Suppressor cells in the effector phase of autologous cytotoxic reactions in cancer patients

Summary Cytotoxicity was induced in lymphocytes (CL) from 10 out of 15 patients by autologous mixed lymphocyte tumor cell culture and further cultivation with recombinant interleukin-2. In cells from 3 of the 10 patients, cytotoxicity was suppressed by more than 50% when autologous peripheral blood mononuclear cells (PBMC) from the patients with large tumors were added to the autologous killing system. The cells responsible for suppressing the cytotoxicity in the effector phase were adherent or nonadherent to plastic depending on the patient examined. The T cell fraction from 1 patient significantly suppressed the cytotoxic activity, and this suppression was seen only in the autologous system. On the other hand, plastic adherent cells but not T cells from PBMC of 2 subjects suppressed the cytotoxic activity of CL. The reason why the main cell population suppressing the CL activity differed among the patients is unclear. However, the findings that the suppression was mostly abrogated following resection of the tumor mass suggested that suppressor cells, either of macrophage lineage or T cells, are induced in patients with a large tumor mass. This speculation is supported by the finding that the PBMC from a patient with tumor recurrence regained the suppressive activity.     

Killer cells induced by stimulation with allogeneic tumor cells and subsequent culture with recombinant interleukin-2

Summary Peripheral blood lymphocytes were cultured for 5 days with allogeneic tumor cells (allogeneic mixed lymphocyte/tumor cell culture), and subsequently cultured with recombinant interleukin-2 for 12 days. These cultured cells were found to be cytotoxic to autologous tumor cells. Results of two-color analysis using monoclonal antibodies to cell markers showed that more than 80% of their cultured cells were CD3⁺ cells, and CD4⁺ cells showed a higher distribution than CD8⁺ cells. However, CD8⁺ cells had a much higher killing activity with autologous tumor than did CD4⁺ cells, when estimated by an elimination study using monoclonal antibodies to T cell phenotypes and complement. The cold-target inhibition test showed that the cytotoxicity of these cells for autologous tumor cells was inhibited by unlabeled autologous tumor cells but not by unlabeled stimulator cells. Furthermore, about 40% of the cytotoxicity was suppressed by blocking of HLA class I antigen with a monoclonal antibody on autologous tumor cells. Thus, cytotoxic activity of lymphocytes to autologous tumor restricted by target cell HLA class I antigen is possibly induced by allogeneic tumor-stimulation.     

Cervicovaginal and endometrial cytology in ovarian cancer

The clinical significance of cytologic examination was studied in 114 patients with ovarian cancer who had received preoperative cytologic examinations. The overall positive rate of the cytologic examinations was 26.3% (30 of 114): 22 (19.3%) of the 114 cases had positive cervicovaginal smears while 13 of 31 endometrial aspiration smears (41.9%) were positive. The positive rate was not related to the volume of ascites but rather to its presence or absence. Thus, if ascites was observed, the positive rate was about 2.1 times higher than if it was absent. In two of four cases of ovarian cancer with no endometrial invasion but a positive cytologic examination of ascitic fluid, fallopian tube specimens contained cancer cells; this suggests that ovarian cancer cells may reach the cervix and/or vagina by passing through the fallopian tube, particularly if ascites is present. Since cytologic examination, especially of endometrial aspiration smears, shows a high positive rate if ovarian cancer cells are observed in the abdominal cavity, cytology should be used as an important ancillary method for the assessment of ovarian cancer.     

A preliminary study on quantitative relations among growth,reproduction and mortality in fishes

As a quantitative approach to the life histories of fishes, the present paper attempted to predict a relation among reproduction, growth and mortality numerically with a technique of control theory, the discrete maximum principle. A method for predicting the relation was derived on the postulate that natural selection maximized the net reproductive rate subject to a few constraints. The derived method was applied to Atlantic cod and Atlantic herring populations in the Southern Gulf of St. Lawrence as numerical examples. The examples demonstrated that the theoretical reproductive effort and body weight were well consistent with the observed ones every age but the theoretical survival rates were slightly different from the observed ones. For the reasons mentioned below, however, it should be interpreted that the examples rather support the adopted postulate to a certain degree. First, in general, it is very difficult to obtain good estimates of the rates with traditional methods. Second, intense fishing pressure possibly changes the life history parameters to some extent in fish populations. Moreover, the examples also suggested that, to examine the postulate in further detail, similar analyses had to be made with the data of many fish populations on which intense fishing pressure had not been exerted.     

Hyaluronan synthesis in cultured tobacco cells (BY‐2) expressing a chlorovirus enzyme: Cytological studies

Extraction of hyaluronan from animals or microbial fermentation has risks including contamination with pathogens and microbial toxins. In this work, tobacco cultured‐cells (BY‐2) were successfully transformed with a chloroviral hyaluronan synthase (cvHAS) gene to produce hyaluronan. Cytological studies revealed accumulation of HA on the cells, and also in subcellular fractions (protoplasts, miniplasts, vacuoplasts, and vacuoles). Transgenic BY‐2 cells harboring a vSPO‐cvHAS construct containing the vacuolar targeting signal of sporamin connected to the N‐terminus of cvHAS accumulated significant amounts of HA in vacuoles. These results suggested that cvHAS successfully functions on the vacuolar membrane and synthesizes/transports HA into vacuoles. Efficient synthesis of HA using this system provides a new method for practical production of HA. Biotechnol. Bioeng. 2013; 110: 1174–1179. © 2012 Wiley Periodicals, Inc.     

Wax ester production from n-alkanes by Acinetobacter sp. strain M-1: ultrastructure of cellular inclusions and role of acyl coenzyme A reductase

Acinetobacter sp. strain M-1 accumulated a large amount of wax esters from an n-alkane under nitrogen-limiting conditions. Under the optimized conditions with n-hexadecane as the substrate, the amount of hexadecyl hexadecanoate in the cells reached 0.17 g/g of cells (dry weight). Electron microscopic analysis revealed that multilayered disk-shaped intracellular inclusions were formed concomitant with wax ester formation. The contribution of acyl-CoA reductase to wax ester synthesis was evaluated by gene disruption analysis.     

Genomic characterization of the filamentous integrative bacteriophages {phi}RSS1 and {phi}RSM1, which infect Ralstonia solanacearum

The genomic DNA sequences were determined for two filamentous integrative bacteriophages, phiRSS1 and phiRSM1, of the phytopathogen Ralstonia solanacearum. The 6,662-base sequence of phiRSS1 contained 11 open reading frames (ORFs). In the databases, this sequence showed high homology (95% identity) to the circular double-stranded DNA plasmid pJTPS1 (6,633 bp) isolated from a spontaneously occurring avirulent mutant of R. solanacearum. Two major differences between the two sequences were observed within phiRSS1 ORF7, corresponding to pIII, a minor coat protein required for host adsorption, and at the phiRSS1 intergenic (IG) region. The 9,004-base sequence of phiRSM1 showed 12 ORFs located on the same strand (plus strand) and 2 ORFs on the opposite strand. Compared with Ff-type phages, two insertions are obvious in the phiRSM1 replication module. Genomic DNA fragments containing the phiRSM integration junctions were cloned and sequenced from phiRSM lysogenic strain R. solanacearum MAFF211270. The att core sequence was identified as 5'-TGGCGGAGAGGGT-3', corresponding to the 3' end of the serine tRNA (UCG) gene. Interestingly, ORF14, located next to the attP site on the phiRSM1 genome, showed high amino acid sequence homology with bacterial DNA recombinases and resolvases, different from XerCD recombinases. attP of phiRSS1 is within a sequence element of the IG region.     

Differential receptor binding characteristics of consecutive phenylalanines in micro-opioid specific peptide ligand endomorphin-2

Endogenous opioid peptides consist of a conserved amino acid residue of Phe(3) and Phe(4), although their binding modes for opioid receptors have not been elucidated in detail. Endomorphin-2, which is highly selective and specific for the mu opioid receptor, possesses two Phe residues at the consecutive positions 3 and 4. In order to clarify the role of Phe(3) and Phe(4) in binding to the mu receptor, we synthesized a series of analogs in which Phe(3) and Phe(4) were replaced by various amino acids. It was found that the aromaticity of the Phe-beta-phenyl groups of Phe(3) and Phe(4) is a principal determinant of how strongly it binds to the receptor, although better molecular hydrophobicity reinforces the activity. The receptor binding subsites of Phe(3) and Phe(4) of endomorphin-2 were found to exhibit different structural requirements. The results suggest that [Trp(3)]endomorphin-2 (native endomorphin-1) and endomorphin-2 bind to different receptor subclasses.     

Novel scaffold for cathepsin K inhibitors

Pyrrolopyrimidine, a novel scaffold, allows to adjust interactions within the S3 subsite of cathepsin K. The core intermediate 10 facilitated the P3 optimization and identified highly potent and selective cathepsin K inhibitors 11-20.