Novel Anti-CD70 Antibody Drug Conjugate for the Treatment of Adult T-Cell Leukemia (ATL).

BACKGROUND/AIM: Adult T-cell leukemia (ATL) is a hematological malignancy caused by infection with human T-cell leukemia virus type 1 (HTLV-1). Chemotherapy, antibody therapy, and bone marrow transplantation are used to treat this disease, however, median survival time has not been significantly improved. Our aim was to develop and evaluate a novel antibody-drug conjugate (ADC) with regards to cell cytotoxicity and target specificity. MATERIALS AND METHODS: In this study, we have constructed a novel ADC, which is composed of an anti-CD70 single chain Fv-Fc antibody conjugated with the anticancer agent emtansine using a novel antibody modification method. Cell cytotoxicity and target specificity were assessed using a cell proliferation assay. RESULTS: The anti-CD70 ADC selectively killed HTLV-1-infected cells and ATL cells without affecting other cells. CONCLUSION: The anti-CD70 ADC offers some chemotherapeutic potential for the treatment of ATL.

Auxiliary role for D-alanylated wall teichoic acid in Toll-like receptor 2-mediated survival of Staphylococcus aureus in macrophages.

We previously reported that Staphylococcus aureus avoids killing within macrophages by exploiting the action of Toll-like receptor 2 (TLR2), which leads to the c-Jun N-terminal kinase (JNK)-mediated inhibition of superoxide production. To search for bacterial components responsible for this event, a series of S. aureus mutants, in which the synthesis of the cell wall was interrupted, were screened for the level of JNK activation in macrophages. In addition to a mutant lacking the lipoproteins that have been suggested to act as a TLR2 ligand, two mutant strains were found to activate the phosphorylation of JNK to a lesser extent than the parental strain, and this defect was recovered by acquisition of the corresponding wild-type genes. Macrophages that had phagocytosed the mutant strains produced more superoxide than those engulfing the parental strain, and the mutant bacteria were more efficiently killed in macrophages than the parent. The genes mutated, dltA and tagO, encoded proteins involved in the synthesis of D-alanylated wall teichoic acid. Unlike a cell wall fraction rich in lipoproteins, D-alanine-bound wall teichoic acid purified from the parent strain by itself did not activate JNK phosphorylation in macrophages. These results suggest that the d-alanylated wall teichoic acid of S. aureus modulates the cell wall milieu for lipoproteins so that they effectively serve as a ligand for TLR2.

Japanese version of cutaneous body image scale: translation and validation.

Cutaneous body image, defined as the individual's mental perception of the appearance of their skin, hair and nails, is an important psychodermatological element in skin diseases. To measure individuals' cutaneous body image, a practical and accurate instrument is necessary. In this study, we translated the Cutaneous Body Image Scale (CBIS), a 7-item instrument originally created by Gupta et al. in 2004, into Japanese using a forward- and back-translation method and evaluated the reliability and validity of the instrument by psychometric tests. A total of 298 healthy adults (64 men and 234 women, aged 28.9 +/- 9.9 years) and 165 dermatology patients (56.7% eczema/dermatitis, 9.8% acne, 7.5% alopecia, 6.9% psoriasis, 19.1% skin tumor/fleck/other) (30 men and 135 women, aged 37.9 +/- 15.2 years) responded to the Japanese version of the CBIS. The internal-consistency reliability of the instrument was high (Cronbach's alpha, healthy adults 0.88, patients 0.84). The CBIS measure demonstrates good test-retest reliability (healthy adults gamma = 0.92, P < 0.0001; patients gamma = 0.79, P < 0.001). Compared to the healthy adults (4.11 +/- 1.80), the CBIS scores among dermatology patients (3.18 +/- 1.69, P = 0.000) were significantly low. The CBIS scores showed moderate correlation with the "emotions" and "global" scores of Skindex-16 in healthy adults (gamma = -0.397 and -0.373, respectively) and in patients (gamma = -0.431 and -0.38, respectively). A stepwise multiple regression analysis revealed that an emotional aspect of skin-condition related quality of life was the best predictor of cutaneous body image in both healthy adults and patients (beta = -0.31 and -0.41, respectively) followed by "body dissatisfaction" (beta = -0.17, and -0.23, respectively). Adjusted R(2) was 0.246 in healthy adults and 0.264 in patients. These were consistent with the results from the original the CBIS. These results suggest that the Japanese version of the CBIS is a reliable and valid instrument to measure the cutaneous body image of Japanese adults and also dermatology patients.

Bridging effect of recombinant human mannose-binding lectin in macrophage phagocytosis of Escherichia coli.

Mannose-binding lectin (MBL) exists in the serum as a complex with MBL-associated serine protease (MASP). A recent paper described how MASP-free recombinant rat MBL stimulates the phagocytosis of Escherichia coli and Staphylococcus aureus by rat Kupffer cells through an increase in the level of a phagocytosis receptor. We have examined the effect of human MBL on the phagocytic action of human macrophages. Purified recombinant human MBL stimulated the phagocytosis of E. coli by THP-1 macrophages, leaving that of latex beads, apoptotic human cells, zymosan particles or S. aureus unchanged. This stimulatory effect was observed when either phagocytes or targets were preincubated with MBL. Furthermore, MBL bound to THP-1 macrophages as well as to E. coli, but not to S. aureus, through lipid A. These results indicated that human MBL in the absence of MASP stimulates macrophage phagocytosis of E. coli by bridging targets and phagocytes.

Involvement of cannabinoid receptor CB2 in dectin-1-mediated macrophage phagocytosis.

Cannabinoid receptors are expressed in macrophages, but little is known of their roles. We here examined their involvement in phagocytosis. The presence of 2-arachidonylglycerol, an endocannabinoid, augmented the phagocytosis of zymosan by mouse macrophages, while the phagocytosis of Escherichia coli, Staphylococcus aureus, apoptotic cells or latex beads remained unaffected. An agonist of the cannabinoid receptors CB1 and CB2 also stimulated the phagocytosis of zymosan. The stimulatory effect of 2-arachidonylglycerol was abolished when phagocytosis reactions were carried out in the presence of an antagonist of CB2 but not of CB1. Furthermore, the phagocytosis of zymosan in the presence of 2-arachidonylglycerol was severely inhibited by the addition of a beta-glucan-containing carbohydrate or antibody neutralizing dectin-1, a beta-glucan-recognizing phagocytosis receptor. These results suggested that the activation of CB2 in macrophages leads to the stimulation of dectin-1-mediated phagocytosis.

TLR2-mediated survival of Staphylococcus aureus in macrophages: a novel bacterial strategy against host innate immunity.

TLR2 plays a role as a pattern-recognition receptor in the innate immune response involving secreted proteins against microbial pathogens. To examine its possible involvement in the cellular response, we determined the levels of the engulfment and subsequent killing of bacteria by macrophages prepared from TLR2-deficient and wild-type mice. The level of the engulfment of Staphylococcus aureus or Escherichia coli was almost the same between TLR2-lacking and wild-type macrophages. However, the colony-forming ability of engulfed S. aureus, but not of E. coli, decreased to a greater extent in TLR2-lacking macrophages than in the wild-type control. The incubation with S. aureus caused activation of JNK in wild-type macrophages but not in TLR2-lacking macrophages, and the pretreatment of wild-type macrophages with a JNK inhibitor increased the rate of killing of engulfed S. aureus, but again not of E. coli. In addition, the number of colonies formed by engulfed S. aureus increased in the JNK-dependent manner when TLR2-lacking macrophages were pretreated with LPS. Furthermore, JNK seemed to inhibit the generation of superoxide, not of NO, in macrophages. These results collectively suggested that the level of superoxide is reduced in macrophages that have engulfed S. aureus through the actions of TLR2-activated JNK, resulting in the prolonged survival of the bacterium in phagosomes. The same regulation did not influence the survival of E. coli, because this bacterium was more resistant to superoxide than S. aureus. We propose a novel bacterial strategy for survival in macrophages involving the hijacking of an innate immune receptor.

Inhibitory effect of Toll-like receptor 4 on fusion between phagosomes and endosomes/lysosomes in macrophages.

Toll-like receptor 4 (TLR4) of macrophages recognizes LPS of Gram-negative bacteria in cooperation with CD14, which is also involved in the recognition of apoptotic cells. In this study we asked whether TLR4 plays a role in the phagocytic clearance of apoptotic cells by macrophages. Macrophages were prepared from peritoneal fluid of thioglycolate-treated mice carrying either a wild-type or a disrupted TLR4-encoding gene and were examined for their ability to phagocytose apoptotic mouse thymocytes, apoptotic Jurkat T cells, Ig-opsonized mouse thymocytes, Ig-opsonized zymosan particles, and latex beads. Both populations of macrophages equally expressed CD14 on their surfaces and showed almost equal activities of binding to and engulfing all these targets. However, apoptotic thymocytes, apoptotic Jurkat cells, and opsonized thymocytes disappeared more rapidly in TLR4-deficient macrophages than in wild-type macrophages, and the fusion between endosomes/lysosomes and phagosomes containing any target cells or particles was accelerated in mutant macrophages. Activation of the transcription factor NF-kappaB appeared not to occur in wild-type macrophages after engulfment, and the rate of apoptotic cell degradation in wild-type macrophages remained the same regardless of the activation of NF-kappaB. Finally, immunohistochemical analyses showed that ectopically expressed TLR4 was associated with phagosomes in a macrophage-derived cell line. All these results collectively indicate that TLR4 negatively regulates the degradation of engulfed cells in macrophages via a pathway independent of NF-kappaB.