Proliferative T cell responses to human papillomavirus type 16 L1 peptides in patients with cervical dysplasia

Abstract

Human papillomavirus type 16 (HPV-16) can cause genital warts, cervical dysplasias and carcinoma of the cervix. Cell-mediated immunity is thought to be important in protection against the virus and in its elimination, but little is known about the mechanisms involved. In a cross-sectional study we have demonstrated proliferative T cell responses to peptides representing the HPV-16 L1 capsid protein (aa 199-409) in the peripheral blood of 63% of patients (n = 41) with histological evidence of cervical dysplasia and in 45 % of healthy age-matched controls (n = 11). This was achieved by generating short-term T cell lines (STLs) from each individual in vitro against a fl-galactosidase-HPV-16 L1 (aa 199-409) fusion protein for 2 weeks, and then identifying the HPV epitopes they recognized with overlapping synthetic peptides (15-mers) spanning this region in 3 day specificity assays. Histological grading and HPV typing by PCR were performed on patients' cervical biopsies taken at the same clinical visit as the peripheral blood samples. An immunogenic region was identified between aa 311-345 in 73 % of patients (18 % in controls) who responded to HPV-16 L1 (aa 199-409). The number ofresponders to this region was significantly higher in patients with HPV-16-positive biopsies when compared to those with HPV-16-negative biopsies (P = 0.006), as was the number of responders to individual peptides 311-325 (NLASSNYFPTPSGSM; P = 0"04) and321-335 (PSGSMVTSDAQIFNK;P = 0.004)representing this region. The mean level of response to each individual peptide was also higher in the patient group than the controls (P < 0.05). The most significant finding was that all patients with evidence of a current HPV-16 infection responded to one or more L1 peptides (P = 0-0004) and 92 % had high grade cervical intraepithelial neoplasia (CIN III). We also found that the CIN III group was more likely to respond to any L1 peptide than either the atypical group (P = 0.04) or the controls (P = 0.05). Data from four individuals showed that the majority of peptide-specific STLs were CD4 + but some CD8 ÷ STLs were also detected.

Distinct regulation and impact of type 1 T‐cell immunity against HPV16 L1, E2 and E6 antigens during HPV16‐induced cervical infection and neoplasia

“…11 Others have reported that the majority of patients with high-grade CIN lesions displayed HPV16 L1-specific proliferative responses, 22,23 but it is unclear whether these responses were associated with the production of IFNg. We, thus, examined the type 1 (IFNg)-associated HPV16 L1 peptide-specific T-cell response in HPV16 DNA-positive CIN III and cervical cancer patients and compared these responses with those found in healthy subjects.…”

“…[21][22][23]33,34 To obtain more detailed information about the magnitude, specificity and functionality of T-cell responses against HPV16 L1, we incubated PBMC isolated from the blood of a group of 20 healthy donors with an overlapping set of 30-mer peptides covering the entire HPV16 L1 sequence and tested T-cell reactivity by IFNg ELISPOT assay. In addition, PBMC were incubated with HPV16 E6 peptides to relate the reactivity against L1 with our previous findings for early antigens.…”

“…[17][18][19] A large HPV16 L1-VLP vaccination trial in humans revealed that vaccine-induced immunity could prevent persistent HPV16 infections. 20 Although the immunologic evaluation of this trial was focused on the role of neutralizing antibodies in preventing viral infection, VLP vaccination must also have affected the underlying CD41 Th responses and possibly Th-dependent cell-mediated effector functions.Previous work has shown that patients diagnosed with HPV16 1 CIN display proliferative responses against HPV16 L1 21,22 and that there was no difference in such proliferative responses (measured by IL-2 production) between patients who cleared their lesions or in whom lesions persisted. 23 Immunity in such subjects may differ not so much in the quantitative aspects of the immune response but more in the quality of the response, as is indicated by our studies on immunity against the HVP16 nonstructural antigens.…”

“…Previous work has shown that patients diagnosed with HPV16 1 CIN display proliferative responses against HPV16 L1 21,22 and that there was no difference in such proliferative responses (measured by IL-2 production) between patients who cleared their lesions or in whom lesions persisted. 23 Immunity in such subjects may differ not so much in the quantitative aspects of the immune response but more in the quality of the response, as is indicated by our studies on immunity against the HVP16 nonstructural antigens.…”

T-cell responses to human papillomavirus type 16 among women with different grades of cervical neoplasia

“…Using either fusion proteins, panels of overlapping peptides, or virus-like particles (VLPs), CD4 responses to HPV16 E6 (Cubie et al, 1989;Strang et al, 1990;Nakagawa et al, 1996;Tsukui et al, 1996;Kadish et al, 1997Kadish et al, , 2002Welters et al, 2003;de Jong et al, 2004), E7 (Cubie et al, 1989;Strang et al, 1990;Altmann et al, 1992;Kadish et al, 1994Kadish et al, , 1997Kadish et al, , 2002de Gruijl et al, 1996ade Gruijl et al, , b, 1998Luxton et al, 1996;Nakagawa et al, 1996;Tsukui et al, 1996;Hopfl et al, 2000;van der Burg et al, 2001;Welters et al, 2003), E2 de Jong et al, 2002de Jong et al, , 2004Welters et al, 2003), E5 (Gill et al, 1998), E4 (Cubie et al, 1989;Nakagawa et al, 1996) and L1 (Strang et al, 1990;Nakagawa et al, 1996;Shepherd et al, 1996;Luxton et al, 1997;de Gruijl et al, 1999) have been demonstrated in both patient and healthy control populations. No clear pattern has yet emerged as to which of these responses, if any, might be associated with regression or progression of disease as only a limited number of prospective studies have been carried out.…”