Antigen chemically coupled to the surface of liposomes are cross-presented to CD8+ T cells and induce potent antitumor immunity

We have previously demonstrated that liposomes with differential lipid components display differential adjuvant effects when Ags are chemically coupled to their surfaces. In the present study, Ag presentation of liposome-coupled OVA was investigated in vitro, and it was found that OVA coupled to liposomes made using unsaturated fatty acid was presented to both CD4+ and CD8+ T cells, whereas OVA coupled to liposomes made using saturated fatty acid was presented only to CD4+ T cells. Confocal laser scanning microscopic analysis demonstrated that a portion of the OVA coupled to liposomes made using unsaturated, but not saturated fatty acid, received processing beyond the MHC class II compartment, suggesting that the degradation of OVA might occur in the cytosol, and that the peptides generated in this manner would be presented to CD8+ T cells via MHC class I. The ability to induce cross-presentation of an Ag coupled to liposomes consisting of unsaturated fatty acid was further confirmed by in vivo induction of CTL and by the induction of tumor eradication in mice; E.G7 tumors in mice that received combined inoculation with OVA(257-264)-liposome conjugates, CpG, and anti-IL-10 mAbs were completely eradicated. In those mice, the frequency of CD8+ T cells reactive with OVA(257-264) peptides in the context of H-2K(b) was significantly increased. These results suggested that, by choosing lipid components for liposomes, surface-coupled liposomal Ags might be applicable for the development of tumor vaccines to present tumor Ags to APCs and induce antitumor responses.     

HIV+/AIDS related bioethical issues in Japan

Annual and cumulative incidences of HIV+ and AIDS in patients reported by the AIDS Surveillance Committee of the Ministry of Health and Welfare are cited to illustrate some characteristics in Japan: nearly 59% of either HIV+ or AIDS patients were infected through injection of blood products or by blood transfusion. A number of plaintiffs have sued the Japanese government and pharmaceutical companies since 1989, but no judicial decisions have yet been made. The incidence of HIV decreases for each of the following routes of infection: the second highest route of transmission being heterosexual, followed by bisexual and unconfirmed or unknown cases, and less frequently homosexual, drug use and lastly via vertical transmission. The most serious bioethical problems with HIV+ and AIDS patients in Japan is the social segregation of these patients. There are many emotional fears among the general public and medical personnel about AIDS because of their inadequate scientific knowledge of this disease. The Japan Hospital Association is doing The Stop AIDS Campaign and made several surveys. Japan has become increasingly aware of the importance of AIDS education and a great deal of effort is being made to enhance bioethical consideration.     

Small increase in triplet repeat length of cerebellum from patients with myotonic dystrophy

Myotonic dystrophy (DM) is genetically characterized by abnormal expansion of an unstable CTG trinucleotide repeat, located in the 3′-untranslated region of mRNA encoding the family of serine-threonine protein kinases. DNA extracted from various organs of patients with DM was analyzed by the Southern blotting method. We identified differently expanded bands in DNAs from various tissues from patients with DM. In studying the length of the CTG repeat in different regions of the brain, we found a noticeably small increase in repeat length in the cerebellum compared with other tissues. While this phenomenon has been reported in other triplet repeat diseases such as Huntington disease, spinocerebellar ataxia type 1, and dentatorubral-pallidoluysian atrophy, we are the first to describe it in DM. Although the mechanism of expansion of the triplet repeat remains to be defined, the tissue-dependent somatic mosaicism suggests that its occurrence may depend on the differentiated state of each tissue. Received: 18 October 1995 / Revised: 20 March 1996     

Plant regeneration via somatic embryogenesis from protoplasts of Uganda cherry orange (Citropsis schweinfurthii)

Protoplasts isolated from embryogenic callus of Citropsis schweinfurthii (Engl.) Swing. & M. Kell were cultured in MT (Murashige and Tucker 1969) basal medium containing 5% sucrose supplemented with 0.0, 0.001, 0.01, 0.1 or 1.0 mg l^–1 BA, 0, 300, 600 or 900 mg l^–1 malt extract and 0.6 M sorbitol. The highest plating efficiency was obtained on MT basal medium containing 5% sucrose supplemented with 0.01 mg l^–1 BA and 600 mg l^–1 malt extract. MT basal medium containing 5% sucrose and supplemented with 0.01 mg l^–1 kinetin was found to be a medium suitable for the development of globular somatic embryos derived from protoplasts into heart-shaped somatic embryos with cotyledon-like structures. The highest percentage of shoot formation was obtained using 0.1 mg l^–1 GA₃. A complete protoplast to-plant system was developed for C. schweinfurthii, which could facilitate the transfer of nuclear and cytoplasmic genes from this species into cultivated Citrus through protoplast fusion.Abbreviations BA N⁶-benzyladenine - 2,4-D 2,4-dichlorophenoxyacetic acid - FDA fluorescein diacetate - GA₃ gibberellin A₃ - ME malt extract     

Melanin Biosynthesis in Cryptococcus neoformans

Pigment production by Cryptococcus neoformans is virulence associated. Dopamine- and 3,4-dihydroxyphenylalanine–melanin products were identified after acidic permanganate oxidation, alkaline hydrogen peroxide oxidation, or hydrolysis with hydriodic acid. These data provide direct chemical evidence for the formation of eumelanin polymers by catecholamine oxidation by laccase alone followed by oxidative coupling of dihydroxyindole.     

Synthesis of creatol, a hydroxyl radical adduct of creatinine and its increase by puromycin aminonucleoside in isolated rat hepatocytes

Creatol is a hydroxyl radical adduct of creatinine and the precursor of methylguanidine (MG), a uremic toxin. We investigate the synthesis of creatol and MG from creatinine and the effect of substances that affect the hydroxyl radical in isolated rat hepatocytes. In the presence of increasing concentrations of creatinine, rising level of creatol were found after 2 h incubation in Krebs-Henseleit bicarbonate buffer. However, further increase of creatol was not observed after 4 and 6 h incubations. On the other hand, MG after 2 h incubation achieved a level of about 50% that of creatol and increased depending on both the creatinine concentration and the incubation period. DMSO, a hydroxyl radical scavenger decreased the generation of creatol and MG by about 50% at 2.5 mM and the inhibition depended on DMSO concentration. Puromycin aminonucleoside (PAN) increased both by about 170%. These findings demonstrated that hepatocytes synthesize creatol prior to MG and are inhibited by a hydroxyl radical scavenger. They also show that PAN increased hydroxyl radical generation in tissue cells.     

Red-winged blackbirds Agelaius phoeniceus use carotenoid and melanin pigments to color their epaulets

Over the past three decades, the red‐winged blackbird Agelaius phoeniceus has served as a model species for studies of sexual selection and the evolution of ornamental traits. Particular attention has been paid to the role of the colorful red‐and‐yellow epaulets that are striking in males but reduced in females and juveniles. It has been assumed that carotenoid pigments bestow the brilliant red and yellow colors on epaulet feathers, but this has never been tested biochemically. Here, we use high‐performance liquid chromatography (HPLC) to describe the pigments present in these colorful feathers. Two red ketocarotenoids (astaxanthin and canthaxanthin) are responsible for the bright red hue of epaulets. Two yellow dietary precursors pigments (lutein and zeaxanthin) are also present in moderately high concentrations in red feathers. After extracting carotenoids, however, red feathers remained deep brown in color. HPLC tests show that melanin pigments (primarily eumelanin) are also found in the red‐pigmented barbules of epaulet feathers, at an approximately equal concentration to carotenoids. This appears to be an uncommon feature of carotenoid‐based ornamental plumage in birds, as was shown by comparable analyses of melanin in the yellow feathers of male American goldfinches Carduelis tristis and the red feathers of northern cardinals Cardinalis cardinalis, in which we detected virtually no melanins. Furthermore, the yellow bordering feathers of male epaulets are devoid of carotenoids (except when tinged with a carotenoid‐derived pink coloration on occasion) and instead are comprised of a high concentration of primarily phaeomelanin pigments. The dual pigment composition of red epaulet feathers and the melanin‐only basis for yellow coloration may have important implications for the honesty‐reinforcing mechanisms underlying ornamental epaulets in red‐winged blackbirds, and shed light on the difficulties researchers have had to date in characterizing the signaling function of this trait. As in several other birds, the melanic nature of feathers may explain why epaulets are used largely to settle aggressive contests rather than to attract mates.     

Germline mutations of the RET proto-oncogene in eight Japanese patients with multiple endocrine neoplasia type 2A (MEN2A)

Multiple endocrine neoplasia type 2A (MEN2A) is a dominantly inherited cancer syndrome characterized by medullary thyroid carcinoma, pheochromocytoma, and parathyroid hyperplasia. The gene responsible for MEN2A was localized by linkage analysis to chromosome 10q11.2 in 1987, and recently mutations in RET, a proto-oncogene in the candidate region, were discovered in patients with MEN. The majority of mutations found so far in MEN2A patients have been located in nucleotide sequences encoding cysteine residues in the extracellular domain of RET. To characterize MEN2A germline alterations in the Japanese population, we screened DNA from eight unrelated patients for mutations in exons 10 and 11 of the RET proto-oncogene and found mutations in all eight patients, at codons 618, 620, or 634; each of these sites encodes a cysteine residue in the extracellular domain of RET. The mutations were confirmed in other affected individuals in the respective families by digestion of polymerase chain reaction (PCR) products containing the mutated codons with restriction enzymes (RsaI, CfoI, or AluI) for which cleavage sites had been generated by the specific genetic alteration. These PCR-restriction enzyme systems will be useful for genetic diagnosis in members of families carrying these mutations.