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S O Sharrow

Publications and source records attributed to S O Sharrow.

140 records · Page 8Linked to original sources

Isolation of glial cell-enriched and -depleted populations from mouse cerebellum by density gradient centrifugation and electronic cell sorting.

Preparative amounts of populations enriched and depleted in glial cells have been isolated from 10-day-old mouse cerebella. Discontinuous density bovine serum albumin (BSA) gradients provide two distinct populations: the one derived from the 10-15% BSA interface is enriched in cyclic nucleotide phosphohydrolase (CNPase) activity, and a percentage of S-100, GFA protein, and NS-1 antigen-positive cells; the other, located as the 15-31% interface, contains a cell population depleted in these compounds. This report also describes the first use of flow microfluorimetry and electronic cell sorting techniques for the analysis and isolation of cell populations derived from the mammalian central nervous system. Glial cell-enriched and -depleted populations obtained by BSA density gradient centrifugation were analyzed for their forward angle light scattering properties and their capacity to bind anti-corpus anti-serum to the cell surface. The glial cell-enriched fraction shows a different frequency distribution of light scattering than the glial-depleted fraction. Anti-corpus callosum antiserum binds preferentially to the glial cell-rich fraction. Cells can be sorted into corpus callosum antigen-positive and -negative cell fractions and recovered with a viability of more than 95% as judged by trypan blue exclusion. Anti-corpus callosum-positive sorted cells are enriched in CNPase activity, S-100, and glial fibrillary acidic proteins.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗

B-lymphocyte heterogeneity: development and characterization of an alloantiserum which distinguishes B-lymphocyte differentiation alloantigens.

CBA/N mice and F1 male mice, which are hemizygous for the CBA/N X chromosome, have an immune defect which is associated with the absence (deficiency) of a subpopulation of mature or late developing B lymphocytes. This characteristic was utilized to develop an antiserum that was specific for this subclass of B cells. C57BL/L mice were immunized with DBA/2 spleen calls, and the resulting antisera was absorbed with lymphoid cells derived from immunologically abnormal (CBA/N female X DBA/2 male)F1 male mice. The absorbed antisera was cytotoxic for a subpopulation of lymphocytes that was present in the spleens of adult DBA/2 and (CBA/N female X DBA/2 male)F1 female mice. The cells killed by the absorbed antisera were Ig-bearing, complement receptor-bearing B lymphocytes, which had a low-to-intermediate density of total surface Ig. Moreover, the cells remaining after treatment of adult (CBA/N female X DBA/2 male)F1 female spleen cells with the absorbed antisera and C had a high ratio of surface IgM to IgD. The development of this cytotoxic alloantisera, which is specific for a late developing (mature) subpopulation of B lymphocytes, will allow the functional characterization of subclasses of B lymphocytes.

Animals↗

Liposome--lymphocyte interaction: saturable sites for transfer and intracellular release of liposome contents.

The water-soluble dye 6-carboxyfluorescein was trapped in the internal aqueous compartments of small sonicated dioleoyl lecithin vesicles and used to assess the kinetics of transfer of vesicle contents to human lymphocytes. By using flow microfluorometry, the initial rate of dye transfer to the cells was measured as a function of the concentration of vesicles in the external medium. The rate of transfer consists of at least two components, one of which saturates at high vesicle concentration and the other of which does not saturate in the range of concentrations explored. The saturable component was competitively inhibited by vesicles not containing dye. Both the saturable and nonsaturable components of transfer were inhibited by fetal calf serum or bovine serum albumin but neither component was affected by bovine IgG, choline chloride, or heparin. Pretreatment of the lymphocytes with trypsin or Pronase had no effect on either component. The saturable component can be interpreted in terms of a two-step process in which vesicles bind reversely to sites on the cell surface, and dye is then transferred into the cell from the vesicle-site complex.

Blood↗

Partial chemical characterization of Ia antigens derived from murine thymocytes.

Previous chemical studies attempting to demonstrate Ia antigens on mouse thymocytes have given contradictory results. We attempted to resolve the question of whether Ia antigens exist on thymocytes (defined as thymus cells that bear a T cell marker) by isolating strain C3H thymocytes free of other contaminating cells using the fluorescence-activated cell sorter, and then chemically testing the purified populations for Ia antigens. Immunoglobulin-negative thymus cells and thymus cells selected with a rabbit antiserum to mouse brain were the two populations of thymocytes labeled with [3H]leucine after sorting. Radiolabeled proteins were solubilized with the non-ionic detergent Nonidet P-40, reacted with anti-Ia antiserum, and analyzed by electrophoresis on discontinuous sodium dodecyl sulfate/polyacrylamide gels. Ia antigens were recovered from both cell populations. These antigens were synthesized by thymocytes and were found on molecules composed of two chains of molecular weight 33,000 and 25,000, respectively, similar to Ia antigens derived from spleen cells. Assuming that all thymocytes bear similar amounts of Ia antigens, we estimated that they have approximately 1/50 the amount of Ia antigens that spleen cells do.

Animals↗

Cell cycle of Saccharomycescerevisiae in populations growing at different rates.

The cell cycle of Saccharomyces cerevisiae in populations growing at different rates was analyzed by flow microflourometry. The results demonstrate that (i) variation in growth rate of the population depends mainly on variation in the G1 phase of the cell cycle, and (ii) atall growth rates initiation of DNA synthesis occurs concomitantly with initiation of budding.

Cell Cycle↗

Murine B lymphocyte heterogeneity: distribution of complement receptor-bearing and minor lymphocyte-stimulating B lymphocytes among cells with different densities of total surface Ig and IgM.

The distribution of complement receptor-bearing (CR+) and minor lymphocyte-stimulating (Mls)-defined lymphocyte-activating determinants (LAD) among B lymphocytes with different densities of total surface immunoglobulin (sIg) and sIgM was determined. B lymphocytes that bore intermediate densities of sIg and low densities of sIgM had the highest frequency of CR+ cells and were the most active in expressing Mls-defined LAD. The distribution of these and other surface markers on B-lymphocyte subpopulations is discussed.

Animals↗

B-lymphocyte heterogeneity: ontogenetic development and organ distribution of B-lymphocyte populations defined by their density of surface immunoglobulin.

The density of total Ig and of IgM, IgG1, IgG2, and IgA on the surface of adult murine splenic B lymphocytes was measured using the technique of rapid flow microfluorometry. In addition, the density of total surface Ig and of IgM on B lymphocytes derived from adult bone marrow, lymph nodes, and Peyer's patches, and from neonatal spleen was determined. Adult spleen and lymph node B lymphocytes are characterized by the presence of a large population of cells with a low-to-intermediate density of total surface Ig, which is seen as a peak in the fluorescence profiles when these cells are labeled with fluorescein-conjugated (F1) anti-Ig. This peak is not detected when neonatal spleen or adult bone marrow are examined; the development of this peak among spleen cells occurs during the first 4 wk of life. Although the characteristic fluorescence intensity peak is not seen when adult spleen cells are labeled with Fl anti-mu, changes in the density of surface IgM do occur during the first few weeks of life and are detected as a decrease in the frequency of cells which have relatively large amounts of surface IgM. The differences seen in the fluorescence patterns of adult spleen cells labeled with Fl anti-Ig and Fl anti-mu may be due to the appearance of IgD on the surface of mature splenic B lymphocytes. This is supported by the similarity of the fluorescence profiles of adult bone marrow cells stained with Fl anti-Ig and Fl anti-mu, as the latter population of cells is reported to lack surface IgD.

Age Factors↗

X-linked B-lymphocyte defect in CBA/N mice. III. Abnormal development of B-lymphocyte populations defined by their density of surface immunoglobulin.

CBA/N mice have an X-linked defect in B-lymphocyte function characterized by a failure to respond to certain thymus-independent antigens. When studied by rapid flow microfluorometry, adult CBA/N splenic B lymphocytes labeled with either fluorescein-conjugated (Fl) anti-Ig or Fl anti-mu had fluorescence profiles which were considerably different from those of B lymphocytes derived from normal mice. By studying progeny of crosses of CBA/N and normal mice, it was shown that the abnormal fluorescence profiles of CBA/N B cells were determined by an X-linked gene. The fluorescence profile of adult CBA/N splenic B lymphocytes labeled with anti-mu were very similar to the patterns of neonatal normal and of neonatal CBA/N splenic B lymphocytes suggesting that the defect of CBA/N mice is due to a failure in the development of a mature B-lymphocyte population. The fluorescence profiles of adult CBA/N splenic B lymphocytes labeled with Fl anti-Ig also had immature characteristics in that the frequency of cells with large amounts of surface immunoglobulin was increased in comparison to that of normal strains and the population of cells with low-to-intermediate density of total surface immunoglobulin, which appear characteristic of normal adult splenic B lymphocytes, was markedly diminished.

Animals↗

Ia alloantigen(s) detected on thymocytes by use of a fluorescence-activated cell sorter.

With the increased sensitivity of detection of fluorescence made possible by a fluorescence-activated cell sorter (FACS), Ia antigen(s) have been demonstrated, although very small amounts, on murine thymocytes by using an indirect immunofluorescent technique. Absorption studies indicate that the Ia antigens detected on thymocytes are also present on spleen B cells, however, they do not rule out the possibility that certain Ia antigens may exist only on B cells. These studies suggest that the surface distribution and/or the decreased density of Ia antigens on thymocytes relative to peripheral B cells may preclude their demonstration by more conventional assays. Although these studies demonstrate Ia antigens on less than 50% of thymocytes, the percentage may in fact be much higher since current methods do not allow an upper limit to be assigned.

Absorption↗

Genetics of the induction of antigen-specific immunity in anti-idiotype-treated mice and derivation of monoclonal Ab3 antibodies.

Antiidiotypic antibodies can be used as a means other than antigen of clone-specific intervention in the immune system. In a number of cases, antiidiotypic antibodies induce potent, antigen-specific responses without exposure of the recipient animals to antigen, and a better understanding of such responses will aid in the application of idiotype manipulation to both immunological and practical problems. The Ia. 7 system expresses a major, cross-reactive idiotype on antibodies to an epitope of the mouse I-E antigen. Here, we examine genetic control of the I-E-specific response to anti-idiotype in this model system. Results demonstrate that both heavy chain allotype-linked and non-allotype-linked loci contribute to the control of this response. In addition, monoclonal antibodies representing the non-antigen-specific portion of the Ab3 response were derived. Two idiotype-positive clones were demonstrated to be of IgM isotype, contrasting with previous data showing that the serum Ab3 response is predominantly IgG1.

Animals↗

Characterization of murine thymocytes with CD3-associated T-cell receptor structures.

The thymus is the major site for T-cell receptor (TCR) gene rearrangement and T-cell maturation. The specific antigen recognition structure (TCR) on murine T cells has been shown to be dependent on a polymorphic set of disulphide-linked heterodimers, containing two integral membrane glycoprotein chains, TCR alpha and TCR beta, expressed in non-covalent association with an invariant complex of proteins, CD3 (T3). Recently, a novel TCR/CD3 complex, that includes the product of the TCR gamma gene, has been identified on a subset of both peripheral cells and thymocytes. Here we examine the expression of TCR/CD3 complexes in fetal ontogeny and in the adult thymus. The results demonstrate that CD3+4-8-(T3+,L3T4-,Lyt2-)cells are detected in day-15 fetal thymi, throughout fetal development and in adult thymus. In situ hybridization studies indicate that these early CD3+ cells express high levels of TCR gamma-specific RNA, low levels of TCR beta-specific RNA and no detectable TCR alpha-specific RNA. Day-16 CD3+,4-,8- fetal thymocytes can be activated to proliferate and demonstrate cytolytic activity when cultured in the presence of anti-CD3 monoclonal antibodies and interleukin-2 (IL-2). These results suggest that CD3-bearing cells, present early in thymic ontogeny, express a functional TCR and may, therefore, be important in repertoire development.

Animals↗

Serological analysis of H-2 mutations using monoclonal antibodies.

Nine H-2Kb and H-2Db mutants were examined for serological differences from the wild type C57BL/6 using a panel of monoclonal antibodies (mAbs). Several differences (between the Kb mutants) were established with these mAbs. The bm3 and bm11 mutants could be distinguished serologically even though they have very similar amino acid changes. Conversely, the bm 1 and bm 10 mice, which differ in their sites of Kb mutation, express a common serological mutation, suggesting that tertiary conformation is involved in antibody binding. Both bm13 and bm14 (H-2Db mutants) exhibited profound serological alterations in H-2Db molecules when tested with mAbs that bind determinants mapping to both the NC1 and C2M domains of the Db molecule. In addition, bm13 showed altered binding of two anti-H-2Kb monoclonals.

Amino Acid Sequence↗