The augmentation of tumor-specific immunity using haptenic muramyl dipeptide (MDP) derivatives

Summary A new haptenic compound, a muramyl dipeptide (MDP) derivative (designated as L4-MDP-ONB) cross-reactive with Bacillus Calmette Guerin (BCG) was synthesized. The cross-reactivity of L4-MDP hapten to BCG was demonstrated from the following evidence; (a) lymph node cells from BCG-primed C3H/HeN mice exhibited appreciable L4-MDP-specific proliferative responses to the in vitro stimulation of L4-MDP-modified syngeneic cells (L4-MDP-self); (b) inoculation of L4-MDP-self into footpads of BCG-primed C3H/HeN mice elicited ample delayed type-hypersensitivity (DTH) responses in vivo as measured by footpad swelling; and (c) BCG-primed mice contained L4-MDP-reactive helper T cell activity which functions to augment the generation of effector T cell responses to cell surface antigens. This crossreactivity between L4-MDP hapten and BCG as measured by the helper T cell activity was applied to enhanced induction of tumor-specific immunity. When BCG-primed C3H/HeN mice were immunized with L4-MDP-modified syngeneic X5563 tumor cells, these mice could generate augmented tumor-specific in vivo protective (tumor neutralizing) immunity as well as in vitro cytotoxic T cell responses. These results indicate the effectiveness of L4-MDP hapten in augmenting tumor-specific immunity. The present approach is discussed in the context of potential advantages of this new hapten for its future application to clinical tumor systems.     

Allelic variants of Ly-5 in inbred and natural populations of mice

Allelic variants of Ly-5 in inbred commensal and other natural populations of mice were analyzed by patterns of restriction fragment length polymorphisms (RFLP) and Southern hybridization using an Ly-5 cDNA probe and by cell-surface staining with a panel of antibodies directed against polymorphic and nonpolymorphic Ly-5 determinants. New Ly-5 alleles were defined by RFLPs generated by both Eco RI and Bam HI restriction enzyme digests. The Mus musculus subspecies and other species within the genus Mus showed a strong correlation between allelic variants defined by restriction enzymes and serologic specificities. The data also suggest the conservation of the Ly-5 gene throughout the genus Mus.     

Neural coding of speech sound in the telencephalic auditory area of the mynah bird

Summary The responses of neurons in field L in the auditory neostriatum of the mynah bird, Gracula religiosa, were recorded during presentation of intact or manipulated mimic voices. A typical mimic voice konnichiwa elicited responses in most of the neurons. Neurons in the input layer (L2) of field L showed many peaks on peristimulus time histograms while those in other layers (L1 and L3) exhibited only one or two peaks. Several neurons in L1 and L3 responded only to the affricative consonant /t/ in the intact mimic voices. They did not respond to the affricative consonant in the isolated segment or to the one in the playbacked voice in reverse. Forty-five percent of the neurons (33/ 73) decreased in firing rates at the affricative consonant in the isolated segment compared with in the intact voice. Some of these neurons, in which neither the affricative consonant in the isolated segment nor bursts of noise alone elicited responses, exhibited clear phasic responses to /t/ in the case when bursts of noise with particular central frequencies preceded the affricative consonant. The responsiveness of these neurons appears to receive temporal facilitation. These results suggest that these neurons code the temporal relationship of speech sound.Abbreviations HVc hyperstriatum ventrale, pars caudale - TFN temporally facilitated neuron - TSN temporally suppressed neuron     

Recessive Nonsense Suppressors in SACCHAROMYCES CEREVISIAE : Action Spectra, Complementation Groups and Map Positions

Three genes SUP111, SUP112 and SUP113 of Saccharomyces cerevisiae have been identified that can mutate to give recessive omnipotent nonsense suppressors. Alleles of these loci can also act as allosuppressors; that is, different phenotypes, due apparently to different efficiencies of suppression, can result from different alleles at a given locus. The SUP111, SUP112 and SUP113 loci map to the right arms of chromosomes VIII, VII and XIII, respectively.     

Expression of Virulence-Associated Antigens of Rhodococcus equi Is Regulated by Temperature and pH

We recently reported that there are two different virulence-associated antigens correlated with virulence levels in Rhodococcus equi isolates from AIDS patients: virulent R. equi that kills mice with 10⁶ cells expresses 15- to 17-kDa antigens and intermediately virulent R. equi that kills mice with 10⁷ cells expresses a 20-kDa antigen. Environmental parameters were evaluated for their effects on the expression of these virulence-associated antigens in virulent R. equi strains by immunoblotting using monoclonal antibodies in this study. Expression of these two virulence-associated antigens of R. equi was regulated by pH and temperature; the antigens were produced maximally when the isolates were grown at 38 C and pH 6.5, but were not produced when grown at 38 C and pH 8, nor at temperatures below 30 C. The 20-kDa antigen was found to be located on the cell surface, as were the 15- to 17-kDa antigens, and showed susceptibility to proteolysis by trypsin. These results indicate that expression of the virulence-associated antigens of R. equi is dependent on the environmental conditions.     

Failure to Reject an Allografted Tumor after Elimination of Macrophages in Mice

After an i.p. transplantation of an allogeneic tumor (Meth A) to C57BL/6 mice, a macrophage (MΦ)-rich, non-T, non-NK cell population is induced as the major infiltrate and cytotoxic cells. We here evaluated the role of the MΦs in the rejection of allografted Meth A cells and characterized the MΦs in comparison with other well-known MΦs. At all time intervals after transplantation, the highest cytotoxic activities against Meth A tumor were obtained with the MΦ-rich population. In addition, the lymphocyte-rich population had a significant but low cytotoxic activity, whereas two other population types, granulocytes and large granular cells, were inactive. When the MΦ-rich or the T cell-depleted MΦ-rich population was i.p. transplanted simultaneously with Meth A cells into untreated C57BL/6 mice, the tumor cells were rejected without growth. After specific elimination of MΦs by in vivo application of dichloromethylene diphosphonate-containing liposomes, the cytotoxic activity against Meth A cells was hardly induced at the transplantation site of Meth A cells and the allografted Meth A tumor continued to grow, indicating that a type of MΦ is the effector cell essential for the rejection. In contrast to other well-known MΦs, the cytotoxic activity against Meth A cells was cell-to-cell contact dependent and soluble factor (e.g., NO and TNF-α) independent. Moreover, the cytotoxic activity of the MΦs (H-2^b) against ⁵¹Cr-labeled Meth A (H-2^d) cells was inhibited by the addition of unlabeled H-2^d, but not H-2^a, H-2^k or H-2^b, lymphoblasts as well as Meth A cells, implying the specific interaction of the MΦs with H-2^d cells.     

A novel transposon-like structure carries the genes for pyocin AP41, a Pseudomonas aeruginosa bacteriocin with a DNase domain homology to E2 group colicins

Summary The genetic determinant for pyocin AP41, a bacteriocin produced by Pseudomonas aeruginosa, has been cloned. The determinant is located on the chromosome flanked by a pair of inverted repeats, forming a transposon-like structure (TnAP41). TnAP41 possesses some features characteristic of the Tn3 family of transposons. Based on a comparison with the structure of the corresponding region of the chromosome of a nonproducer strain, we propose that P. aeruginosa has acquired pyocinogeny by the transposition of TnAP41 into the chromosome. The determinant comprises two ORFs encoding the protein subunits responsible for the killing action (the large component) and immunity (the small component). Amino acid sequences of the C-terminus of the large component (the deoxyribonuclease domain) and the immunity protein show remarkable homology to those of E2 group colicins, suggesting that these bacteriocins, which are produced by distantly related species, have originated from a common ancestor.     

Soybean Lipoxygenase L-4, a Component of the 94-kilodalton Storage Protein in Vegetative Tissues: Expression and Accumulation in Leaves Induced by Pod Removal and by Methyl Jasmonate

A lipoxygenase L-4 gene was isolated from a soybean genomiclibrary. The amino acid sequence of lipoxygenase L-4 is highlyhomologous with the partial amino acid sequence of the 94-kDavegetative storage protein, vsp94, found in paraveinal mesophyllcells in the leaves of depodded soybean plants. No L-4 expressionwas observed in maturing seeds. The L-4 gene is highly expressedin the vegetative tissues of young seedlings, including cotyledons,hypocotyls, roots and primary leaves. L-4 expression followedthe same pattern as lipoxygenase activity in cotyledons peaking3 to 5 days after germination, and returning to a basal levelby 9 days after germination. L-4 gene expression was low inthe roots, stems and leaves of 10-week-old plants. Exposureof 4-week-old plants to atmospheric methyl jasmonate increasedL-4 mRNA in leaves. Continuous pod removal from 7-week-old plantsover a 2 week period resulted in dramatic accumulation of L-4mRNA in leaves. Accumulation of the L-4 protein and three otherlipoxygenase fractions in the leaves of depodded plants wasdemonstrated by ion exchange chromatography. These results indicatethat lipoxygenase L-4 is a component of vsp94. (Received May 31, 1993; Accepted August 9, 1993)     

Determination of human plasma xanthine oxidase activity by high-performance liquid chromatography

An assay for human plasma xanthine oxidase activity was developed with pterin as the substrate and the separation of product (isoxanthopterin) by high-performance liquid chromatography with a fluorescence detector. The reaction mixture consists of 60 μl of plasma and 240 μl of 0.2 M Tris-HCl buffer (pH 9.0) containing 113 μM pterin. With this assay, the activity of plasma xanthine oxidase could be easily determined despite its low activity. As a result, it could be demonstrated that the intravenous administration of heparin or the oral administration of ethanol did not increase plasma xanthine oxidase activity in normal subjects, and also that plasma xanthine oxidase activity was higher in patients with hepatitis C virus infection than in healthy subjects or patients with gout. In addition, a single patient with von Gierke's disease showed a marked increase in the plasma activity of this enzyme, relative to that apparent in normal subjects.     

Nδ-benzoyl-l-ornithine and Nδ-benzoyl-l-γ-hydroxyornithine from Vicia pseudo-orobus

Two new non-protein amino acids, N^δ-benzoyl-l-ornithine and N^δ-benzoyl-l-γ-hydroxyornithine have been characterized from the seeds of Vicia pseudo-orobus.