Mayumi Nakagawa

Cytotoxic T Lymphocyte Responses to E6 and E7 Proteins of Human Papillomavirus Type 16: Relationship to Cervical Intraepithelial Neoplasia

Cytotoxic T lymphocyte (CTL) responses to the human papillomavirus (HPV) type 16 E6 and E7 proteins were measured in 20 women with known HPV and cervical disease status. CTL assays were performed after stimulation with E6 or E7 fusion proteins using autologous B lymphoblastoid cells infected with vaccinia viruses expressing E6 or E7. CTL responses to E6 and E7 were detected in 6 (75%) of 8 and 5 (56%) of 9 HPV-16-positive women without cervical intraepithelial neoplasia (CIN), respectively. Responses to E6 or E7 were each detected in only 2 (29%) of 7 HPV-16-positive women with CIN. Responses to both antigens were found in 63% of women without CIN and 14% of those with CIN. CTL responses to E6 or E7 are more commonly detectable in HPV-16-positive women without CIN than in HPV-16-positive women with CIN, suggesting that CTL response may play a role in disease protection.

Cell-Mediated Immune Response to Human Papillomavirus Infection

Acquisition of human papillomavirus (HPV) results in an infection of variable duration which may or may not be associated with clinically apparent lesions. Lesions caused by skintropic HPV types generally manifest as cutaneous warts and most often resolve over a period of months to years. On the other hand, anogenital infections are more likely to remain clinically inapparent. The development of DNA amplificationbased tests has demonstrated that anogenital infections are quite common and generally self-limited. For example, we and others have shown by PCR testing of multiple samples collected at different points in time-that 70 to 90% of sexually active adolescents and young women who develop an incident cervical HPV infection will show clearance of infection within 12 to 30 months (47, 61, 94). The factors influencing the natural history of these infections are not well understood. Given that persistent anogenital infection with oncogenic HPV types is associated with increased risk of neoplasia and invasive cancers (22, 59, 70, 71, 94, 124) and that cervical carcinoma remains a leading cause of death among women in developing countries (129), understanding these factors is of considerable importance. Substantial effort has been directed recently at understanding the role of the host’s immune response in the natural history of HPV, and in particular, anti-viral, cell-mediated immunity. Empirical evidence for the importance of cell-mediated immunity in control of HPV infection comes from an extensive body of literature documenting the increased prevalence of HPV infection and associated disease among immunosuppressed populations, including those with iatrogenic immunosuppression such as renal transplant recipients and individuals with human immunodeficiency virus (HIV) infection. Sillman and coauthors (128) reported in 1984 on 20 immunosuppressed women with various causes of immunosuppression who had lower genital neoplasia, describing evidence of associated HPV infection in all 20. Penn, in 1986, reported a 100-fold increase in cancer of the vulva and anus in renal transplant recipients (111). In the 1990s, as molecular testing for HPV infection came into its own, several reports confirmed increased incidence of HPV infection (50) and associated morbidities, including warts (77) and cervical squamous intraepithelial lesions (SIL) (104), among immunosuppressed renal

Persistence of Human Papillomavirus Type 16 Infection Is Associated with Lack of Cytotoxic T Lymphocyte Response to the E6 Antigens

Our cross-sectional study suggested that cytotoxic T lymphocyte (CTL) responses have a protective effect in squamous intraepithelial lesion (SIL) development. More CTL responses in women with human papillomavirus type 16 (HPV 16) infection without SILs than with SILs were detected. In the current longitudinal study, the role of CTL in clearing HPV 16 infection in women without SILs was investigated. Women with HPV 16 infection (n=51) were enrolled, along with HPV 16-negative control women (n=3). Twenty-two (55%) of 40 women who cleared HPV 16 infection had an E6 CTL response at least once, compared with none of 9 women who had HPV 16 persistence (P=.003). Such a difference was not demonstrated for E7; 25 (63%) of 40 women who cleared HPV 16 infection responded, versus 5 (56%) of 9 women with persistence (P=.720). It appears that lack of response to E6 is important in the persistence of HPV 16 infection.

Evidence that multiple residues on both the α-helices of the class I MHC molecule are simultaneously recognized by the T cell receptor

Single amino acid substitutions at nine different positions on the H-2Kb molecules from in vitro-mutagenized, immunologically altered, somatic cell variants were correlated with their patterns of recognition by monoclonal antibodies (MAbs) and allogeneic cytotoxic T lymphocyte (CTL) clones. While MAbs were found to detect spatially discrete, domain-specific sites, CTLs interacted simultaneously with multiple residues on the alpha 1 and alpha 2 domains of the Kb molecule. The computer graphic three-dimensional Kb model structure showed that, of the seven CTL-specific residues analyzed, six residues were located on the alpha-helical regions of the two domains. Every CTL clone was found to interact with a distinct pattern of residues composed of a specific subset of the CTL-specific residues.

Recipients of blood from a donor with multiple HLA antibodies: a lookback study of transfusion-related acute lung injury

BACKGROUND:  The effects of transfusion of HLA antibodies to patients with corresponding antigens are not well known.

Acute and transient decrease in neutrophil count in transfusion-related acute lung injury: cases at one hospital

BACKGROUND:  Transfusion‐related acute lung injury (TRALI) is a rare but serious complication of blood transfusion. The syndrome is characterized by new acute lung injury developing during or within 6 hours of blood transfusion.

Cell-mediated immune responses to human papillomavirus 16 E6 and E7 antigens as measured by interferon gamma enzyme-linked immunospot in women with cleared or persistent human papillomavirus infection.

Cell-mediated immune responses have been thought to be important in the control of human papillomavirus (HPV) infections. We examined cell-mediated immune responses to HPV-16 E6 and E7 in the peripheral blood using interferon gamma (IFN-&ggr;) enzyme-linked immunospot assay (Cellular Technology Ltd, Cleveland, Ohio) in women with HPV-16 infection who showed clearance and compared these women to women with HPV-16 persistence. Women participating in a longitudinal study of cervical HPV were recruited once cervical HPV-16 infection was detected by polymerase chain reaction. Four groups of women were examined: (1) persistent, (2) intermittent, (3) transient, and (4) cleared. Ninety-six samples from 55 women were compared. Comparing IFN-&ggr; enzyme-linked immunospot to the HPV-16 clearance of 10 women with recent persistence, none had response to either E6 or E7; of 24 women with recent clearance, 14 had E6 and 8 had E7 response. Women with intermittent persistence behaved similarly to the clearance group than recent persistors: 50% were positive to E6 and 20% to E7. In summary, anti-E6 responses seem critical in the immediate control of HPV, and in some women, an immune tolerance eventually develops if HPV is not eliminated soon after infection.

Inhibition of Human Papillomavirus Type 16 E7 Phosphorylation by the S100 MRP-8/14 Protein Complex

ABSTRACT The human papillomavirus type 16 (HPV16) E7 is a major viral oncoprotein that is phosphorylated by casein kinase II (CKII). Two S100 family calcium-binding proteins, macrophage inhibitory-related factor protein 8 (MRP-8) and MRP-14, form a protein complex, MRP-8/14, that inactivates CKII. The MRP-8/14 protein complex may inhibit CKII-mediated E7 phosphorylation and therefore may alter its interaction with cellular ligands and reduce E7 oncogenic activity. We examined the inhibitory effect of the MRP-8/14 complex on CKII activity and HPV16 E7 phosphorylation. We have shown that CKII activity and HPV16 E7 phosphorylation were inhibited by uptake of exogenous MRP-8/14 and activation of endogenous MRP-8/14. MRP-8/14-mediated inhibition of E7 phosphorylation occurred at the G1 phase of the cell cycle. Analysis of MRP expression in primary keratinocytes and in HPV16- and 18-transformed cervical and foreskin epithelial cell lines showed that expression of MRP-8, MRP-14, and the MRP-8/14 complex was detected only in primary untransformed keratinocytes and not in the HPV-infected immortalized epithelial cells. CKII activity in HPV-immortalized keratinocytes was approximately fourfold higher than in HPV-negative primary keratinocytes. Treatment of HPV-positive immortalized epithelial cells with exogenous MRP-8/14 resulted in E7 hypophosphorylation and complete inhibition of cell growth within 2 weeks, compared with HPV-negative primary and immortalized HPV-negative cervical epithelial cells, which showed 25 and 40% growth inhibition, respectively. Together these results suggests that the MRP-8/14 protein complex in HPV-infected epithelial cells may play an important role in regulation of CKII-mediated E7 phosphorylation and inhibition of its oncogenic activity.

HLA Class I Binding Promiscuity of the CD8 T-Cell Epitopes of Human Papillomavirus Type 16 E6 Protein

ABSTRACT One of the critical steps in the progression to cervical cancer appears to be the establishment of persistent human papillomavirus (HPV) infection. We have demonstrated that the lack of cytotoxic T-lymphocyte response to HPV type 16 (HPV 16) E6 protein was associated with persistence and that the potential presence of dominant CD8 T-cell epitopes was most frequently found (n = 4 of 23) in the E6 16-40 region by examining the pattern of CD8 T-cell epitopes within the E6 protein in women who had cleared their HPV 16 infections. The goal of this study was to define the minimal/optimal amino acid sequences and the HLA restricting molecules of these dominant CD8 T-cell epitopes as well as those of subdominant ones if present. Three dominant epitopes, E6 29-38 (TIHDIILECV; restricted by the HLA-A0201 molecule), E6 29-37 (TIHDIILEC; restricted by B48), and E6 31-38 (HDIILECV; restricted by B4002), and one subdominant epitope, E6 52-61 (FAFRDLCIVY; restricted by B35) were characterized. Taken together with a previously described dominant epitope, E6 52-61 (FAFRDLCIVY; restricted by B57), the CD8 T-cell epitopes demonstrated striking HLA class I binding promiscuity. All of these epitopes were endogenously processed, but the presence of only two of the five epitopes could have been predicted based on the known binding motifs. The HLA class I promiscuity which has been described for human immunodeficiency virus may be more common than previously recognized.

Different Methods of Identifying New Antigenic Epitopes of Human Papillomavirus Type 16 E6 and E7 Proteins

ABSTRACT Human papillomavirus (HPV) infection is the most common cause of sexually transmitted viral infection and is the main cause of cervical cancer. Identification of HPV T-cell epitopes would be instrumental not only in our understanding of the protective immune response but also in the development of vaccines and immunotherapies. In contrast to viruses which cause systemic infection, identification of HPV epitopes is technically challenging because HPV causes a localized mucosal infection and the frequency of pathogen-specific T lymphocytes in peripheral blood is expected to be low. Here we describe three new antigenic epitopes (E7 7-15 [TLHEYMLDL], E6 52-61 [FAFRDLCIVY], and E7 79-87 [LEDLLMGTL]) of HPV 16 E6 and E7 proteins which have oncogenic activities. E7 7-15 was identified among peptides previously shown to bind to human leukocyte antigen (HLA)-A2.1 molecule, but it was found likely to be restricted by the HLA-B48 molecule. E6 52-61 (likely to be restricted by HLA-B57) and E7 79-87 (likely to be restricted by HLA-B60) were detected, based on the magnitude of the T-cell immune responses, in another individual. In particular, T-cell clones specific for the E6 52-61 epitope were isolated effectively by magnetically selecting them based on gamma interferon secretion. This is an efficient method of identifying new epitopes of antigens for which the number of specific T lymphocytes in the circulation is expected to be small, and it should be widely applicable in identifying new T-cell epitopes.