摘要:

SummaryThe persistence of Langerhans cells, melanocytes and ABH red cell antigens in human epidermal cell cultures derived from neonatal foreskin explants has been investigated. Langerhans cells were recognised via the detection of ATPase activity and by immunohistochemical staining for T6 and HLA‐DR antigens. Melanocytes were detected by the dihydroxyphenylalanine (DOPA) technique; whilst the presence of red cell antigens was confirmed by immunohistochemical tests using monoclonal anti‐A, anti‐B, and anti‐H antibodies.Langerhans cells were not detected in the cultured epidermis, and few melanocytes were found more than 0.2 mm from the periphery of the explants. However, both Langerhans cells and melanocytes were found to persist for up to 4 weeks in the explants themselves. Red cell antigens, consistent with the blood group of the donor infant, were consistently detected on the surface of the differentiating keratinocytes throughout theirin vitrolifespan. The significance of these findings is discussed.

ISSN:0004-945X    

DOI:10.1038/icb.1986.33

出版商:Nature Publishing Group    

年代:1986

数据来源: WILEY

摘要:

SummaryThe frequency of cytotoxic T lymphocyte precursors (CTL‐P) reactive to plasmacytoma (PCT) tumour‐associated antigens (TAA) was studied in BALB/c mouse spleen. Progressively decreasing numbers of responder BALB/c spleen cells were cultured with mitomycin C‐treated stimulator MPC‐11 BALB/c PCT cells, and a Poisson analysis was performed of the wells scored positive in a51Cr release assay with PCT target cells. It was found that approximately 2 per million BALB/c spleen cells were CTL‐P reactive to TAA of MPC‐11, and about one in three of these precursors responded to a TAA expressed by MPC‐11 which was shared with the C3H PCT C1.18. The frequency of CTL‐P reactive to TAA was shown to be 30 to 500 fold lower than that for CTL reactive to various major histocompatibility complex alloantigens, and the addition of exogenous Interleukin‐2 only resulted in a 2‐3 fold increase in this CTL‐P frequency. These results suggest that the weak levels of tumour immunity induced in vivo by immunisation of BALB/c mice with MPC‐11 are, at least in part, due to a very low frequency of CTL‐P reactive to TAA of that PCT.

ISSN:0004-945X    

DOI:10.1038/icb.1986.34

出版商:Nature Publishing Group    

年代:1986

数据来源: WILEY

摘要:

SummaryAdultNematospiroides dubiuscrude soluble homogenate consistently produced five fractions (Fl‐5) after filtration through Sephadex G‐200 with molecular weights of>300,000, 240,000, 83,000, 31,000 and300,000). Immunization with smaller molecular weight fractions also reduced worm recoveries following challenge infections but to a lesser extent.

ISSN:0004-945X    

DOI:10.1038/icb.1986.35

出版商:Nature Publishing Group    

年代:1986

数据来源: WILEY

摘要:

SummaryMice of the strain 129/J bred at this Institute (WEHI 129/J) were exposed once or repeatedly to cercariae ofSchistosoma mansoniand worm burdens determined. In keeping with reports ofS. japonicuminfection in these mice, a high level of resistance was recorded. Radio‐labelled extracted antigens ofS. mansoniadult worms were reacted with sera from exposed 129/J mice and infected BALB/c mice. Immunoprecipitated antigens preferentially recognized by antibodies in 129/J mice include proteins of Mr 99,000 and 21,000. Whether responses to these antigens are a cause or a consequence of resistance remains to be established.

ISSN:0004-945X    

DOI:10.1038/icb.1986.36

出版商:Nature Publishing Group    

年代:1986

数据来源: WILEY

摘要:

SummaryToxoplasma gondiiDNA from RH strain tachyzoites was purified from contaminating murine DNA by isopycnic density gradient ultracentrifugation in CsCI containing the fluorescent dye Hoechst 33258. Quantitative hybridization studies with DNA from uninfected mice and DNA extracted from oocysts of the ME49 strain ofT. gondiiconfirmed that RH strain DNA could be obtained at least 90% pure with a high recovery. Preliminary characterization studies on such purified DNA showed that it had a G + C content of 50% and was not significantly methylated.

ISSN:0004-945X    

DOI:10.1038/icb.1986.37

出版商:Nature Publishing Group    

年代:1986

数据来源: WILEY

摘要:

SummaryCell suspensions from the bone marrow (BM), spleen, thymus, liver and lymph nodes of 14 foetal lambs from 85‐135 days gestation were incubated in vitro with3H ‐thymidine (TdR). Cells from the long bones, the humerus, tibia and femur, yielded similar results, viz., (a) the total leucocyte population of the bone increased from a mean of 8 8×106at 85‐90 days (N = 4) to a mean of 487×106at 130‐135 days (N = 3); (b) the rate of incorporation of TdR varied from 22460‐45960 c.p.m./h/106cells with no clear trend related to foetal age; this rate is consistent with active mitosis occurring in the expanding BM cell population; (c) bone weight and cell number/bone increased in parallel, and the total mitotic capacity of the bone showed a similar pattern. In the liver, spleen and thymus the incorporation of TdR per 106cells decreased during the latter part of gestation. Despite growth of the liver (from 18 g to 71 g), the number of white blood cells (WBC) extracted from this tissue was lower at 135 days than at 85 days, suggesting that the haemopoietic capacit of the liver declined during this period. The marked increase in total WBC numbers in the thymus suggests tihs tissue may be supplying circulating lymphocytes to the growing foetus.

ISSN:0004-945X    

DOI:10.1038/icb.1986.38

出版商:Nature Publishing Group    

年代:1986

数据来源: WILEY

摘要:

SummaryTwo staphylococcal plasmids, pWG4 and pWG25, encode production of a diffusible pigment and resistance to erythromycin and spectinomycin. The former was found occurring naturally in a clinical isolate ofStaphylococcus aureusand the latter inS. epidermidis. Both plasmids are conjugative, capable of high‐frequency, interspecies transfer, only isolated in the open‐circular form and identical in molecular weight and pattern of restriction‐endonuclease fragments. The only difference between the plasmids is in the expression of resistance, pWG4 encoding inducible and pWG25 constitutive erythromycin resistance. The resistance determinants of both plasmids behave as hitch‐hiking transposons in cultural conditions that favour phage‐mediated or phage‐independent conjugation, always inserting a copy of themselves into the recipient's chromosome, except inS. epidermidisin which the chromosomal insertion site may be absent. The resistance determinants have been cloned and located on a 4 7 kbpEcoRl/HindIII restriction fragment which has a restriction map similar to that of the right arm of Tn554 (Murphy and Lofdahl, 1984). The hitch‐hiking transposon of plasmid pWG25 has been designated Tn3853.

ISSN:0004-945X    

DOI:10.1038/icb.1986.39

出版商:Nature Publishing Group    

年代:1986

数据来源: WILEY

摘要:

SummaryThe relative level of blood flow through thecal capillaries (RTF) in individual atretic and non‐atretic follicles>1 mm was measured in conscious ewes by injecting 15 μm radioactive microspheres into the aorta near the origin of the ovarian artery, and determining the ratio of radioactivity per mg protein in theca of individual follicles to that in the non‐luteal portion (stroma plus follicles0·05) on the relative level of blood flow within individual thecae or of atresia on thecal protein content.These data indicate that reduced thecal blood flow is associated with advanced atresia of antral follicles and are in accordance with the findings of previous histological studies. Whether thecal ischaemia is a factor involved in the onset of atresia, or occurs as a consequence of the degenerative process, remains uncertain.

ISSN:0004-945X    

DOI:10.1038/icb.1986.40

出版商:Nature Publishing Group    

年代:1986

数据来源: WILEY

摘要:

SummaryFive conscious rabbits each received a single injection of almitrine bismesylate via a marginal ear vein. Measurements were made of ventilation and breathing pattern using a barometric method, and blood gases, pH and lactate concentration ([Lac]) were measured from arterial blood samples throughout the hour following the injection. Almitrine caused an immediate increase in ventilation through an increase in tidal volume (VT), frequency (f) showing a small decline. After 15 min f increased to above control level and VTdeclined. Slower, deeper breathing was reinstated by 40 min post‐injection. Large changes in blood gases occurred in the first 15 min, withPO2raised by 30 Torr andPCO2lowered by 20 Torr. These recovered to be within 10 and 7·5 Torr of control at the end of 1 h. [Lac] increased steeply at first, then declined towards control levels. The acid‐base situation was mixed, comprising a respiratory alkalosis, resulting from CO2washout, and a metabolic acidosis from high [Lac]. These results are discussed in the context of assessing the primary and secondary effects of almitrine and recognition of the possibility that the drug may act at more than one site to alter respiration.

ISSN:0004-945X    

DOI:10.1038/icb.1986.41

出版商:Nature Publishing Group    

年代:1986

数据来源: WILEY

ISSN:0004-945X    

DOI:10.1038/icb.1986.42

出版商:Nature Publishing Group    

年代:1986

数据来源: WILEY