Induction and characterization of minor histocompatibility antigens. Specific primary cytotoxic T lymphocyte responses in vitro

A definite cytotoxic activity was developed in a BALB/c (H-2d) anti-DBA/2 primary mixed leukocyte culture (MLC), which received interleukin 2 (IL-2) on day 3 of culture. This cytotoxic activity was minor histocompatibility antigens (MIHA)-specific at the stimulator level, and was not developed in a syngeneic (BALB/c anti-BALB/c) MLC. The addition of IL-2 on day 3 of culture was crucial; no or very weak cytotoxic activity was developed in MLC receiving IL-2 on day 0 or on both day 0 and day 3. Only appropriate MIHA-allogeneic tumor cells were lysed as the target of the cytotoxic activity. The cytotoxic activity seemed MIHA-specific also at the target level; it lysed tumor cells of DBA/2 mouse origin but not those of BALB/c (syngeneic) origin. Phenotypes of the cytotoxic effector cell were Thy-1+ Lyt-2+. We concluded from these results that MIHA-specific cytotoxic T lymphocytes (CTL) were generated in the MIHA-allogeneic primary MLC. In this newly developed system, we studied genetic and antigenic requirements for primary anti-MIHA CTL responses in vitro. We demonstrated; among spleen cells (SC) of seven B10 H-2-congenic strains only SC of B10.D2 strain whose major histocompatibility complex (MHC) (H-2d) was compatible with the responder MHC effectively stimulated responder BALB/c (H-2d) SC for an anti-MIHA (DBA-C57BL-common) CTL response. Similarly, only SC of two out of seven C x B recombinant inbred strains (C x B.H and C x B.D), which were compatible at the MHC with responder SC, activated responder BALB/c SC for the response. The possibility that cells responding to H-2 alloantigens suppressed the anti-MIHA response was ruled out. Additional experiments showed that compatibility at the H-2K-end or the H-2D-end of the MHC was sufficient for a definite anti-MIHA response. These provided formal evidence that primary anti-MIHA CTL responses in vitro were MHC-restricted at the stimulator level. We then showed that sonication-disrupted SC or Sephadex G-10 column-passed nonadherent SC failed to stimulate responder SC for a primary anti-MIHA CTL response, whereas G-10-passed nonadherent SC responded well to adherent stimulator cells. Further study demonstrated that Ia+ adherent cells were the most active cell type as stimulator. Finally, we confirmed that the primary anti-MIHA CTL responses to adherent stimulator cells was MHC-restricted.     

Studies on hst, a transforming gene which belongs to a new superfamily of growth factors

The hst gene was originally identified in surgically obtained human gastric mucosae as a transforming gene which could transform NIH3T3 cells morphologically. The hst cDNA clone was synthesized from mRNA of one of the NIH3T3 transformants. A human leukocyte genomic library was screened with this cDNA clone, and an hst genomic fragment was obtained. This genomic fragment itself had transforming activity, and the protein coding sequences were proved to be completely identical to those of the cDNA clone prepared from mRNA of the NIH3T3 transformant. This fact suggests that rearrangement or other structural alterations in the coding sequence are not required for the activation of the hst gene. The predicted hst protein consists of 206 amino acids and has a significant homology (40-50%) to fibroblast growth factors and int-2 protein. They together make up a new superfamily of growth factors and transforming genes.     

Host-mediated antiviral activity of Lactobacillus casei against cytomegalovirus infection in mice

The protective effect of heat-killed Lactobacillus casei (LC) against murine cytomegalovirus (MCMV) infection was examined. ICR mice treated once with LC 1 day or 2 days before challenge survived lethal infection, but untreated or Lactobacillus fermentum (LF)-treated mice did not. The protective effect was evidenced by an increase in plaque-forming units (PFU) per 50% lethal dose (LD50) and a decrease in titers of infectious viruses replicated in the target organs. This was further confirmed by severity of histopathological damage to the target organs, especially the liver. LC neither inactivated MCMV nor inhibited its replication in mouse embryonic fibroblasts (MEF). The spleen cells from LC-treated mice inhibited its replication in MEF on co-cultivation. Augmentation by LC of splenic natural killer (NK) cell activity correlated with survival of mice from otherwise lethal MCMV infection. Cytotoxic activity of peritoneal cells and level of serum interferon (IFN) were elevated after MCMV infection, but they were not associated with survival of mice nor with treatment of LC. The protective effect of LC was not clear in NK-deficient beige mutant (bgJ/bgJ) mice, when compared with that in their littermate (bgJ/+) mice. Poor protection of bgJ/bgJ mice by LC treatment correlated with failure to induce NK cell activity by LC treatment in the mutant mice. Thus, it is likely that LC protects mice from MCMV infection by augmentation of NK cell activity.     

Distribution and development of the serotonin-and RFamide-like immunoreactive neurons in the arrowworm,Paraspadella gotoi (Chaetognatha)

Summary The distribution and development of serotonin-and RFamide-like immunoreactivities in the nervous system of Chaetognatha, Paraspadella gotoi, were examined in whole-mount preparations. In adults, a single serotonin-like immunoreactive (5HTLI) neuron and numerous RFamide-like immunoreactive (RFaLI) neurons were found in the central nervous system. Based on the structure of the fins, hooks, and eyes, seven postembryonic developmental stages were recognized. The most obvious features of the stages are: stage 1, newly hatched young; stage 2, elongation of a continuous lateral tail fin; stage 3, separation of the lateral and tail fins; stage 4, appearance of hooks; stage 5, pigmentation of eyes, stage 6, attachment by tail adhesive fins; stage 7, prey capture. Stage 1 did not show any immunoreactivity. The 5HTLI neuron first appeared at stage 4 and its axonal pathway became similar to the adult at stage 6. On the other hand, the RFaLI neurons appeared at stage 3 in the ventral ganglion. Some of their somata disappeared at stage 5 and the neuronal architecture resembled the adult at stage 7 although the RFaLI neurons in the cerebral ganglion were complete at the juvenile stage.We are sad to announce that Dr. M. Yoshida died on 29 October 1988     

RFP is a DNA binding protein associated with the nuclear matrix.

We reported that the RFP gene encodes a protein with putative zinc finger domains and was involved in the activation of the ret proto-oncogene. To further characterize the RFP protein, we developed a polyclonal antibody against the product synthesized from a fragment of the RFP cDNA expressed in Escherichia coli. Western blot analysis showed that RFP was identified as a 58 kDa protein in cell lysates from four human and rodent cell lines and from mouse testis. In addition, a unique 68 kDa protein was detected in the testis. Using AH7974 (rat ascites hepatoma) and Raji (human Burkitt lymphoma) cells, we demonstrated strong association of RFP with the nuclear matrix. Furthermore, RFP solubilized from the nuclear matrix had DNA-binding activity although it appears to bind more preferentially to double-stranded DNA than to single-stranded DNA. These results thus suggest that RFP may play a role in molecular processes which occur in the nuclear matrix.     

Comparative studies of the effects of stilbene compounds on hepatic ornithine decarboxylase and S-adenosylmethionine decarboxylase induction in rats

Trans-Stilbene oxide (TSO, 2 mmol/kg, ip.) induced ornithine decarboxylase (ODC) and S-adenosylmethionine decarboxylase (SAMDC) to 60-fold and 5-fold of the controls, respectively, in the liver of rats. Parallel to ODC induction, there was a marked increase in putrescine content to 50-fold of the control levels. Cis-Stilbene oxide (CSO), a stereoisomer of TSO, also produced the induction of ODC and SAMDC and the increase in putrescine content. There was no difference in the ability to induce ODC and SAMDC between TSO and CSO with respect to the extents of induction and the time needed to reach maximal levels. Trans-Stilbene (TS), a mother compound of TSO, did not show such an effect on ODC, while cis-stilbene (CS) induced both ODC and SAMDC. Treatment with glutathione inhibited TSO- and CSO-mediated induction of ODC and SAMDC. These findings add new information concerning the abilities of TSO, CSO and CS on hepatic polyamine metabolism.     

Chilling-Induced Inactivation and Its Recovery of Tonoplast H-ATPase in Mung Bean Cell Suspension Cultures

The processes involved in adaptation to cold temperature were examined by growing suspension cultured cells of mung bean (Vigna radiata [L.] Wilczek) at 2°C for various periods of time and assaying the activities of various membrane-bound enzymes in vitro. The tonoplast H⁺-ATPase activity and the ATP-proton transport extracted from cells incubated at 2°C declined rapidly and reached a minimum level after 10 hours. The inactivation was reversible within 24 hours of chilling. The recovery of the cold-inactivated H⁺-ATPase was found to proceed in two steps, a faster recovery of ATP hydrolysis activity and a slower recovery of the proton transport. The recovery was markedly inhibited by the presence of azide, but not affected by 0.578 millimolar cycloheximide. This suggested the involvement of an energy process that had no requirement for de novo synthesis of protein. The cold-induced inactivation of the H⁺-ATPase may be due to a structural alteration of the enzyme. The slower recovery of proton transport relative to ATP hydrolysis during warming suggests that the protogenic domains in the enzyme may be affected differently by chilling.     

Radiation-induced myeloid leukemia in C3H/He mice and the effect of prednisolone acetate on leukemogenesis

We found that the incidence of spontaneous myeloid leukemia in C3H/He male mice was less than 1%, but it could be increased considerably by total-body X irradiation. The induction of myeloid leukemia was seen to increase after doses from 0.47 Gy (3%) to 2.84 Gy (23.9%), and then decrease after a dose of 4.73 Gy (13.6%). The administration of prednisolone acetate (synthesized glucocorticoid) after irradiation resulted in a significant increase in the incidence of myeloid leukemia from 23.9 to 38.5% after a dose of 2.84 Gy; however, corticosterone, a glucocorticoid secreted by cells, did not have such an enhancing effect.     

Reduced cholecystokinin in the brain of LEC rats with hepatic encephalopathy.

Levels of cholecystokinin (CCK) immunoreactivity and distribution of CCK immunoreactive cells were studied in the cerebral cortex of LEC (Long Evans Cinnamon) rats with hepatic encephalopathy. CCK immunoreactivity in water extract of cerebral cortex of LEC rats with hepatic encephalopathy (n = 7) was 41.5 +/- 2.6 (mean +/- S.E.M. pmol/g wet wt.) and that of LEC rats without encephalopathy (n = 8) was 67.1 +/- 6.9, the difference being significant (P less than 0.01). CCK immunoreactive cells assessed by immunohistochemistry were also markedly decreased in the cortex of LEC rats with hepatic encephalopathy of stage IV. Thus, CCK reduction was observed in the cerebral cortex of LEC rats with hepatic encephalopathy which are provided as a model for analysis of the pathogenesis of acute hepatic encephalopathy.