Aikichi Iwamoto

Detection and Typing of Multiple Genital Human Papillomaviruses by DNA Amplification with Consensus Primers

Many types of human papillomavirus (HPV) are associated with genital lesions. In order to develop simple and sensitive diagnostic procedures for HPV infection, we took advantage of the polymerase chain reaction (PCR). We compared the published nucleotide sequences of the LI region from six genital HPV types and designed a pair of consensus primers for LI region. The PCR with the consensus primers for LI region (Ll‐PCR) could amplify at least nine genital HPV types, 6,11, 16, 18, 31, 33, 42, 52 and 58, and the amplified HPV DNA could be typed by subsequent restriction mapping. Ll‐PCR was compared to Southern blot analysis and also to the consensus primer‐mediated PCR for E6 region (E6‐PCR) described before. Although both our PCR systems are nonradioactive, the sensitivity in detecting HPV DNA was even better than that obtained by using Southern blot analysis. By means of the PCR systems we detected HPV DNA in 100% of cervical condylomas (10/10), 92% of cervical intraepithelial neoplasias (33/36) and 96% of invasive cervical carcinomas (53/55), while we detected HPV DNA in 12% of normal cervices (12/102).

Impaired Processing and Presentation of Cytotoxic-T-Lymphocyte (CTL) Epitopes Are Major Escape Mechanisms from CTL Immune Pressure in Human Immunodeficiency Virus Type 1 Infection

ABSTRACT Investigating escape mechanisms of human immunodeficiency virus type 1 (HIV-1) from cytotoxic T lymphocytes (CTLs) is essential for understanding the pathogenesis of HIV-1 infection and developing effective vaccines. To study the processing and presentation of known CTL epitopes, we prepared Epstein-Barr virus-transformed B cells that endogenously express the gag gene of six field isolates by adopting an env/nef-deletion HIV-1 vector pseudotyped with vesicular stomatitis virus G protein and then tested them for the recognition by Gag epitope-specific CTL lines or clones. We observed that two field variants, SLFNTVAVL and SVYNTVATL, of an A*0201-restricted Gag CTL epitope SLYNTVATL, and three field variants, KYRLKHLVW, QYRLKHIVW, and RYRLKHLVW, of an A24-restricted Gag CTL epitope KYKLKHIVW escaped from being killed by the CTL lines, despite the fact that they were recognized when the synthetic peptides corresponding to these variant sequences were exogenously loaded onto the target cells. Thus, their escape is likely due to the changes that occur during the processing and presentation of epitopes in the infected cells. Mutations responsible for this mode of escape were located within the epitope regions rather than the flanking regions, and such mutations did not influence the virus replication. The results suggest that the impaired antigen processing and presentation often occur in HIV-1 field isolates and thus are one of the major mechanisms that enable HIV-1 to escape from CTL recognition. We emphasize the importance of testing HIV-1 variants in an endogenous expression system.

Impaired Replication Capacity of Acute/Early Viruses in Persons Who Become HIV Controllers

ABSTRACT Human immunodeficiency virus type 1 (HIV-1) controllers maintain viremia at <2,000 RNA copies/ml without antiretroviral therapy. Viruses from controllers with chronic infection were shown to exhibit impaired replication capacities, in part associated with escape mutations from cytotoxic-T-lymphocyte (CTL) responses. In contrast, little is known about viruses during acute/early infection in individuals who subsequently become HIV controllers. Here, we examine the viral replication capacities, HLA types, and virus sequences from 18 HIV-1 controllers identified during primary infection. gag-protease chimeric viruses constructed using the earliest postinfection samples displayed significantly lower replication capacities than isolates from persons who failed to control viremia (P = 0.0003). Protective HLA class I alleles were not enriched in these early HIV controllers, but viral sequencing revealed a significantly higher prevalence of drug resistance mutations associated with impaired viral fitness in controllers than in noncontrollers (6/15 [40.0%] versus 10/80 [12.5%], P = 0.018). Moreover, of two HLA-B57-positive (B57+) controllers identified, both harbored, at the earliest time point tested, signature escape mutations within Gag that likewise impair viral replication capacity. Only five controllers did not express “protective” alleles or harbor viruses with drug resistance mutations; intriguingly, two of them displayed typical B57 signature mutations (T242N), suggesting the acquisition of attenuated viruses from B57+ donors. These data indicate that acute/early stage viruses from persons who become controllers have evidence of reduced replication capacity during the initial stages of infection which is likely associated with transmitted or acquired CTL escape mutations or transmitted drug resistance mutations. These data suggest that viral dynamics during acute infection have a major impact on HIV disease outcome.

Identification of Antigenic Proteins Encoded by Human Herpesvirus 8 and Seroprevalence in the General Population and among Patients with and without Kaposi's Sarcoma

ABSTRACT To establish a sensitive and specific antibody assay, potent antigenic proteins encoded by human herpesvirus 8 (HHV8) were studied. Fifteen recombinant HHV8-encoded proteins were produced as glutathioneS-transferase fusion proteins. The sera from AIDS-associated Kaposis sarcoma (KS) patients reacted with four proteins encoded by open reading frames (ORFs) K8.1, 59, 65, and 73 in a Western blot assay. An enzyme-linked immunosorbent assay (ELISA) using these four proteins as antigens (mixed-antigen ELISA) revealed that all 26 sera derived from KS patients (24 with and 2 without human immunodeficiency virus infection) became positive for anti-HHV8 antibodies. The presence of HHV8 was demonstrated in 14 (1.4%) of 1,004 sera from the Japanese general population and 10 (1.9%) of 527 sera from patients without HHV8-associated diseases. The presence of immunoglobulin G (IgG) and IgM antibodies against HHV8 examined further by the mixed-antigen ELISA and Western blotting revealed IgG antibody in all ELISA-positive sera, while IgM antibody against ORF K8.1 was absent. These data suggest that the ORF 73 and 65 proteins are potent antigens for a sensitive serological assay.

Bat Origins of MERS-CoV Supported by Bat Coronavirus HKU4 Usage of Human Receptor CD26

Summary The recently reported Middle East respiratory syndrome coronavirus (MERS-CoV) is phylogenetically closely related to the bat coronaviruses (BatCoVs) HKU4 and HKU5. However, the evolutionary pathway of MERS-CoV is still unclear. A receptor binding domain (RBD) in the MERS-CoV envelope-embedded spike protein specifically engages human CD26 (hCD26) to initiate viral entry. The high sequence identity in the viral spike protein prompted us to investigate if HKU4 and HKU5 can recognize hCD26 for cell entry. We found that HKU4-RBD, but not HKU5-RBD, binds to hCD26, and pseudotyped viruses embedding HKU4 spike can infect cells via hCD26 recognition. The structure of the HKU4-RBD/hCD26 complex revealed a hCD26-binding mode similar overall to that observed for MERS-RBD. HKU4-RBD, however, is less adapted to hCD26 than MERS-RBD, explaining its lower affinity for receptor binding. Our findings support a bat origin for MERS-CoV and indicate the need for surveillance of HKU4-related viruses in bats.

Polymorphism in the Interleukin-4 Promoter Affects Acquisition of Human Immunodeficiency Virus Type 1 Syncytium-Inducing Phenotype

ABSTRACT The emergence of syncytium-inducing (SI) variants of human immunodeficiency virus type 1 (HIV-1) in infected individuals is an indicator of poor prognosis and is often correlated with faster CD4+ cell depletion and rapid disease progression. Interleukin-4 (IL-4) is a pleiotropic cytokine with various immune-modulating functions including induction of immunoglobulin E (IgE) production in B cells, down-regulation of CCR5 (a coreceptor for HIV-1 non-SI [NSI] strains), and up-regulation of CXCR4 (a coreceptor for HIV-1 SI variants). Here we show that homozygosity of a polymorphism in the IL-4 promoter region, IL-4 −589T, is correlated with increased rates of SI variant acquisition in HIV-1-infected individuals in Japan. This mutation was also shown to be associated with elevated serum IgE levels in HIV-1-infected individuals, especially in those at advanced stages of disease. In contrast, neither a triallele polymorphism in IL-10, another Th2 cytokine, nor a biallele polymorphism in the RANTES promoter affected acquisition of the SI phenotype. This finding suggested that IL-4-589T increases IL-4 production in the human body and thus accelerates the phenotypic switch of HIV-1 from NSI to SI and possibly disease progression of AIDS.

A CCR2-V64I polymorphism affects stability of CCR2A isoform.

Objective: A valine to isoleucine substitution at position 64 of CCR2 (CCR2-64I) is associated with a delay in progression to AIDS in HIV-1-infected individuals. The aim of the present study is to elucidate the molecular mechanism underlying the effect of this allele. Design: We analysed the effect of the 64I substitution on levels of expression of CCR2A and CCR2B, two CCR2 isoforms produced by alternative splicing. Methods: Sendai virus vector was used to express CCR2 molecules. Results: While CCR2B trafficked well to the cell surface, CCR2A, which differs from CCR2B only by the sequence of its C-terminal cytoplasmic tail, was detected predominantly in the cytoplasm. The level of expression of CCR2A-64I was significantly higher than that of CCR2A without the substitution. On the other hand, the 64I substitution did not affect levels of CCR2B expression. Pulse–chase experiments revealed that the 64I substitution increased the half-life of CCR2A in cells. When co-expressed with CCR5, CCR2A-64I interfered more severely with cell surface expression of CCR5 than did wild-type CCR2A. Furthermore, immunoprecipitation experiments showed that CCR2A co-precipitated with an immature form of CCR5. Conclusion: These results suggest that CCR2A binds to CCR5 in the cytoplasm and down-modulates its surface expression. We propose that the increased ability of CCR2A-64I to down-modulate CCR5 expression might be a possible cause of a delay in HIV-1 disease progression in patients with this allele.

Yeast-derived human immunodeficiency virus type 1 p55(gag) virus-like particles activate dendritic cells (DCs) and induce perforin expression in Gag-specific CD8(+) T cells by cross-presentation of DCs.

ABSTRACT To evaluate the immunogenicity of human immunodeficiency virus (HIV) type 1 p55gag virus-like particles (VLPs) released by budding from yeast spheroplasts, we have analyzed the effects of yeast VLPs on monocyte-derived dendritic cells (DCs). Yeast VLPs were efficiently incorporated into DCs via both macropinocytosis and endocytosis mediated by mannose-recognizing receptors, but not the mannose receptor. The uptake of yeast VLPs induced DC maturation and enhanced cytokine production, notably, interleukin-12 p70. We showed that yeast membrane components may contribute to DC maturation partly through Toll-like receptor 2 signaling. Thus, Gag particles encapsulated by yeast membrane may have an advantage in stimulating Gag-specific immune responses. We found that yeast VLPs, but not the control yeast membrane fraction, were able to activate both CD4+ and CD8+ T cells of HIV-infected individuals. We tested the effect of cross-presentation of VLP by DCs in two subjects recruited into a long-term nonprogressor-slow progressor cohort. When yeast VLP-loaded DCs of these patients were cocultured with peripheral blood mononuclear cells for 7 days, approximately one-third of the Gag-specific CD8+ T cells were activated and became perforin positive. However, some of the Gag-specific CD8+ T cells appeared to be lost during in vitro culture, especially in a patient with a high virus load. Our results suggest that DCs loaded with yeast VLPs can activate Gag-specific memory CD8+ T cells to become effector cells in chronically HIV-infected individuals, but there still remain unresponsive Gag-specific T-cell populations in these patients.

Establishing and characterizing a CD30-positive cell line harboring HHV-8 from a primary effusion lymphoma.

Primary effusion lymphoma (PEL, or body‐cavity‐based lymphoma [BCBL]) is a new subtype of non‐Hodgkins lymphoma in which tumor cells locate in the body cavity exclusively. PEL/BCBL is widely accepted as one of the neoplastic complications of AIDS, associated mostly with human herpesvirus 8 (HHV‐8/Kaposis sarcoma‐associated herpesvirus [KSHV]) and Epstein‐Barr virus (EBV). We established and characterized a PEL cell line named TY‐1 from a 47‐year‐old patient with AIDS. TY‐1 exhibits indeterminate immunophenotype, expressing CD45 and CD30 cell surface antigens but not expressing B‐ or T‐cell markers. Cytogenetic analysis revealed the representative karyotype of 50,XYq‐,+7,+8,+11,+15. Southern blot analysis demonstrated HHV‐8 and EBV genomes in the original tumor cells obtained from the pericardial effusion, while HHV‐8 but not EBV was detected in TY‐1 using PCR or Southern blot analysis. Tetradecanylphorbol acetate treatment induced some TY‐1 cells to proceed to the reproductive phase. This cell line may be an useful tool for research on PEL and HHV‐8. J. Med. Virol. 58:394–401, 1999.

Human Herpesvirus 8–Associated Solid Lymphomas that Occur in AIDS Patients Take Anaplastic Large Cell Morphology

Human herpesvirus type 8 (HHV-8; Kaposis sarcoma–associated herpesvirus) is a recently isolated human herpesvirus frequently identified in Kaposis sarcoma, primary effusion lymphoma, and multicentric Castlemans disease. Here we report three cases of HHV-8–bearing solid lymphomas that occurred in AIDS patients (Cases 1–3). All three patients were homosexual men presenting extranodal masses in the lungs (Case 1) or skin (Cases 2 and 3), together with the presence of Kaposis sarcoma (Case 1), primary effusion lymphoma (Case 2), or multicentric Castlemans disease (Case 3). These solid lymphomas exhibited anaplastic large cell morphology and expressed CD30, corresponding to the recent diagnostic criteria of anaplastic large cell lymphoma (ALCL). The chromosomal translocation t(2;5)-associated chimeric protein p80NPM/ALK was not observed in any of these cases. HHV-8 was detected in all of these cases by polymerase chain reaction, immunohistochemistry of HHV-8–encoded ORF73 protein, and in situ hybridization of T1.1. Epstein-Barr virus was detected only in Cases 2 and 3 by in situ hybridization. It is interesting that inoculation of a cell line obtained from a primary effusion lymphoma cell in Case 2 to severe combined immunodeficiency mice produced HHV-8–positive and Epstein-Barr virus–negative tumors in inoculated sites. These tumor cells exhibited phenotypes of ALCL that were identical to the subcutaneous tumor cells of this particular patient. These findings clearly show that HHV-8 can associate with solid lymphomas and that it can take anaplastic large cell morphology. Those lymphomas should be distinguished from the classical ALCL as were defined by the revised European-American classification of lymphoid neoplasms even though morphology and a part of immunophenotype mimic that of classical ALCL.