Selective impairment of lymphocyte reactivity to varicella-zoster virus antigen among untreated patients with lymphoma.

Herpes zoster is a frequent complication of lymphoreticular malignancy. In this study two assays of in vitro cellular immune response to varicella-zoster virus (VZV) antigen, lymphocyte transformation and interferon production, were performed in normal subjects with recent and remote VZV infection. The responses of patients with lymphoma were measured before treatment and during long-term remission and then compared with those of normal subjects. Despite levels of antibody to VZV that were equivalent to those in normal subjects, 44% of the untreated lymphoma patients showed a lower transformation response to VZV antigen than the normal patients. Production of interferon in response to VZV antigen was absent in 32% of the untreated patients. In contrast, lymphocyte responses in untreated patients to herpes simplex virus antigen were within the range observed in a normal population. Interferon production by lymphocytes in response to cytomegalovirus antigen was also lower among untreated lymphoma patients than among normal patients, but lymphocyte transformation was not. Twenty-two percent of lymphoma patients in long-term remission continued to have diminished cellular immune responses to VZV antigen. Observations in these patient populations and in normal subjects with acute herpes zoster suggest that deficiencies in in vitro lymphocyte responses may correlate with increased susceptibility to clinical infection with VZV.     

Role of endogenous retroviruses in autoimmune diseases

Endogenous retroviruses (ERVs) correspond to the integrated proviral form of infectious retroviruses that are trapped within the genome by mutations. Endogenous retroviruses represent a key molecular link between the host genome and infectious viral particles. Proteins encoded by ERVs are recognized by antiviral immune responses and become targets of autoreactivity. Activation of ERVs, such as human ERV-K or a human T-cell lymphotropic virus-related endogenous sequence, may also mediate pathogenicity of Epstein-Barr virus. Endogenous retrovirus peptides can directly regulate immune responses. Thus, molecular mimicry and immunomodulation by ERVs may account for self-reactivity and abnormal T- and B-cell functions in autoimmune disorders.     

Interspecies radioimmunoassay for the major structural proteins of primate type-D retroviruses.

A competition radioimmunoassay has been developed in which type-D retroviruses from three primate species compete. The assay utilizes the major structural protein (36,000 daltons) of the endogenous squirrel monkey retrovirus and antisera directed against the major structural protein (27,000 daltons) of the Mason-Pfizer monkey virus isolated from rhesus monkeys. Purified preparations of both viruses grown in heterologous cells, as well as extracts of heterologous cells infected with squirrel monkey retrovirus or Mason-Pfizer monkey virus, compete completely in the assay. Addition of an endogenous virus of the langur monkey also results in complete blocking. No blocking in the assay is observed with type-C baboon viruses, woolly monkey virus, and gibbon virus. Various other type-C and type-B viruses also showed no reactivity. An interspecies assay has thus been developed that recognizes the type-D retroviruses from both Old World monkey (rhesus and langur) and New World monkey (squirrel) species.     

In Vitro Stimulation of Sensitized Lymphocytes by Herpes Simplex Virus and Vaccinia Virus

Splenic lymphocytes from rabbits immunized with herpes simplex virus (HSV) were incubated in vitro with ultraviolet light-inactivated HSV, and the degree of lymphocyte transformation was determined by measurement of the incorporation of [(3)H]thymidine into acid-insoluble material. Lymphocytes from immunized rabbits were stimulated as much as 30-fold, whereas lymphocytes from control rabbits were unaffected. Lymphocyte sensitization occurred within 3 days after immunization; sensitized lymphocytes could still be detected 120 days after immunization. The antigenicity of the ultraviolet light-inactivated crude virus pool was found to reside primarily in the virion. Infectious virus, in comparison with inactivated virus, produced less lymphocyte stimulation. Studies on the interaction of the humoral and cellular immune responses showed that incubation of anti-HSV antibody with HSV antigens did not reduce the capacity of the viral antigens to stimulate sensitized lymphocytes. Other experiments revealed that lymphocytes from both the spleen and peripheral blood of animals immunized with vaccinia virus could be stimulated by vaccinia, but not by HSV. Conversely, lymphocytes from animals immunized with HSV could not be stimulated by vaccinia. The transformation of sensitized lymphocytes by viral antigens appears to be a simple, highly specific, and quantitative in vitro technique for the study of the cellular immune response to viral infections.     

Humoral and cellular immune responses to an envelope-associated antigen of herpes simplex virus.

The humoral and cellular immune responses of rabbits and guinea pigs to the envelope-associated antigen of herpes simplex virus type I were studied. Neutralizing antibody (at high titer) and lymphocytes reactive to herpes simplex virus were detected in both guinea pigs and rabbits after immunization with the antigen. In a standard assay of cellular immunity to herpes simplex virus, the antigen stimulated blast transformation of herpes simplex virus-reactive splenic lymphocytes in vitro. Furthermore, immunization of rabbits with the envelope-associated antigen protected the animals from a lethal dose of live herpes simplex virus. Thus an antigen of herpes simplex virus can be prepared which contains neither infectious nor noninfectious viral particles and which stimulates immunity to the virus in laboratory animals.     

Recombinant HIV structural proteins detect specific cellular immunity in vitro in infected individuals

Peripheral blood mononuclear cell (PBMC) cultures were established from patients with antibody to human immunodeficiency virus (HIV). Asymptomatically infected patients [5 of 19] had significant lymphocyte transformation responses induced in culture by a purified, recombinant envelope glycoprotein (rgp120) from the virus. A few (4 of 55) subjects with AIDS related complex (ARC) and no subjects with AIDS (0 of 29) had proliferative responses to this protein. These responses correlated directly with circulating levels of helper/inducer lymphocytes (p less than .01) and indirectly with virus antigen in blood (p = .04). Also, these responses occurred significantly less frequently than responses to herpes simplex virus (HSV) or cytomegalovirus (CMV) antigens in seropositive ARC patients (p less than .005). These data indicate that the frequency of immune cellular responses to rgp120 decline in association with disease progression, and become undetectable in frank AIDS. As rgp120-induced proliferation was not observed in cells from 15 seronegative immunocompetent subjects, this response appears immune specific. Immune T-lymphocyte-mediated responses to this HIV envelope glycoprotein may allow the prediction of future clinical events and may be useful in monitoring immune-enhancing therapy in patients with ARC and AIDS.     

Viruses and lymphocytes in rheumatoid arthritis. II. Examination of lymphocytes and sera from patients with rheumatoid arthritis for evidence of retrovirus infection.

The possible involvement of retroviruses in the aetiology of rheumatoid arthritis (RA) was investigated. Retrovirus antigens were not expressed on rheumatoid synovial and peripheral blood lymphocytes as judged by membrane immunofluorescence, radioimmunoassay, and complement-mediated cytotoxicity. The specific antiretroviral (anti-RD-144 and anti-SSAV) sera used in this study were produced in rabbits immunised with viral antigens grown in a homologous system (rabbit cells and medium supplemented with normal rabbit serum), avoiding non-specific immunofluorescence previously detected with donated antiretroviral sera. Immune complexes lodged in the rheumatoid synovial membranes did not contain, and other cells within the membranes did not express, retroviral antigens. Antibodies cross-reacting with primate retrovirus antigens were sought in sera from patients with 'autoimmune' diseases by means of solid phase radioimmunoassay. There were no retrovirus antibodies in the 3 groups of patients studied, that is, those with rheumatoid arthritis, systemic lupus erythematosus, and with non-RA conditions. Absorption of rheumatoid factor did not alter this conclusion. These results give little support to the hypothesis that activation of endogenous human retroviruses or an infection with horizontally transmitted retroviruses is associated with the rheumatoid process.     

Association between nuclear antigens and endogenous retrovirus in the generation of autoantibody responses in murine lupus

OBJECTIVE: (NZB x NZW)F(1) (NZB/NZW) mice and other strains of mice with experimental lupus frequently produce autoantibodies to both chromatin constituents and murine leukemia virus envelope gp70. These autoantibody responses are involved in the glomerulonephritis that develops in these mice. This study was undertaken to explore possible connections between these 2 antigen systems. METHODS: We used monoclonal antibodies (mAb) derived from unmanipulated NZB/NZW mice to investigate the specificity of anti-gp70 and antichromatin autoantibodies for chromatin constituents, recombinant gp70, NZB retroviruses, and retrovirally infected cells. NZB mice were also immunized with retroviral particles and followed up for study of autoantibody responses. RESULTS: Spontaneous autoantibody production in NZB/NZW mice reflects high-level autoimmune responses to nuclear antigens and gp70 that do not cross-react with the other antigen. However, both types of autoantibodies have the capability to bind to the endogenous xenotropic virions NZB-X1 or NZB-X2. The mAbs to recombinant gp70 cross-reacted only with the NZB-X2 virus, whereas the antichromatin mAb frequently bound to both retroviruses. The binding of antichromatin autoantibodies was mediated by nuclear material complexed to the retrovirus, and studies showed that this material can be acquired through the budding process. Immunization with NZB-X1 or NZB-X2 virions induced strong responses to gp70 and was much more effective than chromatin at inducing autoantibody responses to chromatin and double-stranded DNA in NZB mice. CONCLUSION: These studies suggest that retroviral virions may harbor nuclear antigens and may link together the autoimmune responses to the disparate antigens, chromatin and gp70.     

HERV-K113 is not associated with multiple sclerosis in a large family-based study

Numerous studies have invoked a role for retroviruses in multiple sclerosis (MS). Most have identified human endogenous retroviruses (HERVs) as possible etiological agents. The majority of HERVs originate from ancestral infection and then become progressively disabled by mutations over millions of years of primate evolution. Their presence in 100% of healthy humans, together with the paucity of functional retroviral genes, argues strongly against a causal role in disease. Recently, a new class of insertionally polymorphic HERVs has been described that is present in only a proportion of the population. One of them, HERV-K113, is notable for open reading frames for all of its genes and is found in 0-28% of humans with widespread geographic and racial variation. Thus HERV-K113 is a credible candidate for causing disease in a manner comparable to infectious retroviruses. Genomic DNA samples from 951 patients with MS were tested for the presence of the HERV-K113 allele by PCR, with their unaffected parents (n = 1902) acting as controls. HERV-K113 provirus was found in 70 out of 951 (7.36%) patients with MS and was not significantly increased compared to the combined parent group (6.52%). The results do not support an association between this endogenous retrovirus and MS. This study also emphasizes the need for large cohorts with controls for race and geographic location when examining possible links between polymorphic HERVs and disease.     

The RD114/simian type D retrovirus receptor is a neutral amino acid transporter

The RD114/simian type D retroviruses, which include the feline endogenous retrovirus RD114, all strains of simian immunosuppressive type D retroviruses, the avian reticuloendotheliosis group including spleen necrosis virus, and baboon endogenous virus, use a common cell-surface receptor for cell entry. We have used a retroviral cDNA library approach, involving transfer and expression of cDNAs from highly infectable HeLa cells to nonpermissive NIH 3T3 mouse cells, to clone and identify this receptor. The cloned cDNA, denoted RDR, is an allele of the previously cloned neutral amino acid transporter ATB0 (SLC1A5). Both RDR and ATB0 serve as retrovirus receptors and both show specific transport of neutral amino acids. We have localized the receptor by radiation hybrid mapping to a region of about 500-kb pairs on the long arm of human chromosome 19 at q13.3. Infection of cells with RD114/type D retroviruses results in impaired amino acid transport, suggesting a mechanism for virus toxicity and immunosuppression. The identification and functional characterization of this retrovirus receptor provide insight into the retrovirus life cycle and pathogenesis and will be an important tool for optimization of gene therapy using vectors derived from RD114/type D retroviruses.     

A new endogenous primate type C virus isolated from the Old World monkey Colobus polykomos.

A new, genetically transmitted retrovirus has been isolated from the Old World monkey Colobus polykomos. This virus, designated CPC-1, is readily transmitted to both feline and human cells in culture. Nucleic acid hybridization studies reveal that there are 50-70 copies of the CPC-1 genome in colobus cellular DNA. Related virogene sequences can be detected in the DNA of all other Old World monkeys, as well as in the DNA of at least one ape species, the chimpanzee, indicating that this virus has been genetically transmitted in primates for 30-40 million years. CPC-1 is partially related to the type C virus previously isolated from stumptail monkeys (MAC-1). These two viruses have nucleic acid sequence homology, antigenic crossreactivity in their major viral structural protein, and a very similar host range in vitro. CPC-1 and MAC-1 therefore belong to the same class of genetically transmitted primate type C viruses and, as such, represent the first example in primates of analogous endogenous retroviruses isolated from two distantly related species.     

Unique angiopathy after herpes virus infection

OBJECTIVE: We describe 3 Japanese patients with peculiar renal and/or coronary arterial stenosis and/or multiple aneurysms after herpes virus infection, following ischemic symptoms. We investigated for viral antigens and viral DNA in situ, and for shared abnormalities of cellular immunity. METHODS: Panarteriography was performed diagnostically, and patients were grouped as follows: 3 patients with peculiar renal and/or coronary artery narrowing and/or multiple aneurysms; another 3 patients with renal fibromuscular dysplasia; and other young adults with effort angina, with no history of herpes virus infection, as controls. Detection of viral antigens and viral DNA in situ was done by polymerase chain reaction method and immunohistochemical staining. Cellular immunity was examined at the time of ischemic symptoms. RESULTS: Viral antigens and DNA were scarcely detected, except in herpes zoster skin lesion with leukocytoclastic vasculitis. However, shared abnormalities of cellular immunity, such as a decreased CD4+ T cell number and reduced natural killer cell activity, were more prominent in the 3 patients with unique vasculopathy after herpes virus infection. CONCLUSION: Unique vasculopathy following herpes virus infection might be a more severe and extensive disease. We speculate that sustained viral infection, repetitive activation of virus related antigens, and suppressed immune state might contribute to formation of peculiar vascular alterations.     

Retroviral gene transfer into primary hepatocytes: implications for genetic therapy of liver-specific functions.

The liver is an important target for potential gene therapy because of the critical role it plays in intermediary metabolism and synthesis of serum proteins. We report the use of retroviral vectors for transfer of recombinant genes into primary mouse hepatocytes. Hepatocytes were grown in a defined serum-free medium and expressed liver-specific functions for up to 14 days. Hepatocytes were transformed to Genticin (G418) resistance by infection with recombinant retroviruses carrying the Tn5 neomycin-resistance gene. The G418-resistant cells exhibited characteristic hepatocyte morphology and continued to express liver-specific gene function. A retrovirus that expresses neomycin resistance driven by a herpes simplex thymidine kinase promoter produced the most efficient transformation compared with viruses using the retroviral long terminal repeat promoter or the simian virus 40 early-region promoter. These experiments indicate that primary hepatocytes can be successfully cultured and transformed with recombinant genes using retroviral vectors. These results provide a model for future somatic gene replacement therapy in which functional genes can be introduced into hepatocytes by viral-mediated gene transfer.     

Specific cell-mediated immunity and infections with herpes viruses in cardiac transplant recipients

Immune responses and infections with herpes viruses were studied prospectively in 36 cardiac transplant reclpients. Specific lymphocyte transformation and interferon production in response to viral antigens, viral culture results, antibody levels, responses to phytohemagglutinin, and T-cell numbers were determined. Responses to phytohemagglutinin and T-cell numbers were depressed for six to 12 weeks. Cytomegalovirus infection occurred in 100 percent of seropositive patients and in 62 percent of seronegative patients. Primary infection was more frequently symptomatic. Heart implantation from a seropositive patient was significantly correlated with subsequent infection in seronegative patients. Depression of transformation in response to cytomegalovirus correlated with prolonged shedding. Herpes simplex infection occurred in 95 percent of seropositive patients but decreased after 12 weeks. Asymptomatic shedding was rare, and primary infection did not occur. Return of transformation in response to herpes simplex was associated with decreased Infection. Herpes zoster occurred in 22 percent during the first year, and transformation responses to varicella-zoster returned thereafter. Depression of interferon production in response to viruses did not correlate with infection as well as did lymphocyte transformation.     

Viral infections of the choroid and retina.

DNA (herpes viruses) and RNA (rubella, rubeola) group viruses are recognized causes of viral retinitis. Severe damage is often the result, not only because the viruses have a cytologic effect but also because the antigens may cause immune complex deposition that results in vasculitis. Most of the viral retinitides are associated with systemic disease; immune-compromised individuals are more susceptible than healthy individuals. A distinct clinical entity, acute retinal necrosis, affects the eye only in healthy individuals and is associated with the herpes family of viruses.     

Lymphocyte response to virus antigens in systemic lupus erythematosus

The cell-mediated immune response of lymphocytes to rubella, measles, parainfluenza types 1, 2, and 3, varicella-zoster, and herpes virus type 1 virus antigens was evaluated in 15 SLE patients and 15 matched controls by incorporating ³H-thymidine in whole blood cultures as a measure of blastic transformation. SLE patients were less responsive than normal individuals to six of eight virus antigens tested. Culture of washed SLE cells in AB plasma did not reverse the hyporesponsiveness. The results indicated that a functional impairment of the circulating lymphocytes appeared to be responsible for the in vitro hyporesponsiveness of SLE patients to virus antigens.     

Retroviruses and chronic arthritis. Possible significance of some recent observations

Retroviruses have been proposed as etiologic agents for the development of chronic arthritis in humans. The arthritis seen in goats infected by caprine arthritis encephalitis virus and the spontaneous arthritis of inbred MRL/l mice illustrate how retroviruses may cause the development of a disorder closely resembling human rheumatoid arthritis. Several investigators have searched for evidence of retrovirus infection in patients with chronic arthritis, but in most cases the results have been disappointing. However, in 1983, Iversen isolated a virus-like particle from a patient with psoriasis. The particle had a buoyant density in sucrose and a protein composition that closely resembled murine and primate retroviruses. Particle proteins participate in immune complex formation in psoriasis, in psoriatic arthritis, and in ankylosing spondylitis. Particle proteins are also present in deposits in psoriatic lesions and in affected synovial tissue resembling immune complex deposits. The possible role for retrovirus-like antigens in the inflammatory process in psoriasis and seronegative arthritis is discussed.