Prevalence and stability of human serum antibodies to simian virus 40 VP1 virus-like particles

Colorectal Carcinoma Affected Patients Are Significantly Poor Responders Against the Oncogenic JC Polyomavirus

Background

Many investigations reported the association between human tumors and JCPyV, a polyomavirus with oncogenic potential. The association has been supported by studies that found JCPyV footprints in CRC and gliomas of different types. Indeed, JCPyV footprints including its nucleic acids and Tag oncoprotein have been revealed in CRC tissues.

Methods

Herein, sera from colorectal carcinoma (CRC) affected patients and healthy individuals (HS), employed as control, were analysed for immunoglobulin G (IgG) antibodies against specific JCPyV viral capsid protein 1 (VP1) antigens. The investigation was carried out employing an innovative immunological assay. Indeed, an indirect enzyme-linked immunosorbent assay (ELISA) with JCPyV VP1 mimotopes was used. JCPyV VP1 mimotopes consisted of synthetic peptides mimicking VP1 epitopes.

Results

Sera from CRC affected patients, evaluated using indirect ELISAs with synthetic mimotopes, showed a significant lower prevalence of IgG antibodies against JCPyV VP1 mimotopes (26%) compared to HS (51%), p<0.005. These data were confirmed by another method, the hemagglutination inhibition (HAI) assay. Altogether these results, i.e. the prevalence of serum IgG antibodies against JCPyV VP1 mimotopes from patients with CRC is approximately 50% lower than in HS, are of interest.

Discussion

Our data suggest that patients with CRC are significantly poor responders against JCPyV VP1 antigens. It is possible that CRC patients are affected by a specific immunological deregulation. This immunological dysfunction, revelled in CRC patients, may account for their predisposition to the colorectal carcinoma onset.

Low efficacy of recombinant SV40 in Ugt1a1-/- mice with severe inherited hyperbilirubinemia

In contrast to AAV, Simian Virus 40 (rSV40) not inducing neutralizing antibodies (NAbs) allowing re-treatment seems a promising vector for neonatal treatment of inherited liver disorders. Several studies have reported efficacy of rSV40 in animal models for inherited liver diseases. In all studies the ubiquitous endogenous early promoter controlled transgene expression establishing expression in all transduced tissues. Restricting this expression to the target tissues reduces the risk of immune response to the therapeutic gene. In this study a liver specific rSV40 vector was generated by inserting a hepatocyte specific promoter. This increased the specificity of the expression of hUGT1A1 in vitro. However, in vivo the efficacy of rSV40 appeared too low to demonstrate tissue specificity while increasing the vector dose was not possible because of toxicity. In contrast to earlier studies, neutralizing antibodies were induced. Overall, the lack of a platform to produce high titered and pure rSV40 particles and the induction of NAbs, renders it a poor candidate for in vivo gene therapy.

Specific antibodies reacting to JC polyomavirus capsid protein mimotopes in sera from multiple sclerosis and other neurological diseases-affected patients

Published data support the hypothesis that viruses could be trigger agents of multiple sclerosis onset. This link is based on evidence of early exposure to viral agents in patients affected by this neurologic disease. JC (JC polyomavirus [JCPyV]), BK (BKPyV), and simian virus 40 (SV40) neurotropic polyomavirus footprints have been detected in brain tissue specimens and samples from patients affected by different neurological diseases. In this investigation, serum samples from patients affected by multiple sclerosis and other inflammatory and noninflammatory neurologic diseases, as well as healthy subjects representing the control, were investigated for immunoglobulin G (IgG) antibodies against JCPyV. To this end, an immunologic approach was employed, which consists of employing indirect enzyme-linked immunosorbent assay testing with synthetic peptides mimicking viral capsid protein 1 antigens. A significantly lower prevalence of IgG antibodies against JCPyV VP1 epitopes, with a low titer, was detected in serum samples from patients with multiple sclerosis (MS) and other neurologic diseases than in healthy subjects. Our study indicates that the prevalence of JCPyV antibodies from patients with multiple sclerosis is 50% lower than in healthy subjects, suggesting specific immune impairments. These results indicate that patients affected by neurological diseases, including MS, respond poorly to JCPyV VP1 antigens, suggesting specific immunologic dysfunctions.

Association Between Simian Virus 40 and Human Tumors

Simian virus 40 (SV40) is a small DNA tumor virus of monkey origin. This polyomavirus was administered to human populations mainly through contaminated polio vaccines, which were produced in naturally infected SV40 monkey cells. Previous molecular biology and recent immunological assays have indicated that SV40 is spreading in human populations, independently from earlier SV40-contaminated vaccines. SV40 DNA sequences have been detected at a higher prevalence in specific human cancer specimens, such as the brain and bone tumors, malignant pleural mesotheliomas, and lymphoproliferative disorders, compared to the corresponding normal tissues/specimens. However, other investigations, which reported negative data, did not confirm an association between SV40 and human tumors. To circumvent the controversies, which have arisen because of these molecular biology studies, immunological researches with newly developed indirect ELISA tests were carried out in serum samples from patients affected by the same kind of tumors as mentioned above. These innovative indirect ELISAs employ synthetic peptides as mimotopes/specific SV40 antigens. SV40 mimotopes do not cross-react with the homologous human polyomaviruses, BKPyV, and JCPyV. Immunological data obtained from indirect ELISAs, using SV40 mimotopes, employed to analyze serum samples from oncological patients, have indicated that these sera had a higher prevalence of antibodies against SV40 compared to healthy subjects. The main data on (i) the biology and genetics of SV40; (ii) the epidemiology of SV40 in the general population, (iii) the mechanisms of SV40 transformation; (iv) the putative role of SV40 in the onset/progression of specific human tumors, and (v) its association with other human diseases are reported in this review.

SV40 seroprevalence in two Latin American countries involved in field trials of candidate oral poliovaccines

OBJECTIVES

This study sought to determine SV40 seroprevalence in residents of two Latin American countries, Colombia and Nicaragua, which were sites of prelicensure oral poliovaccine (OPV) trials.

METHODS

Archival sera were tested for SV40 neutralizing antibody using a virus-specific plaque-reduction assay. Samples included 517 sera from Colombia and 149 sera from Nicaragua.

RESULTS

Overall SV40 seroprevalence was 22.8% for Colombian subjects and 12.8% for Nicaraguans. Subgroups of Colombian subjects ranged in frequency of SV40 seropositivity from 10.0% to 38.6%. Birth cohorts both older and younger than the age cohort that contained potential OPV vaccinees from both countries had SV40 antibodies. Gender and ethnicity had no significant effects on SV40 seropositivity.

CONCLUSIONS

Inhabitants of both Colombia and Nicaragua had detectable SV40 neutralizing antibody, including those of ages presumably not recipients of potentially SV40-contaminated OPV. This observation provides support for the concept that transmission of SV40 human infections can occur. Frequency of SV40 antibody positivity was elevated over that reported for the US where there was limited use of contaminated OPV. This investigation indicates also that study results of SV40 infections in humans will reflect whether subject populations had probable exposures to contaminated poliovaccines and to environmental conditions favoring cycles of viral transmission.

High prevalence of serum IgG antibodies reacting to specific mimotopes of BK polyomavirus, a human oncogenic polyomavirus, in patients affected by uveal melanoma

The uveal melanoma (UM) is the most common human intraocular tumor. The BK polyomavirus (BKPyV) is a small DNA tumor virus whose footprints have been detected in different human cancers. BKPyV has oncogenic potential. Indeed, BKPyV, when inoculated into experimental animals, induces tumors of different histotypes, whereas in vitro, it transforms mammalian cells, including human cells from distinct tissues. In this investigation, the association between UM and BKPyV was studied employing indirect enzyme-linked immunosorbent assays (ELISAs) using synthetic peptides that mimic BKPyV viral capsid 1 (VP1) antigens. Indirect ELISAs were used to detect serum IgG antibodies against this polyomavirus with oncogenic potential in samples from patients with UM and controls, represented by healthy subjects (HS). It was found that serum samples from patients with UM had a higher prevalence of BKPyV antibodies, 85% (51/60), compared with that detected in HS1, 62% (54/87), and HS2, 57% (68/120). The different prevalence of BKPyV antibodies detected in UM versus the two control groups, HS1 and HS2, is statistically significant (p < 0.005). Our immunologic data suggest a significantly higher prevalence of antibodies against BKPyV VP1 epitopes in serum samples from patients with UM compared with HS. These results indicate an association between UM and BKPyV, suggesting that this small DNA tumor virus may be a cofactor in the UM onset or progression.

Specific Detection of Serum Antibodies against BKPyV, A Small DNA Tumour Virus, in Patients Affected by Choroidal Nevi

Ocular or choroidal nevus (CN) is a rare benign neoplastic lesion of the eye. The cause of CN onset/progression, which arises from the transformation of ocular melanocytes, is not known. A fraction of CN patients may develop uveal melanoma. The objective of this study was to investigate the association between CN and BK polyomavirus (BKPyV), a small DNA tumor virus. Serum IgG antibodies which react with BKPyV antigens were analyzed. An indirect E.L.I.S.A. using synthetic peptides that mimic BKPyV antigens was employed. Serum antibodies against BKPyV were also investigated by haemagglutination inhibition (HAI) assay. Sera were from CN patients and healthy subject (HS) were the control. A statistically significant higher prevalence of antibodies against BKPyV capsid protein antigens in serum samples from CN patients was detected, compared to HS, using two independent techniques, indirect E.L.I.S.A. and HAI (87.3% CN vs. 62.1% HS and 91.5% CN vs. 64.4% HS, respectively; p < 0.005). Our data suggest an association exists between CN and BKPyV indicating that this small DNA tumor virus could be responsible in the onset of this benign neoplastic lesion affecting eye melanocytes. This investigation reports the association between choroidal nevi and BKPyV infection for the first time. These data are innovative in this field and may represent a starting point for further investigation into the putative role of BKPyV in CN onset/progression.

Polyomaviruses

Over the last 10 years, the number of identified polyomaviruses has grown to more than 35 subtypes, including 13 in humans. The polyomaviruses have similar genetic makeup, including genes that encode viral capsid proteins VP1, 2, and 3 and large and small T region proteins. The T proteins play a role in viral replication and have been implicated in viral chromosomal integration and possible dysregulation of growth factor genes. In humans, the Merkel cell polyomavirus has been shown to be highly associated with integration and the development of Merkel cell cancers. The first two human polyomaviruses discovered, BKPyV and JCPyV, are the causative agents for transplant-related kidney disease, BK commonly and JC rarely. JC has also been strongly associated with the development of progressive multifocal leukoencephalopathy (PML), a rare but serious infection in untreated HIV-1-infected individuals and in other immunosuppressed patients including those treated with monoclonal antibody therapies for autoimmune diseases systemic lupus erythematosus, rheumatoid arthritis, or multiple sclerosis. The trichodysplasia spinulosa-associated polyomavirus (TSAPyV) may be the causative agent of the rare skin disease trichodysplasia spinulosa. The remaining nine polyomaviruses have not been strongly associated with clinical disease to date. Antiviral therapies for these infections are under development. Antibodies specific for each of the 13 human polyomaviruses have been identified in a high percentage of normal individuals, indicating a high rate of exposure to each of the polyomaviruses in the human population. PCR methods are now available for detection of these viruses in a variety of clinical samples.

Serum IgG Antibodies from Pregnant Women Reacting to Mimotopes of Simian Virus 40 Large T Antigen, the Viral Oncoprotein

Simian virus 40 (SV40) large T antigen (LT) coding sequences were revealed in different human samples, whereas SV40 antibodies (Ab) were detected in human sera of cancer patients and healthy individuals, although with a lower prevalence. Previous studies carried out by the neutralization assay gave a SV40 seroprevalence, in the general population, up to 8%, although higher rates, 12%, were detected in kidney transplant children, in a group of HIV-positive patients, and in healthy females. In this study, serum samples from pregnant women, together with those from non-pregnant women, were analyzed to check the prevalence of IgG Ab reacting to SV40 LT antigens. Serum samples were collected from pregnant and non-pregnant women, with the same mean age. Women were in the range of 15-48 years old. Samples were assayed by an indirect ELISA employing specific SV40 LT mimotopes as antigens, whereas functional analysis was performed by neutralization of the viral infectivity in cell cultures. As a control, sera were analyzed for Ab against BK polyomavirus (BKPyV), which is a human polyomavirus homologous to SV40. Statistical analyses employed chi-square with Yates' correction, and Student's t tests. Indirect ELISAs indicated that pregnant women tested SV40 LT-positive with a prevalence of 17% (23/134), whereas non-pregnant women had a prevalence of 20% (36/180) (P > 0.05). Ab against BKPyV were detected with a prevalence of 80% in pregnant women and with a prevalence of 78% in non-pregnant women. These data indicate that SV40 infects at a low prevalence pregnant women. We may speculate that SV40, or a close human polyomavirus still undetected, could be transmitted from mother to fetus.

Specific IgG Antibodies React to Mimotopes of BK Polyomavirus, a Small DNA Tumor Virus, in Healthy Adult Sera

BK polyomavirus (BKPyV) was isolated in 1971 from the urine of a kidney transplant patient. Soon after its identification, BKPyV was characterized as a kidney-tropic virus, which is responsible of a significant fraction of the rejection of transplant kidney in the host. Moreover, in experimental conditions, BKPyV is able to transform different types of animal and human cells and to induce tumors of different histotypes in experimental animals. BKPyV DNA sequences have been detected in healthy individuals and cancer patients using polymerase chain reaction/Shouthern blot hybridization methods. Serum antibodies against this polyomavirus were revealed using immunological techniques, which, however, cross-react with other polyomaviruses such as JC (JCPyV) and Simian Virus 40. These non-specific data indicate the need of novel immunological methods and new investigations to check in a specific manner, BKPyV spread in humans. To this aim, mimotopes from BKPyV structural capsid protein 1 (VP1) were employed for specific immunological reactions to IgG antibodies of human serum samples. An indirect enzyme-linked immunosorbent assay with synthetic peptides mimicking immunogenic epitopes of BKPyV VP1 was set up and employed to test sera of healthy adult subjects. Data from this innovative immunological assay indicate that serum antibodies against BKPyV VP1 mimotopes are detectable in healthy subjects ranging from 18 to 90 years old. The overall prevalence of serum samples that reacted to BKPyV VP1 mimotopes was 72%. The strong points from this investigation are the novelty of the immunological method, its simplicity of the approach, and the specificity of BKPyV antibody reaction to VP1 mimotopes.

Specific Antibodies Reacting with SV40 Large T Antigen Mimotopes in Serum Samples of Healthy Subjects

Simian Virus 40, experimentally assayed in vitro in different animal and human cells and in vivo in rodents, was classified as a small DNA tumor virus. In previous studies, many groups identified Simian Virus 40 sequences in healthy individuals and cancer patients using PCR techniques, whereas others failed to detect the viral sequences in human specimens. These conflicting results prompted us to develop a novel indirect ELISA with synthetic peptides, mimicking Simian Virus 40 capsid viral protein antigens, named mimotopes. This immunologic assay allowed us to investigate the presence of serum antibodies against Simian Virus 40 and to verify whether Simian Virus 40 is circulating in humans. In this investigation two mimotopes from Simian Virus 40 large T antigen, the viral replication protein and oncoprotein, were employed to analyze for specific reactions to human sera antibodies. This indirect ELISA with synthetic peptides from Simian Virus 40 large T antigen was used to assay a new collection of serum samples from healthy subjects. This novel assay revealed that serum antibodies against Simian Virus 40 large T antigen mimotopes are detectable, at low titer, in healthy subjects aged from 18–65 years old. The overall prevalence of reactivity with the two Simian Virus 40 large T antigen peptides was 20%. This new ELISA with two mimotopes of the early viral regions is able to detect in a specific manner Simian Virus 40 large T antigen-antibody responses.

Serum antibodies from epileptic patients react, at high prevalence, with simian virus 40 mimotopes

BACKGROUND AND PURPOSE

It has been demonstrated that inflammation may contribute to epileptogenesis and cause neuronal injury in epilepsy. In this study, the prevalence of antibodies to simian virus 40 (SV40), a kidney and neurotropic polyomavirus, was investigated in serum samples from 88 epileptic children/adolescents/young adults.

METHODS

Serum antibodies reacting to specific SV40 peptides were analysed by indirect enzyme-linked immunosorbent assay. Synthetic peptides corresponding to the epitopes of viral capsid proteins 1-3 were used as SV40 antigens.

RESULTS

A significantly higher prevalence of antibodies against SV40 was detected in sera from epileptic patients compared to controls (41% vs. 19%). Specifically, the highest significant difference was revealed in the cohort of patients from 1.1 to 10 years old (54% vs. 21%), with a peak in the sub-cohort of 3.1-6 years old (65% vs. 18%).

CONCLUSION

Our immunological data suggest a strong association between epilepsy and the SV40 infection.

Significant association between human osteosarcoma and simian virus 40

BACKGROUND

Simian virus 40 (SV40) has been considered to be an oncogenic viral agent in the development of osteosarcoma (OS), which to the authors' knowledge continues to be of unknown etiology.

METHODS

In the current study, serum samples from patients with OS were investigated with an indirect enzyme-linked immunoadsorbent assay (ELISA) to test for the presence of immunoglobulin G antibodies, which react with SV40 antigens. In ELISA, SV40 antigens were represented by 2 synthetic polypeptides that mimic epitopes of the viral capsid proteins 1 to 3. Additional sera from patients with breast cancer and undifferentiated nasopharyngeal carcinoma as well as healthy subjects were the controls.

RESULTS

Immunologic results suggested that antibodies that react with SV40 mimotopes were more prevalent (44%) in serum samples from patients with OS compared with healthy subjects (17%). The difference in prevalence between these cohorts was statistically significant (P<.001). It is interesting to note that in the patients with OS, significance indicated the difference between OS versus breast cancer (44% vs 15%; P<.001) and OS versus undifferentiated nasopharyngeal carcinoma (44% vs 25%; P<.05).

CONCLUSIONS

The data from the current study indicate an association between OS and SV40. These data could be transferred to clinical applications for innovative therapies to address SV40-positive OS.

Significant low prevalence of antibodies reacting with simian virus 40 mimotopes in serum samples from patients affected by inflammatory neurologic diseases, including multiple sclerosis

Many investigations were carried out on the association between viruses and multiple sclerosis (MS). Indeed, early studies reported the detections of neurotropic virus footprints in the CNS of patients with MS. In this study, sera from patients affected by MS, other inflammatory (OIND) and non-inflammatory neurologic diseases (NIND) were analyzed for antibodies against the polyomavirus, Simian Virus 40 (SV40). An indirect enzyme-linked immunosorbent assay (ELISA), with two synthetic peptides, which mimic SV40 antigens, was employed to detect specific antibodies in sera from patients affected by MS, OIND, NIND and healthy subjects (HS). Immunologic data indicate that in sera from MS patients antibodies against SV40 mimotopes are detectable with a low prevalence, 6%, whereas in HS of the same mean age, 40 yrs, the prevalence was 22%. The difference is statistically significant (P = 0.001). Significant is also the difference between MS vs. NIND patients (6% vs. 17%; P = 0.0254), whereas no significant difference was detected between MS vs OIND (6% vs 10%; P>0.05). The prevalence of SV40 antibodies in MS patients is 70% lower than that revealed in HS.

Neutralizing and IgG antibodies against simian virus 40 in healthy pregnant women in Italy

OBJECTIVE

Polyomavirus simian virus 40 (SV40) sequences have been detected in various human specimens and SV40 antibodies have been found in human sera from both healthy individuals and cancer patients. This study analyzed serum samples from healthy pregnant women as well as cord blood samples to determine the prevalence of SV40 antibodies in pregnancy.

METHODS

Serum samples were collected at the time of delivery from two groups of pregnant women as well as cord bloods from one group. The women were born between 1967 and 1993. Samples were assayed by two different serological methods, one group by neutralization of viral infectivity and the other by indirect ELISA employing specific SV40 mimotopes as antigens. Viral DNA assays by real-time polymerase chain reaction were carried out on blood samples.

RESULTS

Neutralization and ELISA tests indicated that the pregnant women were SV40 antibody-positive with overall prevalences of 10.6% (13/123) and 12.7% (14/110), respectively. SV40 neutralizing antibodies were detected in a low number of cord blood samples. Antibody titers were generally low. No viral DNA was detected in either maternal or cord bloods.

CONCLUSIONS

SV40-specific serum antibodies were detected in pregnant women at the time of delivery and in cord bloods. There was no evidence of transplacental transmission of SV40. These data indicate that SV40 is circulating at a low prevalence in the northern Italian population long after the use of contaminated vaccines.

Significant prevalence of antibodies reacting with simian virus 40 mimotopes in sera from patients affected by glioblastoma multiforme

BACKGROUND

Glioblastoma multiforme (GBM) is a rare tumor, which affects 1/100 000 individuals, but it represents 30% of central nervous system malignancies. GBM is a severe tumor responsible for 2% of all cancer-related deaths. Although characterized by genotypic and phenotypic heterogeneities, GBM invariably resists conventional chemo- and radiotherapies. Several chromosome alterations and gene mutations were detected in GBM. Simian virus 40 (SV40), a small DNA tumor virus, has been found in GBM specimens by some studies, while other investigations have not confirmed the association.

METHODS

An indirect enzyme-linked immunosorbent assay with 2 synthetic peptides mimicking SV40 antigens of viral capsid proteins 1-3 was employed to detect specific antibodies against SV40 in serum samples from GBM-affected patients, together with controls represented by patients affected by breast cancer and normal subjects of the same median age.

RESULTS

Our data indicate that in serum samples from GBM-affected patients (n = 44), the prevalence of antibodies against SV40 viral capsid protein antigens is statistically significantly higher (34%, P = .016 and P = .03) than in the control groups (15%), represented by healthy subjects (n = 101) and patients affected by breast cancer (n = 78), respectively.

CONCLUSION

Our data indicate that SV40, or a closely related yet undiscovered human polyomavirus, is associated with a subset of GBM and circulates in humans. Our study can be transferred to the clinical oncology application to discriminate different types of heterogeneous GBM, which in turn may address an innovative therapeutic approach to this fatal cancer.

Antibodies reacting with Simian virus 40 mimotopes in serum samples from patients with thalassaemia major

BACKGROUND

Simian virus 40 (SV40) is a small DNA tumour virus. Footprints of the virus have been detected in different humam lymphoproliferative disorders and in blood specimens of blood from healthy blood donors. This study was carried out to verify whether SV40 antibodies can be detected in serum samples from multiply transfused patients with thalassaemia major.

MATERIALS AND METHODS

An indirect enzyme-linked immunosorbent assay was employed, using SV40 specific synthetic peptides mimicking the antigens of the viral capsid proteins 1-2-3, to test for the presence of antibodies to SV40 in serum samples taken from patients affected by transfusion-dependent thalassaemia major (n=190) and healthy blood donors (n=251).

RESULTS

The prevalence of antibodies against SV40 was higher in patients than in controls (24% vs 17%). The prevalence increased and was significantly higher in the older age group of patients affected by thalassemia major than in controls (38% vs 20%, p<0.04).

DISCUSSION

The higher prevalence of serum antibodies against simian virus 40 in older, multiply transfused patients with thalassamia major than in controls suggests that this virus, or a closely related yet unknown human polyomavirus, could have been transmitted in the past by transfusion with whole blood. At the same time, our data indicate no significant differences in prevalence of SV40 antibodies in patients and controls of younger age thus suggesting that current transfusion methods with leucodepletion and filtered red cells are safe.

Serological evidence of an early seroconversion to Simian virus 40 in healthy children and adolescents

At present Simian virus 40 (SV40) infection in humans appears to be transmitted independently from early contaminated vaccines. In order to test the spread of SV40 infection in children, an immunologic assay employing specific SV40 synthetic peptides corresponding to its viral protein (VP) antigens was employed to estimate the seroprevalence of this polyomavirus in Italian infants and adolescents. Serum samples from 328 children and adolescents, up to 17 years, were investigated. Serum antibodies against SV40 VPs were detected by indirect enzyme-linked immunosorbent assays. The seroprevalence of this polyomavirus was calculated after stratifying the subjects by age. Anti-viral capsid protein 1-2-3 SV40 IgG antibodies were detected in 16% of the study participants. The prevalence of antibodies against SV40 VPs tended to increase with age in children, up to 10 year old (21%). Then, in the cohort of individuals aged 11–17 years, the prevalence decreased (16%). A higher prevalence rate (23%) of SV40 VP antibodies was detected in the cohorts of 1–3 year and 7–10 year old children, than in children and adolescents of the other age groups. This age corresponds to children starting nursery and primary school, respectively, in Italy. IgM antibodies against SV40 VP mimotopes were detected in 6–8 month old children suggesting that SV40 seroconversion can occur early in life. SV40 VP antibodies are present at low prevalence in Italian children (16%), suggesting that SV40 infection, although acquired early in life, probably through different routes, is not widespread. The low SV40 seroprevalence suggests that SV40 is less transmissible than other common polyomaviruses, such as BKV and JCV. Alternatively, our immunologic data could be due to another, as yet undiscovered, human polyomavirus closely related to SV40.

High prevalence of serum antibodies reacting with simian virus 40 capsid protein mimotopes in patients affected by malignant pleural mesothelioma

Human malignant pleural mesothelioma (MPM) is considered a rare tumor, but recent estimations indicate that one-quarter million people will die of this neoplasm in Europe in the next three decades. The mineral asbestos is considered the main causative agent of this neoplasm. MPM is largely unresponsive to conventional chemotherapy/radiotherapy. In addition to asbestos exposure, genetic predisposition to asbestos carcinogenesis and to simian virus (SV)40 infection has also been suggested. SV40 is a DNA tumor virus found in some studies to be associated at high prevalence with MPM. SV40 sequences have also been detected, although at a lower prevalence than in MPM, in blood specimens from healthy donors. However, some studies have failed to reveal SV40 footprints in MPM and its association with this neoplasm. These conflicting results indicate the need for further investigations with new approaches. We report on the presence of antibodies in serum samples from patients affected by MPM that specifically react with two different SV40 mimotopes. The two SV40 peptides used in indirect ELISAs correspond to viral capsid proteins. ELISA with the two SV40 mimotopes gave overlapping results. Our data indicate that in serum samples from MPM-affected patients (n = 97), the prevalence of antibodies against SV40 viral capsid protein antigens is significantly higher (26%, P = 0.043) than in the control group (15%) represented by healthy subjects (n = 168) with the same median age (66 y) and sex. Our results suggest that SV40 is associated with a subset of MPM and circulates in humans.

Serologic evidence of frequent human infection with WU and KI polyomaviruses

WU polyomavirus (WUPyV) and KI polyomavirus (KIPyV) are novel human polyomaviruses. They were originally identified in human respiratory secretions, but the extent of human infection caused by these viruses has not been described to date. To determine the seroepidemiology of WUPyV and KIpyIV, we used an ELISA to screen serum samples from 419 patients at the St. Louis Children's Hospital and Barnes-Jewish Hospital during 2007-2008. The age-stratified deidentified samples were examined for antibodies to the major capsid proteins of WUPyV and KIPyV. Seropositivity for each virus was similar; antibody levels were high in the youngest age group (<6 months), decreased to a nadir in the next age group (6 to <12 months), and then steadily increased with subsequent age groups, eventually reaching a plateau of approximate, equals 80% for WUPyV and approximate, equals 70% for KIPyV. These results demonstrate that both KIPyV and WUPyV cause widespread infection in the human population.

Simian virus 40 in humans

Simian virus 40 (SV40) is a monkey virus that was administered to human populations by contaminated vaccines which were produced in SV40 naturally infected monkey cells. Recent molecular biology and epidemiological studies suggest that SV40 may be contagiously transmitted in humans by horizontal infection, independently from the earlier administration of SV40-contaminated vaccines.SV40 footprints in humans have been found associated at high prevalence with specific tumor types such as brain and bone tumors, mesotheliomas and lymphomas and with kidney diseases, and at lower prevalence in blood samples from healthy donors. Contrasting reports appeared in the literature on the circulation of SV40 in humans by contagious transmission and its association, as a possible etiologic cofactor, with specific human tumors. As a consequence of the conflicting results, a considerable debate has developed in the scientific community. In the present review we consider the main results obtained by different groups investigating SV40 sequences in human tumors and in blood specimens, the putative role of SV40 in the onset/progression of specific human tumors, and comment on the hypotheses arising from these data.

Identification of a novel polyomavirus from patients with acute respiratory tract infections

We report the identification of a novel polyomavirus present in respiratory secretions from human patients with symptoms of acute respiratory tract infection. The virus was initially detected in a nasopharyngeal aspirate from a 3-year-old child from Australia diagnosed with pneumonia. A random library was generated from nucleic acids extracted from the nasopharyngeal aspirate and analyzed by high throughput DNA sequencing. Multiple DNA fragments were cloned that possessed limited homology to known polyomaviruses. We subsequently sequenced the entire virus genome of 5,229 bp, henceforth referred to as WU virus, and found it to have genomic features characteristic of the family Polyomaviridae. The genome was predicted to encode small T antigen, large T antigen, and three capsid proteins: VP1, VP2, and VP3. Phylogenetic analysis clearly revealed that the WU virus was divergent from all known polyomaviruses. Screening of 2,135 patients with acute respiratory tract infections in Brisbane, Queensland, Australia, and St. Louis, Missouri, United States, using WU virus–specific PCR primers resulted in the detection of 43 additional specimens that contained WU virus. The presence of multiple instances of the virus in two continents suggests that this virus is geographically widespread in the human population and raises the possibility that the WU virus may be a human pathogen.

We have identified a novel virus, referred to as WU virus, in the family Polyomaviridae by screening of human respiratory secretions. Two human polyomaviruses, BK and JC, were identified in 1971 and infect the majority of humans around the world. These two viruses are closely related to each other and are both are pathogenic in immunocompromised individuals. Earlier this year, a third polyomavirus, KI, was described in human clinical specimens, although its pathogenicity and prevalence in humans has not yet been established. The discovery of WU virus brings the number of polyomaviruses detected in humans to four. WU differs from BK and JC significantly in its genome sequence and in its relative tissue tropism, suggesting that it is likely to have unique biological properties. This discovery raises many questions for further investigation, such as, Is WU virus a human pathogen? If so, what kind of disease does it cause? Where in the body does WU virus reside? At what age does infection typically occur? Perhaps most importantly, there are likely to be many more as of yet unidentified viruses infecting the human body.

Molecular and clinical perspectives of polyomaviruses: emerging evidence of importance in non-kidney transplant populations

JC virus (JCV), BK virus (BKV) and simian virus 40 (SV40) are deoxyribonucleic acid (DNA) viruses, members of the family Polyomaviridae. These viruses establish persistent infections, and reactivate from latency in their host under immunosuppression. During the last few years there has been recognition of the morbidity related to polyomaviruses, particularly BKV in kidney transplant recipients. More importantly, recent studies indicate the potential implication of JCV, BKV, and SV40 in renal dysfunction among nonrenal organ transplant patients. Polyomaviruses are tumor-inducing viruses and animal models have provided evidence of the oncogenicity of these pathogens. Although data are not conclusive, molecular studies suggest an association of BKV and SV40 with malignancies among solid organ transplant patients. As new and potent immunosuppressive agents are introduced into clinical practice, it is believed that the incidence of polyomavirus-related diseases in organ transplantation might increase. This review evaluates the biologic and epidemiologic features of these 3 viruses, the data regarding their infections in nonkidney organ transplant patients and describes future directions in the management and research of these opportunistic pathogens.

Is there a role for SV40 in human cancer?

The question of whether Simian Virus 40 (SV40) can cause human tumors has been one of the most highly controversial topics in cancer research during the last 50 years. The longstanding debate began with the discovery of SV40 as a contaminant in poliovirus vaccine stocks that were used to inoculate approximately 100 million children and adults in the United States between 1955 and 1963, and countless more throughout the world. Concerns regarding the potential health risk of SV40 exposure were reinforced by studies demonstrating SV40's potential to transform human cells and promote tumor growth in animal models. Many studies have attempted to assess the relationship between the potential exposure of humans to SV40 and cancer incidence. Reports of the detection of SV40 DNA in a variety of cancers have raised serious concerns as to whether the inadvertent inoculation with SV40 has led to the development of cancer in humans. However, inconsistent reports linking SV40 with various tumor types has led to conflicting views regarding the potential of SV40 as a human cancer virus. Several recent studies suggest that older detection methodologies were flawed, and the limitations of these methods could account for most, if not all, of the positive correlations of SV40 in human tumors to date. Although many people may have been exposed to SV40 by polio vaccination, there is inadequate evidence to support widespread SV40 infection in the population, increased tumor incidence in those individuals who received contaminated vaccine, or a direct role for SV40 in human cancer.

Quantitative real-time PCR assay for detection of human polyomavirus infection

The human polyomaviruses BK (BKV) and JC (JCV) affect immunosuppressed patients and are associated with urogenital tract (BKV) and CNS disorders (JCV) and in humans, the pathogenic role of the rhesus monkey virus, Simian virus 40 (SV40), is uncertain. These three viruses have somewhat overlapping tissue pathogenicity and detection of all three polyomaviruses is desirable. A broadly targeted, simple, single tube real-time degenerated quantitative PCR (QPCR) technique for detection of JCV, BKV and SV40 DNA was developed. To avoid false positive results, due to contamination with commonly used SV40 T-antigen plasmids, a conserved region of the VP2 gene was targeted. Down to 1-10 copies of target DNA per PCR reaction were detected. The QPCR was compared with a nested PCR on 41 clinical samples (urine, serum and plasma): 24 (58.5%) tested positive by nested PCR, whereas 31 (75.6%) were positive with QPCR. One CSF sample, from a patient with progressive multifocal leukoencephalopathy, was negative with the nested PCR but determined as positive by QPCR. Sera from 24 blood donors were negative with QPCR. The QPCR described had a high sensitivity. Its specificity was confirmed sequencing. The QPCR is simple to perform and is valuable for diagnosis of polyomavirus infection.