Summary of the publications
Philippa C. Matthews*, Madoka Koyanagi*, Henrik N. Kloverpris*, Mikkel Harndahl, Anette Stryhn, Tomohiro Akahoshi, Hiroyuki Gatanaga, Shinichi Oka, Claudia Juarez Molina, Humberto Valenzuela Ponce, Santiago Avila Rios, David Cole, Jonathan Carlson, Rebecca P. Payne, Anthony Ogwu, Alfred Bere, Thumbi Ndungfu, Kamini Gounder, Fabian Chen, Lynn Riddell, Graz Luzzi, Roger Shapiro, Christian Brander, Bruce Walker, Andrew K Sewell, Gustavo Reyes Teran, David Heckerman, Eric Hunter, Soren Buus, Masafumi Takiguchi, and Philip J. R. Goulder (*Equal contribution), Differential clade-specific HLA-B*3501 association with HIV-1 disease outcome is linked to immunogenicity of a single Gag epitope. J. Virol. 86:12643-12654, 2012
The strongest genetic influence on immune control in HIV-1 infection is the HLA class I genotype. Rapid disease progression in B-clade infection has been linked to HLA-B*35 expression, in particular to the less common HLA-B*3502 and HLA-B*3503 subtypes but also to the most prevalent subtype, HLA-B*3501. In these studies we first demonstrated that whereas HLA-B*3501 is associated with a high viral set point in two further B-clade-infected cohorts, in Japan and Mexico, this association does not hold in two large C-clade-infected African cohorts. We tested the hypothesis that clade-specific differences in HLA associations with disease outcomes may be related to distinct targeting of critical CD8(+) T-cell epitopes. We observed that only one epitope was significantly targeted differentially, namely, the Gag-specific epitope NPPIPVGDIY (NY10, Gag positions 253 to 262) (P = 2 ~ 10(-5)). In common with two other HLA-B*3501-restricted epitopes, in Gag and Nef, that were not targeted differentially, a response toward NY10 was associated with a significantly lower viral set point. Nonimmunogenicity of NY10 in B-clade-infected subjects derives from the Gag-D260E polymorphism present in ?90% of B-clade sequences, which critically reduces recognition of the Gag NY10 epitope. These data suggest that in spite of any inherent HLA-linked T-cell receptor repertoire differences that may exist, maximizing the breadth of the Gag-specific CD8(+) T-cell response, by the addition of even a single epitope, may be of overriding importance in achieving immune control of HIV infection. This distinction is of direct relevance to development of vaccines designed to optimize the anti-HIV CD8(+) T-cell response in all individuals, irrespective of HLA type.
Yoshinori Sato, Sayaka Nagata, and Masafumi Takiguchi, Effective elicitation of human effector CD8+ T cells in HLA-B*51:01 transgenic humanized mice after infection with HIV-1. PLoS ONE 7: e42776, 2012
Humanized mice are expected to be useful as small animal models for in vivo studies on the pathogenesis of infectious diseases. However, it is well known that human CD8(+) T cells cannot differentiate into effector cells in immunodeficient mice transplanted with only human CD34(+) hematopoietic stem cells (HSCs), because human T cells are not educated by HLA in the mouse thymus. We here established HLA-B*51:01 transgenic humanized mice by transplanting human CD34(+) HSCs into HLA-B*51:01 transgenic NOD/SCID/Jak3(-/-) mice (hNOK/B51Tg mice) and investigated whether human effector CD8(+) T cells would be elicited in the mice or in those infected with HIV-1 NL4-3. There were no differences in the frequency of late effector memory and effector subsets (CD27(low)CD28(-)CD45RA(+/-)CCR7(-) and CD27(-)CD28(-)CD45RA(+/-)CCR7(-), respectively) among human CD8(+) T cells and in that of human CD8(+) T cells expressing CX3CR1 and/or CXCR1 between hNOK/B51Tg and hNOK mice. In contrast, the frequency of late effector memory and effector CD8(+) T cell subsets and of those expressing CX3CR1 and/or CXCR1 was significantly higher in HIV-1-infected hNOK/B51Tg mice than in uninfected ones, whereas there was no difference in that of these subsets between HIV-1-infected and uninfected hNOK mice. These results suggest that hNOK/B51Tg mice had CD8(+) T cells that were capable of differentiating into effector T cells after viral antigen stimulation and had a greater ability to elicit effector CD8(+) T cells than hNOK ones.
Takuya Naruto*, Hiroyuki Gatanaga*, George Nelson, Keiko Sakai, Mary Carrington, Shinichi Oka*, and Masafumi Takiguchi* (*Equal contribution), HLA class I-mediated control of HIV-1 in the Japanese population, in which the protective HLA-B*57 and HLA-B*27 alleles are absent. J. Virol. 86:10870-10872, 2012
We investigated the effect of HLA class I alleles on clinical parameters for HIV-1 disease progression in the Japanese population, where two strongly protective alleles, HLA-B*57 and HLA-B*27, are virtually nonexistent. HLA-B alleles showed a dominant role, primarily through HLA-B*67:01 and the HLA-B*52:01-C*12:02 haplotype. Neither a rare-allele nor a heterozygote advantage was found, suggesting that the effect of HLA alleles in the Japanese population is either different from those observed in Africans and Caucasians or undetectable due to limited power.
Masao Hashimoto, Tomohiro Akahoshi, Hayato Murakoshi, Naoki Ishizuka, Shinichi Oka, and Masafumi Takiguchi, CTL recognition of HIV-1-infected cells via cross-recognition of multiple overlapping peptides from a single 11-mer Pol sequence. Eur. J. Immunol. 42:2621-2631, 2012
It is known that overlapping HIV-1 peptides of different lengths can be presented by a given HLA class I molecule. However, the role of those peptides in CD8(+) T cells recognition of HIV-1-infected cells remains unclear. Here we investigated the recognition of overlapping 8-mer to 11-mer peptides of Pol 155-165 by HLA-B*54:01-restricted CD8(+) T cells. The analysis of ex vivo T cells using ELISPOT and tetramer binding assays showed that there were different patterns of CD8(+) T-cell responses to these peptides among chronically HIV-1-infected HLA-B*54:01(+) individuals, though the response to the 9-mer peptide was the strongest among them. CD8(+) T-cell clones with TCRs specific for the 9-mer, 10-mer, and/or 11-mer peptides effectively killed HIV-1-infected cells. Together, these results suggest that the 9-mer and 10-mer peptides could be predominantly presented by HLA-B*54:01, though it remains possible that the 11-mer peptide was also presented by this HLA allele. The present study demonstrates effective CD8(+) T-cell recognition of HIV-1-infected cells via presentation of multiple overlapping HIV-1 peptides and cross-recognition by the CD8(+) T cells.
Hiroshi Takata, Takuya Naruto, and Masafumi Takiguchi, Functional heterogeneity of human effector CD8+ T cells. Blood. 119:1390-8, 2012
Effector CD8(+) T cells are believed to be terminally differentiated cells having cytotoxic activity and the ability to produce effector cytokines such as INF- and TNF-. We investigated the difference between CXCR1(+) and CXCR1(-) subsets of human effector CD27(-)CD28(-)CD8(+) T cells. Both subsets similarly expressed cytolytic molecules and exerted substantial cytolytic activity, whereas only the CXCR1(-) subset had IL-2 productivity and self-proliferative activity and was more resistant to cell death than the CXCR1(+) subset. These differences were explained by the specific up-regulation of CAMK4, SPRY2, and IL-7R in the CXCR1(-) subset and that of pro-apoptotic DAPK1 in the CXCR1(+) subset. The IL-2 producers were more frequently found in the IL-7R(+) subset of the CXCR1(-) effector CD8(+) T cells than in the IL-7R(-) subset. IL-7/IL-7R signaling promoted cell survival only in the CXCR1(-) subset. The present study has highlighted a novel subset of effector CD8(+) T cells producing IL-2 and suggests the importance of this subset in the homeostasis of effector CD8(+) T cells.
Tomohiro Akahoshi, Takayuki Chikata, Yoshiko Tamura, Hiroyuki Gatanaga, Shinichi Oka, and Masafumi Takiguchi, Selection and accumulation of an HIV-1 escape mutant by three types of HIV-1-specific CTLs recognizing wild-type and/or escape mutant epitopes. J. Virol. 86:1971-1981, 2012@
It is known that cytotoxic T lymphocytes (CTLs) recognizing HIV-1 escape mutants are elicited in HIV-1-infected individuals,but their role in the control of HIV-1 replication remains unclear. We investigated the antiviral ability of CTLs recognizing the HLA-A24:02-restricted Gag28 -36 (KYKLKHIVW) epitope and/or its escape mutant (KYRLKHIVW) elicited in the early and chronic phases of the infection. Wild-type (WT)-epitope-specific CTLs, as well as cross-reactive CTLs recognizing both WT and K30R (3R) epitopes, which were predominantly elicited at early and/or chronic phases in HLA-A24:02 individuals infected with the WT virus, suppressed the replication of the WT virus but failed to suppress that of the 3R virus, indicating that the 3R virus was selected by these 2 types of CTLs. On the other hand, cross-reactive and 3R-specific CTLs, which were elicited in those infected with the 3R virus, did not suppress the replication of either WT or 3R virus, indicating that these CTLs did not contribute to the control of 3R virus replication. High accumulation of the 3R mutation was found in a Japanese population recently recruited. The selection and accumulation of this 3R mutation resulted from the antiviral ability of these Gag28-specific CTLs and high prevalence of HLA-A24:02 in a Japanese population. The present study highlighted the mechanisms for the roles of cross-reactive and mutant-epitope-specific CTLs, as well as high accumulation of escape mutants, in an HIV-1-infected population.
Kazutaka Honda, Nan Zheng, Hayato Murakoshi, Masao Hashimoto, Keiko Sakai, Mohamed Ali Borghan, Takayuki Chikata, Madoka Koyanagi, Yoshiko Tamura, Hiroyuki Gatanaga, Shinichi Oka, and Masafumi Takiguchi, Selection of escape mutant by HLA-C-restricted HIV-1 Pol-specific cytotoxic T lymphocytes carrying strong ability to suppress HIV-1 replication. Eur. J. Immunol.@41:97-106, 2011
HIV-1 mutants escaping from HLA-A- or HLA-B-restricted CTL have been well studied, but those from HLA-C-restricted CTL have not. Therefore we investigated the ability of HLA-C-restricted CTL to select HIV-1 escape mutants. In the present study, we identified two novel HLA-Cw(*) 1202-restricted Pol-specific CTL epitopes (Pol328-9 and Pol463-10). CTL specific for these epitopes were detected in 25-40% of chronically HIV-1-infected HLA-Cw(*) 1202(+) individuals and had strong abilities to kill HIV-1-infected cells and to suppress HIV-1 replication in vitro, suggesting that these CTL may have the ability to effectively control HIV-1 in some HLA-Cw(*) 1202(+) individuals. Sequence analysis of these epitopes showed that a V-to-A substitution at the 9th position (V9A) of Pol 463-10 was significantly associated with the HLA-Cw(*) 1202 allele and that the V9A mutant was slowly selected in the HLA-Cw(*) 1202(+) individuals. Pol 463-10-specific CTL failed both to kill the V9A virus-infected cells and to suppress replication of the V9A mutant. These results indicate that the V9A mutation was selected as an escape mutant by the Pol463-10-specific CTL. The present study strongly suggests that some HLA-C-restricted CTL have a strong ability to suppress HIV-1 replication so that they can select HIV escape mutants as in the case of HLA-A-restricted or HLA-B-restricted CTL.