The target minor H antigen for F1 cytotoxic T lymphocytes induced by Igh-congenic parental spleen cells is coded for by gene linked to H-2

Graft-vs-host reaction (GvHR) induced in (B10.BR X CWB)F1 (BWF1; H-2k/b, Ighb/b) by i.v. injection with CWB (H-2b, Ighb) spleen cells resulted in complete suppression of cytotoxic T lymphocyte (CTL) responsiveness of the F1 host spleen cells (GvHR-associated immunosuppression). In contrast, GvHR induced in BWF1 mice with CSW (H-2b, Ighj; Igh-congenic to CWB) spleen cells did not affect CTL responsiveness of the F1 host spleen cells at all. The BWF1 hosts undergoing the CSW-induced GvHR generated anti-CSW CTL in their spleens, and the subsequent culture of such BWF1 spleen cells with CSW stimulator cells, augmented the CTL activity. The BWF1 anti-CSW CTL lysed both Con A- and LPS-induced splenic blasts from mouse strains carrying the Ighj allele in the context of self H-2Kb. However, determination of the Igh haplotype in the serum IgG and of the susceptibility of the splenic lymphocytes to the BWF1 anti-CSW CTL on backcross mice, which carry either Ighb/j or Ighb/b in the context of H-2b/b or H-2b/k, showed clearly that Ighj and the gene coding for the target antigen for the BWF1 anti-CSW CTL segregated at ratios close to 1:1. The study in which linkage between the gene(s) coding for the target antigen for the BWF1 anti-CSW CTL and H-2 was examined on CWB X (C3H X CWB)F1 backcross mice and (B10.BR X CSW)F1 X B10 mice demonstrated that the gene, most likely a single gene, coding for the target antigen for the BWF1 anti-CSW CTL is located at 8.5 +/- 4.3 cross-over units to the right or left of the H-2 complex. We designated the minor H antigen to be recognized by the BWF1 anti-CSW CTL as H-X+, and we discuss the distinction between the H-X+ locus and the other minor H loci on chromosome 17.     

Demonstration of structural polymorphism among MB3 light chains by two-dimensional gel electrophoresis

The heavy and light chain subunits of MB3 molecules were isolated from KT2 (DKT2, DR4, MB3 homozygous), ER (Dw4, DR4, MB3 homozygous), JMe (Dw5, DR5, MB3 homozygous), EBV-Sh (DSh, DRw6.2, MB3 homozygous), and EBV-Ky (DKy, DRw9, MB3 homozygous) cells and were compared with one another by two-dimensional gel electrophoresis. The MB3 light chains from KT2, ER, and EBV-Ky cells were clearly different in terms of their isoelectric points, whereas those from ER, JMe, and EBV-Sh cells were indistinguishable. No differences in charge or m.w. were noted for the MB3 heavy chains from the five cell lines. Thus, three out of the five MB3-positive, D/DR-disparate cell lines were found to express structurally distinct MB3 molecules, demonstrating that MB3 is a public serologic specificity shared by at least three structurally distinct MB (human I-A-like) molecules. Because the DR light chain subunits isolated from EBV-Wa, KT2, ER, JMe, EBV-Sh, and EBV-Ky cells differed from one another in their isoelectric points, the DR light chains were apparently more polymorphic than the MB3 light chains.     

In vivo priming of mouse CTL precursors directed to product of a newly defined minor H-42 locus is under a novel control of class II MHC gene

In a previous study, we discovered a new mouse minor histocompatibility antigen encoded by a locus at 8.5 cM apart from the H-2 complex, and we have since named the locus H-42. One allele of H-42, which is named H-42a, had been elucidated, but the other alleles, which we tentatively named H-42b, have not been elucidated. In the present study, we explored MHC control on the anti-H-42a cytotoxic T lymphocyte (CTL) responsiveness in H-42b mice. In vivo immunization (i.v. injection) of H-42b mice with 5 to 30 X 10(6) spleen cells (SC) bearing allogeneic H-42a antigen but carrying H-2 complex (mouse MHC) matched with the H-42b mice failed to prime anti-H-42a CTL but induced stable and specific anti-H-42a CTL unresponsiveness, i.e., tolerance, in the H-42b recipient mice. In contrast, H-2 heterozygous H-42b F1 mice injected with SC bearing H-42a alloantigen on either of the parental H-2 haplotypes were effectively primed to generate anti-H-42a CTL. Exploration of the region or subregion in the H-2 complex of H-42a donor SC that should be compatible with H-42b recipient mice for the induction of their anti-H-42a CTL tolerance demonstrated that the compatibility at I region, most probably I-A subregion, but not at K, S, or D region, determined the induction of the tolerance. MHC class II compatible H-42a skin graft (SG) to H-42b mice, however, consistently primed the anti-H-42a CTL in the H-42b recipients. These results were discussed in several aspects, including uniqueness of MHC class II control on the CTL response to minor H-42a antigen, possibility of inactivation of responding anti-H-42a precursor CTL or helper T cells in H-42b mice by encountering the veto cells present in MHC class II-matched H-42a SC population, and significance of the present observations as a mechanism of CTL tolerance to self-components.     

Bombesin evoked acetylcholine release from the guinea pig antrum

Bombesin induced contraction and acetylcholine (ACh) release of the longitudinal muscle strip of the guinea pig antrum were examined using the standard organ bath technique and the superfusion system. Bombesin increased frequency and tonus of rhythmic contraction in a dose dependent manner (10(-10)M - 10(-7)M). The effects of bombesin on frequency of contraction were not affected by atropine, propranolol, phentolamine, hexamethonium and tetrodotoxin. The effects on tonus, on the other hand, were significantly reduced by atropine, and the dose response curve to bombesin was shifted to the right. There was a remarkable increase of 3H-ACh release by the superfusion of bombesin (10(-8)M), which was almost completely abolished in Ca-free medium, but not affected by hexamethonium and tetrodotoxin. These results suggest that mechanism of bombesin effects on frequency is different from that on tonus; frequency response to bombesin is not dependent on autonomic nervous system but due to a direct effect on smooth muscle cells, whereas tonic response to the peptide is partly mediated by ACh release via a mechanism independent of sodium spike.     

Nitroarenes in Suimon River sediment

Mutagenic activity was observed in sediments of the Suimon River bed with and without S9 mix. The direct-acting mutagens in the sediment were investigated. The sediment was extracted with methanol and fractionated on a Silica gel column. The benzene fraction from the Silica gel column exhibited mutagenic activity without S9 mix in strain TA98, while it failed to show mutagenic activity in nitroreductase-deficient strain TA98NR. This observation led to the suspicion that nitro compounds were the direct-acting mutagens of these samples. The benzene fraction was treated by heptafluorobutyric anhydride (HFBA) and investigated with gas chromatography equipped with an electron capture detector (GC-ECD). 2-Nitrofluorene, 4,4'-dinitrobiphenyl, 2,7-dinitrofluorene and 1-nitropyrene were detected and measured quantitatively. The mutagenic activity of a mixture of these compounds was compared with that of the original fraction and the direct-acting mutagenicity of Suimon River sediment can be explained by these nitroarenes, especially 1-nitropyrene.     

Changes in synthetic activity of cell walls during the cell cycle in a synchronous culture of Catharanthus roseus

The incorporation rates of [¹⁴C] glucose into various fractions of the cell walls and into the sugar constituent of each fraction were investigated in a synchronous culture of Catharanthus roseus (L.) G. Don in order to elucidate the synthetic aspects of the cell walls during the cell cycle. Changes in the incorporation of radioactivity were closely correlated with changes in the amount of each cell wall fraction as well as with those in sugar composition as reported previously (S. Amino et al. Physiol. Plant. 60: 326–332, 1984). The specific activity of galactose was higher than that of other sugars throughout the cell cycle, and a temporary increase in the incorporation of radioactivity into all cell wall fractions except cellulose was observed just before the increase in cell numbers. The synthetic activities may play key roles in the regulation of cell wall polysaccharide dynamics during the cell cycle.     

A Comparison of Tomato Fruit Chloroplast and Chromoplast DNAs as Analyzed with Restriction Endonucleases

Chromoplast DNA was isolated from ripe-red tomato fruits, andits structure compared with that of chloroplast DNAs from maturegreen fruits and leaves. There was a good correspondence betweenthe structures analyzed by BamHI or EcoRI digestion and by hybridizationwith a probe for the gene of the ribulose 1,5-bisphosphate carboxylase/oxygenaselarge subunit. ¹ Present address: Koryo International College, Nisshin, Aichi470-01, Japan. (Received November 5, 1984; Accepted February 6, 1985)     

In vitro growth of adult amphibian (Xenopus laevis) hepatocytes and characterization of hepatocyte-proliferating activity in homologous serum

Adult frog (Xenopus laevis) hepatocytes were found to proliferate in a culture medium containing adult homologous serum. Insulin and dexamethasone were required for a net proliferation of hepatocytes. Dose-response analysis showed that a low concentration of serum (greater than or equal to 0.5%) was enough to induce DNA synthesis and mitosis, but a higher concentration (5%) caused certain necrotic changes. Under optimal conditions, there was a two- to threefold increase in nuclei per culture 10 days after serum treatment. Heterologous sera (fetal bovine, calf and chick) showed less proliferative activity. Based on our results, hepatocyte-proliferating activity in adult frog serum is considered to be heat-unstable and acidic protein(s). Thus, adult frog serum may contain hepatopoietin possibly different from well-known growth factors.     

In vivo effects of epidermal and fibroblast growth factors on DNA replication in mouse skin

A method was developed for measuring in vivo DNA synthesis after exposure to epidermal growth factor (EGF) or fibroblast growth factor (FGF) in a local area of mouse skin using ring-shaped forceps in combination with autoradiography. The technique should be useful for analysing the effects of growth factors on individual cells of the skin in vivo. EGF induced semisynchronized DNA synthesis in basal cells of the epidermis dose-dependently, but FGF did not. Time course study showed that EGF-induced DNA synthesis in basal cells increased with time for 24 h, and then decreased rapidly. EGF-induced DNA synthesis in basal cells was proportional to the time exposed to EGF (0-60 min). FGF and EGF both had little effect on dermal fibroblastic cells. The discrepancy between in vivo observations and those with cultured mammalian cells is discussed.     

Transient glucose intolerance during attacks of thyrotoxic periodic paralysis

In a 19-year-old Japanese male (case 1) with thyrotoxic periodic paralysis (TPP), an increase of plasma glucose concentration together with abnormally high levels of serum immunoreactive insulin (IRI) was observed preceding a spontaneous attack of paralysis. Therefore, the plasma glucose, glucagon, epinephrine, norepinephrine, serum IRI, growth hormone and cortisol levels, and the erythrocyte insulin receptors were measured in case 1 and a 40-year-old Japanese male (case 2) with TPP during attacks of paralysis induced by prolonged glucose loading. In case 1, the serum IRI concentration was elevated to the extraordinarily high level of 655.0 microU/ml at the beginning of paralysis, and at that time, the plasma glucose concentration was 147 mg/dl. However, when paralysis was not induced by a similar glucose loading during methimazole treatment, the serum IRI and plasma glucose levels at the corresponding time after glucose loading were 20.9 microU/ml and 87 mg/dl, respectively. Furthermore, the affinity of the erythrocyte insulin receptors was decreased during the attack. In case 2, plasma glucose and serum IRI concentrations were increased in accordance with the initiation of paralysis although the blood levels of hormones counteracting insulin were not significantly changed. These findings suggest that there is something interacting with the normal action of the insulin in the early phase of paralysis.