Molecular basis for cryoprecipitation.
Explore the source record for details and available documents.
Biomedical subjects
Publications and source records attributed to A C Wang.
Explore the source record for details and available documents.
Isolated light chains of IgM-type immunoglobulins of carcharhine sharks were analyzed by serological and biochemical means. When analyzed by isoelectric focusing analysis, light chains of the tiger shark (Galecerdo cuvieri), the galapagos shark (Carcharhinus galapagensis) and the sandbar shark (Carcharhinus plumbeus) showed a broad, but patterned, spectrum of bands ranging from pI 5.0 to 7.7 in which discrete families were observed. Serologically, light chains of the galapagos shark cross-reacted with rabbit antibodies against mouse immunoglobulin and a synthetic peptide corresponding to the J segment of T cell receptor beta chain. The latter cross-reaction is shared among light chains and T cell receptors. Although there was considerable heterogeneity in isoelectric focusing analysis, the light chains were homogeneous on the basis of apparent mass (23 kDa) and those of tiger shark and galapagos shark had relatively homogeneous dominant N-terminal sequences representing the first framework. The N-terminal sequences of these two shark light chains, were strongly homologous to one another and showed 75% identity to certain V kappa sequences of man and dog. Homology was also shown to V lambda sequences, but the degree of identity was approximately 50%. Following cleavage of the tiger shark light chain with o-iodosobenzoic acid which cleaves at tryptophanyl residues, a constant region peptide was isolated by gel filtration. It was possible to identify the homolog of this peptide within the constant regions of mammalian kappa and lambda chain, but the relationship to C kappa chain was stronger. The degree of identity among the corresponding C region peptides of mammalian, avian and elasmobranch species was much less than that observed for the framework 1 sequence of the light chain variable region. These data support the concept that variable and J region sequence have been conserved in the evolution of placoderm-derived vertebrates, but that constant regions show much greater phylogenetic variation.
We have previously shown that three human T cell lines (MOLT-3, HUT-78 and HUT-102) were able to react with anti-human brain Thy-1 sera by cell surface immunofluorescence. However, the possibility that the antisera might cross-react with molecules other than Thy-1 could not be entirely excluded. In this report, mRNA prepared from these three T cell lines as well as from a murine T cell line (EL4) and a human B cell line (Raji) was subjected to Northern blot analysis and probed with a murine Thy-1.2 gene fragment. The result confirms our cell surface immunofluorescence data and indicates that HUT-78 and HUT-102 cells have approximately 20-fold more of the Thy-1 mRNA than MOLT-3 cells do. The Thy-1 mRNA was not detectable in the human B cell line Raji. This work is the first demonstration that the Thy-1 gene is expressed in human T cell lines. The finding is helpful in clarifying the current confusion regarding the expression of Thy-1 in human lymphoid cells and it also provides a possible model system for exploring the function of Thy-1 in cultured human T lymphocytes.
A mouse IgG2b(kappa) monoclonal antibody (MAb) HB-2S-1 against human brain Thy-1 was secreted by a hybridoma clone after fusion of mouse myeloma cells with spleen cells from a mouse that went through a prolonged immunization procedure before fusion. When tested against isolated human Thy-1 by the enzyme-linked immunosorbent assay (ELISA), MAb HB-2S-1 in culture supernatant showed a titer of over 100,000, and a titer of over 10 million in ascites of a mouse injected with the hybrid clone. By immunoblotting, this antibody was found to bind a doublet of protein bands of approximately 25,000 daltons among all proteins solubilized by deoxycholate (DOC) from membrane of human brain cells. When tested on human lymphoid cell lines by immunofluorescence, MAb HB-2S-1 strongly stained four T lymphoma cell lines, C91-Pl, HUT-102, HUT-78, and C5-MJ; and weakly two leukemia cell lines, MOLT-3 and Jurkat(clone E6-1). It did not stain a third T leukemia cell line, CCRF-CEM; a human B cell line, Raji; a plasmacytoma cell line, HMy2; or a myelomonocytic cell line, HL-60. Peripheral blood lymphocytes from ten normal human adults and the viable T cells isolated from another normal individual were also negative.
Explore the source record for details and available documents.
Two forms of Thy-1 homologues of apparent mol. wt of 25,000 (designated BTp25) and 45,000 (designated BTp45) were isolated from bovine thymocyte membrane by solubilization, affinity chromatography with Con A, and preparative SDS-PAGE. Both forms reacted with a rabbit antiserum to murine Thy-1 in an enzyme-linked immunosorbent assay (ELISA). BTp45 is most likely a dimer of BTp25, since the two are indistinguishable in their amino acid compositions. Comparison of amino acid compositions of BTp25 and BTp45 to that of rodent and human Thy-1 by the S delta Q index revealed significant relatedness among these molecules. BTp25 and BTp45 demonstrate more structural homology to rodent Thy-1 than to human Thy-1. Detailed chemical analyses indicate that bovine Thy-1 homologues contain neutral sugars and fatty acids covalently bound to the polypeptide chain; therefore, they are lipoglycoproteins.
Monoclonal antibodies to ligandin (YaYa) and glutathione (GSH) S-transferase B (YaYc) were produced by hybridomas derived from the fusion of mouse myeloma cells and spleen cells of mice immunized with the YaYa or YaYc proteins, respectively. Enzyme-linked immunosorbent assay was used to screen for antibody-producing clones. Immunoblotting of the subunits of transferase B, ligandin, and another GSH S-transferase containing Yb subunits showed that the monoclonal antibodies produced by two anti-YaYa subclones recognized the Ya subunits of both ligandin and transferase B, but they did not bind Yc or Yb subunits. It was also revealed that antibodies produced by several anti-YaYc subclones recognized the Yc subunit, but not the Ya subunit of the antigen which was used for the immunization of the mice. However, these monoclonal antibodies did bind the Ya subunit of ligandin. These results indicate that the Ya subunits of GSH S-transferase B and of ligandin do share at least one common determinant. However, these two Ya subunits are structurally distinct as evidenced by their differences in binding by monoclonal anti-YaYc antibodies.
Proteins on the outer surface of cultured human and murine lymphoblastoid T cells were labelled with 125I. The labelled cells were incubated with the enzyme phosphatidylinositol-specific phospholipase C (PI-PLC). Proteins cleaved from the cell membrane by the enzyme were immunoprecipitated with anti-Thy-1 antibodies, separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), and identified by autoradiography. A doublet of Thy-1 bands of approximately 16,000 daltons were detected. The result suggests that: Thy-1 is present on the human and murine T cells which we tested, and Thy-1 is attached to the cell membrane via a phosphatidylinositol domain.
Explore the source record for details and available documents.
The serum of a patient with Waldenstrom's macroglobulinemia was shown to contain two IgM(kappa) paraproteins of different electrophoretic mobilities on cellulose acetate and immunoelectrophoresis and were designated IgM slow (s) and IgM fast (f). Both existed as high molecular weight polymers and contained a J chain. The two pentameric IgM monoclonal proteins were shown to be completely distinct in carbohydrate composition as determined by gas chromatography and periodic acid-Schiff staining, in molecular weight, by physicochemical properties, peptide mapping, amino-acid composition, NH2-terminal sequence, subgroup of light chains, and by lack of shared idiotypic determinants as determined by hemagglutination inhibition studies. Our study presents strong evidence for the 'bioclonal' nature of this gammopathy. We conclude that both paraproteins are distinct and originated from different B cells.
By sodium dodecylsulfate polyacrylamide gel electrophoresis, the heavy chain of the serum immunoglobulin (IgM) of the goldfish (Carassius auratus) differs not only from other studied vertebrate serum IgM heavy chains, but also from other vertebrate lymphocyte membrane IgM heavy chains including those from the goldfish itself. This difference, an increase in apparent Mr of approximately 5000, was investigated by assessing in comparison with the IgM heavy chain of human and rainbow trout (Salmo gairdneri) the following properties: (1) molecular size by gel filtration in denaturing buffers; (2) carbohydrate content, by direct analysis; (3) intrinsic net charge, by isoelectric focusing; (4) net hydrophobicity, deduced from amino acid analysis; and (5) sodium dodecylsulfate binding by direct measurement. Results indicate that goldfish IgM heavy chain is indistinguishable from other IgM heavy chains in terms of (a) its gel-filtration behavior in denaturing conditions, (b) its carbohydrate content (which is similar to trout IgM heavy chain) and (c) its intrinsic net charge and hydrophobicity. However, goldfish IgM does differ from the other proteins studied in its detergent-binding ability and it is this behavior that is concluded to be the cause of its unusual mobility in sodium dodecylsulfate polyacrylamide gel electrophoresis.
Proposed relationships of DNA repair, mutation, and the process of generation of antibody diversity allow new insights into the mechanism of aging. Pathways of antibody development are reviewed with special attention to steps which generate diversity. The normal process of combinatorial fusion of V region gene segments (i.e. V, D, and J) coding for the entire V region, plus the somatic variation within the fusing sites, appear to be enough to account for adequate antibody diversity without a hypermutation mechanism. We propose that the somatic hypermutation commonly observed in antibody V regions may have limited usefulness to expand the diversity of the antigen-binding capacity of the individual. Rather, such mutation may serve as a time clock for aging. Knowledge about humans with specific abnormal repair and/or mutation functions will allow testing of this proposal.
A 40 000 M.W. glycoprotein was isolated from human thymus. This molecule binds lentil lectin, reacts with an antiserum made against the p25 antigen (the human Thy 1 homologue) and possesses almost identical amino acid composition as the p25 antigen and its 40 000 M.W. dimer.
Explore the source record for details and available documents.
Acidic proline-rich salivary proteins, PRPI, PRPII, PRPIII, PRPIV, upper Db and Statherin, were isolated from parotid saliva and tested for interaction with complement. It was determined that each of the isolated proline-rich proteins blocked C1 hemolytic activity in assay systems where C1 was rate-limiting. Further studies comparing the specific activity of the proline-rich proteins to unfractionated parotid saliva indicated that other salivary substances (sensitive to urea treatment of parotid saliva) were also interacting with the first complement component but in a time-dependent manner. Based on a series of experiments examining the effect of the sequence of addition of the proline-rich proteins in the complement assay systems, it is postulated that these salivary proteins are able to block the proper interaction of C1 with EAC4 cells (sheep erythrocytes coated with antibody and C4gp). The proline-rich salivary proteins had no effect on C1 once C1 was bound to the immune complexes on the EAC4 cells. The C1 macromolecular complex undergoes conformational changes upon interaction with immune complexes resulting in a more avid binding of the C1q-Clr-Cls subunits with one another. Thus it is speculated that the EAC4-bound C1 becomes resistant to disruption by the proline-rich salivary proteins. Although the urea-sensitive factors had the highest specific C1-fixing activity, the activity of the acidic proline-rich proteins on C1 is important because of their relatively high concern in salivary secretions. Since complement-containing serous exudates and transudates are present on inflamed mucosal tissues, salivary substances which interact with C1 may play a role in regulating the initiation of the classical complement pathway, particularly at those mucosal sites where there is a high ratio of salivary secretion to serous exudate.
A human T cell differentiation antigen (p25) previously described as being the mouse theta equivalent has been examined for shared antigenic determinants with immunoglobulin. A strong cross-reactivity of an antiserum prepared against p25 antigen was established with human IgG subclasses. This antiserum does not react with human IgM or IgA, nor with primate immunoglobulins. The shared determinants appear to be associated with the disulphide-bonded cysteines in the first and third constant domains of the IgG molecule and the 9-112 disulfide bond of Thy 1.
Forty-one patients with various forms of systemic sclerosis (scleroderma) and positive antinuclear antibodies of nucleolar (ten patients), speckled (eleven patients), or centromere pattern (twenty patients) were selected for study of immune complexes by the radioisotope labeled Clq binding and the radioisotope labeled protein A binding methods. The presence of immune complexes was found by the Clq binding assay in sixteen patients (39%) and by a protein A binding assay in eight patients (20%). Overall, 46% of patients (19/41) had immune complexes. A lower incidence of organ involvement and fewer positive results in the screening of serum immune complexes were observed in patients with centromere antibody (35%) than in patients with nucleolar (60%) or speckled pattern (55%). Patients with immune complexes had higher frequencies of kidney, heart, and muscle involvement and digital ulceration than did patients with no detectable immune complexes, but the differences were not statistically significant. Diffuse skin involvement was not related to the presence of immune complexes.
The problem of the relationship between the immunoglobulin-related T cell receptor (IgT) and classical immunoglobulin heavy chain variable regions (VH) was approached by determining the capacity of a xenoantiserum made against the immune affinity purified product of a permanent in vitro T cell line of mature, amplifier phenotype to react with human and murine monoclonal immunoglobulins with completely sequenced VH regions. Most of the amino acid residues identified as critical for the observed serological cross-reaction were localized within the disulfide-bonded loop and all of these occur on the surface of the 3-dimensional structure of the VH molecule. The most strongly correlated residues were restricted to the second complementarity determining region and the third framework region. This suggests that IgT need not contain complete VH regions, but that the serological cross-reaction might result from the insertion of 'minigenes' into a non-immunoglobulin framework or from short stretches of shared sequence between VH and the products of separate VT gene cluster.