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81.
82.
Inhibition of IL 2-driven proliferation of murine T lymphocyte clones by supraoptimal levels of immobilized anti-T cell receptor monoclonal antibody 总被引:11,自引:0,他引:11
G J Nau R L Moldwin D W Lancki D K Kim F W Fitch 《Journal of immunology (Baltimore, Md. : 1950)》1987,139(1):114-122
Both cloned murine helper T lymphocytes (HTL) and cytolytic T lymphocytes (CTL) proliferated and secreted lymphokines when stimulated with immobilized anti-T cell receptor monoclonal antibody (anti-TCR mAb). However, although proliferation of CTL increased and reached plateau levels as concentrations of anti-TCR mAb were increased, the proliferation of HTL decreased with high concentrations of anti-TCR mAb. A reduction of IL 2-dependent proliferation by CTL was observed when IL 2 was added to cultures of CTL in the presence of high concentrations of anti-TCR mAb, whereas IL 2-independent proliferation appeared to be unaffected by these concentrations of anti-TCR mAb. Inhibition of IL 2-driven proliferation caused by high concentrations of immobilized anti-TCR mAb did not seem to be mediated by soluble factors. Cells continued to express cell surface receptors for IL 2 and transferrin after treatment with immobilized anti-TCR mAb. Inhibition of IL 2-driven proliferation by high concentrations of immobilized anti-TCR mAb may represent a mechanism for regulating the proliferation of T lymphocytes. This inhibitory mechanism is initiated by stimulation of the T cell receptor, in this case by immobilized anti-TCR mAb, and is independent of other cells and factors. 相似文献
83.
84.
CTL/HTL hybrid clones provide a unique system that allows detailed analysis of the role of Lyt-2, L3T4, and other structures involved in T cell functions. We have demonstrated previously that the fusion of cloned murine CTL and helper T lymphocytes with defined specificity generated hybrid cells that expressed both Lyt-2 and L3T4 as well as two TCR. Data obtained with these hybrid clones demonstrated that cytolysis is closely linked to the CTL TCR. We have analyzed the effects of anti-Lyt-2 and anti-L3T4 as well as anti-TCR mAb on cytolysis, proliferation, and lymphokine release by a number of hybrid clones. We found that anti-Lyt-2 and anti-L3T4 mAb were able to inhibit both proliferation and lymphokine release by the hybrid clones in response to stimulation of either the CTL or helper T lymphocyte parent TCR. In contrast, only anti-Lyt-2 and anti-CTL TCR mAb were able to block cytolysis of target cells bearing the Ag recognized by the CTL TCR. These results provide further evidence that cytolysis is closely linked to the CTL TCR and that Lyt-2 and L3T4 have more than a passive role as accessory molecules on the surface of T lymphocytes. 相似文献
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87.
Genetic affinities of inbred mouse strains of uncertain origin 总被引:5,自引:1,他引:4
Phylogenetic analyses of genetic data arising from 144 gene loci are used
to describe the interrelationships among 24 widely used inbred strains of
mice. An unordered-parsimony analysis gives a cladogram that is virtually
identical to the known genealogy of the mouse strains. A loss-parsimony
analysis is used to evaluate the hypothesis that the observed patterns of
genetic divergence among these 24 strains can be explained by the
segregation of residual heterozygosity arising from a small population of
highly heterozygous mice. The loss-parsimony cladogram is very similar to
both the unordered-parsimony cladogram and the known genealogy of the mice.
The phylogenetic analyses of these 144 loci are integrated with data on the
type and origin of the Y chromosome. Inclusion of the Y-chromosome data
provides additional insights into the genetic composition of several of the
original stocks used to produce the current inbred strains of mice. Ten
strains of uncertain origin are contained in these analyses, including AKR,
BUB, CE, I, NZB, P, RF, SJL, ST, and SWR. SJL is hypothesized to have been
derived from the same Swiss albino stock previously used to produce SWR.
The BUB strain appears to have had a complex origin and shows closest
genetic similarity to SWR and ST. AKR and RF are shown to be closely
related, while the I strain shows greatest genetic similarity to DBA/2 for
the 144 loci. However, I and DBA possess different types of Y chromosome.
The NZB strain shows genetic similarity to several stocks of both U.S. and
European origins. The power of the genetic data used in these analyses
reiterates that inbred strains of mice can be a valuable paradigm for
studies in evolutionary biology.
相似文献
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Walter M. Fitch 《Biochemical genetics》1971,5(3):231-241
This study answers the question: Are the variable and invariable codons of cytochrome c largely the same in all species? A method is presented for estimating the number of invariable (as opposed to unvaried) codons common to two taxa. The two taxa in this study were comprised of four fungi and four metazoans. Given the number of mutations fixed in each taxon, one calculates the number of codons that would be expected to have fixed mutations in both taxa, in one taxon only, in the other taxon only, and in neither taxon. This expectation depends upon the number of invariable codons that are assumed to be common to both taxa. In the present example, the assumption of 41 invariable codons in common leads to estimates that deviate by less than 2% from the values actually observed. This leads to the conclusion that there are 46 positions that are variable in one taxon but invariable in the other, thereby demonstrating that the invariable codons are not largely the same between the fungi and the metazoans. 相似文献