatment of hormone-independent prostate cancers.

Indirect recruitment of a CD40 signaling pathway in dendritic cells by B7-DC cross-linking antibody modulates T cell functions.

The human IgM B7-DC XAb protects mice from tumors in both therapeutic and prophylactic settings. Its mechanism of action is mediated by its binding to B7-DC/PD-L2 molecules on the surface of dendritic cells (DCs) to induce a multimolecular cap and subsequent activation of signaling cascades that determine a unique combination of DC phenotypes. One such phenotype, the B7-DC XAb-induced antigen accumulation in mTLR-matured DCs, has been linked to signaling through TREM-2, but the signals required for other DC phenotypes critical for the therapeutic effects in animal models remain unclear. Here, FRET and co-immunoprecipitation studies show that CD40 is recruited to the multi-molecular complex by B7-DC XAb. Signals emanating from CD40 are important, as CD40(-/-) DCs treated with B7-DC XAb (DC(XAb)) activated DAP12, but failed to activate NFkappaB, and were not protected from cell death upon cytokine withdrawal or treatment with Vitamin D(3). CD40(-/-) DC(XAb) also failed to secrete IL-6 and were unable to support the conversion of T regulatory cells into IL-17+ effector T cells in vitro. Importantly, the expression of CD40 was required for the overall ability of B7-DC XAb to induce anti-tumor CTL, to provide protection from a number of tumor types, and for DC(XAb) to be effective anti-tumor vaccines in vivo. These results indicate that B7-DC XAb modulation of DC phenotypes is through its ability to indirectly recruit common signaling molecules and elements of their endogenous signaling pathways through targeted binding to a cell-specific surface determinant.

Asthma-related environmental fungus, Alternaria, activates dendritic cells and produces potent Th2 adjuvant activity.

Asthma is thought to result from dysregulated Th2-like airway inflammatory responses to the environment. Although the etiology of asthma is not fully understood in humans, clinical and epidemiological evidence suggest a potential link between exposure to environmental fungi, such as Alternaria, and development and/or exacerbation of asthma. The goal of this project was to investigate the mechanisms of airway Th2 responses by using Alternaria as a clinically relevant model for environmental exposure. Airway exposure of naive animals to an experimental Ag, OVA, or a common allergen, short ragweed pollen, induced no or minimal immune responses to these Ags. In contrast, mice developed strong Th2-like immune responses when they were exposed to these Ags in the presence of Alternaria extract. Extracts of other fungi, such as Aspergillus and Candida, showed similar Th2 adjuvant effects, albeit not as potently. Alternaria stimulated bone marrow-derived dendritic cells (DCs) to express MHC class II and costimulatory molecules, including OX40 ligand, in vitro. Importantly, Alternaria inhibited IL-12 production by activated DCs, and DCs exposed to Alternaria enhanced Th2 polarization of CD4(+) T cells. Furthermore, adoptive airway transfer of DCs, which had been pulsed with OVA in the presence of Alternaria, showed that the recipient mice had enhanced IgE Ab production and Th2-like airway responses to OVA. Thus, the asthma-related environmental fungus Alternaria produces potent Th2-like adjuvant effects in the airways. Such immunogenic properties of certain environmental fungi may explain their strong relationships with human asthma and allergic diseases.

TREM-2 mediated signaling induces antigen uptake and retention in mature myeloid dendritic cells.

Myeloid dendritic cells (mDC) activated with a B7-DC-specific cross-linking IgM Ab (B7-DC XAb) take up and retain Ag and interact with T cell compartments to affect a number of biologic changes that together cause strong antitumor responses and blockade of inflammatory airway disease in animal models. The molecular events mediating the initial responses in mDC remain unclear. In this study we show that B7-DC XAb caused rapid phosphorylation of the adaptor protein DAP12 and intracellular kinases Syk and phospholipase C-gamma1. Pretreatment of mDC with the Syk inhibitor piceatannol blocked B7-DC XAb-induced Ag uptake with a concomitant loss of tumor protection in mice. Vaccination with tumor lysate-pulsed wild-type B7-DC XAb-activated mDC, but not TREM-2 knockout XAb-activated mDC, protected mice from lethal melanoma challenge. Multimolecular caps appeared within minutes of B7-DC XAb binding to either human or mouse mDC, and FRET analysis showed that class II, CD80, CD86, and TREM-2 are recruited in tight association on the cell surface. When TREM-2 expression was reduced in wild-type mDC using short hairpin RNA or by using mDC from TREM-2 knockout mice, in vitro DC failed to take up Ag after B7-DC XAb stimulation. These results directly link TREM-2 signaling with one change in the mDC phenotype that occurs in response to this unique Ab. The parallel signaling events observed in both human and mouse mDC support the hypothesis that B7-DC cross-linking may be useful as a therapeutic immune modulator in human patients.

T-bet expression by dendritic cells is required for the repolarization of allergic airway inflammation.

By cross-linking B7-DC on dendritic cells (DC) the human IgM antibody (B7-DC XAb) shifts polarized immune responses from Th2 to Th1 in an antigen-specific manner. The molecular determinants governing the ability of DC to reprogram the polarity of T cell recall responses are not yet known. In addition to the expected role of T-bet expressed by T cells in regulating Th1 responses, we find using in vitro assays and an established in vivo model of allergic airway inflammation that T-bet expression by DC is also required for the polarity shift promoted by B7-DC XAb. T-bet expression by both T cells and DC is critically important for B7-DC XAb-induced down-regulation of IL-4, up-regulation of IFN-gamma and suppression of allergic airway inflammation. Moreover, retroviral reconstitution of T-bet expression in T-bet-deficient DC rescued their ability to modulate both naive and memory T-cell responses from Th2 to Th1. Our observations further our understanding of the critical mediators controlling the ability of DC to modify the responses of previously activated T cells and reveal the interesting use of the same transcription factor to regulate the inductive phenotype of DC and the inducible phenotype of T cells.

Reprogrammed FoxP3+ T regulatory cells become IL-17+ antigen-specific autoimmune effectors in vitro and in vivo.

Lymphocyte differentiation from naive CD4(+) T cells into mature Th1, Th2, Th17, or T regulatory cell (Treg) phenotypes has been considered end stage in character. In this study, we demonstrate that dendritic cells (DCs) activated with a novel immune modulator B7-DC XAb (DC(XAb)) can reprogram Tregs into T effector cells. Down-regulation of FoxP3 expression after either in vitro or in vivo Treg-DC(XAb) interaction is Ag-specific, IL-6-dependent, and results in the functional reprogramming of the mature T cell phenotype. The reprogrammed Tregs cease to express IL-10 and TGFbeta, fail to suppress T cell responses, and gain the ability to produce IFN-gamma, IL-17, and TNF-alpha. The ability of IL-6(+) DC(XAb) and the inability of IL-6(-/-) DC(XAb) vaccines to protect animals from lethal melanoma suggest that exogenously modulated DC can reprogram host Tregs. In support of this hypothesis and as a test for Ag specificity, transfer of DC(XAb) into RIP-OVA mice causes a break in immune tolerance, inducing diabetes. Conversely, adoptive transfer of reprogrammed Tregs but not similarly treated CD25(-) T cells into naive RIP-OVA mice is also sufficient to cause autoimmune diabetes. Yet, treatment of normal mice with B7-DC XAb fails to elicit generalized autoimmunity. The finding that mature Tregs can be reprogrammed into competent effector cells provides new insights into the plasticity of T cell lineage, underscores the importance of DC-T cell interaction in balancing immunity with tolerance, points to Tregs as a reservoir of autoimmune effectors, and defines a new approach for breaking tolerance to self Ags as a strategy for cancer immunotherapy.

Fast-tracked CTL: rapid induction of potent anti-tumor killer T cells in situ.

Current strategies to elicit cytolytic T cell responses specific for tumor-associated or over-expressed self antigens rely on multiple immunizations and in vitro expansion schemes. Here we report the in vivo induction of activated tumor-specific CD8(+) CTL just 6 days after treatment with the IgM immune modulator B7-DC XAb. Antibody treatment of mice at the time of tumor challenge elicited potent CTL with a specificity that distinguished between MHC-compatible tumors. Remarkably, these effector cells were not generated by the extensive proliferation of naive CTL precursors, though their induction required CD4(+) T cell help and classical B7 costimulatory signals. Tumor targets were recognized and lysed in an MHC-restricted, perforin-dependent manner, indicating that these rapidly induced effectors resemble traditionally defined CTL, despite the finding that strong increases in the expression of the effector/memory marker CD44 and the activation marker CD69 were not elicited. These CTL were induced in animals bearing well-established tumors and resulted in anti-tumor protection, underscoring the therapeutic potential of this type of effector T cell population in cancer patients.

Induction of a Th1 response from Th2-polarized T cells by activated dendritic cells: dependence on TCR:peptide-MHC interaction, ICAM-1, IL-12, and IFN-gamma.

Dendritic cells (DC) are important regulators of T cell immunity. The degree of stimulation, the pattern of costimulatory molecules expressed, and the cytokines secreted by DC dictate the nature of the effector and memory cells generated, particularly with respect to their Th1 or Th2 phenotypes. In this study, we demonstrate that the addition of activated DC to spleen cultures containing established Th2-polarized CD4(+) T cells was sufficient to suppress Th2 and induce Th1 cytokines in a recall response, a phenomenon referred to as phenotype reversal. The ability of activated DC to induce phenotype reversal displayed exquisite Ag specificity. The DC activator B7-DC cross-linking Ab (XAb) was >10,000-fold more efficient at inducing phenotype reversal than the TLR agonists CpG-oligodeoxynucleotide and Gardiquimod. Characterization of the mechanisms governing phenotype reversal revealed the requirement for cognate interaction between the TCR:peptide-MHC complex, the expression of the costimulation/adhesion molecule ICAM-1, and secretion of IL-12 and IFN-gamma by the activated DC. The requirement for the costimulation/adhesion molecule SLAM (signaling lymphocytic activation molecule) was found to be quantitative. Thus, activation of DC, particularly by crosslinking B7-DC, can modulate well-established Th2 T cell responses in an Ag-specific manner. Because the regulation of mouse and human DC by B7-DC XAb overlaps in several significant ways, immune modulation with B7-DC XAb is a potential strategy for treating Th2-mediated diseases.

B7-DC/PD-L2 cross-linking induces NF-kappaB-dependent protection of dendritic cells from cell death.

Cross-linking cell surface molecules with IgM Abs is a specific approach for activating cells in vitro or in vivo. Dendritic cells (DC) activated with a human B7-DC (PD-L2)-specific IgM Ab can induce strong antitumor responses and block inflammatory airway disease in experimental models, yet the Ab-mediated molecular events promoting these responses remain unclear. Analysis of human or mouse DC treated with the B7-DC cross-linking Ab revealed PI3K-dependent phosphorylation of AKT accompanied by mobilization of NF-kappaB. Ab-activated DC up-regulated expression of cytokine and chemokine genes in an NF-kappaB-dependent manner. Importantly, PI3K-->AKT-->NF-kappaB activation was found to be indispensable for B7-DC cross-linking Ab-mediated protection of DC from cell death caused by cytokine withdrawal. Although other DC activators similarly protect DC from cell death, a synergy between cross-linking B7-DC and ligating RANK was observed. The parallel signaling events induced in human and mouse DC demonstrate that activation of cells using IgM Ab results in a response governed by a common mechanism and support the hypothesis that B7-DC cross-linking using this Ab may provide beneficial therapeutic immune modulation in human patients similar to those seen in animal models.

Induction of a gene expression program in dendritic cells with a cross-linking IgM antibody to the co-stimulatory molecule B7-DC.

While bivalent antibodies can block ligand-receptor interactions, IgM pentamers efficiently cross-link cell surface targets and evoke physiological responses. We have described one such interaction between an IgM antibody (Ab) and the B7-DC costimulatory molecule expressed by dendritic cells that induces strong antitumor immunity and modulates pathogenic responses associated with allergic asthma. Progressive changes in gene expression in dendritic cells activated by an IgM B7-DC cross-linking Ab resulted in the increased expression in 350 genes and decreased expression of more than 200 genes over the course of 24 h following Ab treatment. In particular, up-regulation of the caspase inhibitor FLIP and the chemokine receptor CCR7, and the down-regulation of the CXCR4 receptor provide a mechanistic basis of Ab-induced survival and enhanced migration into draining lymph nodes. Increased expression of both cell surface and secreted molecules known to be mediators of the immunomodulatory properties of dendritic cells was detected at both the levels of RNA and protein expression. This analysis documents the ability of IgM Ab to activate a gene expression cascade leading to important biological changes in cellular function and provides mechanistic insight into the potent immunomodulatory properties attributed to this Ab.