Circulating tumor DNA methylation marker MYO1-G for diagnosis and monitoring of colorectal cancer.

BACKGROUND: Circulating tumor DNA (ctDNA) is a promising diagnostic and prognostic marker for many cancers and has been actively investigated in recent years. Previous studies have already demonstrated the potential use of ctDNA methylation markers in the diagnosis and prognostication of colorectal cancer (CRC). This retrospective study validated the value of methylation biomarker MYO1-G (cg10673833) in CRC diagnosis and disease monitoring using digital droplet PCR (ddPCR), a biomarker selected from our previous study due to its highest diagnostic efficiency. METHODS: Blood samples of CRC and control samples from tumor-free individuals at two institutions were collected to quantify the methylation ratio using ddPCR. Area under curve (AUC) was calculated after constructing receiver operating characteristic curve (ROC) for CRC diagnosis. Sensitivity and specificity were estimated and comparisons of methylation ratio in different groups were performed. RESULTS: We collected 673 blood samples from 272 patients diagnosed with stage I-IV CRC and 402 normal control samples. The methylation biomarker discriminated patients with CRC from normal controls with high accuracy (area under curve [AUC] = 0.94) and yielded a sensitivity of 84.3% and specificity of 94.5%. Besides, methylation ratio of MYO1-G was associated with tumor burden and treatment response. The methylation ratio was significantly lower in patients after their radical operation than when compared with those before surgeries (P < 0.001). Methylation ratio was significantly higher in patients with disease progression than those with stable disease (P = 0.002) and those with complete response or partial response (P = 0.009). CONCLUSIONS: Together, our study indicated that this methylation marker can serve as a potential biomarker for diagnosing and monitoring CRC.

Expression of glutamine metabolism-related proteins in Hürthle cell neoplasm of thyroid: Comparison with follicular neoplasm.

PURPOSE: We evaluated the expression of glutaminolysis-related proteins in Hurthle cell neoplasms (HCN) and follicular neoplasms (FN) of the thyroid, and investigated its clinical implication. METHODS: Tissue microarrays were constructed from 264 FNs (112 follicular carcinomas [FCs] and 152 follicular adenomas [FAs]) and 108 HCNs (27 Hurthle cell carcinomas [HCCs] and 81 Hurthle cell adenomas [HCAs]. The immunohistochemical staining result of 3 glutaminolysis-related proteins (Glutaminase 1 [GLS1], glutaminate dehydrogenase [GDH] and alanine- serine, cysteine-preferring transporter 2 [ASCT2]) was analyzed. RESULTS: GLS1 and GDH showed significantly higher expression rates in HCN compared to FN (P<0.001). More HCN cases showed co-positivity of multiple glutaminolysis-related proteins than those of FN cases (P<0.001). In silico analysis, both GLUD1 and GLUD2 showed higher expression rate in HCA compared to FA (P=0.027 and P=0.018, respectively). SLC1A5 expression was highest in HCA, followed by FC and FA (HCA vs FC, P=0.023; FC vs FA, P=0.002). CONCLUSION: FN and HCN exhibit a different expression pattern for glutaminolysis-related proteins, and GLS1 and GDH have higher expression rates in HCN and FN.

Natural Killer T Cells and Mucosal-Associated Invariant T Cells in Lung Infections.

The immune system has been traditionally divided into two arms called innate and adaptive immunity. Typically, innate immunity refers to rapid defense mechanisms that set in motion within minutes to hours following an insult. Conversely, the adaptive immune response emerges after several days and relies on the innate immune response for its initiation and subsequent outcome. However, the recent discovery of immune cells displaying merged properties indicates that this distinction is not mutually exclusive. These populations that span the innate-adaptive border of immunity comprise, among others, CD1d-restricted natural killer T cells and MR1-restricted mucosal-associated invariant T cells. These cells have the unique ability to swiftly activate in response to non-peptidic antigens through their T cell receptor and/or to activating cytokines in order to modulate many aspects of the immune response. Despite they recirculate all through the body via the bloodstream, these cells mainly establish residency at barrier sites including lungs. Here, we discuss the current knowledge into the biology of these cells during lung (viral and bacterial) infections including activation mechanisms and functions. We also discuss future strategies targeting these cell types to optimize immune responses against respiratory pathogens.

Upregulated EBI3 Correlates with Poor Outcome and Tumor Progression in Breast Cancer.

BACKGROUND AND AIM: So far, the understanding of the role of Epstein-Barr virus-induced gene 3 (EBI3) in breast cancer has been limited. This study uncovers the functional role and clinical significance of EBI3 in breast cancer patients. PATIENTS AND METHODS: The expression levels of EBI3, IL-27p28, and IL-12p35 were measured by quantitative real-time reverse transcription (RT)-polymerase chain reaction (PCR). Correlations of EBI3 expression with IL-27p28 and IL-12p35 expression were analyzed using Pearson's correlation assay. The prognostic performance of EBI3 was assessed via Kaplan-Meier survival assay and Cox regression analysis. RESULTS: EBI3 expression was increased in cancerous tissues compared with the controls (P < 0.05). This overexpression of EBI3 was correlated with lymph node metastasis and clinical stage (both P < 0.05). Besides, elevated expression of EBI3 was usually found in patients with positive lymph node metastasis (P < 0.05), and similar results were obtained in advanced clinical-stage breast cancer cases (P < 0.05). Increases in both IL-27p28 and IL-12p35 expression were identified in breast cancer tissues (all P < 0.05), and IL-12p35 expression was found to be associated with EBI3 expression (R = 0.888, P < 0.001). Survival curves revealed that high EBI3 expression was correlated with poor overall survival (log-rank P < 0.05). The Cox analysis indicated that EBI3 was an independent prognostic factor in breast cancer. CONCLUSION: Taken together, overexpression of EBI3 was associated with poor prognosis and might be involved in the progression of breast cancer.

Identification of genes involved in the four stages of colorectal cancer: Gene expression profiling.

BACKGROUND: Colorectal cancer (CRC) is a common cancer with high morbidity and mortality. However, its molecular mechanism is not clear, nor the genes related to CRC stages. METHODS: Gene expression data in CRC and healthy colorectal tissues were obtained from gene expression omnibus. Limma package was used to identify the differentially expressed genes (DEGs) between control and CRC (stage I, II, III, and IV), obtaining 4 DEG sets. VennPlex was utilized to find all DEGs and intersection DEGs. Functional interactions between all DEGs and protein-protein interactions (PPIs) between intersection DEGs were analyzed using ReactomeFIViz and STRING, respectively, and networks were visualized. Known CRC-related genes were down-loaded from Comparative Toxicogenomics Database and mapped to PPI network. RESULTS: Totally, 851, 760, 729, and 878 DEGs were found between control and CRC stage I, II, III, and IV, respectively. Taken together, 1235 DEGs were found, as well as 128 up-regulated intersection DEGs, 365 down-regulated intersection DEGs, and 0 contra-regulated DEG. A functional interaction network of all DEGs and a PPI network of intersection DEGs were constructed, in which CDC20, PTTG1, and MAD2L1 interacted with BUB1B; UGT2B17 interacted with ADH1B; MCM7 interacted with MCM2. BUB1B, ADH1B, and MCM2 were known CRC-related genes. Gradually upregulated expressions of CDC20, PTTG1, MAD2L1, UGT2B17, and MCM7 in stage I, II, III, and IV CRC were confirmed by using quantitative PCR. Besides, up-regulated intersection DEGs enriched in pathways about Cell cycle, DNA replication, and p53 signaling. CONCLUSION: CDC20, PTTG1, MAD2L1, UGT2B17, and MCM7 might be CRC stage-related genes.

Intact Protein Analysis at 21 Tesla and X-Ray Crystallography Define Structural Differences in Single Amino Acid Variants of Human Mitochondrial Branched-Chain Amino Acid Aminotransferase 2 (BCAT2).

Structural technologies are an essential component in the design of precision therapeutics. Precision medicine entails the development of therapeutics directed toward a designated target protein, with the goal to deliver the right drug to the right patient at the right time. In the field of oncology, protein structural variants are often associated with oncogenic potential. In a previous proteogenomic screen of patient-derived glioblastoma (GBM) tumor materials, we identified a sequence variant of human mitochondrial branched-chain amino acid aminotransferase 2 as a putative factor of resistance of GBM to standard-of-care-treatments. The enzyme generates glutamate, which is neurotoxic. To elucidate structural coordinates that may confer altered substrate binding or activity of the variant BCAT2 T186R, a ~45 kDa protein, we applied combined ETD and CID top-down mass spectrometry in a LC-FT-ICR MS at 21 T, and X-Ray crystallography in the study of both the variant and non-variant intact proteins. The combined ETD/CID fragmentation pattern allowed for not only extensive sequence coverage but also confident localization of the amino acid variant to its position in the sequence. The crystallographic experiments confirmed the hypothesis generated by in silico structural homology modeling, that the Lys59 side-chain of BCAT2 may repulse the Arg186 in the variant protein (PDB code: 5MPR), leading to destabilization of the protein dimer and altered enzyme kinetics. Taken together, the MS and novel 3D structural data give us reason to further pursue BCAT2 T186R as a precision drug target in GBM. Graphical Abstract ᅟ.

Visualization of Endoplasmic Reticulum Aminopeptidase 1 under Different Redox Conditions with a Two-Photon Fluorescent Probe.

Endoplasmic reticulum aminopeptidase 1 (ERAP1), a metallopeptidase belonging to the M1 peptidase family, plays an important role in antigen processing in vivo. Additionally, many diseases are caused by ERAP1 perturbation. Thus, an efficient method for monitoring its content is extremely important for disease diagnosis and treatment. However, few fluorescent probes have been reported for efficiently monitoring ERAP1 in living cells and tissues. In this work, a two-photon fluorescent probe (SNCL) containing 1,8-naphthalimide (two-photon fluorophore), l-leucine (trigger moiety), and a methyl sulfonamide moiety (endoplasmic reticulum-targeting group) for imaging ERAP1 activity in living cells is reported for the first time. The optimized probe exhibited high sensitivity toward ERAP1, with about a 95-fold fluorescence enhancement at 550 nm. Herein, we monitored ERAP1 with SNCL by introducing interferon-γ to induce ERAP1 activity in living cells. The content of ERAP1 was dependent on the redox state of the endoplasmic reticulum, which was demonstrated by using SNCL to monitor the enzymatic activity of ERAP1 under different redox conditions. Excitingly, SNCL was also successfully applied for monitoring ERAP1 in tumor tissue with an imaging depth of 50-120 µm. In conclusion, SNCL not only can be used for the sensitive detection of endogenous ERAP1 in living cells and tumor tissues but also can serve as a potentially useful tool to reveal ERAP1-related diseases.

Vav3 is linked to poor prognosis of pancreatic cancers and promotes the motility and invasiveness of pancreatic cancer cells.

BACKGROUND/OBJECTIVES: The aim of this study was to investigate the role of the guanine nucleotide exchange factor Vav3 in the motility and invasiveness of pancreatic ductal adenocarcinoma (PDAC) cells. METHODS: Immunohistochemistry was used to determine whether high Vav3 expression in human PDAC tissues is correlated with poor prognosis. Immunocytochemistry was used to determine the association and intracellular distribution of Vav3, Rac1 and Akt in PDAC cells. Phosphoprotein array analysis was performed to determine the Vav3-associated intracellular signaling pathways. Immunocytochemistry and Matrigel invasion assays were used to examine the effects of Vav3 on the formation of cell protrusions and PDAC cell invasion. RESULTS: Expression of Vav3 in PDAC tissue was significantly correlated with overall survival. Vav3 was localized in cell protrusions of migrating PDAC cells. Knockdown of Vav3 inhibited the motility and invasiveness of PDAC cells through a decrease in cell protrusions. The levels of active Rac1 or active Akt were not associated with the concentration of Vav3 in cell protrusions. The Vav3-dependent promotion of motility and invasiveness was not modulated by Rac1 or Akt. Additionally, knockdown of Vav3 increased phosphorylated WNK1 in PDAC cells, and knockdown of WNK1 inhibited the motility and invasiveness. This study suggests that Vav3 can be a useful marker for predicting the outcome of patients with PDAC and that Vav3 can promote PDAC cell motility and invasion through association with dephosphorylation of WNK1. CONCLUSIONS: Vav3 was accumulated in cell protrusions, contributed to the formation of membrane protrusions, and thereby increased the motility and invasiveness of PDAC cells.

[Frequency of minor histocompatibility antigens among Chilean blood donors]. / Frecuencia génica de antígenos menores de histocompatibilidad en la población chilena y estimación de sus efectos inmunológicos en el trasplante alogénico de progenitores hematopoyéticos.

BACKGROUND: Minor histocompatibility antigens (mHAgs) play a critical role in the immune responses associated with allogeneic stem cell transplantation, such as graft versus host disease (GVHD) and graft-versus-tumor (GVT). AIM: To determine the gene frequencies of the mHAgs HA-1, HA-2 and HA-8 in Chilean Blood Bank donors. MATERIAL AND METHODS: Blood from 192 blood donors was analyzed. The presence of haplotype HLA-A*02 was determined by flow cytometry. The frequency of mHAgs was determined by allele specific polymerase chain reaction in genomic DNA. RESULTS: Sixty one participants were carriers of the haplotype HLA-A*02. The relative allele frequency HA-1H was 45%, HA-Ir 55%, HA-2V 80.6%, HA-2M 19.4%, HA-8R 49.8% and HA-8P was 50.2%. Based on mHAgs disparity between HA-1, HA-2 or HA-8, the probability to generate a GVT response in HLA-A*02 individuals was 40%. CONCLUSIONS: The mHAgs frequency in Chilean population is under Hardy-Weinberg equilibrium and they are similar to those of other ethnic populations in the world.

Frecuencia génica de antígenos menores de histocompatibilidad en la población chilena y estimación de sus efectos inmunológicos en el trasplante alogénico de progenitores hematopoyéticos / Frequency of minor histocompatibility antigens among Chilean blood donors

Background: Minor histocompatibility antigens (mHAgs) play a critical role in the immune responses associated with allogeneic stem cell transplantation, such as graft versus host disease (GVHD) and graft-versus-tumor (GVT). Aim: To determine the gene frequencies of the mHAgs HA-1, HA-2 and HA-8 in Chilean Blood Bank donors. Material and Methods: Blood from 192 blood donors was analyzed. The presence of haplotype HLA-A*02 was determined by flow cytometry. The frequency of mHAgs was determined by allele specific polymerase chain reaction in genomic DNA. Results: Sixty one participants were carriers of the haplotype HLA-A*02. The relative allele frequency HA-1H was 45%, HA-Ir 55%, HA-2V 80.6%, HA-2M 19.4%, HA-8R 49.8% and HA-8P was 50.2%. Based on mHAgs disparity between HA-1, HA-2 or HA-8, the probability to generate a GVT response in HLA-A*02 individuals was 40%. Conclusions: The mHAgs frequency in Chilean population is under Hardy-Weinberg equilibrium and they are similar to those of other ethnic populations in the world.

Rapid identification of clinical relevant minor histocompatibility antigens via genome-wide zygosity-genotype correlation analysis.

PURPOSE: Identification of minor histocompatibility antigens (mHag) with classic methods often requires sophisticated technologies, determination, and patience. We here describe and validate a nonlaborious and convenient genetic approach, based on genome-wide correlations of mHag zygosities with HapMap single-nucleotide polymorphism genotypes, to identify clinical relevant mHags within a reasonable time frame. EXPERIMENTAL DESIGN: Using this approach, we sought for the mHag recognized by a HLA-DRB1*1501-restricted T-cell clone, isolated from a multiple myeloma patient during a strong graft-versus-tumor effect associated with acute graft-versus-host disease grade 3. RESULTS: In a period of 3 months, we determined the mHag phenotype of 54 HapMap individuals, deduced the zygosity of 20 individuals, defined the mHag locus by zygosity-genotype correlation analyses, tested the putative mHag peptides from this locus, and finally showed that the mHag is encoded by the arginine (R) allele of a nonsynonymous single-nucleotide polymorphism in the SLC19A1 gene. CONCLUSIONS: We conclude that this powerful and convenient strategy offers a broadly accessible platform toward rapid identification of mHags associated with graft-versus-tumor effect and graft-versus-host disease.

Hematopoietic stem cells and progenitors of chronic myeloid leukemia express leukemia-associated antigens: implications for the graft-versus-leukemia effect and peptide vaccine-based immunotherapy.

The cure of chronic myeloid leukemia (CML) patients following allogeneic stem cell transplantation (SCT) is attributed to graft-versus-leukemia (GVL) effects targeting alloantigens and/or leukemia-associated antigens (LAA) on leukemia cells. To assess the potential of LAA-peptide vaccines in eliminating leukemia in CML patients, we measured WT1, PR3, ELA2 and PRAME expression in CD34+ progenitor subpopulations in CML patients and compared them with minor histocompatibility antigens (mHAgs) HA1 and SMCY. All CD34+ subpopulations expressed similar levels of mHAgs irrespective of disease phase, suggesting that in the SCT setting, mHAgs are the best target for GVL. Furthermore, WT1 was consistently overexpressed in advanced phase (AdP) CML in all CD34+ subpopulations, and mature progenitors of chronic phase (CP) CML compared to healthy individuals. PRAME overexpression was limited to more mature AdP-CML progenitors only. Conversely, only CP-CML progenitors had PR3 overexpression, suggesting that PR1-peptide vaccines are only appropriate in CP-CML. Surface expression of WT1 protein in the most primitive hematopoietic stem cells in AdP-CML suggest that they could be targets for WT1 peptide-based vaccines, which in combination with PRAME, could additionally improve targeting differentiated progeny, and benefit patients responding suboptimally to tyrosine kinase inhibitors, or enhance GVL effects in SCT patients.

Refinement of molecular approaches to improve the chance of identification of hematopoietic-restricted minor histocompatibility antigens.

Minor histocompatibility antigens (mHAgs) constitute the target antigens of the T cell-mediated graft-versus-leukemia response after HLA-identical allogeneic stem cell transplantation (SCT). Several human mHAgs have been identified, but only a few are selectively expressed by hematopoietic cells representing potential targets for specific immunotherapy. Molecular approaches including cDNA library screening and genetic linkage analysis have been successfully applied to identify T cell-defined mHAgs, but each approach has its drawbacks which may lead to mis-identification of the mHAg of interest. We improved both molecular strategies to facilitate more robust identification of hematopoietic-restricted mHAgs. First, we adapted cDNA library cloning by using 293T cells with stable expression of the relevant MHC class I allele, CD80 and CD54. We demonstrated that cDNA library screening using this 293T expression system results in strong activation of cytotoxic T lymphocytes, which significantly contributes to improvement of the assay sensitivity. Second, we refined genetic linkage analysis using single nucleotide polymorphism (SNP) genotyping to narrow down the defined genetic region that holds the mHAg-encoding gene. We showed that SNP marker analysis provides additional information about the genetic position of the antigen-encoding gene. Application of these optimized molecular approaches will lead to more rapid and reliable molecular identification of hematopoietic-restricted mHAgs.

Tetanus toxoid provides efficient T-cell help for the induction of HA-1(H) cytotoxic T cells.

BACKGROUND: In vitro generation and expansion of leukemia-reactive T cells may improve the efficacy and specificity of cellular immunotherapy against hematologic malignancies in the context of allogeneic stem cell transplantation. Since the expression of minor histocompatibility antigen HA-1(H) is limited to hematopoietic cells, ex vivo generated HA-1(H)-specific CD8+ cytotoxic T lymphocytes (CTLs) can be used for adoptive immunotherapy. STUDY DESIGN AND METHODS: Numerous studies have shown that primary CTL induction from naïve precursors requires professional antigen-presenting cells. Here, the feasibility of ex vivo induction of HA-1(H)-specific CD8+ CTLs is demonstrated from unfractionated peripheral blood mononuclear cells (PBMNCs) from healthy blood donors when CD4+ T-cell help is provided during primary stimulation. As a stimulus for the induction of T-cell help, tetanus toxoid (TT) was used. RESULTS: After the second restimulation cycle, approximately 1 percent of CD8+ T cells stained positively with the HLA-A*0201/HA-1(H) pentamer. Positive T cells were further expanded more than 1000-fold by antigen-independent stimulation with anti-CD3/CD28 monoclonal antibodies. HA-1(H)-induced T cells showed the classical phenotype for CD8+ memory effector cells: the phenotype changed from a mixed CD45RA/RO phenotype to an activated phenotype characterized by high expression of CD45RO and no expression of CCR7. The generated T cells revealed a very potent CTL response, even at low E:T ratios. CONCLUSION: This study demonstrates that TT provides a very potent and cost-effective tool for the in vitro induction of antigen-specific CTLs from precursor PBMNCs that can easily be adapted to GMP conditions for translational purposes.

Therapeutic and diagnostic applications of minor histocompatibility antigen HA-1 and HA-2 disparities in allogeneic hematopoietic stem cell transplantation: a survey of different populations.

Minor histocompatibility antigens (mHags) HA-1 and HA-2 are encoded by biallelic loci, with immunogenic variants, HA-1H and HA-2V, which induce strong HLA-A2-restricted alloreactive T-cell responses, and nonimmunogenic counterparts, HA-1R and HA-2M, which represent functional null alleles that are poorly presented by HLA class I molecules. HA-1 and HA-2 are potential targets of selective graft-versus-leukemia and graft-versus-tumor reactivity after allogeneic hematopoietic stem cell transplantation (HSCT); however, these applications are restricted to a limited number of patients. Here, we show that a far more frequent application of HA-1 and HA-2 disparity relies on their use as markers for the state of host chimerism after allogeneic HSCT. We have determined allelic frequencies of 29.3% and 70.7% for HA-1H and HA-1R, respectively, and of 83.7% and 16.3% for HA-2V and HA-2M, respectively, in >200 healthy individuals from northern Italy. Similar frequencies were observed in nearly 100 patients affected by hematologic malignancies or solid tumors, thus showing that HA-1 and HA-2 variability are not associated with the presence of cancer. On the basis of these data, we predict that HA-1 and HA-2 can be used in 32.8% and 23.5% of Italian transplant patients, respectively, as markers for the state of host chimerism, whereas exploitation of disparity for these mHags for targeted immunotherapy will be possible in 10.7% and 1.1% of Italian patients, respectively. Retrospective HA-2 typing of bone marrow aspirates obtained from a patient during complete remission or recurrence of acute myeloid leukemia after haploidentical HSCT showed the feasibility of using HA-2 as a surrogate marker for disease monitoring. Because of an apparent north-south gradient for HA-1 allelic frequencies, with higher frequencies for the HA-1H variant reported in white populations from Southern Europe as compared with Northern Europe and North America, the diagnostic applicability of HA-1 disparity will be slightly more frequent in transplant patients from the north. Taken together, our data show that determination of HA-1 and HA-2 variability can be an important parameter for the selection of allogeneic stem cell donors, in particular for patients affected by hematologic malignancies without a tumor-specific molecular marker.

T cell-mediated graft-versus-leukemia reactions after allogeneic stem cell transplantation.

Allogeneic hematopoietic stem cell transplantation represents the only curative approach for many hematological malignancies. During the last years the impact of the conditioning regimen has been re-assessed. With the advent of reduced-intensity conditioning the paradigm has changed from cytoreduction executed by high-dose radio-chemotherapy to immunological surveillance of leukemia by donor cells. Distinct subsets of T cells and NK cells contribute to graft-versus-leukemia reactions. So far, cytotoxic T lymphocytes are the mainstay of allogeneic immunotherapy. Here, we summarise the current knowledge of T cell-mediated graft-versus-leukemia reactions and present results from pre-clinical and clinical studies of T cell-based adoptive immunotherapy. We address the issues of feasibility and specificity of adoptive immunotransfer from a clinical point of view and discuss the prerequisites for successful clinical applications. Finally, the prospects for immunological research that have evolved with the increasing use of reduced-intensity conditioning and allogeneic stem cell transplantation are highlighted.

Detection of microchimerism by minor histocompatibility antigen HA-1 allele-specific nested polymerase chain reaction.

Minor histocompatibility antigens (mHags) can induce T-cell reactivities with important consequences for the graft-versus-leukemia effect and the development of graft-versus-host disease in HLA-matched stem cell transplantation settings. Recently, mHag-specific T cells were also demonstrated in multiparous woman and in solid organ transplant recipients. Microchimeric cells have been detected in the latter settings. To study whether microchimerism is instrumental in the induction and/or maintenance of mHag T cells, we developed an HA-1 allele-specific nested polymerase chain reaction. To optimize and validate the reliability of this method at different levels of microchimerism, serial dilutions of HA-1(H) cells titrated into HA-1(R) cells were tested. We demonstrated that the HA-1(H) allele can be reliably and consistently detected at concentrations as low as 1:10(5) without losing specificity. The developed HA-1-specific nested polymerase chain reaction is an important tool that facilitates the detection of HA-1 microchimerism in various clinical specimens and that promotes investigation of the effects of microchimerism on induction of mHag-specific T cells in the various settings of immunization.

A class II-restricted cytotoxic T-cell clone recognizes a human minor histocompatibility antigen with a restricted tissue distribution.

Following a human leucocyte antigen (HLA)-identical allogeneic stem cell transplantation (allo-SCT), minor histocompatibility antigens (mHags) play an important role in the induction of graft-versus-leukaemia (GvL) and graft-versus-myeloma (GvM). Many mHags show ubiquitous tissue expression and are associated with GvL and graft-versus-host disease. Here we describe a cytotoxic CD4(+) T lymphocyte line and a cytotoxic, CD4(+) T cell clone (CTC), 3AB11, which recognized a tissue-restricted mHag. This CTC was isolated from a multiple myeloma patient with clinical GvM following an HLA-matched allo-SCT. CTC 3AB11 was activated in a HLA-DP*0401 restricted fashion and the antigen was expressed by 27% of HLA-DP*0401 positive Epstein-Barr virus (EBV)-transformed B-cell lines (EBV-B). Tissue distribution analysis of antigen 3AB11 showed it to be expressed by patient-derived EBV-transformed B cell lines (EBVp), the myeloma plasma cell-line UM9 and monocytes. It was weakly expressed by peripheral blood-derived phytohaemagglutinin-induced T-cell blasts and absent on CD40L stimulated peripheral B (CD40L B) cells and stromal cells. The relatively high prevalence of the HLA class II-restricted 3AB11 antigen, together with its apparent haematopoietic-restricted expression, makes it an antigen of interest for cellular immunotherapy.

Major histocompatibility antigens and antigen-processing molecules in uveal melanoma.

PURPOSE: Malignant transformation of cells is frequently associated with abnormalities in the human leukocyte antigen (HLA) expression. These abnormalities may play a role in the clinical course of the disease, because HLA antigens mediate interactions of tumor cells with T cells and natural killer cells. Uveal melanoma is a highly malignant tumor of the eye and is characterized by hematogenic spread to liver. Antigen-processing molecules (APMs) are necessary for efficient expression of HLA class I antigens. We studied the expression of HLA antigens and the APM in uveal melanomas by immunohistochemistry and correlated clinicopathologically. EXPERIMENTAL DESIGN: HLA class I antigen, beta(2)-microglobulin (beta(2)-m), HLA class II antigens, and the APM comprising proteasomal subunits low molecular mass polypeptide (LMP) 2, beta-subunit of LMP2-Delta, LMP 10, transporter associated protein 1 subunit, and chaperone molecules tapasin and calnexin were studied in 41 primary uveal melanoma archival specimens by immunohistochemistry. Immunoanalysis was done by a semiquantitative method and correlated with extrascleral extension, cell types, and the largest tumor diameter. RESULTS: HLA class I antigen, beta(2)-m, HLA class II antigen, and the APM were decreased (negative staining in 29 tumors and dull staining in 3 tumors) in 100% (32 of 32) uveal melanomas with no extrascleral extension. (P = 0.01) and positive (bright staining) in 67% (4 of 9) tumors with liver metastasis. Decreased immunoexpression of HLA antigens and the APM was seen in nonepithelioid cell melanomas. There was no correlation with largest tumor diameter. CONCLUSIONS: Our data suggest decreased expression of HLA, and APM are seen in uveal melanomas with no extrascleral extension and in nonepithelioid cell melanomas. Decreased expression of APM may contribute to decreased HLA class I antigen expression.