Failure to infect embryos after virus injection in mouse zygotes

BACKGROUND

The intracytoplasmic injection of sperm raises the problem that viral elements may be transported into the oocyte by the spermatozoon or the surrounding medium. It also raises questions about how the developing zygote will behave.

METHODS

We used the murine model to microinject murine cytomegalovirus (MCMV) into the zygote ooplasm and followed the changes in these microinjected zygotes in vivo and in vitro over time.

RESULTS

80% of zygotes microinjected with viral suspension, and 80% injected with medium alone, survived. Although MCMV DNA was detected in 56% of injected embryos, up until the blastocyst stage, the mice born from these injected zygotes developed normally and did not contain MCMV DNA. When embryonic stem cells were co-incubated with MCMV and then transferred into healthy blastocysts, the offspring were normal and did not contain any MCMV DNA.

CONCLUSIONS

Our observations suggest that even if MCMV DNA persists from the zygote to the blastocyst stage, its presence has no detrimental effect on pre-implantation or post-implantation development.

Periodontal infections and cardiovascular disease--how strong is the association?

In the past decade there has been renewed interest in the old hypothesis that infections increase the risk of developing cardiovascular disease and stroke. There is now a convincing body of evidence that atherosclerosis has a major inflammatory component and is much more than the simple vascular accumulation of lipids. Infectious agents that have been linked to an increased risk of coronary heart disease (CHD) include Chlamydia pneumoniae, Helicobacter pylori, cytomegalovirus, and herpesviruses. The concept has emerged that each of these agents is an independent risk factor for CHD and that common chronic infections are important. In addition, periodontal infections have also been implicated as one of several factors contributing to the development of CHD. Evidence supporting a causative role of chronic infections in CHD is largely circumstantial. However, the evidence is sufficiently strong to warrant further examination of the possible link between chronic infections and CHD. In this review the lines of evidence for a causative role of C. pneumoniae in the development of CHD are summarized and contrasted with the lines of evidence suggesting a periodontal infection--CHD association. If common or widespread chronic infections are truly important risk factors for CHD, it is unlikely that a single infection will be shown to be causative. It is likely that the entire microbial burden of the patient from several simultaneous chronic infections is more important (e.g., H. pylori-caused gastric ulcers + C. pneumoniae-caused bronchitis + periodontitis). Increased cooperation between cardiologists and periodontists will be required to determine if, and what, combinations of common chronic infections are important in the pathogenesis of CHD and stroke.

Studies on persistent infections of tissue cultures. II. Nature of the resistance to vesicular stomatitis virus

Efforts were made to elucidate the nature of the resistance to vesicular stomatitis virus (VSV) observed in MCN cultures persistently infected with Newcastle disease, mumps, or 6-6 viruses (MCN_NDV, MCN_Mps and MCN_6-6, respectively). Cells derived from persistently infected cultures adsorbed VSV to the same extent as their uninfected counterparts. Only a fraction of the adsorbed virus could be recovered from the cells indicating that it enters into an eclipse in all of the cell types. While propagation of VSV in MCN cells is largely inhibited at low pH levels, the resistance of persistently infected cultures could not be ascribed to their increased lactic acid formation. Resistance was not absolute in that a few cells in persistently infected cultures apparently supported VSV reproduction. Furthermore resistance of the cultures was found to be transitory in that the VSV infection gradually gained the upper hand after 2 to 4 weeks of incubation. Addition of ultraviolet-inactivated NDV to MCN cultures induced resistance to VSV as long as the equivalent of at least one ID₅₀ (for chick embryos) of inactivated virus was provided per cell. Establishment of resistance required some time and its duration depended upon whether or not the free inactivated NDV was removed or neutralized after given adsorption periods. The transitory nature of resistance in persistently infected cultures, or in MCN cells following adsorption of inactivated NDV, is most likely explained by the fact that the cells continue to divide and that the daughter cells are, at least in part, susceptible to VSV. The results are compatible with the conclusion that the resistance observed represents another example of interference between 2 viruses.

[Alpha-herpesvirus infection in the central nervous system]

Herpes simplex virus type 1 (HSV1) encephalitis is commonly observed, but HSV1 myelitis is rare. On the other hand, HSV2 is common etiologic agent for ascending necrotizing myelitis associated with diabetes mellitus, malignant tumors, AIDS and immunocompromised hosts. It is suggested that latent infection of the virus of root ganglia or primary infected virus is possibly followed by spread of infection to the central nervous system, particularly in immunocompromised patients. In this report, pathological findings and clinical symptoms of our recent encephalitis and myelitis cases infected with HSV2 and HSV1 are described.

[Study of alpha-herpesvirus: present state and future developments]

The herpesvirus is a ubiquitous infectious agent present in a variety of vertebrates including humans. The virus has a duplex DNA molecule of 120-240 kbp within an icosahedral capsid surrounded by an envelope. Latency is a central feature of herpesvirus biology. Studies of herpesviruses relate to 1) diagnosis, prevention, and the treatment of diseases associated with herpesvirus infections, 2) elucidation of biological mechanisms of mammalian cells using herpesviruses, 3) construction of vaccine and vector systems for gene therapy, and 4) establishment of putative associations of herpesviruses with host organisms during evolution (suggesting the host-linked evolution of herpesvirus).

[Clinical manifestations of the subfamily alpha-herpesvirinae in childhood]

Herpes simplex virus(HSV) and varicella-zoster virus(VZV) belonging to the subfamily of alpha-herpesvirinae have the capacity to establish latent infection in neural tissues and to reactivate from these sites. HSV infection is characterized by a vesicular eruption, fever, and other constitutional symptoms but frequently inapparent both in primary and recurrent infections. However, the infection produces a wide spectrum of illness ranging from the trivial fever blisters to the most severe fatal sporadic encephalitis and neonatal infection. In contrast, VZV develops varicella, a common contagious disease of childhood during primary infection and zoster by reactivation of latent virus acquired during varicella. In normal children, the systemic symptoms of both diseases are mild, whereas serious complications are often observed in children with deficiencies in cell-mediated immunity. Acyclovir has been the drug of choice for treatment of severe infection with HSV and VZV for approximately 2 decades. Now, two new agents, valacyclovir and famciclovir will supplant acyclovir for certain indications.

[Alphaherpesvininae--dermatology]

The subfamily alphaherpesuvirinae contains herpes simplex virus(HSV) and varicella-zoster virus(VZV) in the Dermatology. HSV infectious diseases are herpetic gingivostomatitis, herpes labialis, facial herpes simplex, Kaposi's varicelliform eruption, genital herpes, lumbosacral herpes simplex, and herpetic whitlow. The primary form of VZV infection is varicella, and the reactivation form is herpes zoster. These infectious diseases in the dermatological clinics usually occur in adult. In this paper we mention clinical manifestations and treatment.

[Alpha herpes virus and facial palsy]

Alpha herpes virus is the major causes of peripheral facial palsy such as Bell's palsy or Ramsay Hunt syndrome. Ramsay Hunt syndrome is caused by varicella zoster virus (VZV) infection, and can be diagnosed by facial nerve paralysis associated with herpetic eruption on the pinna, and complication of by vestibulo-cochlear dysfunction. On the other hand, Bell's palsy presents only facial palsy and its diagnosis is made by the exclusion of known conditions. The causes of Bell's palsy had been unknown for many years, however, recently it was revealed that herpes simplex type 1 was the major cause of Bell's palsy by PCR. Because early treatment with acyclovir and prednisone was proven to be effective, we should make efforts to diagnose these diseases as early as possible.

[Is multiple sclerosis a disease of viral origin?]

MS is a multifactorial disease in which host genetic factors as well as environmental factors may interact. Among them, the role of viruses is still debated since none has been directly or indirectly involved in the disease up to now. The latest candidates are HHV6 and MSRV. Recently, HHV6 antigens have been found in MS brain, but these results require further investigation. MSRV is a retroviral sequence isolated from MS tissue and it belongs to the already known ERV9 family of endogenous retroviruses. Its role in MS is only putative. To conclude, "MS virus" is still unidentified. Nevertheless, the search for a virus in MS should be pursued. In that perspective, animal models illustrate how host immune system interacts with viruses to lead to demyelination, a common feature of a multi-step process of diverse origins.

Fatal herpesvirus-6 encephalitis in a recipient of a T-cell-depleted peripheral blood stem cell transplant from a 3-loci mismatched related donor

Human herpesvirus-6 (HHV-6), like all the other herpes viruses, remains latent in host cells after primary infection but can be reactivated in immunocompromised patients causing fever, skin rash, bone marrow (BM) suppression, pneumonitis, sinusitis and meningoencephalitis. We describe the case of a man with chronic myelogenous leukemia who developed encephalitis associated with acute graft-versus-host disease two months after a T-cell-depleted mismatched peripheral blood stem cell transplant. Magnetic resonance images of the brain revealed multiple bilateral foci of signal abnormality. HHV-6 was the only pathogen detected in cerebrospinal fluid by PCR. Treatment with both ganciclovir and foscarnet was unsuccessful and the patient gradually deteriorated and died. Other cases of HHV-6 encephalitis after bone marrow transplantation are reviewed.

[Neoplastic disorders and organ transplantation]

INTRODUCTION

Organ transplantation is associated with an increased risk of neoplasia, which seems to be caused by the total effect of immunosuppression, i.e., the combination of factors involved, rather than by the use of a specific class of immunosuppressants. The presence and proliferation of viral oncogenes is frequently observed during this immunosuppressive state. The neoplasia in immunosuppressed patients therefore has particular histological, clinical, evolutive, and therapeutical characteristics.

CURRENT KNOWLEDGE AND KEY POINTS

The oncogenic mechanisms in immunosuppressed patients have been progressively clarified. A viral infection is associated with each type of neoplasia: thus, B lymphoma are generally associated with Epstein-Barr viral infection. Skin and uterine cervical carcinomas frequently appear after viral dysplasia due to papillomavirus. The significant increase in the incidence of Kaposi sarcoma shows the role of the immune system in the control of the infection by the human herpes virus 8, which has been recently discovered. Liver cancer is associated with a history of hepatitis B or C chronic infection.

FUTURE PROSPECTS AND PROJECTS

Post-transplantation neoplasia constitutes a major problem in patient follow-up, as the number of transplant patients has increased and their survival rate has improved. In addition, there is an increasingly powerful new generation of immunosuppressive drugs. A precise knowledge of the immune system's control mechanisms regarding neoplasic cells and viral infection is an important step in the prevention and efficient treatment of these forms of cancer. Further research into the relationship between the immune system and viral oncogenesis should therefore be considered a major aim.

Etiology of multiple myeloma: what's new

Both the tumor cells and the microenvironment of dendritic stromal cells appear to be involved in the etiology of multiple myeloma. Switch translocations in myeloma tumor cells often involve oncogenes. These translocations have a clearly established role in the etiology of lymphoma and may prove to have a role in the transformation process of myeloma. Dendritic stromal cells infected with human herpesvirus-8 may provide a growth and antiapoptosis advantage for myeloma bone marrow stromal cells via viral interferon regulatory factor expression. In addition, increased vascular endothelial growth factor expression secondary to viral interleukin-8 receptor gene expression stimulates angiogenesis and inhibits development of uninfected dendritic cells, providing an advantage to infected dendritic cells. These recent advances in the understanding of the etiology of multiple myeloma provide potential new genetic, viral, and cytokine targets for therapy of this fatal malignancy.

Advances in the biology of multiple myeloma: therapeutic applications

Recent advances in the biology of multiple myeloma cell growth and survival have suggested new avenues for treatment and potential cure of this disease. Adhesion molecules on the myeloma cell surface mediate their localization in the bone marrow via binding to extracellular matrix proteins and stromal cells. Stromal cell to tumor cell contact and the secretion of transforming growth factor by tumor cells triggers interleukin-6 secretion from stromal cells and paracrine tumor cell growth. CD40 activation of myeloma cells changes their cell surface phenotype, triggers autocrine interleukin-6 secretion, and can regulate myeloma cell cycle in a p53-dependent fashion. Interleukin-6 is both a growth and survival factor for myeloma cells, and delineation of the signaling cascades mediating its effects permits the development of novel therapies either to interrupt growth or trigger apoptosis. New immune therapies offer the opportunity to treat minimal residual disease after stem cell transplantation, thereby improving outcome. Selected donor lymphocyte infusions after allografting and infusion of activated autologous T cells following autografting are examples of adoptive immunotherapy. Myeloma cell to dendritic cell fusions have been used in a vaccination strategy both to prevent and treat myeloma in an animal model, providing the rationale for similar clinical trials in humans. For the first time, a variety of novel treatment strategies derived from advances in understanding the disease pathogenesis offer the potential to achieve long-term disease-free survival in patients with multiple myeloma.

Epstein-Barr virus and other candidate viruses in the pathogenesis of Hodgkin's disease

The epidemiologic and clinicopathologic features of Hodgkin's disease (HD) suggest that an infectious agent is involved in the etiology. Over the last 12 years, evidence has accumulated suggesting that Epstein-Barr virus (EBV) is associated with a proportion of cases: EBV genomes are present in Reed-Sternberg (HRS) cells and viral proteins including LMP1, which has oncogenic potential, are expressed. HD has a complex epidemiology and EBV-associated cases are not randomly distributed. Disease occurring in early childhood and older adult age groups is more likely to be EBV-associated than for young adult cases. Paradoxically, there is more evidence supporting an infectious etiology in the latter group of younger patients. Defective EBV genomes and "hit and run" mechanisms involving EBV cannot account for all cases, and the direct involvement of known viral agents, including other lymphotropic herpesviruses, has largely been excluded. Hitherto unknown virus may be responsible for the peak incidence in young adults, which is a feature of HD in developed countries.

[Granular lymphocyte-proliferative disorder following initiation of protease inhibitor therapy in a patient with acquired immunodeficiency syndrome]

The authors experienced granular lymphocyte-proliferative disorder (GLPD) with increased lymphocyte and CD4 cell counts after HIV treatment with a protease inhibitor indinavir in a 51-year-old male AIDS patient. GLPD proved to be the chronic type, but we could not differentiate whether it was the T-cell type or the NK-cell type. EB virus was found to be activated and its chronic activity was suggested. We should note in this case that EB virus was involved in the GLPD onset and that GLPD followed the treatment with a protease inhibitor.

Absence of a directly causative role for human herpesvirus 7 in human lymphoma and a review of human herpesvirus 6 in human malignancy

In search of a (new) viral etiological agent, we screened 64 lymph node samples from Hodgkin's disease (HD) and 43 samples (32 lymph node and 11 skin biopsies) from non-Hodgkin's lymphoma (NHL) for human herpesvirus 7 (HHV-7). Twenty-nine control samples were tested as well, including 17 with benign lymphadenopathy. None of the samples tested positive by Southern blot hybridization using HHV-7-specific probes. We conclude that there is no major HHV-7 load in human lymphoma and that HHV-7 is not likely to be directly involved in its etiology. This is in contrast to a small minority of human lymphoproliferative diseases in which HHV-6 can be found at high copy number, but in which an etiological role is still uncertain.

The use of an anti-CD3 immunotoxin to prevent the development of lymphoproliferative disease in SCID/PBL mice

Severe combined immunodeficient mice (SCID) reconstituted with normal PBLs (SCID/PBL) from Epstein-Barr virus-positive (EBV+) human donors often develop fatal human B lymphomas which resemble the EBV-induced lymphoproliferative disease (LPD) observed in immunosuppressed individuals. This phenomenon appears to be T cell dependent. In this study we used an immunotoxin (IT) prepared by conjugating the monoclonal anti-CD3 antibody, 64.1, to deglycosylated ricin A chain (dgRTA) to prevent LPD in SCID/PBL mice. We show that the incidence of LPD is greatly reduced by either a combination of in vitro treatment of PBLs followed by one in vivo treatment of the xenografted mice with 64.1-dgRTA immunotoxin or by repeated treatments in vivo with the immunotoxin. In contrast, in vitro treatment alone or in vivo treatment with only one injection of 64.1-dgRTA were less effective. As expected, this IT did not have any non-specific cytotoxic effects on already established EBV+ tumors from SCID/PBL mice. The use of this IT, therefore, represents a simple method to avoid LPD when injecting blood-containing tissues into SCID mice.

Murine gammaherpesvirus 68: a model for the study of gammaherpesvirus pathogenesis

Murine gammaherpesvirus 68 (MHV-68) is a naturally occurring herpesvirus of wild rodents and is genetically related to human herpesvirus 8 and Epstein-Barr virus. The ability of MHV-68 to establish acute and persistent infection within laboratory mice offers a unique opportunity to investigate immunological and virological aspects of gammaherpesvirus pathogenesis.

Epstein-Barr virus infections and their association with human malignancies: some key questions

Epstein-Barr virus (EBV) expresses genes that stimulate cells to divide in culture. This property, coupled with the close association of the virus with numerous malignancies, has prompted its designation as a human DNA tumour virus. Before human herpesvirus 8 (HHV-8, alternatively KS virus) was discovered, EBV was unique in this property among the human herpesviruses. EBV infection has been best characterised in terms of gene expression in B lymphocytes and epithelium, which represent cells found in the best known of the associated malignancies, Burkitt's lymphoma and poorly differentiated nasopharyngeal carcinoma. The bulk of evidence supports B cells as the primary EBV reservoir with the viral route into other cell types remaining ill-defined. Molecular studies on gene expression in the associated tumours suggest that EBV encodes a number of functions associated with cell growth; whether they are expressed or silent may largely be under control of the host cell. Many questions partly addressed here remain with regard to this virus, two critical ones relating to the mechanisms by which viral gene products escape T-cell recognition - relevant from the fact that gene expression is not tightly restricted to nonimmunogenic functions in tumours - and whether EBV can invoke cell growth in a manner not requiring its continued presence. The latter seems a plausible hypothesis and is of particular importance with regard to identifying and understanding pathologies associated with EBV, as viral transcriptional transactivators may on initial infection permanently perturb cell regulation.

[Occurrence of non-Hodgkin's lymphoma in chronic viral hepatitis C]

INTRODUCTION

We report the occurrence of non-Hodgkin's lymphoma during the course of chronic hepatitis C treated with alpha-interferon.

EXEGESIS

Specific viruses such as Epstein-Barr virus and human T-cell leukemia viruses I and II may be at the origin of various lymphomas in human. The presence of B cell lymphoma in the course of chronic hepatitis C has already been described and could be related to the lymphoid tropism of hepatitis C virus.

CONCLUSION

This new report of an association between chronic hepatitis C and B cell lymphoma should lead physicians to search for signs of lymphoma in patients with chronic hepatitis C.

Preliminary evidence for an association of Epstein-Barr virus with pre-ulcerative oral lesions in patients with recurrent aphthous ulcers or Behçet's disease

In this study we used the polymerase chain reaction (PCR), slot blot and Southern blot hybridization, direct sequencing and in situ hybridization (ISH) to show the possible presence of EBV-DNA in pre-ulcerative oral aphthous lesions of patients with recurrent aphthous ulcers (RAU) or Behçet's disease (BD). For this purpose, formalin-fixed biopsy specimens were obtained from 13 pre-ulcerative oral aphthous lesions of nine RAU and four BD patients. Five specimens of normal oral mucosa (NOM) from five normal control subjects and 10 specimens of oral erosive or ulcerative lesions from 10 patients with erosive lichen planus (ELP) were also included. EBV-DNA was detected by PCR in 5 of the 13 (38.5%) pre-ulcerative oral aphthous lesions, two from RAU patients and three from BD patients. However, no EBV-DNA was demonstrated in five NOM specimens from normal control subjects and in 10 specimens of oral lesions from ELP patients. EBV-DNA was also demonstrated in patients' peripheral blood lymphocytes and/or plasma, suggesting that the lymphocytes may be the reservoir of latent EBV infection and there is EBV shedding in the plasma. EBV-DNA was detected by ISH in only one PCR-positive case; the reaction product was found to deposit on the nuclei of some of the epithelial cells and lymphocytes. By immunohistochemistry, expression of Epstein-Barr nuclear antigen and EBV/C3d receptors was also noted in some of the epithelial cells and lymphocytes in this ISH-positive case. Therefore, we suggest that the epithelial cells of pre-ulcerative oral aphthous lesions may be infected by EBV through EBV-infected lymphocytes; also, the cytotoxic T lymphocyte-induced lysis of the EBV-infected epithelial cells, but not the virus-induced cytolysis, may be the main mechanism causing oral ulcer formation. Our data provide preliminary evidence for an association of EBV with pre-ulcerative oral aphthous lesions in RAU and BD patients.

Viruses in human oral cancers

The role of viruses in the etiology of human oral cancer is critically reviewed. Available evidences show a positive correlation for human oral cancer with human papilloma virus (HPV), herpes simplex virus (HSV) and human herpes virus type-6 (HHV-6), having strongest association with HPV. These viruses may act alone or in combination with other carcinogens in the genesis of head and neck malignancies.