"The Herpesvirus hypothesis"--are Koch's postulates satisfied?

Etiology of cervical cancer: current concepts

The data on the etiological factors presented here may enable us to suggest a synergism between the various factors associated with the pathogenesis of cervical cancer. Infection of the cervix by HPV 16/18 may result in persistence of viral DNA. The persistent HPV-DNA undergoes disruption at the E2 region, when integrated into the host genome. The transcriptional products E6 and E7 oncoproteins bind to and cause the degradation of p53 and Rb tumor-suppressor gene products. It is possible that, at that point, other cofactors may be involved in the progression toward a precancerous or cancerous condition. Those cofactors may include cigarette smoking, by introducing co-carcinogens to the tissue or by suppressing the local or systemic immune resistance similar to the effect of depressed immune resistance seen in AIDS or immunosuppression of transplant patients; hormones, by enhancing growth of HPV and transformation of HPV infected cells; low serum vitamin levels leading to decreased tissue resistance; or other infections causing local inflammation and the production of free radicals. CIN develops, leading eventually to cervical cancer.

Peripheral blood lymphocyte subpopulations in Indian women with cervical intraepithelial neoplasia and invasive cancer--an immunocytochemical study using monoclonal antibodies

The peripheral blood lymphocyte subpopulations in Indian women with various grades of cervical intraepithelial neoplasia [33], invasive cancer [22] and matched controls [30] were studied using specific monoclonal antibodies and biotin avidin immunofluorescence technique. Our results showed a significant fall in peripheral T (CD2) B(CD22) cells in patients with CIN III and invasive cervical cancer lesions compared to controls (P less than 0.001). Similarly the quantum of T helper cells (CD4) decreased according to the severity of cervical lesions (P less than 0.01 - P less than 0.001), whereas the T suppressor cells (CD8) depicted an increasing trend in patients with higher grade of cervical lesions (CIN III and invasive cancer, P less than 0.001) as compared to controls. Further, the CD4/CD8 ratio showed a significant downfall with the severity of cervical lesions (P less than 0.01 - P less than 0.001), indicating a perturbance in the homeostasis of host cellular immunity.

HSV infected RAJI-cells specify HSV specific immediate early and/or early DNA-binding proteins

Herpes Simplex Virus specified DNA-binding proteins were purified from virus infected VERO and RAJI cells. The expression of the proteins differed depending on the type of the host cell. Polypeptides corresponding to HSV-1 specific ICP 8 and HSV-2 specific ICSP 11/12 were the major products of HSV-infected VERO cells. In RAJI cells polypeptides with a corresponding molecular weight, together with a cellular protein having almost similar mobility on SDS gels could be detected. Using immuno-blotting technique the HSV origin of these 135K molecular weight proteins synthesized in the HSV-1 and HSV-2-infected RAJI cells could be confirmed.

Prevalence of human papillomavirus type 16 DNA sequences in cervical intraepithelial neoplasia and invasive carcinoma of the cervix

The frequency of human papillomavirus (HPV) type 16 in premalignant and malignant lesions of the cervix was investigated and compared with the detection of HPV type 6. In cervical intraepithelial neoplasia (CIN) grades I-III HPV 6 was detected in 28% and HPV 16 in 62% of patients whereas 90% of malignant lesions contained HPV 16 only. In the CIN lesions there was an increase in HPV 16 detection as the severity of disease increased while the level of detection of HPV 6 decreased. Only three (18%) of the cervices that were colposcopically and histologically normal contained HPV genomes; although two of these three women had either a history of genital warts or a sexual partner with penile warts.

Chlamydial cervicitis and cervical intraepithelial neoplasia: an immunohistochemical analysis

Studies using serological and culture techniques indicate that chlamydial infection is frequently associated with cervical intraepithelial neoplasia (CIN). This relationship was investigated by examining a series of biopsies containing normal epithelium, non-neoplastic condylomatous epithelium, and neoplastic epithelium (CIN). In each case the degree of inflammation and the presence of reparative atypia were recorded from an examination of the hematoxylin and eosin stained sections and serial sections were stained for chlamydial antigens using a polyclonal antichlamydial antibody and the immunoperoxidase technique. Overall, staining for chlamydia was positive in 0, 2, and 16% of biopsies with mild, moderate, and severe inflammation, respectively. In cases of severe inflammation positive staining was present in 20, 25, and 8% of biopsies containing non-neoplastic, condylomatous, and neoplastic epithelium, respectively. In all positive cases the staining was most prevalent in areas of the most intense inflammation. A spectrum of squamous epithelial changes was found in the infected biopsies and their distinction from CIN is discussed. This study suggests that tissue staining for chlamydia is related more to the extent of the coexisting inflammation than the presence or absence of CIN. Chlamydial infection, however, was frequently associated with inflammation-related squamous atypia in the transformation zone, which may be confused histologically with CIN.

Expression and cellular compartmentalization of a herpes simplex virus type 2 protein (ICP 10) in productively infected and cervical tumor cells

Antiserum to ICP 10, a herpes simplex virus type 2 (HSV-2) protein that is expressed in cells neoplastically transformed by viral DNA sequences within the Bgl II/Hpa I CD fragment, specifically precipitates the ICP 10 protein from HSV-2 infected cells and stains cells infected with HSV-2 for 4 to 16 hrs by indirect immunofluorescence. At 4 hr post infection (p.i.), the staining is primarily perinuclear, while at 16 hr p.i., it is cytoplasmic and intranuclear. Compartmentalization studies indicate that the 35S-[L]-methionine labeled ICP 10 is detectable in both the cytoplasmic and nuclear fractions early and late in infection. However, in its phosphorylated form, ICP 10 is undetectable in the nuclear fraction late in the viral reproductive cycle. Anti-ICP 10 serum stains a high (75%-83%) proportion of cervical tissue with pathological findings of dysplasia or carcinoma, as well as atypical exfoliated cells from these patients. Cervical tumor tissue from 4 of 12 patients also stains with antiserum to another purified viral protein complex designated ICP 12/14. In the majority of atypical cells with mild or moderate changes, ICP 10 localizes in the cytoplasm, while the majority of atypical cells with severe changes also display nuclear staining with anti-ICP 10 serum. While exfoliated atypical cells from 60% of patients with dysplasia are positive for ICP 10, those from only one half of these patients stain also with anti-ICP 12/14 serum and this staining is strictly cytoplasmic. Atypical cells from three patients in these series stain with the anti-HSV-2 serum but are negative for both ICP 10 and ICP 12/14. Exfoliated atypical cells from patients with CIS or invasive cancer stain equally well with all three antisera.