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.

Serologic investigation of undifferentiated nasopharyngeal carcinoma and simian virus 40 infection.

BACKGROUND: The association between undifferentiated nasopharyngeal carcinoma (NPC) and Epstein-Barr virus (EBV) is well established. Nevertheless, available evidence suggests that other cofactors are required for the development of undifferentiated NPC. Several investigations reported simian virus 40 (SV40) footprints in human tumors of different histotypes. METHODS: Serum samples from patients with undifferentiated NPC (n = 64) and healthy subjects (n = 130) were analyzed by an indirect enzyme-linked immunosorbent assay (ELISA) with SV40 synthetic peptides to detect antibodies against viral peptide (VP) capsid proteins VP1, 2, and 3. RESULTS: Immunologic data indicate that in sera from patients with undifferentiated NPC, the prevalence of SV40 antibodies was 25%, whereas in controls it was 16%. This difference is not statistically significant (p > .05). CONCLUSION: A similar prevalence of SV40 antibodies was detected in undifferentiated NPC and healthy subjects. Our serologic data suggest no association between undifferentiated NPC and SV40 infection. This investigation may stimulate further studies aimed at determining the possible contribution of other risk factors in the pathogenesis of undifferentiated NPC.

Immunologic evidence of a strong association between non-Hodgkin lymphoma and simian virus 40.

BACKGROUND: Non-Hodgkin lymphoma (NHL), the most common cancer of the lymphatic system, is of unknown etiology. The identification of etiologic factors in the onset of NHL is a key event that could facilitate the prevention and cure of this malignancy. Simian virus 40 (SV40) has been considered an oncogenic agent in the onset/progression of NHL. METHODS: In this study, an indirect enzyme-linked immunosorbent assay with 2 synthetic peptides that mimic SV40 antigens of viral capsid proteins 1 to 3 was employed to detect specific antibodies against SV40. Serum samples were taken from 2 distinct cohorts of NHL-affected patients (NHL1 [n = 89] and NHL2 [n = 61]) along with controls represented by oncologic patients affected by breast cancer (BC; n = 78) and undifferentiated nasopharyngeal carcinoma (UNPC; n = 64) and 3 different cohorts of healthy subjects (HSs; HS1 [n = 130], HS2 [n = 83], and HS3 [n = 87]). RESULTS: Immunologic data indicated that in serum samples from NHL patients, antibodies against SV40 mimotopes were detectable with a prevalence of 40% in NHL1 patients and with a prevalence of 43% in NHL2 patients. In HSs of the same median age as NHL patients, the prevalence was 16% for the HS1 group (57 years) and 14% for the HS2 group (65 years). The difference was statistically significant (P < .0001 and P < .001). Interestingly, the difference between NHL1/NHL2 patients and BC patients (40%/43% vs 15%, P < .001) and between NHL1/NHL2 patients and UNPC patients (40%/43% vs 25%, P < .05) was significant. CONCLUSIONS: Our data indicate a strong association between NHL and SV40 and thus a need for innovative therapeutic approaches for this hematologic malignancy.

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 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.

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.

Specific antibodies reacting with simian virus 40 capsid protein mimotopes in serum samples from healthy blood donors.

Simian virus 40 (SV40), a small DNA tumor virus, was inadvertently administered to human populations with the use of contaminated vaccines. SV40 sequences have mainly been detected in healthy individuals and cancer patients using polymerase chain reaction techniques. However, some studies have failed to reveal the presence of SV40 in human specimens. These conflicting results indicate the need for new research to verify whether SV40 is circulating in humans. Mimotopes from SV40 structural peptides were tested to investigate for specific reactions to human sera antibodies. An indirect enzyme-linked immunosorbent assay with synthetic peptides from SV40 viral capsid proteins 1-2-3 (VPs 1-2-3) was set up and employed to test 855 serum samples from healthy blood donors. Data from immunologic assays indicate that serum antibodies against SV40 VP mimotopes are detectable, although with a low titer, in blood donors 18 to 65 years old. The overall prevalence of serum samples that reacted with the 2 SV40 VP peptides was 18%. The strong points for this novel method include the simplicity of its approach and the potential to discriminate between SV40-specific antibody responses and to draw correlations between responses to the 2 independent SV40 peptides. These data suggest that SV40, or a yet undetected closely related polyomavirus, is circulating in human populations, but with lower prevalence than that of the ubiquitous BK and JC human polyomaviruses.

Cell discohesion and multifocality of carcinoma in situ of the bladder: new insight from the adhesion molecule profile (e-cadherin, Ep-CAM, and MUC1).

Urothelial cell carcinoma in situ (CIS) of the bladder is a superficially diffusive and highly discohesive disease. The authors analyzed the expression of some adhesion molecules (e-cadherin and Ep-CAM) and MUC1 in 32 unifocal and multifocal bladder urothelial cell CIS in an attempt to clarify this discohesion. E-cadherin was strongly expressed, in more than 75% of the cases. The presence of methylation of the CDH1 e-cadherin promoter gene was also investigated, but methylation was found in only one case. Ep-CAM was present in all the cases with a heterogeneous staining pattern. Similarly, MUC1/episialin was variously present in 94% of the cases without a polarized staining pattern and was expressed more strongly in cases with multifocal disease. Because loss of MUC1 polarization leads to interference with cell-cell adhesion mechanisms mediated by cadherins, these findings help explain why bladder urothelial cell CIS often shows a discohesive morphology and multifocality despite a strongly expressed adhesion molecule profile. Finally, Ep-CAM expression might provide some support for future target therapy trials.