EPI Update, August 17, 2007

Weekly newsletter for Center For Acute Disease Epidemiology of Iowa Department of Public Health.

Kajaanissa 17/12 -28

Kirje 17.12.1928

Motor Vehicle Accident Fatalities for the Week Ending, August 17, 2007

Record of the Fatalities for Motor Vehicle Accidents in Iowa per week.

Neuroprotection by inhibiting the c-Jun N-terminal kinase pathway after cerebral ischemia occurs independently of interleukin-6 and keratinocyte-derived chemokine (KC/CXCL1) secretion.

BACKGROUND: Cerebral ischemia is associated with the activation of glial cells, infiltration of leukocytes and an increase in inflammatory mediators in the ischemic brain and systemic circulation. How this inflammatory response influences lesion size and neurological outcome remains unclear. D-JNKI1, an inhibitor of the c-Jun N-terminal kinase pathway, is strongly neuroprotective in animal models of stroke. Intriguingly, the protection mediated by D-JNKI1 is high even with intravenous administration at very low doses with undetectable drug levels in the brain, pointing to a systemic mode of action, perhaps on inflammation. FINDINGS: We evaluated whether D-JNKI1, administered intravenously 3 h after the onset of middle cerebral artery occlusion (MCAO), modulates secretion of the inflammatory mediators interleukin-6 and keratinocyte-derived chemokine in the plasma and from the spleen and brain at several time points after MCAO. We found an early release of both mediators in the systemic circulation followed by an increase in the brain and went on to show a later systemic increase in vehicle-treated mice. Release of interleukin-6 and keratinocyte-derived chemokine from the spleen of mice with MCAO was not significantly different from sham mice. Interestingly, the secretion of these inflammatory mediators was not altered in the systemic circulation or brain after successful neuroprotection with D-JNKI1. CONCLUSIONS: We demonstrate that neuroprotection with D-JNKI1 after experimental cerebral ischemia is independent of systemic and brain release of interleukin-6 and keratinocyte-derived chemokine. Furthermore, our findings suggest that the early systemic release of interleukin-6 and keratinocyte-derived chemokine may not necessarily predict an unfavorable outcome in this model.

ABD e-News, August 17, 2007

Weekly newsletter

Antibody-indocyanin conjugates for immunophotodetection of human squamous cell carcinoma in nude mice.

We have recently shown that immunophotodetection of human colon carcinomas in nude mice and in patients is possible by using anti-carcinoembryonic antigen monoclonal antibodies (MAb) coupled to fluorescein. The most common clinical application of photodiagnosis has been for the detection of squamous cell carcinomas (SCC) in the upper respiratory tract, but the free dyes used have a poor tumor selectivity. We selected the known MAb E48 directed against SCC and coupled it to a fluorescent dye: indopentamethinecyanin (indocyanin). This dye has an advantage over fluorescein in that it emits a more penetrating fluorescent red signal at 667 nm after excitation with a laser ray of 640 nm. In vitro, an conjugate with an indocyanin:MAb molar ratio of 2, and an additional trace labeling with 125I, showed more than 80% of binding to cells from the SCC line A431. In vivo, when injected i.v. into nude mice bearing xenografts of the same carcinoma line, the MAb E48-(indocyanin)2 conjugate was almost as efficient as the unconjugated MAb E48 in terms of specific tumor localization: 15% of the injected dose per g of tumor at 24 h after injection and a tumor:overall normal tissue ratio of 6-8. There was no selective tumor localization of an irrelevant IgG1-(indocyanin)2 conjugate. Immunophotodetection of the s.c. SCC xenografts on mice given injections of 100 micrograms of MAb E48-(indocyanin), conjugate (representing 1 microgram of indocyanin) was performed at 24 h. Upon laser irradiation, clearly detectable red fluorescence from the indocyanin-MAb conjugate was observed specifically in the SCC xenografts across the mouse skin. In comparison, injection of 100 micrograms of a MAb E48 coupled to 2 micrograms of fluorescein gave a specific green fluorescence signal in the tumor xenografts, which was detectable, however, only after removing the mouse skin. Injection i.v. of a 15 times higher amount of free indocyanin (15 micrograms) gave a diffuse red fluorescence signal all over the mouse body with no definite increase in intensity in the tumor, indicating a lack of tumor selectivity of the free dye. The results demonstrate the possibility of broadening and improving the efficiency of tumor immunophotodiagnosis by coupling to a MAb directed against SCC, a fluorescent dye absorbing and emitting at higher wavelength than fluorescein, and thus having deeper tissue penetration and lower tissue autofluorescence. Such a demonstration opens the way to a new form of clinical immunophotodiagnosis and possibly to the development of a more specific approach to phototherapy of early bronchial carcinomas.

Tal med anledning av regeringsformens 40-årsjubileum (17.7.1959 i radio och TV)

Puhe

Fate of TLR-1/TLR-2 agonist functionalised pDNA nanoparticles upon deposition at the human bronchial epithelium in vitro.

BACKGROUND: Plasmid DNA vaccination is a promising approach, but studies in non-human primates and humans failed to achieve protective immunity. To optimise this technology further with focus on pulmonary administration, we developed and evaluated an adjuvant-equipped DNA carrier system based on the biopolymer chitosan. In more detail, the uptake and accompanying immune response of adjuvant Pam3Cys (Toll-like receptor-1/2 agonist) decorated chitosan DNA nanoparticles (NP) were explored by using a three-dimensional (3D) cell culture model of the human epithelial barrier. Pam3Cys functionalised and non-functionalised chitosan DNA NP were sprayed by a microsprayer onto the surface of 3D cell cultures and uptake of NP by epithelial and immune cells (blood monocyte-derived dendritic cells (MDDC) and macrophages (MDM)) was visualised by confocal laser scanning microscopy. In addition, immune activation by TLR pathway was monitored by analysis of interleukin-8 and tumor necrosis factor-α secretions (ELISA). RESULTS: At first, a high uptake rate into antigen-presenting cells (MDDC: 16-17%; MDM: 68-75%) was obtained. Although no significant difference in uptake patterns was observed for Pam3Cys adjuvant functionalised and non-functionalised DNA NP, ELISA of interleukin-8 and tumor necrosis factor-α demonstrated clearly that Pam3Cys functionalisation elicited an overall higher immune response with the ranking of Pam3Cys chitosan DNA NPâeuro0/00>âeuro0/00chitosan DNA NPâeuro0/00=âeuro0/00DNA unloaded chitosan NPâeuro0/00>âeuro0/00control (culture medium). CONCLUSIONS: Chitosan-based DNA delivery enables uptake into abluminal MDDC, which are the most immune competent cells in the human lung for the induction of antigen-specific immunity. In addition, Pam3Cys adjuvant functionalisation of chitosan DNA NP enhances significantly an environment favoring recruitment of immune cells together with a Th1 associated (cellular) immune response due to elevated IL-8 and TNF-α levels. The latter renders this DNA delivery approach attractive for potential DNA vaccination against intracellular pathogens in the lung (e.g., Mycobacterium tuberculosis or influenza virus).