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2.
A model has been established for investigating the cellular interactions for the generation and regulation of primary cytotoxic T lymphocyte (CTL) responses to Qa-1 alloantigens. Although NZB anti-BALB/c one-way mixed leukocyte cultures (MLC) generate anti-Qa-1b CTL, anti-Qa-1 CTL responses are not generated during BALB/c anti-NZB one-way MLC or during two-way MLC with NZB and BALB/c spleen cells. However, depletion of L3T4+ cells from the spleens of BALB/c mice before two-way MLC with NZB spleen cells resulted in anti-Qa-1b CTL responses. Likewise, the addition of anti-L3T4 monoclonal antibody (mAb) or anti-I-Ad mAb to two-way MLC with NZB and BALB/c spleen cells resulted in the generation of anti-Qa-1b CTL. Conversely, anti-Lyt-2 mAb inhibited the generation of anti-Qa-1 CTL. These data indicate that class II major histocompatibility complex-restricted cellular interactions are capable of suppressing the generation of Ia-unrestricted anti-Qa-1 CTL responses by Lyt-2+ responder cells. This model provides a novel opportunity to both characterize the cellular interactions responsible for regulating primary CTL responses to the Qa/Tla-encoded class I molecule Qa-1, and determine the contribution of this L3T4+ Ts-dependent defect in NZB mice to the pathogenesis of autoimmunity. 相似文献
3.
Regulation of primary cytotoxic T lymphocyte responses generated during mixed leukocyte culture with H-2d identical Qa-1-disparate cells 总被引:2,自引:0,他引:2
D P Huston G Tavana R R Rich S E Gressens 《Journal of immunology (Baltimore, Md. : 1950)》1986,137(6):1776-1781
Cytotoxic lymphocyte (CTL) responses are not usually generated during primary mixed leukocyte culture (MLC) with H-2 identical cells. Thus NZB mice are unusual in that their spleen cells do mount CTL responses during primary MLC with H-2d identical stimulator cells; the predominant target antigen for these NZB responses is Qa-1b. Considering the numerous immunoregulatory defects in NZB mice, we postulated that these NZB anti-Qa-1 primary CTL responses were due to an abnormality in T suppressor cell activity. Cellular interactions capable of suppressing NZB anti-Qa-1 primary CTL responses were investigated by using one-way and two-way MLC with spleen cells from NZB mice and other H-2d strains. Although H-2d identical one-way MLC with the use of NZB responders resulted in substantial CTL responses, only minimal CTL responses were detected from two-way MLC with the use of NZB spleen cells plus nonirradiated spleen cells from other H-2d mice. Thus the presence of non-NZB spleen cells in the two-way H-2d identical MLC prevented the generation of NZB CTL. Noncytotoxic mechanisms were implicated in the suppression of the NZB CTL responses during two-way MLC, because only minimal CTL activity was generated when NZB spleen cells were cultured with semiallogeneic, H-2d identical (e.g., NZB X BALB) F1 spleen cells. The observed suppression could be abrogated with as little as 100 rad gamma-irradiation to the non-NZB spleen cells. The phenotype of these highly radiosensitive spleen cells was Thy-1+, Lyt-1+, Lyt-2-, L3T4+. The functional presence of these cells in the spleens of semiallogeneic, H-2d identical F1 mice indicated that their deficiency in NZB mice was a recessive trait. These data suggest that NZB mice lack an L3T4+ cell present in the spleens of normal mice that is capable of suppressing primary anti-Qa-1 CTL responses. This model system should facilitate additional investigations of the cellular interactions and immunoregulatory mechanisms responsible for controlling primary CTL responses against non-H-2K/D class I alloantigens. The model may also provide insight into the immunoregulatory defects of autoimmune NZB mice. 相似文献
4.
Cellular requirements for the generation of primary cell-mediated lympholysis responses to Qa-1 antigens 总被引:1,自引:0,他引:1
D P Huston R N Jenkins S E Gresens R Smith R R Rich 《Journal of immunology (Baltimore, Md. : 1950)》1985,134(4):2198-2204
Mixed leukocyte cultures (MLC) between NZB responder spleen cells and Qa-1-disparate stimulator spleen cells were employed to determine the cellular requirements for the generation of primary anti-Qa-1 cell-mediated lympholysis (CML) responses. Although primary anti-Qa-1 cytotoxic lymphocytes (CTL) were generated during H-2-homologous stimulation, anti-Qa-1 CTL were not detectable from MLC in which the stimulators were H-2 allogeneic. Anti-Qa-1 CTL also were not generated from MLC in which the stimulators were semiallogeneic. Thus, H-2 identity between responder and stimulator cells was not sufficient to permit the generation of primary anti-Qa-1 CTL when H-2 disparity was also present. The capacity for H-2 disparity to prevent anti-Qa-1 CML responses was further demonstrated in MLC containing both H-2-allogeneic and H-2-homologous stimulator cells. Therefore, in subsequent studies we employed NZB responders and H-2-homologous, Qa-1-disparate stimulators. When various subpopulations of stimulator cells were studied for their ability to induce anti-Qa-1 CTL, nylon wool-adherent cells were found to be potent stimulators, but nylon wool-nonadherent cells were not. Furthermore, depletion of macrophages from the stimulator population abrogated the generation of anti-Qa-1 CML responses, despite the presence of responder macrophages in the culture. In contrast, all fractionated subpopulations stimulated anti-H-2 CML responses. When macrophage-enriched cells were used as stimulators, anti-Qa-1 CTL could be generated with approximately 80-fold fewer stimulator cells than when unfractionated splenocytes were used as stimulators. These findings indicated that stimulator macrophages were essential for the generation of primary anti-Qa-1 CTL. Direct evidence for macrophage expression of Qa-1-antigens was obtained by using a Qa-1b-specific CTL clone. These studies provide i) the first evidence for Qa-1 expression on macrophages, ii) a basis for comparison of the cellular interactions necessary to generate CTL against H-2K/D-encoded vs Qa-1-encoded class 1 antigens, and iii) a model for investigating the mechanisms responsible for the immunodominance of H-2K/D alloantigens. 相似文献
5.
Hardies SC; Martin SL; Voliva CF; Hutchison CA d; Edgell MH 《Molecular biology and evolution》1986,3(2):109-125
6.
The effects of diet on mineral concentrations in serum, liver and endometrium were determined at points in the reproductive cycle in heifers. Dietary treatments extended 134 d and included feeding a basal hay (negative control), basal hay with concentrate (feed control), feed control with phosphorus and feed control with both phosphorus and trace minerals. Samples of serum and liver were taken at the beginning and end of the trial. Within an estrous cycle during the trial (endometrial biopsy) the cows were sampled either at Day 1 or Day 12 for determining progesterone levels and mineral elements in the blood, liver and endometrial tissue. Trace element concentrations in serum and liver did not differ among collection periods pretrial, endometrial biopsy and post breeding nor among treatment groups. However, endometrial tissue concentrations of copper, manganese and zinc were higher at Day 1 than at Day 12 (P < 0.05) in reverse of serum progesterone, which was higher at Day 12 (P < 0.05). Supplemental trace minerals appeared to increase concentrations of copper (P < 0.20), manganese (P < 0.10) and zinc (P < 0.20) at Day 1 but decrease concentrations of these same elements at Day 12 (P < 0.05, P < 0.10 and P < 0.05, respectively). The large differences in trace element concentrations observed in endometrial tissue at the estral phases and under different diets suggest the possible importance of trace elements and trace element nutrition in fertilization and (or) embryo survival. 相似文献
7.
8.
The conformational transition between the α- and 310-helical states of α-methylalanine homopeptides is studied with molecular mechanics. Conformational transition pathways for Ace-(MeA)n-NMe with n = 7, 9, and 11 are obtained with the algorithms of Elber and co-workers [R. Czerminski & R. Elber (1990) International Journal of Quantum Chemistry, Vol. 24, pp. 167–186; A. Ulitsky & R. Elber (1990) Journal of Chemical Physics, Vol. 92, pp. 1510–1511]. The free energy surface, or potential of mean force, for the conformational transition of Ace-(MeA)9-NMe is calculated from molecular dynamics simulations, and a method is presented for the decomposition of the free energy surface into the constituent energetic and entropic terms, via the calculation of the required temperature derivatives in situ. For the AMBER/OPLS model employed here, the conformational transition pathways each contain a single 310-helical-like transition state, and the transition state potential energy relative to the 310-conformation is 3 kcal/mol, independent of peptide length. Entropic stabilization in the barrier region significantly lowers the activation free energies for the forward and reverse transitions from the estimates of the barrier heights based simply on potential energy alone. © 1994 John Wiley & Sons, Inc. 相似文献
9.
Summary Microsomal and soluble fractions of Pleurotus pulmonarius exhibited a reduced carbon monoxide difference spectrum with P450 maxima at 448nm and 450–452nm respectively. Substrate induced Type I spectra were observed on addition of benzo(a)pyrene to both fractions. Benzo(a)pyrene hydroxylation was measured using the aryl hydrocarbon hydroxylase assay and was observed to be P450 dependent as indicated by carbon monoxide inhibition together with the substrate binding characteristics. The activity of the fractions were observed to give Km of 200mM and 660mM and Vmax of 1.25 nmol/min/nmol P450 and 0.57 nmol/min/nmol P450 for the microsomal and cytosolic fractions respectively. 相似文献
10.
E. E. Hiatt L. Georgi S. Huston D. C. Harshman S. A. Lewis A. G. Abbott 《Journal of nematology》1995,27(2):143-152
The genetic heterogeneity of two M. arenaria race 2 populations (designated Pelion and Govan) was examined using RFLP analysis of 12 clonal lines established from single egg masses (six distinct clonal lines from each population). These populations are essentially identical by traditional biochemical and race identification schemes; however, the Govan population is more aggressive than the Pelion population, producing larger galls and exhibiting greater reproductive capabilities on many soybean cultivars and experimental accessions. Variation at the genomic DNA level was examined using probes representative of expressed DNA sequences present in the eukaryotic genome. Ribosomal DNA, interspersed repeated sequences, and cDNA probes were tested for detection of polymorphism within and between single egg mass lines of each population. Cloned cDNAs and ribosomal intergenic spacer sequences detect polymorphism both within and between populations, demonstrating the usefulness of these sequence classes for molecular genetic analysis of population structure and genome evolution. 相似文献