Human papillomavirus type 16 E6/E7-specific cytotoxic T lymphocytes in women with cervical neoplasia.

Infection with oncogenic human papillomavirus (HPV) types is associated with the development of cervical neoplasia (CIN). The E6 and E7 oncoproteins are constitutively expressed in these lesions and are therefore putative targets for the immune response against HPV. The relation between HPV 16-specific memory cytotoxic T-cell precursor (mCTLp) activity to both oncoproteins and the natural course of cervical dysplasia was analyzed in 38 patients participating in a nonintervention cohort study of women with CIN and 11 HPV 16-positive cervical carcinoma patients. In a cross-sectional study at the end of follow-up prior to biopsy, 8 of 20 patients with a persistent HPV 16 infection had specific mCTLp against at least one of the two oncoproteins. By contrast, no specific mCTLp activity was detected in 11 HPV-negative patients or in 7 patients who had cleared an HPV 16 infection at the end of follow-up. However, 5 of 11 cervical carcinoma patients showed mCTLp activity against the E7 protein only. This study demonstrates that HPV 16 oncogene-specific mCTLp are present in women with HPV 16-positive CIN prior to any intervention. Since HPV-specific mCTLp were detected predominantly in women with high-grade lesions or invasive cervical carcinoma and not in women who cleared the virus, the role of naturally occurring mCTLp in the protection against HPV-associated cervical neoplasia remains to be established.

Differences in cytokine mRNA profiles between premalignant and malignant lesions of the uterine cervix.

The aim of this study was to assess the expression of cytokine transcripts, reflecting the type of ongoing immune responses at the site of human papillomavirus (HPV) infection, in relation to the development of cervical neoplasia. To this end reverse transcription-polymerase chain reaction (RT-PCR) was performed for interferon (IFN) gamma, interleukin (IL)-2, IL-4, IL-5, IL-10, IL-12 (p35 and p40), and transforming growth factor (TGF beta 1) in snap-frozen cervical biopsies, which were tested for the presence of high risk HPV DNA and histologically classified from normal to invasive carcinoma (n = 40). IFN gamma, IL-10 and IL-12 (p35 and p40) transcripts were found to be expressed at significantly lower frequencies in invasive carcinoma as compared with premalignant biopsies (P = 0.006, P = 0.007 and P = 0.002, respectively). IFN gamma IL-10 mRNA were associated with the presence of the IL-12 p35 and p40 transcripts (P = 0.008 and P < 0.00001, respectively). These results are consistent with a locally reduced cellular (type 1) immunity correlating with HPV-induced invasive cervical carcinoma.

Assessment of cytotoxic T-lymphocyte phenotype using the specific markers granzyme B and TIA-1 in cervical neoplastic lesions.

Cervical carcinomas are closely associated with high-risk human papillomavirus (HPV) types and are preceded by cervical intraepithelial neoplasia (CIN). Most CIN lesions regress spontaneously and will not evolve to invasive carcinoma. The cellular immune system mediated by cytotoxic T lymphocytes (CTLs) and natural killer (NK) cells are thought to play an important role in the ultimate decline of CIN lesions. Although TIA-1 is constitutively expressed in the majority of circulating T cells and defines a subpopulation of CD8+ T cells with cytotoxic potential, granzyme B is only expressed in CTLs upon activation. In the present study we have evaluated the expression of these proteins by lymphocytes present in 24 randomly chosen CIN lesions with increasing degree of atypia and in 14 cervical squamous cell carcinomas. As major histocompatibility complex (MHC) class I expression is frequently down-regulated in HPV-induced lesions, thus possibly frustrating tumour cell recognition by infiltrating CTLs, these lesions were also analysed for MHC class I expression. The results indicated that in most CIN lesions only a minority of CTLs are activated, whereas in some carcinomas a massive infiltration of activated, i.e. granzyme B-positive, CTLs were observed. The percentage of activated CTLs was not related to expression of MHC class I on neoplastic cells. These results suggest that in some carcinomas proper activation of CTLs occurs but that most likely local factors or immunoselection of resistant neoplastic cells inhibit a proper response of CTLs to these neoplastic cells.