Imaging and therapy of experimental schwannomas using HSV amplicon vector-encoding apoptotic protein under Schwann cell promoter.

Schwannomas are benign tumors forming along peripheral nerves that can cause deafness, pain and paralysis. Current treatment involves surgical resection, which can damage associated nerves. To achieve tumor regression without damage to nerve fibers, we generated an HSV amplicon vector in which the apoptosis-inducing enzyme, caspase-1 (ICE), was placed under the Schwann cell-specific P0 promoter. Infection of schwannoma, neuroblastoma and fibroblastic cells in culture with ICE under the P0 promoter showed selective toxicity to schwannoma cells, while ICE under a constitutive promoter was toxic to all cell types. After direct intratumoral injection of the P0-ICE amplicon vector, we achieved marked regression of schwannoma tumors in an experimental xenograft mouse model. Injection of this amplicon vector into the sciatic nerve produced no apparent injury to the associated dorsal root ganglia neurons or myelinated nerve fibers. The P0-ICE amplicon vector provides a potential means of 'knifeless resection' of schwannoma tumors by injection of the vector into the tumor with low risk of damage to associated nerve fibers.

Nociceptive-specific activation of ERK in spinal neurons contributes to pain hypersensitivity.

We investigated the involvement of extracellular signal-regulated protein kinases (ERK) within spinal neurons in producing pain hypersensitivity. Within a minute of an intense noxious peripheral or C-fiber electrical stimulus, many phosphoERK-positive neurons were observed, most predominantly in lamina I and IIo of the ipsilateral dorsal horn. This staining was intensity and NMDA receptor dependent. Low-intensity stimuli or A-fiber input had no effect. Inhibition of ERK phosphorylation by a MEK inhibitor reduced the second phase of formalin-induced pain behavior, a measure of spinal neuron sensitization. ERK signaling within the spinal cord is therefore involved in generating pain hypersensitivity. Because of its rapid activation, this effect probably involves regulation of neuronal excitability without changes in transcription.

Stressor-induced alterations in immune response and viral clearance following infection with herpes simplex virus-type 1 in BALB/c and C57B1/6 mice.

Extending earlier studies of stress-induced modulation of herpes simplex virus (HSV) infection and immunity, we investigated the effects of electric foot shock (0.3 mA) on cytokine production and immune effector function in response to a nonlethal inoculum of HSV-1 in two strains of inbred mice, C57B1/6 and BALB/c. Increased levels of infectious virus at the site of infection were observed in foot-shocked mice of both strains compared to control mice. The specific pattern of changes in interleukin (IL)-2 and interferon-gamma, as well as IL-4 and IL-10, induced by foot-shock stress differed between the two strains. IgM anti-HSV antibody responses were, however, increased in both strains.

Similar immune response to nonlethal infection with herpes simplex virus-1 in sensitive (BALB/c) and resistant (C57BL/6) strains of mice.

Previous investigations have demonstrated a strain-associated differential susceptibility to herpes simplex virus-1 (HSV-1) infection in mice; C57BL/6 mice are more resistant to infection than BALB/c mice. Despite considerable research dealing with the immune response to HSV-1, relatively little attention has been paid to differences in immune responses between strains with different sensitivities to the virus. Here we report that immune responses (i.e., cytokine profiles, CTL activity, serum antibody, and natural killer cell activity) following footpad infection with a sublethal dose of HSV-1 do not substantially differ between the two strains. It is notable that C57BL/6 mice are also more resistant than BALB/c mice to other pathogens, including Leishmania, and this resistance is associated with a predominant TH1 response in C57BL/6 mice versus a predominant TH2 response in BALB/c mice. However, unlike several other pathogens, the increased susceptibility to HSV-1 infection of BALB/c mice, compared to C57BL/6 mice, does not appear to involve an obvious difference in the TH1 vs TH2 dominance of the immune response to this virus.

Sympathetic nervous system modulation of the immune system. III. Alterations in T and B cell proliferation and differentiation in vitro following chemical sympathectomy.

Functional changes in lymph node (LN) and spleen lymphocytes were examined following sympathetic denervation of adult mice with 6-hydroxydopamine (6-OHDA). Sympathectomy reduced in vitro proliferation to concanavalin A (ConA) by LN cells and decreased LN Thy-1+ and CD4+ T cells. At the same time, ConA-induced interferon-gamma (IFN-gamma) production was increased, but interleukin-2 (IL-2) production was not altered. After sympathectomy, lipopolysaccharide (LPS)-stimulated proliferation of LN B cells was enhanced, in parallel with an increase in the proportion of sIgM+ cells. LPS-induced polyclonal IgM secretion was decreased, whereas polyclonal IgG secretion was dramatically enhanced. In the spleen, ConA and LPS responsiveness was reduced after sympathectomy, as was IL-2 and IFN-gamma production. The decreased proliferation was not associated with changes in splenic T and B cell populations. The uptake blocker desipramine prevented the 6-OHDA-induced changes in spleen and LN, indicating that these alterations were dependent upon neuronal destruction. These results provide evidence for heterogeneity of sympathetic nervous system regulation of T and B lymphocyte function and for organ-specific influences on immune function.

Sympathetic nervous system modulation of tumor metastases and host defense mechanisms.

The sympathetic nervous system can signal cells of the immune system through release of norepinephrine (NE), and may thus modulate several aspects of immune reactivity. We have examined the consequences of chemical denervation using 6-hydroxydopamine (6-OHDA) on the response of BALB/c mice to tumor cell challenge. In this study, chemical axotomy prior to the intravenous (i.v.) injection of the alveolar carcinoma line 1 significantly increased the number of pulmonary metastases. In contrast, axotomy performed after i.v. injection of tumor cells had no effect on the number of lung metastases. Line 1 tumor cells have been reported to be susceptible to lysis by natural killer (NK) cells. To examine possible mechanisms through which prior axotomy leads to increased lung metastases, we tested the effects of axotomy on in vitro and in vivo NK cell activity. No differences in NK cell activity were found between 6-OHDA- and vehicle-treated mice. Line 1 tumor cell growth in vitro was unaffected by both 6-OHDA and NE, and the tumor cells do not express beta-adrenergic receptors. Priming mice with lethally irradiated line 1 cells significantly reduced the number of lung metastases following challenge with live tumor cells; axotomy did not alter this decrease in metastases associated with priming. In summary, chemical axotomy of mice prior to injection of alveolar carcinoma cells resulted in an increased number of pulmonary metastases that was not correlated with alterations in either NK cell cytotoxicity or the putative immunological consequences of in vivo priming.

Increased pulmonary metastases and natural killer cell activity in mice following handling.

We have demonstrated that holding BALB/c female mice for two minutes per day for two weeks prior to injection of line 1, a BALB/c derived alveolar carcinoma, results in a significant increase in pulmonary metastases compared to unhandled controls. Handling did not affect splenic in vitro or in vivo natural killer (NK) cell activity but, surprisingly, was associated with increased NK cell activity in the lungs of these handled mice. These results demonstrate that a simple psychosocial manipulation may effect the metastatic process. The implications of these findings and potential mechanisms are discussed.

Winteraceous pollen in the lower cretaceous of Israel: early evidence of a magnolialean angiosperm family.

Pollen of the primitive angiosperm family Winteraceae has been discovered in the Aptian-Albian of Israel, extending the fossil record of this phylogenetically important family of flowering plants from the uppermost Upper Cretaceous back some 40 million years to the upper Lower Cretaceous. This appears to represent the earliest known record of a magnolialean angiosperm family and is convincing evidence for the existence in the Early Cretaceous of an extant family of angiosperms.