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.     

Economical Speed and Energetically Optimal Transition Speed Evaluated by Gross and Net Oxygen Cost of Transport at Different Gradients

The oxygen cost of transport per unit distance (CoT; mL·kg^-1·km^-1) shows a U-shaped curve as a function of walking speed (v), which includes a particular walking speed minimizing the CoT, so called economical speed (ES). The CoT-v relationship in running is approximately linear. These distinctive walking and running CoT-v relationships give an intersection between U-shaped and linear CoT relationships, termed the energetically optimal transition speed (EOTS). This study investigated the effects of subtracting the standing oxygen cost for calculating the CoT and its relevant effects on the ES and EOTS at the level and gradient slopes (±5%) in eleven male trained athletes. The percent effects of subtracting the standing oxygen cost (4.8 ± 0.4 mL·kg^-1·min^-1) on the CoT were significantly greater as the walking speed was slower, but it was not significant at faster running speeds over 9.4 km·h^-1. The percent effect was significantly dependent on the gradient (downhill > level > uphill, P < 0.001). The net ES (level 4.09 ± 0.31, uphill 4.22 ± 0.37, and downhill 4.16 ± 0.44 km·h^-1) was approximately 20% slower than the gross ES (level 5.15 ± 0.18, uphill 5.27 ± 0.20, and downhill 5.37 ± 0.22 km·h^-1, P < 0.001). Both net and gross ES were not significantly dependent on the gradient. In contrast, the gross EOTS was slower than the net EOTS at the level (7.49 ± 0.32 vs. 7.63 ± 0.36 km·h^-1, P = 0.003) and downhill gradients (7.78 ± 0.33 vs. 8.01 ± 0.41 km·h^-1, P < 0.001), but not at the uphill gradient (7.55 ± 0.37 vs. 7.63 ± 0.51 km·h^-1, P = 0.080). Note that those percent differences were less than 2.9%. Given these results, a subtraction of the standing oxygen cost should be carefully considered depending on the purpose of each study.     

Molecular mimicry between a uveitopathogenic site of S-antigen and viral peptides. Induction of experimental autoimmune uveitis in Lewis rats.

S-Antigen (S-Ag) is a well characterized 45,000 m.w. photoreceptor cell protein. When injected into susceptible animal species, including primates, it induces an experimental autoimmune uveitis, a predominantly T cell-mediated autoimmune disease of the retina and uveal tract of the eye, and of the pineal gland. In this study we found an amino acid sequence homology between a uveitopathogenic site of S-Ag, several viral proteins and one additional nonviral protein. An experimental autoimmune uveitis and pinealitis was induced in Lewis rats with these different synthetic peptides, corresponding to the amino sequence of hepatitis B virus DNA polymerase, gag-pol polyprotein of Baboon endogenous virus and gag-pol polyprotein of AKV murine leukemia virus and potato proteinase inhibitor IIa, which contain three or more consecutive amino acids identical to peptide M in S-Ag. Lymph node cells from rats immunized with either peptide M or the different synthetic peptides showed a significant degree of cross-reaction. Mononuclear cells from monkeys (Macaca fascicularis) immunized with peptide M also showed significant proliferation when incubated with either peptide M or synthetic peptides as measured by in vitro lymphocyte mitogenesis assay using [3H]TdR. Based on our findings we conclude that a viral infection may sensitize the mononuclear cells that can cross-react with self proteins by a mechanism termed molecular mimicry. Tissue injury from the resultant autoantigenic event can take place in the absence of the infectious virus that initiated the immune response.     

Regulation and function of the Drosophila segmentation gene fushi tarazu

The Drosophila segmentation gene fushi tarazu (ftz) is expressed in a pattern of seven stripes at the blastoderm stage. Two cis-acting control elements are required for this expression: the zebra element, which confers the striped pattern by mediating the effects of a subset of segmentation genes; and the upstream element, an enhancer element requiring ftz+ activity for its action. Fusion of the upstream element to a basal promoter results in activation of the heterologous promoter in a ftz-dependent striped pattern, supporting the idea that ftz regulates itself by acting through its enhancer. The upstream element can also confer expression patterns similar to that of the homeotic gene Antennapedia, suggesting that a similar element may play a role in the activation of Antennapedia.     

Detection of Trp-P-1 and Trp-P-2, carcinogenic tryptophan pyrolysis products, in dialysis fluid of patients with uremia

In order to estimate the exposure levels of mutagenic and carcinogenic heterocyclic amines in humans, we developed a high-performance liquid chromatography method to detect 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1) and 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2) in dialysis fluid of patients with uremia. Using this methods, dialysis fluid of 12 patients who had received hemodialysis treatment or continuous ambulatory peritoneal dialysis was examined. Trp-P-1 was detected in dialysate of all uremic patients (727 +/- 282 pmoles, n = 12). In patients who had been treated with continuous ambulatory peritoneal dialysis, the average amount of Trp-P-1 found in whole dialysate (6 l) per day was 710 +/- 203 pmoles (mean +/- S.D., n = 8). Moreover, Trp-P-2 could be detected in 5 out of 12 patients (206 +/- 85 pmoles, n = 5). These results indicate that patients with uremia are actually exposed to carcinogenic tryptophan pyrolysis products. The average exposure level of Trp-P-1 in uremic patients apparently exceeded 710 pmoles (150 ng) per day.     

In addition to the ARS core, the ARS box is necessary for autonomously replicating sequences

Summary Autonomously replicating sequences (ARSs) were cloned from nuclear and mitochondrial DNA of D. melanogaster using YIp5, which is composed of pBR322 and the yeast ura3 gene, as the cloning vector and YNN27, a Ura^- yeast strain as the recipient. The nucleotide sequences of six ARSs, two from nuclear bulk, two from the nuclear 1.688 satellite, and two from mitochondorial DNA, were determined. The relationship between the transformation frequency and the inclusion of the ARS core, 5 _T ^A TT-TAT _A ^G TTT _T ^A 3, of these fragments was analysed. All the ARSs contained an ARS core or a single base change of it. However, not all the fragments that contained a single base change of the ARS core were able to transform the recipient cells, suggesting that certain bases in the ARS core were not exchangeable. It is suggested by transformation experiments with subfragments that in addition to an ARS core, an ARS box which is located within 25 bp upstream of the ARS core and whose sequence is composed of 5TNT _G ^A AA 3, is necessary for autonomous replication.     

Biosynthesis of Purine Alkaloids in Camellia Plants

The metabolism of [8-¹⁴C]adenine and [8-¹⁴C]hypoxanthine infour species of Camellia plants was investigated in relationto the synthesis of purine alkaloids, caffeine and theobromine.Young leaves of C. sinensis had the ability to synthesize caffeine,but in C. irrawadiensis, these labelled precursors were incorporatedinto theobromine, not caffeine. No synthesis of purine alkaloidscould be detected in C. japonica and C. sasanqua leaves. Conventional"salvage" and degradation pathways of purines were present inall species of Camellia plants examined. ¹ Present address: Research Center, Mitsubishi Chemical IndustriesLtd., 1000 Kamisida-cho, Midori-ku, Yokohama, 227 Japan. (Received September 29, 1986; Accepted January 22, 1987)     

Transport and Fixation of Inorganic Carbon during Photosynthesis in Cells of Anabaena Grown under Ordinary Air: III. Some Characteristics of the HCO3--Transport System in Cells Grown under Ordinary Air

In cells of cyanobacterium Anabaena variabilis grown under ordinaryair (low-CO₂ cells), the transport of both CO₂ and HCO₃^–was significantly enhanced by Na⁺. This effect was pronouncedas the external pH increased. When low-CO₂ cells were treatedwith an inhibitor of carbonic anhydrase (CA), only CO₂ transportbut not HCO₃^– transport, was inhibited. The initial rateof photosynthetic carbon fixation as a function of the concentrationof internal inorganic carbon (IC) was practically the same irrespectiveof whether CO₂ or HCO₃^– was externally supplied. Theseresults suggest that IC is actively transported through theplasma membrane in a form of HCO₃^– probably by some transporterand that the transmembrane Na⁺ gradient is involved in thisIC transport system. Free CO₂ may be hydrated by CA to HCO₃^–and then transported to the cells by this transporter. On the other hand, CO₂ is actively taken up by cells grown withair containing 5% CO₂ (high-CO₂ cells) though the enhancingeffect of Na⁺ was much smaller in high- CO₂ cells than in low-CO₂cells. The initial rate of fixation as a function of internal IC concentrationindicated that the rate of the carboxylation reaction of accumulatedIC is higher in I0W-CO₂ cells than in high-CO₂ cells. The studieswith ethoxyzolamide indicated that even in low-CO₂ cells, CAdoes not function inside Anabaena cells. These results suggestthat inside the low-CO₂ cells of Anabaena, some mediator(s)facilitates the transport of IC to RuBPCase. (Received January 23, 1987; Accepted April 24, 1987)