摘要:

SummaryDaily administration of increasing closes intraperitoneally of 2·5–4·0 mg NaCN/kg to male Wistar rats for 5 weeks produced acute signs of poisoning immediately post‐injection hut no sign of chronic toxicity except lower final body weights than in control rats. CN−‐treated rats had less liver copper than controls, but not below the range of normality, and their liver mitochondrial membranes were 24% less able to bind adenine nucleotides than control membranes. No other biochemical or pathological sign of copper deficiency occurred. Liver cytochrome oxidase activity was normal after the 5 weeks of CN−administration, as was the ability of liver mitochondria to synthesize phospholipids. The ultrastructure of hepatocytes was normal without evidence of the enlarged, misshapen mitochondria produced by copper deficiency. Normal cytochrome oxidase activity of liver mitochondria, together with reduced liver copper levels and reduced binding affinity of mitochondrial membranes for adenine nucleotides, indicate that the membrane binding site for adenine nucleotides is not cytochrome oxidaseper sebut may involve copper, perhaps by virtue of its cationicity. With repeated exposure to CN−rats develop tolerance to acute poisoning. It is suggested that this may he due to the switch in glucose cata‐bolism towards the pentose pathway at the expense of other pathways.

ISSN:0004-945X    

DOI:10.1038/icb.1975.39

出版商:Nature Publishing Group    

年代:1975

数据来源: WILEY

摘要:

SummaryThe deposition of melanin on the surface of the cell wall of the crayfish‐plague fungus,Aphanomyces astaci, in infected cuticles of Australian crayfish seemed to be correlated with some degree of resistance to infection.The most obvious reactions towards the fungal structures present in the bloodin vivawere their encapsulation by blood cells, many of which then disintegrated. This was followed by melanization of the fungal surface. Crayfish blood inhibited completely hyphal growthin vitroand the disintegrating blood cells were apparently responsible for this effect as well as for the melanization. Phagocytosis of fungal structures was not observed. Melanizationin vivoandin vitro, due to a polyphenoloxidase released by the blood cells, was stimulated by the presence of the fungal cell wall surface. This seems to be a typical reaction of the crayfish in general.It was known earlier that European and Japanese freshwater crayfish are very susceptible to attack by the crayfish‐plague fundgs but that North American crayfish have a higher, although not complete, resistance and may be the natural hosts for the parasite. Nine species from different parts of Australia and from New Guinea were tested in aquaria and were all found to be susceptible, often very susceptible. Their susceptibility to infection was very similar to that of the European species, and the results support strongly the hypothesis that the parasite originated in North America and not in the Australian region or elsewhere, It would appear that man has not yet introduced the disease to the Australian region. Should this, however, occur, it will probably prove disastrous to the Australian and New Guinean freshwater crayfish fauna.

ISSN:0004-945X    

DOI:10.1038/icb.1975.40

出版商:Nature Publishing Group    

年代:1975

数据来源: WILEY

摘要:

SummaryLyophilized cultures ofV. cholerae569B slowly lose their virulence for neonatal and adult mite during long term storage. Following a single passage in orally infected 6‐day old mice, a highly virulent strain (designated 569B/MP) was isolated. This organism causes rapidly fatal intestinal infections in 6‐day old mice; large numbers can he isolated in pure culture from the intestinal fluid. Freezing and storage at −60° of dead animals provides a simple means of maintaining the high virulence of the culture over a period of at least 9 months.This strain produces choleraic symptoms and death in approx. 50% of adult mice following oral infection. Large numbers of viable organisms may also be isolated from the small intestine over a period of at least 40 h. These criteria have been used as a basis for assessing protection against cholera infection induced by immunization with living or heat‐killedV. choleraegiven orally or intraperitoneally.

ISSN:0004-945X    

DOI:10.1038/icb.1975.41

出版商:Nature Publishing Group    

年代:1975

数据来源: WILEY

摘要:

SummaryIn an investigation into the characteristics of the rosette‐inhibiting antibody of antilymphocyte serum (ALS), rabbit anti‐mouse ALS were assayed for antibodies against lymphoid cells from the spleen, lymph nodes and thymus of Quackenbush (Q) mice, and against spleen cells from athymic nude mice. The lymphagglutinating and lymphocytotoxic titres were similar with both Q and nude cells, and the titres showed no significant correlation with skin graft survival times in mice receiving the corresponding ALS. A significant depletion of peripheral blood lymphocytes occurred in animals receiving both an immunosuppressive and a non‐immunosuppressive ALS, suggesting that the antibodies involved in this depletion are not significant in determining the immunosuppressive activity of ALS.In contrast, the rosette inhibition titres showed a significant correlation with graft survival times in the results obtained in tests using Q spleen, lymph node and thymus cells. No inhibition of rosette formation was obtained when using nude spleen cells. However, the numbers of spontaneous rosettes formed by both the mixed B and T cell populations from Q spleen were not significantly different from the numbers formed by the largely B cell population from nude spleen.These results confirm that the antibodies of ALS which are responsible for both thein vitroinhibition of spontaneous rosette function and thein vivosuppression of graft rejection are specifically directed against a T cell population, and it is suggested that the antibodies are related if not identical.

ISSN:0004-945X    

DOI:10.1038/icb.1975.42

出版商:Nature Publishing Group    

年代:1975

数据来源: WILEY

摘要:

SummarySheep were immunised with mouse P815 tumour cell suspensions and at intervals afterwards lymph was collected draining from the stimulated lymph nodes. The lymph samples were fractionated by column chromatography into IgM, IgG1 and IgG2 antibody fractions; these were then assayed for cytolytic functions on51Cr labelled target P815 cells. Complement dependent antibodies were assayed using sheep complement; activity was first detected in the IgM fraction 3–4 days after immunisation and in the IgG1 fraction at 5–6 days. No CDA activity was found in fractions of the IgG2 antibody subclass at any time. Leucocyte dependent antibodies were detected only in the IgG fraction, and they appeared simultaneously in both IgG1 and IgG2 subclasses 5–6 days after immunisation.

ISSN:0004-945X    

DOI:10.1038/icb.1975.43

出版商:Nature Publishing Group    

年代:1975

数据来源: WILEY

摘要:

SummaryThe normal human lymphocyte population which exhibits “spontaneous” cytolysis of EB2Burkitt's lymphoma fells has been characterized. The effector cell has EA and EAC' receptors but lacks E receptors and probably surface Ig. “Spontaneous” anti‐EB2cytotoxicity was not reduced by preincubation of the effector cells with plastic or iron carbonyl or by passage through cotton wool or agarose columns but was reduced by passage through nylon wool columns. Thymocytes were not cytotoxic to EB2cells, and chronic lymphocytic leukaemia cells (of B cell characteristics) had reduced cytotoxicity compared with normal lymphocytes.Cells from various lymphoid organs of rats and guinea‐pigs were also cytotoxic to EB2cells with reactivity in spleen blood ⩾ lymph>nodes, Spleen cells from neonatally thymectomized rats had increased cytotoxicity compared with normal rat spleen cells, suggesting that T lymphocytes are not essential. The effector cell in rat spleen did not adhere to cotton wool or agarose columns, indicating some resemblance to its counterpart in human peripheral blood.

ISSN:0004-945X    

DOI:10.1038/icb.1975.44

出版商:Nature Publishing Group    

年代:1975

数据来源: WILEY

摘要:

SummaryThe resistance of neonatal rats to sustaining adoptive immune responses against heterologous erythrocytes following the transfer of normal thoracic duct lymphocytes was examined. Irradiation of the neonatal rat at levels as low as 350 rad was found to be effective in overcoming this resistance, although preliminary exposure to antigen could interfere with facilitation of adoptive responses by irradiation. It is suggested that the failure of the neonate to sustain adoptive immune responses is explicable on the basis of an active suppression and, as a corollary, unresponsiveness resulting either from macrophage immaturity or the transfer of maternal antibody is discounted as a likely explanation for the immunological behaviour of the newborn rat towards the antigens examined.

ISSN:0004-945X    

DOI:10.1038/icb.1975.45

出版商:Nature Publishing Group    

年代:1975

数据来源: WILEY

摘要:

SummaryThe role of thymus‐derived cells in controlling the process of immunological maturation in the neonatal rat has been examined. Thymectomy performed on the day of birth resembled irradiation given at this time in that it permitted adoptive immune responses to sheep erythrocytes to be initiated in the neonatal host. Whereas the consequences of irradiation could be demonstrated if antigenic challenge was given on the following day, adoptive responses were not sustained unless an interval in excess of 24 h had elapsed after thymectomy, suggesting that extra‐thymic suppressor cells persist for at least this period. Suppression of adoptive responses was achieved in irradiated hosts with thymus cells obtained from rats on their day of birth but not with cells from older donors. Using the transfer of allogeneic lymphocytes as a stimulus, antibody‐forming cell precursors were shown to be plentiful in the newborn rat and it was accordingly suggested that thymic suppressor cells are responsible for the poor responsiveness of newborn rats to antigenic challenge.

ISSN:0004-945X    

DOI:10.1038/icb.1975.46

出版商:Nature Publishing Group    

年代:1975

数据来源: WILEY

摘要:

SummaryThe intravenous injection of as few as 15 Walker tumour cells into newborn rats consistently resulted in the development of pulmonary metastases and the death of the recipient within 2 weeks. Neither the outcome of tumour cell injection nor the interval until death could be modified by transferring 2 × 107lymphocytes from tumour‐immune adult rats to the neonatal hosts. In contrast with this failure to transfer adoptive anti‐tumour immune responses to intact recipients, the administration of 350 rad irradiation before transfer of 10° immune lymphocytes constantly afforded protection against inoculated tumour cells. The simultaneous transfer of neonatal thymus cells with immune lymphocytes interfered with the establishment of an adoptive response in the irradiated newborn. Initiation of a graft‐versus‐host response in F1hybrid neonates by injecting parental strain lymphocytes conferred resistance to tumour growth on the recipient, the magnitude of this effect increasing with the strength of the graft‐versus‐host reaction.

ISSN:0004-945X    

DOI:10.1038/icb.1975.47

出版商:Nature Publishing Group    

年代:1975

数据来源: WILEY

摘要:

SummaryIf sufficient normal syngeneic lymphocytes to effect skin graft rejection are transferred to homograft tolerant rats, a prolonged period elapses before lymphoid cells from the recipient acquire normal levels of GvH responsiveness against tissues of which the donor was previously tolerant (Silvers and Billingham, 1970; Elkins, 1972; Miyamoto and McCullagh, 1974). Although the ability of lymphoid populations of such animals to mount GvH reactions can be demonstrated to reside in donor type cells during the weeks immediately after transfer, reactive cells are ultimately derived from the host itself (Elkins, 1973; Miyamoto and McCullagh, 1974). Not only are lymphoid cells from tolerant rats which have been injected recently with normal lymphocytes poorly responsive in a GvH assay, but they have been observed in some experiments to suppress the GvH activity of normal syngeneic lymphoid cells (Elkins, 1972; Atkins and Ford, 1972). It is not clear whether the cells mediating suppression of the normal lymphocytes were derived from the tolerant host itself or, alternatively, from the normal lymphocytes injected into it to terminate the tolerant state.The present experiments sought to delineate the origin of any suppressor cells within populations of lymphocytes collected from rats in which tolerance had recently been terminated. They indicate that suppression of the normal donor cells within such populations may be exerted by cells derived from the tolerant host.

ISSN:0004-945X    

DOI:10.1038/icb.1975.48

出版商:Nature Publishing Group    

年代:1975

数据来源: WILEY