摘要:

SummaryStrains of a new flavivirus, for which the name Saumarez Reef Virus is proposed, were isolated from seabird ticks collected from four localities. Two strains were isolated from ticks of the speciesOrnithodoros capensisNeumann 1901 collected from the nests of Sooty Terns,Sterna fuscataLinnaeus 1766 on coral cays off the east coast of Queensland, Australia. The other three strains were isolated from ticks of the speciesIxodes eudyptidisMasked 1885 taken from two dead Silver GullsLarus novachollandiaeStephens 1826 in northern Tasmania. The new virus was compared serologically with 50 other flaviviruses at the Yale Arbovirus Research Unit and was found to be most closely related to Tyuleniy virus.

ISSN:0004-945X    

DOI:10.1038/icb.1977.49

出版商:Nature Publishing Group    

年代:1977

数据来源: WILEY

摘要:

SummaryWhile the virgin AFC‐progenitors for an adoptive immune response in neonatal germ‐free CBA mouse spleen are small, dense cells, the equivalent cells in the adult are a larger, lighter density population. The effects of injections of unrelated antigens on the physical properties of the AFC‐progenitors in neonatal spleen were investigated to test the postulate that the physically distinct “virgin” AFC‐progenitors in the adult arose by a process of non‐specific activation.Spleen cells from 7‐day‐old germ‐free CBA mice were separated by sedimentation at unit gravity or by density on continuous albumin gradients, and the fractions were tested for NIP‐specific AFC‐progenitor activity using an adoptive immune assay which gave a direct linear measure of B cell activity. If the donor neonatal animals were injected one day previously with POL or PPD, the NIP‐specific AFC‐progenitor activity shifted from the typical small, dense lymphocytes to larger, lighter cells. The physical properties of these stimulated AFC‐progenitors resembled those of IgM AFC‐progenitors in normal adult mice. These results experimentally confirm the theory that environmental stimuli induce a non‐specific “activation” of a particular subset of “virgin” B cells.

ISSN:0004-945X    

DOI:10.1038/icb.1977.50

出版商:Nature Publishing Group    

年代:1977

数据来源: WILEY

摘要:

SummarySome changes produced in the cell populations of intestinal lymph by infection with the enteric nematodeTrichostrongylus colubriformis.were studied in sheep regularly re‐infused with all discharged lymph. Lymphocyte traffic through the intestinal lymphatic duct was reduced until day 35 of primary infection, mainly due lo the‐ absence of lymphocytes with smaller cell volumes but was increased two‐fold after day 70 and in immune sheep. Antigen‐reactive lymphocytes in Mood and lymph were assayed by the uptake of:3H‐thymidine in cell culture stimulated by extracts from the larvae ofT. colubriformis.Cells from the blood and lymph of immune sheep were highly reactive to worm antigen. A relatively smaller reactivity was present in the blood of worm‐free sheep and was abolished during the first 12 days of primary infection. Antigen‐reactive cells were not detected in intestinal lymph until 12 days after primary infection, midin vitroantigen reactive in intestinal lymph of immune sheep was increased after challenge with infective larvae. Responses to the mitogens, concanavalin A and phytohaemagglutinin in cultures of cells from both intestinal lymph and blood were depressed on days 7 and 12 of primary infection.It is proposed that the diminished traffic of lymphocytes in intestinal lymph and the reduced numbers of mitogen and nematode antigen‐reactive lymphocytes in both blood and intestinal lymph during the early stages of infection withT. colubriformisis closely related to the slow development of protective immunity to this parasite.

ISSN:0004-945X    

DOI:10.1038/icb.1977.51

出版商:Nature Publishing Group    

年代:1977

数据来源: WILEY

摘要:

SummaryFollowing the injection of polymeric flagellin (POL), foetal sheep older than 70 days gestation produced haemagglutinating. antibody and synthesized IgM. The maximum titre of antibody in the blood increased with the; age at which the foetus was injected. All foetuses synthesized 2‐meracapto‐ethanol‐sensitive antibodies, while older foetuses (approximately 120 days gestation) also produced 2‐mercaptoethanol‐resistant antibodies and synthesized IgG1. During the primary immune response, there was a poor correlation between the antibody titre and the amount of immunoglobulin synthesized. The majority of IgM synthesized and almost all IgG1, had no demonstrable specificity for POL. During the secondary response to POL the majority of IgG1synthesized was specific and in one case appeared to be monoclonal. There was no detcetable' primary antibody response in foetal sheep to the somatic antigens ofSalmonella typhimurium, although all foetuses synthesized IgM. Only one of six: foetuses receiving a second injection of antigen produced antibody. There was an increase in the numbers of blood lymphocytes following the injection of both POL and S.typhimurium, but only POL induced a rapid increase in the numbers of neutrophils in the blood and produced histological changes in the draining lymph nodes and spleen.

ISSN:0004-945X    

DOI:10.1038/icb.1977.52

出版商:Nature Publishing Group    

年代:1977

数据来源: WILEY

摘要:

SummaryThe nature of infected stimulator cells in thein vitrosecondary cytotoxic T cell response to ectromelia infection was investigated. It was found that macrophages were better stimulator cells than spleen cells. B cells (Ig‐positive cells) were superior to T cells (Ig‐negative cells) both on a relative proportion and on a cell‐to‐cell basis. Concanavalin A and lipopolysaccharide‐stimulated lymphocytes were also effective stimulator cells but appeared to be slightly inferior to spleen cells. Spleen cells depleted of la‐positive cells were markedly inferior to normal spleen cells as stimulators. It was also found that primary and secondary cytotoxic T cells were largely Ia‐negative.These findings are discussed in relation to the likely events during T cell responses to infectionin vivo.

ISSN:0004-945X    

DOI:10.1038/icb.1977.53

出版商:Nature Publishing Group    

年代:1977

数据来源: WILEY

摘要:

SummaryWhen virus‐immune cytotoxic T cells were generated in secondary responsesin vitroto syngeneic, infected stimulator cells, they only killed infected targets that sharedH‐2KorH‐2Dgenes with the T cells and stimulator cells.H‐2Iregion compatibility was neither sufficient nor necessary. The role ofH‐2K, H‐2DandH‐2Igenes in the interaction between memory T cells and infected stimulator cells was then investigated. Initial attempts failed because of escape of virus into the responder population. Steps were taken to eliminate this problem; confirming their efficacy was the finding that when (CBA/H × BALB/c) F1memory T cells were stimulated by either parental type, the cytotoxic T cells generated only killed the target cell type syngeneic to the stimulator cell used to induce the response. Using recombinant strain macrophages as infected stimulator cells, it was further shown that K orDregion sharing between stimulator and responder cells was sufficient to induce the response.Iregion homology, on the other hand, although stimulating high levels of3H‐thymidine incorporation, did not give rise to significant amounts of cytotoxic activity against virus‐infected target cells. These results are compatible with the interpretation that the inductive signal to cytotoxic T cell precursors (memory T cells) in thein vitrosecondary response is an antigenic pattern containing virus‐induced and selfH‐2KorH‐2Dcomponents; the response of the cytotoxic cells may be facilitated by a “helper”, DNA‐synthesizing subclass which responds to antigenic patterns containing both virus‐induced andIregion‐determined components.Evidence from cytotoxic T cell induction with semi‐compatible infected macrophages shows thatH‐2K(orH‐2D) antigens and viral antigen must be in the same cell membrane for efficient stimulation to occur. This suggests that both the antigens, and the T cell receptors for them, are closely associated in the infected cell and T cell membranes respectively.

ISSN:0004-945X    

DOI:10.1038/icb.1977.54

出版商:Nature Publishing Group    

年代:1977

数据来源: WILEY

摘要:

SummaryData presented show thatin vivoperitoneal exudate cells of mice immune to infection withNematospiroides dubiusare capable of damaging the infective third stage larvae of this parasite. Experiments utilising chambers closed with membranes of different pore size and implanted in the peritoneal cavity indicated that damage requires intimate contact between the cells and larvae. Examination of the cells in contact with the larvae revealed that these cells were predominantly macrophages. The fact that peritoneal exudate cells of normal mice are unable to damage the third stage larvae even in the presence of serum from immune animals, although binding to the larvae, suggest that cells of immune mice have been “activated”.

ISSN:0004-945X    

DOI:10.1038/icb.1977.55

出版商:Nature Publishing Group    

年代:1977

数据来源: WILEY

摘要:

SummaryLow protein diets initiated at weaning in Balb/c mice cause a rapid and profound reduction in thymus weight and cellularity. Thymus weight falls to less than that of the involuted thymus of adult mice and remains depressed for as long as diets are fed. Although most peripheral T cell functions do not appear to be depressed, suppressor cell activity was not as vigorous in deprived animals despite the presence of functional suppressor populations. Thymus growth was reinitiated promptly when high protein diets were fed to deprived animals.Thymus regeneration appeared to he due to both a resident population of stem cells which persisted in the thymus through the period of deprivation and a second, probably bone‐marrow derived, population of stem cells. It is suggested that in normal mice the synchronized growth of the first population produces the characteristic innate growth pattern of the thymus. This is superimposed on the growth of the second population which continuously seeds the thymus and is constantly replaced. Protein deprivation severely restricts the growth of the first and second population, but both maintain their capacity for growth during long periods of protein restriction.

ISSN:0004-945X    

DOI:10.1038/icb.1977.56

出版商:Nature Publishing Group    

年代:1977

数据来源: WILEY

摘要:

SummaryThe proliferative response of various separated populations of mouse spleen and thymus lymphocytes to the mitogen phytohaemagglutinin (PHA) was not a direct function of the level of responsive T cells, but was governed by other regulatory effects. These included a stimulation by adherent macrophages, an inhibition by a separate population of adherent cells and an adherent cell independent restriction of proliferation at high cell concentration. In contrast, the proliferate response Concanavalin A (Con A) was more closely related to the level of responsive T cells. All density and electrophoretically isolated sub‐sets of splenic T cells appeared capable of a proliferative response to PHA and Con A, although under some conditions the PHA responsiveness of certain fractions was suppressed. In the thymus, the minor lowθsub‐population appeared capable of response to both mitogens, and accounted for all the activity of the unfractioned thymus cells. No response to either mitogen could be obtained from the major, highθthymocyte population.

ISSN:0004-945X    

DOI:10.1038/icb.1977.57

出版商:Nature Publishing Group    

年代:1977

数据来源: WILEY

摘要:

SummaryExtracts of porcine pituitaries can be separated into two fractious, each containing immunoreactive growth hormone, (GH) by gel filtration on Sephadex G‐200. The void volume peak contained 0·2–0·5% (large GH) and the remainder fluted atKd= 0·6 (small GH). 50–60% of the immunoreactive large CH was absorbed on to a large excess of anti‐GH coupled to Sepharose 2B during an 18 hour incubation at 4°. Over 80% of the absorbed immunoreactivity eluted with neutral 6 M NaSCN at 4°. The pituitary extracts also contained RNA which was absorbed and eluted along with the large GH. Upon rechro‐matography on Sephadex G‐200 the eluate contained small GH, suggesting that large GH was dissociated to small GH. The RNA ran in the void volume. RNA was also non‐specifically absorbed when Sepharose coupled with bovine serum gamma globulin was substituted for anti‐GH Sepharose. However, interference by RNA could be avoided if large GH was converted to small GH using 6 M NaSCN and rechromatographed before immunoabsorption. Contamination by prolactin was found.Following a 2 hour incubation of porcine pituitary slices with (3H) leucine, the specific activity of large GH was 10–100 times that of small GH. It is concluded, firstly, that pituitary large GH is not small GH covalently bound to RNA, and, secondly, that pituitary large GH represents a different metabolic pool from pituitary small GH. This may be newly synthesized small GH, not yet incorporated into granules, making it susceptible to non‐specific binding to RNA or other proteins.

ISSN:0004-945X    

DOI:10.1038/icb.1977.58

出版商:Nature Publishing Group    

年代:1977

数据来源: WILEY