Characterization of ASKP1240, a fully human antibody targeting human CD40 with potent immunosuppressive effects

Blocking the CD40-CD154 interaction is reported to be effective for transplantation management and autoimmune disease models in rodents and nonhuman primates. However, clinical trials with anti-CD154 mAbs were halted because of high incidence of thromboembolic complications. Thus, we generated and characterized a fully human anti-CD40 mAb ASKP1240, as an alternative to anti-CD154 mAb. In vitro ASKP1240 concentration-dependently inhibited human peripheral blood mononuclear cell proliferation induced by soluble CD154. In addition, ASKP1240 did not destabilize platelet thrombi under physiological high shear conditions while mouse anti-human CD154 mAb (mu5C8) did. And ASKP1240 itself did not activate platelet and endothelial cells. In vivo administration of ASKP1240 (1 or 10 mg/kg, intravenously) to cynomolgus monkeys, weekly for 3 weeks, significantly attenuated both delayed-type hypersensitivity and specific antibody formation evoked by tetanus toxoid. The immunosuppressive effect was well correlated with the CD40 receptor saturation. Thus, these results suggest that ASKP1240 is immunosuppressive but not prothromboembolic, and as such appears to be a promising therapeutic candidate for the management of solid organ transplant rejection and autoimmune diseases therapy.

The Internet's role in a biodosimetric response to a radiation mass casualty event

Response to a large-scale radiological incident could require timely medical interventions to minimize radiation casualties. Proper medical care requires knowing the victim's radiation dose. When physical dosimetry is absent, radiation-specific chromosome aberration analysis can serve to estimate the absorbed dose in order to assist physicians in the medical management of radiation injuries. A mock exercise scenario was presented to six participating biodosimetry laboratories as one individual acutely exposed to Co under conditions suggesting whole-body exposure. The individual was not wearing a dosimeter and within 2-3 h of the incident began vomiting. The individual also had other medical symptoms indicating likelihood of a significant dose. Physicians managing the patient requested a dose estimate in order to develop a treatment plan. Participating laboratories in North and South America, Europe, and Asia were asked to evaluate more than 800 electronic images of metaphase cells from the patient to determine the dicentric yield and calculate a dose estimate with 95% confidence limits. All participants were blind to the physical dose until after submitting their estimates based on the dicentric chromosome assay (DCA). The exercise was successful since the mean biological dose estimate was 1.89 Gy whereas the actual physical dose was 2 Gy. This is well within the requirements for guidance of medical management. The exercise demonstrated that the most labor-intensive step in the entire process (visual evaluation of images) can be accelerated by taking advantage of world-wide expertise available on the Internet.

ASKP1240, a fully human anti-CD40 monoclonal antibody, prolongs pancreatic islet allograft survival in nonhuman primates

A strategy for inhibiting CD40 has been considered as an alternative approach for immunosuppression because of undesirable effects of anti-CD154 monoclonal antibodies (mAbs). Previously, we demonstrated that ASKP1240, which is a fully human anti-CD40 mAb, significantly prolonged kidney and liver allograft survival in cynomolgus monkeys without causing thromboembolic complications. Herein, we evaluated the effect of ASKP1240 on pancreatic islet transplantation (PITx) in cynomolgus monkeys. Diabetes was induced by total pancreatectomy, and islet allografts were transplanted into the liver. Following PITx (8201-12 438 IEQ/kg), blood glucose levels normalized promptly in all animals. Control islet allografts were rejected within 9 days (n = 3), whereas ASKP1240 (10 mg/kg) given on postoperative days 0, 4, 7, 11 and 14 (induction treatment, n = 5) significantly prolonged graft survival time (GST) to >15, >23, 210, 250 and >608 days, respectively. When ASKP1240 (5 mg/kg) was administered weekly thereafter up to post-PITx 6 months (maintenance treatment, n = 4), GST was markedly prolonged to >96, >115, 523 and >607 days. During the ASKP1240 treatment period, both anti-donor cellular responses and development of anti-donor antibodies were abolished, and no serious adverse events were noted. ASKP1240 appears to be a promising candidate for immunosuppression in clinical PITx.

Epidemiological impact of mass tuberculosis screening: a 2-year follow-up after a national prevalence survey

OBJECTIVE

To assess the epidemiological impact of mass tuberculosis (TB) screening in the community and the prognosis of bacteriologically negative individuals with abnormal findings on chest radiography (CXR).

METHODS

A follow-up study consisting of two parts--a register match of notified TB cases with 22,160 participants in a national TB prevalence survey, and a repeat medical examination for the subjects of a prevalence survey with abnormal findings on CXR--was conducted 2 years after the prevalence survey in Cambodia.

RESULTS

Thirty-four cases with new smear-positive TB were detected by register match, giving a standardised notification ratio of 0.38 (95%CI 0.27-0.52). An additional seven new smear-positive TB cases and 93 new smear-negative, culture-positive TB cases were detected by medical examination. The incidence rates of bacteriologically positive TB were 8.5% per year (95%CI 6.3-11.2) in cases with a CXR suggestive of active TB and 2.9% per year (95%CI 2.2-3.7) in those with a CXR with other abnormalities.

CONCLUSIONS

Detection and treatment of smear-negative, culture-positive TB cases as well as smear-positive TB cases was associated with a rapid reduction in subsequent incidence of new smear-positive TB. Sputum culture-negative individuals with abnormal CXR findings are at a high risk of disease progression, and require follow-up and potentially preventive treatment.

Increased Virus Replication and Cytotoxicity of Non-pathogenic Simian Human Immuno Deficiency Viruses-NM-3rN After Serial Passage in a Monkey-Derived Cell Line

BACKGROUND

Infection and disease induction of variants of HIV type 1 (HIV-1) in vivo, especially their persistence, replication and rate of disease progression, have been found to depend on phenotypic characteristics. However, the mechanism (s) underlying these diverse phenotypic characteristics remain poorly understood.

AIM

It was aimed at determining whether a SHIV that had been adapted to a monkey-derived cell line could be used to explain the mechanism that underlies adaptive evolution of a virus to its host cell environment.

MATERIALS AND METHODS

Standard procedures in virology such as cell culturing, FACS analysis and ELISA were employed to measure virus replication and growth kinetics, cell viability, reverse transcriptase (RT) activity assay and CD4 cells down-regulation.

RESULTS

After about 20 passages, LT efficiently adapted to the monkey-derived cell line and replicated much better than the parent virus. LT accumulated a number of mutations in its entire genome with a majority of them being monkey cell-specific.

CONCLUSION

Thus we think we have obtained a virus that may enable studies to determine which of these mutations are specifically related to in vitro viral replication and which are specifically related to cytotoxicity so as to explain the mechanism associated with viral cytotoxicity and host cell specificity.

Abstract P2-10-32: Sialyl LewisX and inflammatory mediators in breast cancer patients: biological correlations and prognostic value

Background: Cytokines and chemokines are known to be involved in tumor growth and progression of disease. Sialyl LewisX (sLeX), a ligand for adhesion molecule E-selectin, is known to affect inflammatory processes and an elevated level is associated with tumor metastasis. Therefore, we assessed serum levels of sLeX and cytokines/chemokines in patients with non-invasive ductal carcinoma in situ (DCIS), early invasive breast cancer (EBC), or metastatic breast cancer (MBC).

Patients and Methods: Sera from 250 patients (26 DCIS, 157 EBC, 67 MBC) and 43 healthy donors (HD) were assayed for sLeX using an immunoassay kit (CSLEX; Nittobo Medical Co. Ltd., Japan) and a panel of cytokines and chemokines using a multiplex assay kit. Differences in serum markers between patients and HD, and among patient groups were determined using the Kruskal-Wallis and Mann-Whitney tests. Spearman's correlation determined the non-parametric correlation between the serum levels of sLeX and the inflammatory mediators. The receiver operating characteristic (ROC) curves and the corresponding area under the curve (AUC) analyses were used to determine the sensitivity and specificity of a given cut-off value for a particular serum marker.

Results: The median sLeX level tended to increase with the stage of disease: MBC > EBC > DCIS albeit without significant differences among the disease stages. Among MBC patients, patients with sLeX below 1.75 U/mL had significantly improved overall survival (OS, mean survival 11.1 vs. 33.7 months, P = 0.002) and progression-free survival (PFS, mean survival 9.7 vs. 20.9 months, p = 0.042). The Hazard Ratio of high sLeX for OS was 5.5 (95% CI 1.6 to 18.9, p = 0.007) and 2.3 for PFS (95% CI 1.0 to 5.2, P = 0.048). EBC and MBC patients have significantly higher serum levels of IL-1, IL-1RA, IL-6, IL-8, MCP-1, MCP-3, and MIP-1βthan those of HD. In addition, there were positive correlations between the serum levels of sLeX and cytokines IL-1β, IL-1RA, IL-2, IL-8, MIP-1β, and MCP-3. The AUC for sLeX was 0.598 (P = 0.016), and a cut-off of 3.13 pg/mL distinguished hormone receptor (HR)-positive from HR-negative patients (χ2 = 4.0, P = 0.045). Likewise, the AUC for TNF-α was 0.620 (P = 0.003), and a cut-off 7.18 pg/mL distinguished HR-positive from HR-negative patients (χ2 = 12.6, P < 0.001). Using a cut-off value established by ROC curves, few MBC patients (9 of 66, 13.6%) had a serum IL-2 level > 7.1 pg/mL compared to 57 of 185 (30.8%) non-MBC patients (χ2 = 7.4, P = 0.007), suggesting that metastatic disease may be associated with immune suppression related to low serum IL-2. Conversely, 31of 66 (47%) MBC patients had a serum MCP-1 level > 750 pg/mL vs. 37 of 185 non-MBC patients (20%) (χ2 = 23.8, P < 0.0001), suggesting that a high level of MCP-1 may play an important role in metastasis.

Conclusion: Serum levels of sLeX were able to distinguish HR-positive from HR-negative patients and predict overall survival in metastatic patients. Serum sLeX and some inflammatory mediators tended to increase with the severity of disease, and together may facilitate local invasion of tumor cells. Furthermore, serum levels of MCP-1 and IL-2 may have prognostic value in breast cancer patients.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P2-10-32.

Exploration and characterization of genes involved in the synthesis of diterpene defence secretion in nasute termite soldiers

Nasutitermes takasagoensis soldiers defend their colonies using characteristic diterpenes. Diterpenes are thought to be synthesized in the frontal gland cells surrounding the gland reservoir. To identify the genes involved in diterpene synthesis, a cDNA library was prepared from the frontal gland cells and exhaustively sequenced using a 454 pyrosequencer (GS Junior; Roche, Branford, CT, USA). A total of 50,290 clean sequences were assembled into 1111 contigs, which were grouped into 774 genes (isogroups). Based on sequence similarity with known proteins, we identified seven genes encoding the following four enzymes associated with diterpene synthesis: 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) synthase (HMGS), HMG-CoA reductase (HMGR), farnesyl diphosphate synthase, and geranylgeranyl diphosphate synthases. The expression levels of two enzymes, HMGS and HMGR, involved in the mevalonate pathway were examined, assuming that the site of the defensive terpenoid synthesis strongly activates the mevalonate pathway, which produces a precursor of terpenoids. Real-time quantitative reverse-transcriptase PCR confirmed significantly higher expression of HMGS and HMGR in the heads of soldiers. We then divided the head into three parts and found that the expression levels of HMGS and HMGR were significantly higher in the part containing class 1 secretory cells of the frontal gland. Overall, the results suggested that the mevalonate pathway for diterpene synthesis occurs in class 1 cells around the frontal gland reservoir.

Favourable outcome of progressive multifocal leukoencephalopathy with mefloquine treatment in combination with antiretroviral therapy in an HIV-infected patient

A 33-year-old man who developed progressive multifocal leukoencephalopathy (PML) with HIV infection is reported. The patient exhibited rapid decline in neurological status after initiation of antiretroviral therapy (ART), which was attributed to the PML-immune re-constitution inflammatory syndrome. Following the administration of mefloquine in combination with ART, the patient's neurological status improved substantially. This case suggests that further investigation of the use of mefloquine might be warranted for treatment of PML in HIV-infected patients.

Tissue engineering lamb heart valve leaflets

Tissue engineered lamb heart valve leaflets (N - 3) were constructed by repeatedly seeding a concentrated suspension of autologous myofibroblasts onto a biodegradable synthetic polymeric scaffold composed of fibers made from polyglycolic acid and polylactic acid. Over a 2-week period the cells attached to the polymer fibers, multiplied, and formed a tissue core in the shape of the matrix. The tissue core was seeded with autologous large-vessel endothelial cells that formed a monolayer which coated the outer surface of the leaflet. The tissue engineered leaflets were surgically implanted in place of the right posterior pulmonary valve leaflet of the donor lamb while on cardiopulmonary bypass. Pulmonary valve function was evaluated by two-dimensional echocardiography with color Doppler which demonstrated valve function without evidence of stenosis and with only trivial regurgitation under normal physiologic conditions. Histologically, the tissue engineered heart valve leaflets resembled native valve leaflet tissue.

Productivity enhancement of recombinant protein in CHO cells via specific promoter activation by oncogenes

To construct a recombinant protein highly producing cell lines, we have previously developed the Oncogene Activated Production (OAP) system by using BHK-21 cells. Here we verified the availability of the OAP system in CHO cells. We firstly generated 'primed' ras amplified CHO cells, ras clone I, by introducing human c-Ha-ras oncogene into CHO cells. This ras clone I enables quick and easy establishment of recombinant protein hyper producing cell lines by introduction reporter gene of interest. Then we generated I13 by introducing human interleukin 6 (hIL-6) gene as a reporter gene, which showed enhanced productivity rate as compared to A7 established by conventional method. Furthermore, we found that hIL-6 production level of I13 was slightly improved by raising the CO(2) concentration from 5 to 8% possibly because of the enhanced growth rate. We further introduced the E1A oncogene, which has been shown to have a synergistic effect on the recombinant protein production of the ras-amplified BHK-21 cells, then evaluated the productivity. When culture in 5% CO(2) condition, only the slight effect can be seen. However when cultured in 8% CO(2) condition, not only cell number, but also productivity increased significantly, resulted in great augmentation of hIL-6 production, maximum production being 88.6 mug/ml/3 days. This study demonstrates that recombinant protein production level reached commercially desirable level by utilizing our OAP system in CHO cells and optimizing the culture condition.