A Contribution of the Trivial Connection to Jones Polynomial and Witten's Invariant of 3d Manifolds I

We use the Chern-Simons quantum field theory in order to prove a recently conjectured limitation on the 1/K expansion of the Jones polynomial of a knot and its relation to the Alexander polynomial. This limitation allows us to derive a surgery formula for the loop corrections to the contribution of the trivial connection to Witten's invariant. The 2-loop part of this formula coincides with Walker's surgery formula for Casson-Walker invariant. This proves a conjecture that Casson-Walker invariant is a 2-loop correction to the trivial connection contribution to Witten's invariant of a rational homology sphere. A contribution of the trivial connection to Witten's invariant of a manifold with nontrivial rational homology is calculated for the case of Seifert manifolds.Comment: 28 page

Phage displayed 6-mer mimotopes with a consensus proline absent in the minimized linear wild-type epitope

Phage displayed random 6-mer libraries were screened with a monoclonal antibody specific for a minimized 'linear' 7-mer epitope of the measles virus hemagglutinin protein. No clone with the wild-type sequence was selected and most clones contained a sequence motif not found in the wild-type sequence. Two mimotopes (LYMPQLS, SEMPQLP) were synthesized which inhibited binding to the measles virus 95-135 times better than a wild-type peptide. Sequence comparison of proteins with known 3D-structure indicates that the epitope corresponds to an alpha-helix, while the best mimotopes have no predicted helix propensity. The proline is thought to be required for inducing a turn necessary for mimicking part of the alpha-helix. The higher intrinsic stability of such a mimotope may explain its improved binding and may be more suitable in immunogenicity experiments.status: publishe

Abnormal thymocyte subset distribution and differential reduction of CD4(+) and CD8(+) T cell subsets during peripheral maturation in diabetes-prone BioBreeding rats

In this study we quantified CD8(+) and CD4(+) T cells in T lymphocytopenic BB rats as compared with control rats at given stages along the maturational pathway from immature thymocytes to mature peripheral T cells. Our results show that BB rats exhibit abnormal thymocyte subset distribution. Numbers of mature TCR(high)/CD4(-)8(+) thymocytes, and also their TCR(high)/CD4(+)8(+) precursors were decreased, as were levels of CD8 expression on all thymocyte subsets investigated. By analogy with mouse thymocyte development, these findings suggest a decreased efficiency for positive selection of CD8 precursors in BB rats. Furthermore, as related to the number of available mature TCR(high) Single positive thymocytes, numbers of CD4(+) and CD8(+) T cells most recently migrated from the thymus were severely decreased in BB blood, indicating either reduced thymic output or rapid cell death after migration. Subsequently, in peripheral blood and cervical lymph nodes, a 95% decrease of CD8(+) and a 50 to 80% decrease of CD4(+) T cells were demonstrated upon maturation from recent thymic migrants to mature peripheral T cells, leaving the BB rat with a severely reduced T cell population, consisting of CD4(+) T cells and a minute population of CD8(+) T cells. The vast majority of the latter was found to have an immature peripheral phenotype. Possible consequences of our findings for the generation of autoreactive CD8(+) T cells are discussed

HIGH-FREQUENCY, BUT REDUCED ABSOLUTE NUMBERS OF RECENT THYMIC MIGRANTS AMONG PERIPHERAL-BLOOD T-LYMPHOCYTES IN DIABETES-PRONE BB RATS

In rats, RT6 and CD45RC are expressed by mature peripheral T cells, The underrepresentation of T cells expressing these markers in the T lymphocytopenic BE rat might therefore be a reflection of a relatively immature T cell population. With the use of Thy-1 as a marker for recent thymic migrants, it was demonstrated that BE rats indeed have a phenotypically less mature T cell population than age-matched control rats. However, this could not account for the reduced percentages of RT6(+) and CD45RC(+) T cells, as these were also decreased among mature Thy-1(-) T cells of BE rats. Although relatively overrepresented, absolute numbers of Thy-1(+) T cells were reduced in BE rats, Absolute numbers of mature Thy-1(-) T cells were also reduced in BE rats, but to a much larger degree than would proportionally be expected, Our findings taken together led us to conclude that both reduced thymic output and a defect in peripheral expansion are involved in the T lymphocytopenia of EB rats. (C) 1995 Academic Press, Inc