Killer cell immunoglobulin-like receptor three domains long cytoplasmic tail 1 gene *007 may modulate disease progression of human immunodeficiency virus-1 infection in the Japanese population.

One of the KIR allele, KIR3DL1*007, was associated with the progression to acquired immunodeficiency syndrome and not with the susceptibility to HIV-1 infection in the Japanese and Indian populations, implying that KIR3DL1*007-positive NK cells might eliminate HIV-infected cells less effectively than NK cells bearing the other KIR3DL1 alleles or KIR3DS1 alleles.

Determination of a T cell receptor of potent CD8+ T cells against simian immunodeficiency virus infection in Burmese rhesus macaques.

Cumulative studies on human immunodeficiency virus (HIV)-infected individuals have shown association of major histocompatibility complex class I (MHC-I) polymorphisms with lower viral load and delayed AIDS progression, suggesting that HIV replication can be controlled by potent CD8+ T-cell responses. We have previously established an AIDS model of simian immunodeficiency virus (SIV) infection in Burmese rhesus macaques and found a potent CD8+ T cell targeting the Mamu-A1*065:01-restricted Gag241-249 epitope, which is located in a region corresponding to the HIV Gag240-249 TW10 epitope restricted by a protective MHC-I allele, HLA-B*57. In the present study, we determined a T cell receptor (TCR) of this Gag241-249 epitope-specific CD8+ T cell. cDNA clones encoding TCR-α and TCR-ß chains were obtained from a Gag241-249-specific CD8+ T-cell clone. Coexpression of these TCR-α and TCR-ß cDNAs resulted in reconstitution of a functional TCR specifically detected by Gag241-249 epitope-Mamu-A1*065:01 tetramer. Two of three previously-reported CD8+ T-cell escape mutations reduced binding affinity of Gag241-249 peptide to Mamu-A1*065:01 but the remaining one not. This is consistent with the data obtained by molecular modeling of the epitope-MHC-I complex and TCR. These results would contribute to understanding how viral CD8+ T-cell escape mutations are selected under structural constraint of viral proteins.

MRTF-A regulates proliferation and survival properties of pro-atherogenic macrophages.

We have previously reported that promoter polymorphism of myocardin-related transcription factor A (MRTF-A) is associated with coronary atherosclerosis. However, the contribution of MRTF-A to the development of atherosclerosis remains unknown. Macrophages are known to be important mediators of atherosclerosis. It has been demonstrated that local proliferation and survival of macrophages are atherogenic. In this study, we found that MRTF-A was highly expressed in lesional macrophages in human carotid atherosclerotic plaque. We then investigated the role of macrophagic MRTF-A in the pathogenesis of atherosclerosis. ApoE null MRTF-A transgenic mice (ApoE-/-/MRTF-Atg/+), in which human MRTF-A was specifically overexpressed in monocytes/macrophages, were established and fed with normal diet to examine the progression of atherosclerosis. We found that ApoE-/-/MRTF-Atg/+ aggravated atherosclerosis and lesional macrophages were more prominently accumulated in the aortic sinus of ApoE-/-/MRTF-Atg/+ than in that of ApoE-/- littermates. We also found that MRTF-A promoted proliferation and mitigated apoptosis of macrophages both in vitro and in vivo, and down regulated the expression of cyclin-dependent kinase inhibitors. From these findings, we conclude that MRTF-A modulates functional properties of pro-atherogenic macrophages. Our study may play a valuable role in understanding the pathological role of macrophagic MRTF-A in the progression of atherosclerosis.

MKL1 expressed in macrophages contributes to the development of murine colitis.

Mice deficient in the megakaryoblastic leukaemia 1 (Mkl1) gene experience less severe dextran sulphate sodium (DSS)-induced colitis, implying that Mkl1 plays a pathological role in inflammatory bowel disease (IBD). However, the contribution of Mkl1 to the development of colitis remains to be elucidated. The expression of Mkl1 is higher in the colonic lamina propria macrophages (LPMac) of DSS-treated mice than in those of control mice. Therefore, we established a transgenic mouse line that overexpresses human MKL1 (MKL1-Tg) specifically in cells of the monocyte/macrophage lineage, in order to investigate the potential role of macrophage MKL1 in the pathogenesis of colitis. MKL1-Tg mice displayed spontaneous colon shortening and rectal prolapse. Flow cytometric and quantitative RT-PCR analyses revealed that, in MKL1-Tg mice compared to littermate controls, the population of LPMac was decreased and had an altered inflammatory phenotype indicative of impaired anti-inflammatory properties, whereas bone marrow-derived macrophages from MKL1-Tg mice skewed towards M1 polarisation. In addition, MKL1-Tg mice had higher susceptibility to DSS-induced colitis than their littermate controls. These observations indicated that MKL1 crucially contributes to the development of colitis via the regulation of the function of macrophages, suggesting that it may be a potential therapeutic target for the prevention of IBD.

Association of lymph-node antigens with lower Gag-specific central-memory and higher Env-specific effector-memory CD8(+) T-cell frequencies in a macaque AIDS model.

Virus-specific CD8(+) T cells exert strong suppressive pressure on human/simian immunodeficiency virus (HIV/SIV) replication. These responses have been intensively examined in peripheral blood mononuclear cells (PBMCs) but not fully analyzed in lymph nodes (LNs), where interaction between CD8(+) T cells and HIV/SIV-infected cells occurs. Here, we investigated target antigen specificity of CD8(+) T cells in LNs in a macaque AIDS model. Analysis of virus antigen-specific CD8(+) T-cell responses in the inguinal LNs obtained from twenty rhesus macaques in the chronic phase of SIV infection showed an inverse correlation between viral loads and frequencies of CD8(+) T cells with CD28(+) CD95(+) central memory phenotype targeting the N-terminal half of SIV core antigen (Gag-N). In contrast, analysis of LNs but not PBMCs revealed a positive correlation between viral loads and frequencies of CD8(+) T cells with CD28(-)CD95(+) effector memory phenotype targeting the N-terminal half of SIV envelope (Env-N), soluble antigen. Indeed, LNs with detectable SIV capsid p27 antigen in the germinal center exhibited significantly lower Gag-N-specific CD28(+) CD95(+) CD8(+) T-cell and higher Env-N-specific CD28(-)CD95(+) CD8(+) T-cell responses than those without detectable p27. These results imply that core and envelope antigen-specific CD8(+) T cells show different patterns of interactions with HIV/SIV-infected cells.

A DFNA5 mutation identified in Japanese families with autosomal dominant hereditary hearing loss.

Mutations in DFNA5 lead to autosomal dominant nonsyndromic hereditary hearing loss (NSHHL). To date, four different mutations in DFNA5 have been reported to cause hearing loss. A 3 bp deletion mutation (c.991-15_991-13del) was identified in Chinese and Korean families with autosomal dominant NSHHL, which suggested that the 3 bp deletion mutation was derived from a single origin. In the present study, we performed genetic screening of mutations in the interval between intron 6 and exon 9 of DFNA5 in 65 Japanese patients with autosomal dominant NSHHL and identified the c.991-15_991-13del mutation in two patients. Furthermore, we compared the DFNA5-linked haplotypes consisting of intragenic SNPs between the reported Chinese and Korean families and found that the Japanese patients showed a shared region spanning 41,874 bp. This is the first report of DFNA5 mutations in Japanese patients with autosomal dominant NSHHL, supporting the suggestion that the 3 bp deletion mutation occurred in their ancestors.

Control of simian immunodeficiency virus replication by vaccine-induced Gag- and Vif-specific CD8+ T cells.

For development of an effective T cell-based AIDS vaccine, it is critical to define the antigens that elicit the most potent responses. Recent studies have suggested that Gag-specific and possibly Vif/Nef-specific CD8(+) T cells can be important in control of the AIDS virus. Here, we tested whether induction of these CD8(+) T cells by prophylactic vaccination can result in control of simian immunodeficiency virus (SIV) replication in Burmese rhesus macaques sharing the major histocompatibility complex class I (MHC-I) haplotype 90-010-Ie associated with dominant Nef-specific CD8(+) T-cell responses. In the first group vaccinated with Gag-expressing vectors (n = 5 animals), three animals that showed efficient Gag-specific CD8(+) T-cell responses in the acute phase postchallenge controlled SIV replication. In the second group vaccinated with Vif- and Nef-expressing vectors (n = 6 animals), three animals that elicited Vif-specific CD8(+) T-cell responses in the acute phase showed SIV control, whereas the remaining three with Nef-specific but not Vif-specific CD8(+) T-cell responses failed to control SIV replication. Analysis of 18 animals, consisting of seven unvaccinated noncontrollers and the 11 vaccinees described above, revealed that the sum of Gag- and Vif-specific CD8(+) T-cell frequencies in the acute phase was inversely correlated with plasma viral loads in the chronic phase. Our results suggest that replication of the AIDS virus can be controlled by vaccine-induced subdominant Gag/Vif epitope-specific CD8(+) T cells, providing a rationale for the induction of Gag- and/or Vif-specific CD8(+) T-cell responses by prophylactic AIDS vaccines.

Impact of vaccination on cytotoxic T lymphocyte immunodominance and cooperation against simian immunodeficiency virus replication in rhesus macaques.

Cytotoxic T lymphocyte (CTL) responses play a central role in viral suppression in human immunodeficiency virus (HIV) infections. Prophylactic vaccination resulting in effective CTL responses after viral exposure would contribute to HIV control. It is important to know how CTL memory induction by vaccination affects postexposure CTL responses. We previously showed vaccine-based control of a simian immunodeficiency virus (SIV) challenge in a group of Burmese rhesus macaques sharing a major histocompatibility complex class I haplotype. Gag(206-216) and Gag(241-249) epitope-specific CTL responses were responsible for this control. In the present study, we show the impact of individual epitope-specific CTL induction by prophylactic vaccination on postexposure CTL responses. In the acute phase after SIV challenge, dominant Gag(206-216)-specific CTL responses with delayed, naive-derived Gag(241-249)-specific CTL induction were observed in Gag(206-216) epitope-vaccinated animals with prophylactic induction of single Gag(206-216) epitope-specific CTL memory, and vice versa in Gag(241-249) epitope-vaccinated animals with single Gag(241-249) epitope-specific CTL induction. Animals with Gag(206-216)-specific CTL induction by vaccination selected for a Gag(206-216)-specific CTL escape mutation by week 5 and showed significantly less decline of plasma viral loads from week 3 to week 5 than in Gag(241-249) epitope-vaccinated animals without escape mutations. Our results present evidence indicating significant influence of prophylactic vaccination on postexposure CTL immunodominance and cooperation of vaccine antigen-specific and non-vaccine antigen-specific CTL responses, which affects virus control. These findings provide great insights into antigen design for CTL-inducing AIDS vaccines.

Diversity of MHC class I haplotypes in cynomolgus macaques.

Cynomolgus macaques are widely used as a primate model for human diseases associated with an immunological process. Because there are individual differences in immune responsiveness, which are controlled by the polymorphic nature of the major histocompatibility (MHC) locus, it is important to reveal the diversity of MHC in the model animal. In this study, we analyzed 26 cynomolgus macaques from five families for MHC class I genes. We identified 32 Mafa-A, 46 Mafa-B, 6 Mafa-I, and 3 Mafa-AG alleles in which 14, 20, 3, and 3 alleles were novel. There were 23 MHC class I haplotypes and each haplotype was composed of one to three Mafa-A alleles and one to five Mafa-B alleles. Family studies revealed that there were two haplotypes which contained two Mafa-A1 alleles. These observations demonstrated further the complexity of MHC class I locus in the Old World monkey.

Major histocompatibility complex class I-restricted cytotoxic T lymphocyte responses during primary simian immunodeficiency virus infection in Burmese rhesus macaques.

Major histocompatibility complex class I (MHC-I)-restricted CD8(+) cytotoxic T lymphocyte (CTL) responses are crucial for the control of human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) replication. In particular, Gag-specific CTL responses have been shown to exert strong suppressive pressure on HIV/SIV replication. Additionally, association of Vif-specific CTL frequencies with in vitro anti-SIV efficacy has been suggested recently. Host MHC-I genotypes could affect the immunodominance patterns of these potent CTL responses. Here, Gag- and Vif-specific CTL responses during primary SIVmac239 infection were examined in three groups of Burmese rhesus macaques, each group having a different MHC-I haplotype. The first group of four macaques, which possessed the MHC-I haplotype 90-010-Ie, did not show Gag- or Vif-specific CTL responses. However, Nef-specific CTL responses were elicited, suggesting that primary SIV infection does not induce predominant CTL responses specific for Gag/Vif epitopes restricted by 90-010-Ie-derived MHC-I molecules. In contrast, Gag- and Vif-specific CTL responses were induced in the second group of two 89-075-Iw-positive animals and the third group of two 91-010-Is-positive animals. Considering the potential of prophylactic vaccination to affect CTL immunodominance post-viral exposure, these groups of macaques would be useful for evaluation of vaccine antigen-specific CTL efficacy against SIV infection.

Polymorphisms of NKG2D ligands: diverse RAET1/ULBP genes in northeastern Thais.

Unique long 16 (UL-16)-binding proteins (ULBP) or retinoic acid early transcripts-1 (RAET1) are ligands to the activating receptor, NKG2D. The human RAET1/ULBP gene family is identified as ten members (RAET1E to N) with six loci encoding for potentially functional proteins. These are ULBP1 or RAET1I, ULBP2 or RAET1H, ULBP3 or RAET1N, and RAET1L, which are glycosylinositol phospholipid (GPI)-linked glycoproteins and ULBP4 or RAET1E and ULBP5 or RAET1G, which are transmembrane glycoproteins. The RAET1 products contain the alpha1 and alpha2 domains but lack the alpha3 domain and do not associate with beta2-microglobulin. RAET1/ULBPs have tissue-specific expressions, and some of them are also polymorphic. In the present study, polymorphic exons 2 and 3 of the RAET1E, G, H, I, L, and N were analyzed using sequence-based typing. One hundred and seventy-six unrelated healthy Northeastern Thais were included in this study. For RAET1E, RAET1G, RAET1H, and RAET1L, there were seven, two, five, and four single nucleotide polymorphisms (SNPs), respectively. Six of these are new SNPs, which are rare in this population. Of these, six new SNPs, two of two in RAET1E, two of three in RAET1H, and none of one in RAET1L are nonsynonymous substitutions. Interestingly, although the RAET1N is polymorphic in Caucasians, RAET1N and RAET1I had no variation in Thais indicating diverse RAET1 genes in different ethnic groups. These data provide the important basis for future analysis on the role of RAET1 genes in immune responses especially in cancer and infectious diseases.

Mapping of susceptibility and protective loci for acute GVHD in unrelated HLA-matched bone marrow transplantation donors and recipients using 155 microsatellite markers on chromosome 22.

Despite matching donors and recipients for the human leukocyte antigens (HLAs) expressed by the major histocompatibility genomic region of the short arm of chromosome 6, several recipients still develop acute graft-versus-host disease (aGVHD) after bone marrow transplantation (BMT). This is possibly due to non-HLA gene polymorphisms, such as minor histocompatibility antigens (mHas) and genes coding for cytokines. However, a detailed genetic background for aGVHD has not yet been established. To find novel susceptibility and/or protective loci for aGVHD, a whole genome-wide association study of donors and recipients needs to be performed. As the first step to such a study, we retrospectively analyzed polymorphisms of 155 microsatellite markers spread across the long arm of chromosome 22 in 70 pairs of HLA-matched unrelated BMT donors and recipients. We performed individual typing and then compared the markers' allele frequencies (1) between all the aGVHD (grades III and IV GVHD) and GVHD-free (grade 0 GVHD) groups in donors and recipients and (2) between the aGVHD and aGVHD-free groups in donor/recipient pairs that were matched and mismatched for the microsatellite marker's allele. Screening of the microsatellite markers revealed five loci with a significant difference between the aGVHD and GVHD-free groups and revealed eight loci on chromosome 22, where the microsatellite allele mismatched markers were associated with aGVHD. This screening analysis suggests that several aGVHD-associated susceptible and protective loci exist on chromosome 22, which may encompass novel gene regions that need to be elucidated for their role in aGVHD.