High-Dose Survival in the Lymphocytic Choriomeningitis Virus Infection Is Accompanied by Suppressed DTH but Unaffected T-Cell Cytotoxicity

Provided that intracerebral inoculation is applied, an increase in the virus dose from 10(2) to 10(4) LD50 of lymphocytic choriomeningitis virus (LCMV) leads to strikingly reduced mortality. To analyse the background for this autointerference, we measured several virologic and immunologic variables in mice infected with these doses of virus. In the high-dose mice we found generally higher organ virus titres and serum interferon titres than in the low-dose mice. Since we could demonstrate that virus-specific T-cell cytotoxicity in spleen, peripheral blood, and meningeal exudate was similar after intracerebral infection with large and small virus doses, and since the LCMV infection in the brain qualitatively and quantitatively was independent of the size of virus inoculum, the explanation for the survival of the high-dose animals is obviously not lack of possibilities for interaction between cytotoxic T cells and infected sensitive targets in the central nervous system. On the other hand, high doses of virus caused a clear suppression of the LCMV-specific delayed-type hypersensitivity (DTH). In addition, when splenocytes from high-dose animals were transferred either intravenously or locally into the footpad of newly virus-challenged mice, DTH was markedly suppressed as compared with the response after transfer of spleen cells from low-dose mice. We therefore conclude that autointerference in the LCMV infection is due to a selective suppression of Td function. Large amounts of persistent virus late after infection with high doses of virus suggest a central role for Td function also in virus clearance. Finally, our results indicate the existence of two subsets of K,D region-restricted T cells, one mediating cytotoxicity and the other mediating DTH. This possibility is discussed.     

DEVELOPING AND EVALUATING THE GRIEFLINK WEB SITE: PROCESSES,PROTOCOLS, DILEMMAS AND LESSONS LEARNED

Despite a profusion of recommendations regarding the quality of web sites and guidelines related to ethical issues surrounding health-related sites, there is little guidance for the design and evaluation of sites relating to loss and grief. This article, which addresses these deficiencies, results from a community consultation process of designing and evaluating a web site—GriefLink—for bereaved consumers and for the professionals who help them. It presents the literature review that informed the project, the recommendations for design and content, the lessons learned through the process itself, and the difficulties of evaluating the benefits of a grief-related web site. Some ethical and legal dilemmas in developing grief-related web sites are discussed and issues of design, content, process, evaluation, and general features are addressed, which may also be applied to other communication forms for loss and grief matters, such as the print media.     

Different Tc Response Profiles are Associated with Survival in the Murine Lymphocytic Choriomeningitis Virus Infection

The pathogenicity of lymphocytic choriomeningitis virus (LCMV) inoculated intracerebrally (i.c.) varies with virus strain and dose as well as with the mouse strain used as host. Recently, results have indicated that susceptibility to lethal disease correlates directly the ability of the host to produce early and high virus-specific Tc activity. However, in the present studies we demonstrate that even though this holds true in many mouse/virus combinations, it does not apply in others. Thus, in C3H mice infected with (moderately) high doses of Traub strain LCMV, early and high Tc activity was found despite a mortality rate of only 10-20%. Similarly, in C3H mice inoculated with the aggressive and docile substrains of UBC strain LCMV, which differ markedly in their pathogenicity for this mouse strain, similar kinetics of Tc induction were observed. Finally, in DBA/2 mice which do not die following infection with the otherwise lethal aggressive substrain, Tc induction could be found to be as efficient as in BALB/c mice, all of which die from acute LCM disease when infected with this virus isolate. The results indicate, therefore, that early and high Tc activity does not constitute a sufficient prerequisite for lethal disease, and that different Tc response profiles may be associated with low mortality following i.c. inoculation with LCMV.     

GIANT GROUP A MARKER CHROMOSOME lN THREE HUMAN LYMPHOBLASTOID CELL STRAINS FROM NASOPHARYNGEAL CARCINOMA

In 1976, at the Kwangtung Conference on Nasopharyngeal Carcinoma (NPC)(1), we reported the presence of a giant submetar:en- tric group A marker chromosome of com- posite structure (1;3p) cytogenetically demons_ trated by banding analysis in 2 NPC lympho- blastoid cell strains from a male and female patient. Meamvhile, the Cancer Institute of Chungshan Medical College, Kxvangchow（2), also reported their findings by conventional karyotyping technic of a giant A rn相似文献   

T-Cell Responsiveness to LCMV Segregates as a Single Locus in Crosses between BALB/cA and C.B-17 Mice. Evidence for Regulation by a Gene Outside the Igh Region

The course of systemic infection with lymphocytic choriomeningitis virus (LCMV) was studied in BALB/ cA and C.B-17 mouse strains differing in the immunoglobulin heavy chain region (Igh). Susceptibility to intracerebral infection and the ability to clear the virus differed significantly between these presumably congenic strains, suggesting that a gene in the Igh region might influence the course of this infection. A difference in virus spread prior to appearance of the immune response could not explain the observed differences. On the other hand, the differences in course of infection correlated with a difference in virus-specific T-cell responsiveness measured in terms of virus-specific cytotoxicity in vitro and delayed-lype hypersensitivity invivo. Analysis of F₁, BC₁ and F2 progeny showed that differential T-cell responsiveness was influenced hy a single gene or gene complex; however, no linkage was found between this locus and the Igh-C region. Taken together, these results indicate that an additional, and previously unknown, genetic difference exists between these two mouse strains, and that the involved locus carries a gene which significantly affects T-cell responsiveness to LCMV.     

Genome-wide DNA methylation profiling identifies two novel genes in cervical neoplasia

DNA methylation analysis may improve risk stratification in cervical screening. We used a pan-epigenomic approach to identify new methylation markers along the continuum of cervical intraepithelial neoplasia (CIN) to cervical cancer. Physician-collected samples (54 normal, 50 CIN1, 40 CIN2 and 42 CIN3) were randomly selected from women at a single-center colposcopy clinic. Extracted DNA was subjected to Illumina Infinium EPIC array analysis, and methylation was assessed blinded to histopathological and clinical data. CpG sites whose state of methylation correlated with lesion grade were assessed (Spearman correlation), and a weighted methylation score was calculated comparing normal to CIN3. Validation of the top selected genes was performed in an independent cohort (100 normal, 50 CIN1, 50 CIN2, 50 CIN3 and 8 cervical cancers) of new patients, referred for colposcopic examination at three hospitals, using targeted DNA methylation Illumina amplicon sequencing. The relationship between a combined weighted marker score and progression from normal through precancerous lesions and cervical cancer was compared using one-way ANOVA. Our analyses revealed 7,715 CpGs whose methylation level correlated with progression (from normal to CIN1, CIN2 and CIN3), with a significant trend of increased methylation with lesion grade. We shortlisted a bigenic (hyaluronan synthase 1, HAS1 and ATPase phospholipid transporting 10A, ATP10A corresponding to cg03419058 and cg13944175 sites) marker set; r = 0.55, p < 0.0001. Validation of the four most discriminating genes (CA10, DPP10, FMN2 and HAS1) showed a significant correlation between methylation levels and disease progression (p-value < 2.2 × 10⁻¹⁶, adjusted R² = 0.952). Translational research of the identified genes to future clinical applications is warranted.     

Circulating intercellular adhesion molecule-1 (ICAM-1) as an early and sensitive marker for virus-induced T cell activation

The effect of systemic virus infection on the level of circulating ICAM-1 (cICAM-1) in serum, and the role of virus-activated T cells in this context, were studied using the murine lymphocytic choriomeningitis virus infection as primary model system. A marked virus-induced elevation in cICAM-1 in serum was revealed, the presence of which coincided with the phase of virus-induced T cell activation. However, high levels of cICAM-1 in serum were observed well before maximal T cell activation could be demonstrated. No increase in cICAM-1 was observed in the serum of infected T cell-deficient nude mice, clearly demonstrating that T cells were mandatory. Analysis of MHC class I and MHC class II-deficient mice revealed that either CD4⁺ or CDS⁺ T cells alone are sufficient, despite a markedly reduced inflammatory exudate in the former animals. These results indicate that virus-activated T cells induce shedding of ICAM-1 into the circulation, and this parameter may be used as an early and sensitive marker for immune activation.     

T-Cell Effector Function and Unresponsiveness in the Murine Lymphocytic Choriomeningitis Virus Infection

When the virus dose is increased from 10(2) (low dose) to 10(4) LD50 (high dose) a fatal lymphocytic choriomeningitis virus (LCMV) infection is changed into a subclinical one, and a selective virus-specific delayed-type hypersensitivity (DTH) unresponsiveness is induced, while the cytotoxic T-cell response remains essentially unchanged. When low-dose spleen effectors were transferred intravenously into intracerebrally infected high-dose mice, fatal LCM disease occurred, which means that infected central nervous system target structures in these animals are sensitive to virus-specific T cells. When low-dose cells were transferred to intravenously infected high-dose mice, these animals regained their TD function (the effect of T cells mediating DTH). Since this indicates that the survival of intracerebrally infected high-dose mice is intimately linked with the absence of virus-specific DTH reactivity, a search for T suppressor (TS) activity in these animals was performed by transferring high-dose spleen cells to lethally (intracerebrally) infected low-dose recipients. In this way we obtained an afferent suppression, which was not H-2 restricted, but was abrogated when the spleen cells were pretreated with neutralizing anti-LCMV serum, indicating a suppressive effect of virus transferred with the infected cells. When tolerance induction was attempted with virus alone, a potentially fatal immune reaction could be altered to unresponsiveness (i.e. survival) as late as 4 days after an otherwise lethal infection with LCMV. The results indicate that the maturation of the virus-specific TD response is sensitive to large amounts of virus antigen. We conclude that this impairment and the resulting DTH unresponsiveness is due to a clonal deletion or anergy rather than to the effect of TS cells, and that the TD effector function is critical to the development of fatal LCM disease.     

Analysis of the Capacity to Produce IL-3 in Murine AIDS

Adult C57BL/6 mice infected with LP-BM5 murine leukaemia virus represent a model of murine AIDS (MAIDS). In this study we have analysed the capacity of CD4⁺ T cells from infected mice to produce IL-3 following stimulation with ConA for 24–72 h. In contrast to the position with IL-2, the production of which is markedly impaired during LP-BM5 infection, similar levels of IL-3 were measured in culture supernatants of splenocytes from infected and uninfected mice harvested at 24 h of stimulation. Forty eight and 72 h of ConA stimulation led to increasing levels of IL-3 being measured in cultures from uninfected mice, whilst in cultures from infected animals, IL-3 levels remained stagnant. Similar results were obtained 4, 8 and 13 weeks post-infection. In view of the fact that parallel experiments revealed markedly impaired proliferative responses to ConA during MAIDS, we conclude that IL-3 production is basically intact at the cellular level in T cells during MAIDS; but when in a situation requiring clonal expansion of the activated T cells, IL-3 production will be inhibited owing to the impaired capacity for proliferation.