Inverse correlation of cellular immune responses specific to synthetic peptides from the E6 and E7 oncoproteins of HPV-16 with recurrence of cervical intraepithelial neoplasia in a cross-sectional study.
BACKGROUND
Epidemiological studies have clearly established that human papillomavirus (HPV) infection is the major risk factor for cervical cancer. Most cervical cancers and pre-cancers are HPV-positive. Not all pre-cancers progress to cancer; a significant number regress. The immunological basis for either spontaneous or treatment-mediated recovery from HPV-associated CIN is not clear. Currently, prophylactic vaccines are successfully inducing antibody responses in HPV negative patients. Therapeutic vaccines for HPV-positive patients with disease are needed. There is a need to understand the immunologic basis for the Cell-Mediated Immune (CMI) response and for histological regression to help the formulation of therapeutic vaccines.


METHODS
Four groups of women were identified for this cross-sectional study of CMI. Group 1 consisted of six women without cytological or histological diagnosis of CIN and with an HPV negative test (CIN((-))/HPV((-))). Group 2 included 31 women with a new histological diagnosis of CIN and HPV positive test (CIN((+))/HPV((+))). Groups 3 and 4 were selected from women who had undergone ablative or excisional treatment for CIN at the colposcopy clinic at least 6 months before the study. The women in groups 3 and 4 were (CIN((+))/HPV((+))) before CIN treatment. Group 3 consisted of 22 women without evidence of recurrence of CIN (Recur((-))), and group 4 included 10 with histological diagnosis of recurrent CIN (Recur((+))). In particular, we investigated CMI responses to synthetic peptides from the E6 and E7 oncoproteins of HPV-16.


RESULTS
Compared to patients with disease recurrence (Recur((+)), n = 10), the majority of individuals who remained recurrence-free post-treatment (Recur((-)), n = 22) exhibited significant proliferative responses to synthetic peptides from the E6 (P = 0.001) and the E7 (P = <0.001). In particular, significant responses were observed with the E6 peptide Q15L (aa 43-57, P = 0.006) and the E7 peptide Q19D (aa 44-62, P = 0.002) in Recur((-)) patients but not Recur((+)) individuals. Additionally, PBMC from women in the Recur((-)) group, but not the Recur((+)) group, produced predominantly TH1 cytokines upon stimulation with the peptides Q15L or Q19D.


CONCLUSIONS
These results indicate an association between significant cellular immune responses specific to synthetic peptides from the E6 and E7 oncoproteins of HPV-16 and recurrence-free survival in HPV patients treated for CIN. We predict that these peptides may be useful as indicators of protective immunity for recovery from CIN and also for potential inclusion in designing immunotherapeutic and immunoprophylactic reagents for HPV-associated CIN.
Sarkar
Asis K
AK
Department of Immunology, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA.
Tortolero-Luna
Guillermo
G
Follen
Michele
M
Sastry
K Jagannadha
KJ
D000293:Adolescent; D000328:Adult; D000595:Amino Acid Sequence; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007111:Immunity, Cellular / Q000276:immunology; D008875:Middle Aged; D008969:Molecular Sequence Data; D009364:Neoplasm Recurrence, Local / Q000276:immunology* / Q000821:virology; D009856:Oncogene Proteins, Viral / Q000276:immunology*; D050725:Papillomavirus E7 Proteins; D030361:Papillomavirus Infections / Q000150:complications / Q000276:immunology*; D010446:Peptide Fragments / Q000276:immunology* / Q000494:pharmacology; D012097:Repressor Proteins / Q000276:immunology*; D002583:Uterine Cervical Neoplasms / Q000276:immunology* / Q000601:surgery / Q000821:virology; D002578:Uterine Cervical Dysplasia / Q000276:immunology* / Q000601:surgery / Q000821:virology
C068651:E6 protein, Human papillomavirus type 16; D009856:Oncogene Proteins, Viral; D050725:Papillomavirus E7 Proteins; D010446:Peptide Fragments; D012097:Repressor Proteins; C059731:oncogene protein E7, Human papillomavirus type 16