[Effects of adult thymectomy on the growth of 203-glioma in mice--analysis of T cell subpopulation in tumor immunology]

The effects of adult thymectomy in C 57 BL/6 mice on in vivo and in vitro responses to syngeneic methylcholanthrene-induced glioma (203-glioma) were investigated in order to analyse the role of T cell subpopulation in relation to the antitumor immunity. The tumor growth in adult mice thymectomized 3 weeks before subcutaneous inoculation of tumor cells was significantly suppressed. On the other hand, in mice thymectomized 7 or 10 weeks before tumor cell inoculation, the tumor growth was enhanced resulting in shorter mean survival time. The cytotoxic activity of the regional lymph node T cells in the former mice was increased from the beginning after tumor cell inoculation with peak observed on day 14 and maintained for about 4 weeks, while it was extremely decreased in the latter mice. The marked enhancement of cytotoxic activity in the former mice is probably due to a reduced proportion of short-lived T lymphocyte population after adult thymectomy. In contrast, the low level of cytotoxic activity in the latter mice may be due to a gradual reduction of long-lived T lymphocyte population in addition to short-lived T lymphocyte population after adult thymectomy. The cytotoxic activity was specific for 203-glioma cells and almost completely eliminated with anti-Thy-1 monoclonal antibody and complement. The surface markers of these killer T cells were checked with the results that in normal mice Lyt-1-.2.3+ and Lyt-1+.2.3+ cells participate in cytotoxic reaction. In mice thymectomized 3-10 weeks before tumor cell inoculation, however, Lyt-1+.2.3+ killer T cells were not detected suggesting strongly that the progenitors of Lyt-1+.2.3+ killer T cells are short-lived cells in contrast to those of Lyt-1-.2.3+ killer T cells which survive more than 10 weeks after adult thymectomy. The tumor growth was also significantly suppressed by the intravenous adoptive transfer of sensitized lymphocytes obtained from mice thymectomized 3 weeks before tumor cell inoculation. This effect of tumor suppression was disappeared by the pretreatment of infused lymphocytes with anti-Thy-1 monoclonal antibody and complement. These evidences may suggest that in tumor bearing mice short-lived suppressor T cells or their precursors exist and regulate the growth and differentiation of killer T cells and that adult thymectomy affects immunoregulation, possibly by altering the generation of suppressor T cells.

Digital nerve grafts in replanted digits

In most cases where digits have been amputated by avulsion and the digital nerve extensively injured, primary nerve suture cannot be performed. For such a digit when replanted, secondary nerve grafting was done under the operating microscope using a lateral femoral cutaneous nerve. Two years after operation, two-point discrimination of these cases proved to be 10.5 mm on average. And in the case of the transplanted three strand cable graft, using a lateral femoral cutaneous nerve yielded the most favourable results. The replacement was superior to the side receiving primary crushed nerve suture. Sensory nerve action potentials indicate that the regenerated nerve does not necessarily mature sufficiently. The recovery of sensitivity even to this degree however was sufficient for the replanted digits to be useful in all cases.

Fluctuation of antigen binding activity during the cell cycle in the synchronized population of the murine T hybridoma cell line

The murine T cell hybridoma line which specifically binds antigen (ovalbumin) was established using a cell fusion technique with Sendai virus. Regional lymph node cells from ovalbumin (OVA) immunized C57BL/6 mice were fused with thymidine kinase deficient variant cells of the EL-4 cell line (originating from a thymoma of a C57BL/6 mouse). Approximately one hundred cell lines were established and the antigen binding activity was determined by rosette formation with OVA coated sheep red blood cells (SRBC). One hybridoma cell line, MMH-77, could form rosettes and this formation was specifically inhibited by the addition of free OVA. The ability of the cell line to form rosettes varied from one stage of the cell cycle to the other with the maximum ability in the S phase.

Regulatory factors of lymphocyte-lymphocyte interaction. II. Characterization of human mitogenic factor derived from the culture supernatant of a mouse-human hybridoma

Cell hybridization of phytohemagglutinin (PHA)-stimulated human peripheral blood lymphocyte (PBL) with murine lymphoma (EL-4) provided three hybridomas (MHH-16, MHH-20, and MHH-22) which spontaneously produced human mitogenic factor (MF). MHH-16 was serially subcloned by limiting dilution procedures, which resulted in maintaining two subclones producing human MF spontaneously for more than one year (PQL-3 and PQL-5 subcloned lines). Human MF MHH-MF) derived from supernatants of PQL-5 line cultures had a molecular weight (m.w.) of about 26,000-30,000 daltons (the major peak) with a minor peak with an m.w. of 15,000 daltons on Sephadex G-100 chromatography, and at a high concentration of NaCl (1 M), the activity of the 26,000-30,000-m.w. fraction became weak and that of the 15,000-m.w. fraction became predominant. MHH-MF had an isoelectric point of Ph 5.0-6.5. On DEAE-cellulose chromatography, MHH-MF was eluted at a fairly low salt concentration (sodium phosphate buffer 0.02 M, pH 8.0, NaCl 10 mM). After periodate treatment of this MHH-MF, the mitogenic activity almost disappeared. MHH-MF was relatively unstable to heating at 56 c for 20 min. In the presence of tunicamycin (0.3 microgram/ml), an inhibitor of N-linked glycosylation the synthesized MHH-MF showed a decrease in m.w. as follows: the major peak shifted from 26,000-30,000 to 23,000 daltons and the minor peak from 15,000 to 10,000 daltons on Sephadex G-100 chromatography. In internal labeling experiments with [3H] leucine, the 3H-labeled MF was partially purified, with mitogenic activity as a guide. This 3H-labeled MHH-MF fraction could be absorbed by PHA blasts but not by normal PBL. On SDS-PAGE under reducing conditions, only the radioactive peak of the 15,000-dalton fraction was recovered. MHH-MF obtained from the hybridoma culture supernatants may be a dimer of the 15,000-dalton fraction and a glycoprotein.

Regulatory factors of lymphocyte-lymphocyte interaction. I. Con A-induced mitogenic factor acts on the late G1 stage of T-cell proliferation

DNA synthesis in murine lymphocytes was augmented by a soluble factor in the supernatant of serum-free cultures of syngeneic spleen cells activated with concanavalin A (Con A). This so-called mitogenic factor (MF), which is probably identical with interleukin II, partially purified by DEAE-cellulose and Sephadex G-75 chromatography, is a fairly homogeneous molecule of 17-25 X 10(3) daltons. By using partially purified MF, the role of MF in lymphocyte proliferation was investigated. Pretreatment of lymphocytes with Con A for the first 3 hr of culture, which does not in itself induce cell proliferation, markedly augmented the effect of MF. The presence of MF, however, is necessary only in a restricted stage(s) of lymphocyte proliferation. The addition and removal of MF at various times during culture showed that MF exerts its effect on a process which occurs 3-6 hr before the beginning of DNA synthesis. These results strongly suggest that MF regulates the proliferation of mitogen-stimulated lymphocytes by acting on a restricted stage(s) of the cell cycle.

Effect of oral administration of lysozyme or digested bacterial cell walls on immunostimulation in guinea pigs

The effect of oral administration of bacteriolytic enzymes and enzymatically digested bacterial cell walls on immunostimulation in guinea pigs was studied. Guinea pigs were given lysozyme or pronase or both orally for a period of 8 days, and on day 7 they were primed with hepatitis B surface antigen. Circulating antibody titers to the antigen in the enzyme-treated group were significantly higher (four to six times, P less than 0.05) than those in nontreated control groups on day 16 after immunization. Stimulation of cellular immunity in the group receiving both lysozyme and pronase simultaneously was significantly increased compared with the group receiving only one of them. The humoral immune response was enhanced by oral administration of enzymatically digested cell walls isolated from Bifidobacterium longum. The result suggested that intestinal bacteria might be solubilized by oral administration of bacteriolytic enzymes and that the absorbable fragment of peptidoglycan released from the bacterial cell walls might be responsible for the enhanced host immune responses.

Plasma cortisol concentrations during Caesarean section

The effects of extradural and general anaesthesia on the adrenocortical response to elective or emergency Caesarean section were studied in 72 patients. Maternal plasma concentrations of cortisol were measured before surgery, at delivery, and 30 and 60 min after skin incision. Umbilical vein and artery plasma cortisol concentrations at delivery were determined also. Maternal plasma cortisol concentrations in patients receiving extradural anaesthesia did not change significantly from control at any of the time intervals. In the general anaesthesia group concentrations were significantly increased from control, at 30 and 60 min after skin incision for elective Caesarean sections, and at 60 min after skin incision during emergency surgery. There were no significant differences between the mean umbilical vein and artery plasma cortisol concentrations compared within or between extradural or general anaesthesia groups. Extradural anaesthesia, in contrast to general anaesthesia, decreases the adrenocortical response to Caesarean section surgery by blocking afferent neurogenic pathways from the surgical site. The method of anaesthesia does not influence the fetal cortisol response.

Anesthesia for cesarean section: further studies

This study was designed to re-evaluate neonatal condition at birth following elective cesarean section performed with epidural anesthesia and a modified technique of general anesthesia. Two groups of 20 patients were studied. Twenty received epidural anesthesia with 2 per cent lidocaine-carbon dioxide-epinephrine, and 20 patients were given general anesthesia. Modifications of our previous general anesthetic technique included the administration, to the mother, of high inspired concentrations of oxygen (66 per cent) prior to delivery, short induction-to-delivery intervals, and positioning of the mother in a 20 degrees left lateral tilt position. No significant differences in oxygen tension and acid-base balance in umbilical venous and arterial blood were demonstrated between the two sets of neonates. One-and five-minute Apgar scores and time to sustained respiration were similar in both groups. Our observations of the infants immediately after delivery led us to conclude that either anesthesia technique is acceptable for elective cesarean section.

Differentiation of mouse T-lymphocytes. 19 Characterization of thymocyte precursors in bone marrow by one G velocity sedimentation

Bone marrow cells were transferred into 700 R X-irradiated syngeneic mice, and regeneration of the thymus was demonstrated by determining the total amount of DNA in the thymus. The amount of DNA in the regenerated thymus 9 days after X-irradiation paralleled the number of cells injected, the range being 0 to 10(6) cells. These results indicate that regeneration during this period reflects the proliferation of thymocyte precursors existing in bone marrow cells, therefore such can be used as an indicator to determine the number of thymocyte precursors. Thymocyte precursors were separated from spleen colony forming cells and soft agar colony forming cells by one G velocity sedimentation. Thymocyte precursors (more than 4.3 mm/hour sedimentation rate) sedimented faster than did spleen colony forming cells (peak at about 3.0 mm/hour) and Thy-1 antigen was already evidenced on the cell surface as demonstrated by complement dependent cytotoxicity. Soft agar colony forming cells also sedimented faster, suggesting that cells destined to become one type of cell are larger than multi-potential stem cells.

Regulatory substances produced by lymphocytes. V. Production of inhibitor of DNA synthesis (IDS) by proliferating T lymphocytes

The conditions neccessary for production of inhibitor of DNA synthesis (IDS) by rat lymphocytes were investigated. In concanavalin A (Con A)-stimulated lymph node cell (LNC) cultures, IDS production was not detected in the culture supernatant during the first 24 hr, and it increased gradually after that to reach a maximum at 3 to 4 days. When the cells were pretreated with mitomycin C, IDS was not produced, suggesting that DNA synthesis of LNC or a LNC subpopulation is necessary for IDS production. In contrast, Con A-stimulated spleen cells priduced a high level of IDS within 24 hr, and its production fell off sharply thereafter. Con A-stimulated rat thymocytes also produced IDS reaching a maximum at 2 to 3 dyas. However, thymus cells from rats treated with hydrocortisone 48 hr previously did not produce IDS. This finding implies that cortisol-sensitive (cortical) thymocytes are capable of producing IDS and cortisol-resistant (medullary) thymocytes are not. IDS production by lymphoblasts was proportional to cell number and unaffected eith by cell density (1 to 10 x 106/ml) or by the concomitant presence of normal cells from spleen, lymph node, or thymus. Thus Con A-stimulated cells, after becoming blasts, appear to produce IDS automatically wihtout affecting or being affected by other cells. Both spleen and thymus cells from rats injected with a large dose of antigen (ovalbumin, 100 mg, i.p.) 24 hr in advance produced substantial amounts of IDS in culture within 24 hr in the absence of mitogen or additional antigen, but not the cells from rats injected with an immunizing dose (1 mg) of the same antigen. The cells producing IDS in the spleen were shown to be adherent to glass wool, and those in the thymus were partially so. IDS production by antigen-stimulated spleen cells was abrogated by injecting rats with bromodexyuridine (BUdR) at 0 and 12 hr after the ovalbumin. These findings suggest that a subpopulation ofadherent spleen cells (possibly resembling cortical thymocytes), which begins to proliferate within a few hours after a large dose of systemic antigen, produces IDS. This may account for increased nonspecific suppressor activity observed at the same time.

Phosphatidylcholine content and fatty acid composition of tracheal and gastric liquids from premature and full-term newborn infants

The phosphatidylcholine content and fatty acid composition of tracheal and gastric liquids from newborn full-term and premature (30-36 weeks) infants were studied. Phosphatidylcholine accounted for about 70% of the total phospholipids in both liquids from the full-term infants but only 55-57% of those from the prematures. There was a significant correlation between tracheal and gastric liquids in the fatty acid composition of phosphatidylcholine. There were significant differences in fatty acid composition between the full-term and premature liquids. These differenences were most apparent in the gastric liquid. It is suggested that phospholipid or fatty acid analysis of tracheal or gastric liquids from newborn infants can be used in the assessment of pulmonary maturity.

Regulatory substances produced by lymphocytes. III. Evidence that lymphotoxin and proliferation inhibitory factor are identical and different from the inhibitor of DNA synthesis

L cell mutant lines which were considerably more resistant to rat lymphotoxin (LT) than the original cell line were obtained by periodic additions of LT, partially purified from sensitized lymph node cell culture supernatants by DEAE-cellulose chromatography and Sephadex gel filtration. Addition of actinomycin D to cultures of these mutant cells abrogated resistance to LT, suqgesting that resistance was not due to a loss of LT receptors but probably to increased activity of a repair mechanisms. These mutant lines were also more resistant to the proliferation inhibitory effect of LT in low concentration and to that of diluted culture supernatants of lymph node cells stimulated with antigen (ovalbumin) than the original cell line, but they remained as sensitive to inhibitor of DNA synthesis (IDS) as the original line. The mutant lines also remained fully sensitive to both complement-dependent lysis by antibody and antibody-dependent cellular cytotoxicity, but showed increased resistance to the killing effect of rat lymph node cells sensitized with orginal L cells in vivo. These findings suggest that the lymphotoxic substance partially purified and characterized in this and in the previous paper may be an important mediator of T cell-mediated cytotoxicity.

Analysis of T-cell-specific functions in continuous lymphocytic cell lines. II. A T-cell line which forms rosettes with normal thymocytes of the same species

Four T-cell lines of mouse origin (EL-4, S-49, R-1, and L-5178Y) with similar characteristics (Thy-1-positive, and PHA-sensitive) were tested for reactivity with various antigens. EL-4 cells alone were shown to form rosettes at 4 degrees C with thymocytes (positive for either Thy-1.1 or Thy-1.2) and with Thy-1-positive lymph node cells of various mouse strains. Comparable rosette formation did not occur with Thy-1-negative lymphnode cells or red blood cells, nor with rat or rabbit thymocytes. The thymocytes which attached to the tumor cells formed a cluster at one pole of the cell after warming at 37 degrees C for 10 min. After incubation for 40 min at 37 degrees C, most of the rosettes disappeared. This process was blocked by sodium azide and dinitrophenol, suggesting that the movement of thymocytes to one pole of the tumor cell and subsequent release are energy-dependent. These results suggest that the EL-4 cell line, originally derived from a carcinogen-induced lymphoma of C57BL/6, may have been an autoimmune lymphoma reactive against T cells.

Regulatory substances produced by lymphocytes. II. Lymphotoxin in the rat

Rat lymphotoxin (LT), a soluble mediator which kills L cells (mouse fibroblasts) within 48 hr, was partially purified by conventional protein fractionation procedures from the culture supernatants of rat lymph node cells stimulated with ovalbumin in vivo and rechallenged with the same antigen in vitro. It appeared, from the elution pattern of DEAE-cellulose chromatography, to be a neutral or slightly basic protein and was inactivated at 60 degrees C. Its molecular weight was estimated by Sephadex gel filtration to be approximately 9 times 10(4) daltons. Partially purified LT, in titration studies, showed single hit kinetics. It also inhibited L cell proliferation at low concentration without significant killing effect. The heat inactivation curves of both cytotoxic and proliferation inhibitory activities were the same, suggesting that these two activities may be caused by the same molecule. However, it had almost no detectable effect on the DNA synthesis of rat lymph node cells stimulated with phytohemagglutinin (PHA), suggesting that lymphocytes, at least those which respond to HA, are rather resistant to LT. It is suggested that activities described as "proliferation inhibitory factor" and "cloning inhibitory factor" by others may represent the activity of dilute LT. The "inhibitor of DNA synthesis" is distinct in molecular character, range of target cells, and target cell kinetics from LT.