Paul M. Hoffman

Induction of Protective CTL Responses in Newborn Mice by a Murine Retrovirus

The susceptibility of neonates to virus-induced disease is thought to reflect, in part, the immaturity of their immune systems. However, inoculation of newborn mice with low doses of Cas-Br-M murine leukemia virus induced a protective cytotoxic T lymphocyte (CTL) response. The inability of neonates to develop a CTL response to high doses of virus was not the result of immunological immaturity but correlated with the induction of a nonprotective type 2 cytokine response. Thus, the initial viral dose is critical in the development of protective immunity in newborns.

Precautions in medical care of, and in handling materials from, patients with transmissible virus dementia (Creutzfeldt-Jakob disease).

We have formulated a series of precautions to be observed in caring for patients with Creutzfeldt-Jakob disease and in handling their tissues. The virus resists inactivation by simple boiling in water. Also ineffective are 10 per cent formalin, 70 per cent alcohol and ionizing and ultraviolet radiation. Autoclaving for one hour at 121 degrees C and 20 psi inactivates the agent completely. Five per cent hypochlorite, 0.03 per cent permanganate, phenolics and iodine solutions are adequate disinfectants inactivating large infective doses of the virus. Special isolation wards for afflicted patients seem unwarranted. Workers exposed to infected saliva, nasopharyngeal secretions, urine or feces need to and should wash thoroughly with ordinary soap. Needles and needle electrodes should be autoclaved or incinerated and discarded. Demented persons should not be used for donations of blood or other tissues. Although precautions are necessary, the epidemiologic evidence does not suggest an unusual risk of Creutzfeldt-Jakob disease for medical workers.

Cellular Immunity in Guamanians with Amyotrophic Lateral Sclerosis and Parkinsonism-Dementia

To test the hypothesis that host resistance factors may be abnormal in Guamanians in whom amyotrophic lateral sclerosis and Parkinsonism-dementia develop, cellular immunity was evaluated in both diseases and compared to that of Guamanians with other nervous-system diseases, normal adult Guamanians and non-Guamanians with amyotrophic lateral sclerosis and Parkinsonism. Diminished responses to skin-test antigens, lymphopenia, diminished per cent and total T cells and, less frequently, decreased mitogen responses were seen in Guamanian patients with amytorophic lateral sclerosis and Parkinsonism-dementia but not in the other patient or normal groups. Guamanian patients with amyotrophic lateral sclerosis and diminished cellular immunity had an increased frequency of HLA-Bw35 (P less than 0.005) and shorter mean duration of disease (P less than 0.05) than those with normal cellular immunity. In Parkinsonism dementia diminished cellular immunity was less strongly associated with HLA-BW35 (P less than 0.05) and was not associated with differences in duration of disease. Normal Guamanians and those with other nervous-system diseases showed no association of diminished cellular immunity with HLA-Bw35. The association appeared disease-related, with onset concomitant with the neurologic expression of Guamanian amyotrophic lateral sclerosis and Parkinsonism-dementia.

Comparison of experimental allergic encephalomyelitis induced with spinal cord, basic protein, and synthetic encephalitogenic peptide☆

Abstract Equally large percentages of guinea pigs receiving maximal encephalitogenic doses of whole spinal cord, bovine basic protein, or synthetic encephalitogenic peptide in Freunds complete adjuvant developed clinical signs of experimental allergic encephalomyelitis. Guinea pigs receiving peptide showed slightly later onset of clinical signs, a greater tendency for spontaneous recovery, and fewer inflammatory lesions per low-power field than did animals injected with basic protein or whole spinal cord. Perivascular demyelination was seen commonly (88%) with whole spinal cord, less frequently (40%) with basic protein and rarely (6%) with synthetic encephalitogenic peptide. These differences were not altered by injecting guinea pigs with 5 and 10 times the maximal encephalitogenic dose of peptide or diluting the dose of whole spinal cord antigen over a 100-fold dilution range, suggesting that other factors present in basic protein and whole spinal cord emulsions play a role in producing these differences in the guinea pig.

Evidence for oxidative damage in a murine leukemia virus‐induced neurodegeneration

Vacuolation in cellular organelles within the central nervous system is a common manifestation of oxidative injury. We found that the spongiform vacuolation observed in PVC‐211 murine leukemia virus (PVC‐MuLV) neurodegeneration was associated with oxidative damage as detected by immunoreactivity for 3‐nitrotyrosine and protein carbonyl groups. This oxidative injury was present in brain before or concomitant with the appearance of activated microglia, vacuolation, and gliosis that characterize PVC‐MuLV neuropathology. Treatment of infected F344 rat pups with the antioxidant vitamin E transiently protected and prolonged the latency of PVC‐MuLV neurodegeneration. Taken together, these findings implicate oxidative damage and lipid peroxidation in the pathogenesis of PVC‐MuLV neurodegeneration. This animal model may be useful for studies of mechanisms and potential therapies for progressive neurodegeneration following a well‐defined insult. J. Neurosci. Res. 62:440–450, 2000. Published 2000 Wiley‐Liss, Inc.

Expression of Inducible Nitric Oxide Synthase and Elevation of Tyrosine Nitration of a 32-Kilodalton Cellular Protein in Brain Capillary Endothelial Cells from Rats Infected with a Neuropathogenic Murine Leukemia Virus

ABSTRACT PVC-211 murine leukemia virus (MuLV) is a neuropathogenic variant of Friend MuLV (F-MuLV) which causes a rapidly progressive spongiform neurodegenerative disease in rodents. The primary target of PVC-211 MuLV infection in the brain is the brain capillary endothelial cell (BCEC), which is resistant to F-MuLV infection. Previous studies have shown that changes in the envelope gene of PVC-211 MuLV confer BCEC tropism to the virus. However, little is known about how infection of BCECs by PVC-211 MuLV induces neurological disease. Previous results suggest that nitric oxide (NO), which has been implicated as a potential neurotoxin, is involved in PVC-211 MuLV-induced neurodegeneration. In this study, we show that expression of inducible nitric oxide synthase (iNOS), which produces NO from l-arginine, is induced in BCECs from PVC-211 MuLV-infected rats. Furthermore, elevated levels of a 32-kDa cellular protein modified by 3-nitrotyrosine, which is a hallmark of NO production, were observed in virus-infected BCECs. BCECs from rats infected with BCEC-tropic but nonneuropathogenic PVF-e5 MuLV, which is a chimeric virus between PVC-211 MuLV and F-MuLV, fail to induce either iNOS expression or elevation of tyrosine nitration of a 32-kDa protein. These results suggest that expression of iNOS and nitration of tyrosine residues of a 32-kDa protein in PVC-211 MuLV-infected BCECs may play an important role in neurological disease induction.

Disparate Regions of Envelope Protein Regulate Syncytium Formation versus Spongiform Encephalopathy in Neurological Disease Induced by Murine Leukemia Virus TR

ABSTRACT The murine leukemia virus (MLV) TR1.3 provides an excellent model to study the wide range of retrovirus-induced central nervous system (CNS) pathology and disease. TR1.3 rapidly induces thrombotic events in brain microvessels and causes cell-specific syncytium formation of brain capillary endothelial cells (BCEC). A single amino acid substitution, W102G, in the MLV envelope protein (Env) regulates the pathogenic effects. The role of Env in determining this disease phenotype compared to the induction of spongiform encephalomyelitis with a longer latency, as seen in several other MLV and in human retroviruses, was determined by studying in vitro-attenuated TR1.3. Virus cloned from this selection, termed TRM, induced progressive neurological disease characterized by ataxia and paralysis and the appearance of spongiform neurodegeneration throughout the brain stem and spinal cord. This disease was associated with virus replication in both BCEC and highly ramified glial cells. TRM did not induce syncytium formation, either in vivo or in vitro. Sequence and mutational analyses demonstrated that TRM contained a reversion of Env G102W but that neurological disease mapped to the single amino acid substitution Env S159P. The results demonstrate that single nucleotide changes within disparate regions of Env control dramatically different CNS disease patterns.

Virus-specific cytotoxic lymphocyte response in a neurotropic murine leukemia virus infection

NFS/N mice infected with neurotropic Cas-Br-M murine leukemia virus (MuLV) at 21 days of age were resistant to neurologic disease and demonstrated MuLV-specific cytotoxic T lymphocyte (CTL) activity in spleen cells after in vitro stimulation. NFS/N mice infected with Cas-Br-M MuLV at 2 days of age failed to generate a significant MuLV-specific CTL response and developed neurologic disease 5-8 weeks later. Protection from neurologic disease transferred with fewer in vitro stimulated immune spleen cells than immune T cells from NFS/N mice infected with Cas-Br-M MuLV at 21 days of age. Cas-Br-M MuLV-specific CTL may play an important role in resistance to the paralytic effects of Cas-Br-M MuLV infection by affecting virus dissemination to the central nervous system.

Effects of viral specific cytotoxic lymphocytes on the expression of murine leukemia virus induced neurologic disease.

A dose and time related effect on neurologic disease expression followed transfer of viral specific cytotoxic T lymphocytes (CTL) to recipient NFS/N mice previously infected at 2 days of age with Cas-Br-M murine leukemia virus. Cas-Br-M MuLV gp70 was expressed in spleen and capillary endothelial cells in the brain and spinal cord of CTL recipients, but the progression of gliosis, vacuolation, and cell death that followed endothelial cell MuLV gp70 expression in unprotected Cas-Br-M MuLV infected mice was interrupted in protected CTL recipients. A direct cytotoxic effect of CTL on infected brain capillary endothelial or neural cells could not be demonstrated. Reduced levels of infectious MuLV and MuLV gp70 expression in brain following syngeneic CTL transfer early in the course of disease suggest that CTL may function by preventing a time-limited interaction of Cas-Br-M MuLV with a susceptible target cell or receptor critical for neurologic disease induction during the perinatal period.

Leukocyte-migration inhibition in guinea pigs. I. Correlation with skin test reactivity and macrophage-migration inhibition.

Abstract Fifteen guinea pigs, immunized with one of three soluble antigens, repeatedly demonstrated inhibition of leukocyte migration and positive skin tests to the immunizing antigens. An additional five animals immunized with ovalbumin demonstrated inhibition of macrophage migration as well as direct and indirect inhibiton of leukocyte migration. Only one of fifteen animals demonstrated inhibition of leukocyte migration and none had a positive skin test with an antigen to which it had not been sensitized, indicating that the assay is antigen specific.