Biomedical subjects

S A Stohlman

Publications and source records attributed to S A Stohlman.

At least 91 records · Page 5Linked to original sources

PubMed1989

Monoclonal antibodies to the matrix (E1) glycoprotein of mouse hepatitis virus protect mice from encephalitis.

Monoclonal antibodies to the matrix or E1 glycoprotein of mouse hepatitis virus (MHV) were tested for their ability to protect mice from a normally lethal challenge of MHV-4. Four antibodies were tested, and two of these, J.1.3 and J.3.9, were protective. Protection did not correlate with virus neutralization in vitro, antibody isotype, recognition of a unique E1 antigenic site, or dependence on complement in vivo. Survival from acute encephalitis was followed by subacute demyelination, as has been shown with protection mediated by neutralizing monoclonal antibodies against the major glycoprotein, E2. These results demonstrate that antibodies which are specific for a viral matrix protein are able to alter the course of disease.

Animals↗

PubMed1989

T-cell-mediated clearance of mouse hepatitis virus strain JHM from the central nervous system.

Clearance of the neurotropic JHM strain of mouse hepatitis virus from the central nervous system was examined by the transfer of spleen cells from immunized donors. A T cell with the surface phenotype of Thy1.2+ CD4+ CD8- asialo-GM1+ Mac-1- was found to be necessary for viral clearance. The surface phenotype and adherence to nylon wool suggest that these cells are activated helper-inducer T cells. Adoptive transfer to congenic histocompatibility strains demonstrated the necessity for compatibility at the D locus of the major histocompatibility complex. The expression of the CD4 surface marker and the requirement for major histocompatibility complex class I were further studied by the transfer of cells to recipients treated with anti-CD4 or anti-CD8 monoclonal antibodies. Treatment of recipients with either the anti-CD8 or the anti-CD4 antibodies inhibited virus clearance from the central nervous system. This suggests that the CD4+ cell acts as a helper and that virus is cleared from the central nervous system. This suggests that the CD4+ cell acts as a helper and that virus is cleared from the central nervous system by CD8+ cells that recognize viral antigen in the context of the H-2Db gene product.

Animals↗

PubMed1988

Antigenic assessment of coronaviruses isolated from patients with multiple sclerosis.

Many studies have either supported or discounted the role of coronaviruses as etiologic agents in multiple sclerosis (MS). Two new approaches were applied to investigate this controversy. First, monoclonal antibodies specific for either murine coronaviruses (mouse hepatitis viruses) or human coronaviruses were used to characterize the antigenic features of MS-derived coronaviruses SK and SD. Both isolates were found to have a mouse hepatitis virus-type profile. Second, serum and cerebrospinal fluid antibodies to different coronaviruses, including SD, were measured in MS and control groups. No significant difference in antibody level to coronaviruses was found between MS and control samples. The results of these antigenic studies do not support a specific association between MS and coronaviruses.

Adult↗

PubMed1988

Maturation of the delayed-type hypersensitivity response in SJL mice: absence of effector cell induction.

Immunization of young adult SJL mice (6 weeks of age) with a wide variety of particulate and soluble antigens does not elicit a delayed-type hypersensitivity (DTH) response. Young adult SJL lack a DTM response through 8 weeks of age but attain the mature adult level of responsiveness at 10 weeks of age. Nylon wool-enriched TDTH effectors and an antigen-specific T cell clone both elicited DTH responses when transferred into 6-week-old SJL. Thus, the cascade of events at the local site appears to be functionally intact in 6-week-old SJL. However, T cells from immunized 6-week-old SJL fail to transfer DTH responsiveness to naive 6-week-old SJL recipients unless macrophages from 12-week-old SJL supplemented the immunization. Thus, the unresponsiveness of 6-week-old SJL appears to be due to a lack of induction of TDTH effectors. In addition, SJL mice immunized at 6 weeks of age and challenged with antigen at the DTH responsive age of 12 weeks did not mount a DTH response. Immunized 6-week-old SJL, supplemented with macrophages from 12-week-old SJL, and 12-week-old SJL did respond to a second antigenic challenge when held for an equivalent 6-week period. Thus, 6-week-old SJL fail to induce TDTH effectors and to generate memory TDTH cells. Finally, antigen-pulsed macrophages from 12-week-old SJL transferred DTH responsiveness into naive 6-week and 12-week-old SJL recipients, while antigen-pulsed cells from 6-week donors were unable to transfer DTH responsiveness. These data indicate that the maturational deficit in the DTH responsiveness of 6-week-old SJL resides in the inability of macrophages to induce TDTH effectors.

Age Factors↗

PubMed1988

Delayed-type hypersensitivity response in the central nervous system during JHM virus infection requires viral specificity for protection.

The JHM strain of mouse hepatitis virus (JHMV) elicits an I-A-restricted delayed-type hypersensitivity (DTH) response mediated by a Thy-1+, Lyt-1+, and CD4+ T cell. Adoptive transfer of these polyclonal CD4+ T cells from immunized mice prevents death in lethally infected recipients without significantly reducing virus titer in the central nervous system (CNS). These observations raise the possibility that the recruitment of mononuclear cells into the CNS may play a critical role in survival from a lethal CNS infection. Transient DTH response to nonviral antigens induced an accumulation of monocytes in the CNS that was maximal at 48 h post-challenge and virtually resolved by 5 days post-challenge. By contrast the induction of prolonged DTH responses resulted in the accumulation of a large number of monocytes that persisted in the CNS for at least 5 days post-challenge. Neither type of DTH reaction suppressed virus replication or prevented death from concomitant lethal JHMV infection.

Animals↗

PubMed1988

Interactions between coronavirus nucleocapsid protein and viral RNAs: implications for viral transcription.

The interaction of the mouse hepatitis virus (MHV) nucleocapsid protein (N) and viral RNA was examined. Monoclonal antibody specific for N protein coimmunoprecipitated MHV genomic RNA as well as all six MHV subgenomic mRNAs found in MHV-infected cells. In contrast, monoclonal antibodies to the MHV E2 or E1 envelope glycoproteins, an anti-I-A monoclonal antibody, and serum samples from lupus patients did not immunoprecipitate the MHV mRNAs. Moreover, the anti-N monoclonal antibody did not coimmunoprecipitate vesicular stomatitis virus RNA or host cell RNA under conditions which immunoprecipitated all MHV RNAs. These data suggest a specific interaction between the N protein and the virus-specific mRNAs. Both the membrane-bound and cytosolic small MHV leader-specific RNAs of greater than 65 nucleotides long were immunoprecipitated only by anti-N monoclonal antibody. These data suggest that an N binding site is present within the leader RNA sequences at a site at least 65 nucleotides from the 5' end of genomic RNA and all six subgenomic mRNAs. The larger leader-containing RNAs originating from mRNA 1 and mRNA 6, as well as the MHV negative-stranded RNA, were also immunoprecipitated by the anti-N monoclonal antibody. These data indicate that the MHV N protein is associated with MHV-specific RNAs and RNA intermediates and may play an important functional role during MHV transcription and replication.

Antibodies, Monoclonal↗

PubMed1988

Specific interaction between coronavirus leader RNA and nucleocapsid protein.

Northwestern blot analysis in the presence of competitor RNA was used to examine the interaction between the mouse hepatitis virus (MHV) nucleocapsid protein (N) and virus-specific RNAs. Our accompanying article demonstrates that anti-N monoclonal antibodies immunoprecipitated all seven MHV-specific RNAs as well as the small leader-containing RNAs from infected cells. In this article we report that a Northwestern blotting protocol using radiolabeled viral RNAs in the presence of host cell competitor RNA can be used to demonstrate a high-affinity interaction between the MHV N protein and the virus-specific RNAs. Further, RNA probes prepared by in vitro transcription were used to define the sequences that participate in such high-affinity binding. A specific interaction occurs between the N protein and sequences contained with the leader RNA which is conserved at the 5' end of all MHV RNAs. We have further defined the binding sites to the area of nucleotides 56 to 65 at the 3' end of the leader RNA and suggest that this interaction may play an important role in the discontinuous nonprocessive RNA transcriptional process unique to coronaviruses.

Base Sequence↗

PubMed1988

In vivo RNA-RNA recombination of coronavirus in mouse brain.

RNA-RNA recombination between different strains of the murine coronavirus mouse hepatitis virus (MHV) occurs at a very high frequency in tissue culture. To demonstrate that RNA recombination may play a role in the evolution and pathogenesis of coronaviruses, we sought to determine whether MHV recombination could occur during replication in the animal host of the virus. By using two selectable markers, i.e., temperature sensitivity and monoclonal antibody neutralization, we isolated several recombinant viruses from the brains of mice infected with two different strains of MHV. The recombination frequency was very high, and recombination occurred at multiple sites on the viral RNA genome. This finding suggests that RNA-RNA recombination may play a significant role in natural evolution and neuropathogenesis of coronaviruses.

Animals↗

PubMed1988

RNA recombination of murine coronaviruses: recombination between fusion-positive mouse hepatitis virus A59 and fusion-negative mouse hepatitis virus 2.

It has previously been shown that the murine coronavirus mouse hepatitis virus (MHV) undergoes RNA recombination at a relatively high frequency in both tissue culture and infected animals. Thus far, all of the recombination sites had been localized at the 5' half of the RNA genome. We have now performed a cross between MHV-2, a fusion-negative murine coronavirus, and a temperature-sensitive mutant of the A59 strain of MHV, which is fusion positive at the permissive temperature. By selecting fusion-positive viruses at the nonpermissive temperature, we isolated several recombinants containing multiple crossovers in a single genome. Some of the recombinants became fusion negative during the plaque purification. The fusion ability of the recombinants parallels the presence or absence of the A59 genomic sequences encoding peplomers. Several of the recombinants have crossovers within 3' end genes which encode viral structural proteins, N and E1. These recombination sites were not specifically selected with the selection markers used. This finding, together with results of previous recombination studies, indicates that RNA recombination can occur almost anywhere from the 5' end to the 3' end along the entire genome. The data also show that the replacement of A59 genetic sequences at the 5' end of gene C, which encodes the peplomer protein, with the fusion-negative MHV-2 sequences do not affect the fusion ability of the recombinant viruses. Thus, the crucial determinant for the fusion-inducing capability appears to reside in the more carboxyl portion of the peplomer protein.

Base Sequence↗

PubMed1987

Experimental neuropathology of chronic demyelination induced by a JHM virus variant (DS).

A small plaque variant of JHM virus has a markedly reduced ability to kill mice following intracerebral inoculation. Spinal cords of mice surviving 13 to 16 months following acute infection with this variant were examined ultrastructurally. Multiple subpial areas of demyelination in the anterior and lateral white matter were found in five of 13 mice. The lesions had more gliosis, fewer oligodendrocytes, and less remyelination than has been described following other infections with JHM virus. No conclusive evidence of active demyelination or viral-like particles was found. The pathogenesis of the lesions observed may be due to a persistent, attenuated infection of oligodendrocytes or to immunologic processes. These lesions were similar to chronic multiple sclerosis plaques. Therefore, this variant should prove to be a useful tool for studying the long-term effects of viral-induced demyelinating diseases.

Animals↗

PubMed1987

RNA recombination of coronavirus.

We have previously shown that Mouse hepatitis virus (MHV) can undergo RNA-RNA recombination at a very high frequency (S. Makino, et al., J. Virol. 57, 729-737, 1986). To better define the mechanism of RNA recombination, we have performed additional crosses involving different MHV strains. We have obtained recombinant viruses with multiple cross-overs. The isolation of such recombinants further indicates the high frequency of coronavirus RNA recombination. By using cell fusion as a selection marker, we have also obtained recombinants between MHV-2 and A59 strains. Some of these recombinants have cross-overs in the 3'-end genes of the genome, thus demonstrating that recombination could occur along the entire genome. Finally, we have obtained recombinants by selecting with neutralizing monoclonal antibodies. These recombinants have cross-overs within gene C which encodes the peplomer protein. The genetic structure of these recombinants allowed us to determine the important domains of the peplomer proteins.

Chromosome Mapping↗

PubMed1987