Varying Degrees Of Reactivity Research Articles

Selective Growth of PbSe on One or Both Tips of Colloidal Semiconductor Nanorods

PbSe nanocrystals with rock-salt structure are grown on the tips of colloidal CdS and CdSe nanorods. The facets of wurtzite rods provide a substrate with various degrees of reactivity for the growth of PbSe. The presence of dangling Cd bonds may explain subtle differences between nonequivalent facets resulting in the selective nucleation of PbSe only on one of the two tips of each CdS rod. This approach has the potential to facilitate the fabrication of heterostructures with tailored optical and electronic properties.

Anti-idiotypes to Oxidized LDL Antibodies in Intravenous Immunoglobulin Preparations--Possible Immunomodulation of Atherosclerosis

Objective : The aim of this study was to examine whether intravenous immunoglobulin (IVIg) preparations contain anti-oxLDL and anti-anti-oxLDL antibodies. Background : Oxidized low-density lipoprotein (oxLDL) is one of the major players in atherogenesis. IVIg can reduce atherosclerosis in experimental animal models. Methods : Six commercial IVIg preparations were tested for the presence of anti-oxLDL antibodies by EIA. Inhibition studies were performed with the different IVIg preparations and IgGs purified from a pool of sera from patients with high anti-oxLDL antibody levels. Absorption assays were carried out to evaluate the presence of anti-idiotypes against anti-oxLDL antibodies in IVIg preparations. Results : IVIg preparations tested had various degrees of reactivity towards oxLDL. Absorption experiments suggested that the reactivity was specific because it could be effectively absorbed by oxLDL and not by an irrelevant antigen PPD. The reactivity was smaller than that observed with the IgG from the pool with high anti-oxLDL antibody levels. Inhibition studies with IVIg demonstrated 20-45% inhibition of anti-oxLDL binding to oxLDL, compared to 76% inhibition by the pool with high anti-oxLDL levels. To investigate the presence of anti-idiotypes against anti-oxLDL antibodies within IVIg, F(ab') 2 fragments of IVIg IgG were used to absorb IgG F(ab') 2 fragments from the pool of sera with high anti-oxLDL levels. The decreased binding to oxLDL of the absorbed supernatants shows that IgG F(ab') 2 fragments of the IVIg preparations had high inhibitory capacities ranging from 65 to 90%. Conclusions : IVIg preparations contain both anti-oxLDL and anti-anti-oxLDL activity. This finding may explain the immunomodulating effect of IVIg in atherosclerosis.

Moving beyond the immune self?

We are witnessing a significant challenge to immunology’s basic tenet, the immune self. Such an ‘entity’ is increasingly regarded as polymorphous and ill defined as transplantation biology and autoimmunity have demonstrated phenomena that fail to allow faithful adherence to a strict dichotomy of self/nonself discrimination. Instead of searching for elusive criteria of ‘self’ and ‘other’, immune responses are increasingly studied as arising within complex contexts, which determine various degrees of reactivity or dormancy. When the character of the immune ‘object’ is determined by the context in which it appears, not its character as ‘foreign’per se, self/nonself discrimination recedes as a governing principle. In such context-based models, ‘ecologic’ controls arise from the entire organism in which the immune system is fully integrated. In these systems, subject–object relationships become blurred. Viewed from this perspective, a new theoretical construction of the immune system, one originally proposed by Jerne, is contending with Burnet’s theory of immune identity. Although it is too early to judge which theory will prove more capacious, it is already apparent that Jerne’s formulation has had a decisive impact in shaping new models of immunity.

Paraffin‐immunohistochemical Analysis of 26 Non‐Hodgkin's Malignant Lymphomas n the Endemic Area of Human T‐cell Leukemia Virus Type 1

A study was conducted to evaluate the usefulness of paraffin-immunohistochemistry for histopathological classification of non-Hodgkin's malignant lymphomas (NHML). the phenotypes of lymphoma cells and other cells were examined using 11 monoclonal and 3 polyclonal antibodies by the ABC method on paraffin-embedded tissue sections of 226 cases of NHML, comprising 94 B-cell lymphomas (B-ML) and 132 T-cell lymphomas (T-ML). In 219 NHML cases (96.8%), lymphoma cells reacted with more than one of these antibodies. A set of MB-1, Mx-pan B, L26, LN-1, LN-2 and anti-immunoglobulin light chain antibodies characterized each subtype of B-MLs, categorized according to the Kiel classification. Mantle-zone lymphoma (MzML) was added as one subtype. L26 stained the largest number of B-MLs (82.8%). B-cell chronic lymphocytic leukemia (B-CLL) was labeled most frequently by MB-1. MzML was characterized by reactivity of lymphoma cells with LN-2 and by the appearance of monoclonal immunoglobulin light chain along the cell membrane. Follicle center cell lymphomas were stained by LN-1 and LN-2, although a small number of proliferating cells were labeled by LN-1 in B-CLL, MzML and the immunocytoma lymphoplasmacytic/cytoid variant. MT-1 and/or UCHL-1 showed various degrees of reactivity with the cell membranes of lymphoma cells in 94.8% of T-MLs. Among the T-cell pleomorphic lymphomas of Suchi and Lennert, the adult T-cell leukemia/lymphoma type, defined by stippled heterochromatin distribution and peculiar huge cells, reacted selectively (p less than 0.05) with anti-phosphokinase C antibody. Anaplastic large cell T-ML reacted with a set of Ber H2, LN-2 and Leu M1. In T-zone lymphomas without hyperplastic follicles, angioimmunoblastic lymphadenopathy with dysproteinemia-type T-ML, lymphoepithelioid cell lymphomas and some pleomorphic lymphomas comprising clear large lymphoma cells, there were many intermingling B cells, and their constitution varied. In some lymphoblastic lymphomas of both the T cell and B-cell type, phenotypes of T cells and B cells were expressed. Consequently, it was shown that paraffin immunohistochemistry was useful for the practical histopathological diagnosis of NHML even in the area where human T-cell leukemia virus type 1 is endemic.

Oxide formation on rare earth/transition metal and bimetallic transition metal thin films: modeling the effect of fourth element modifiers on O 2 and H 2O surface chemistries

The chemical reactions undergone by both O 2 and H 2O on (a) rare earth (Tb), (b) rare-earth transition metal alloy (FeTbCo), (c) transition metal (Fe and Ti), and (d) transition metals, modified with thin overlayers of another metal (Fe/Ti), have been studied by surface photoelectron spectroscopies, starting with the clean metals in UHV environment. Various degrees of reactivity are indicated, especially for adsorption and dissociation of H 2O, depending upon whether the pure metals are studied, or mixtures of metals, which change the type and extent of dissociation of H 2O (oxide vs. hydroxide formation).

Antigenic variations in bovine viral diarrhea viruses detected by monoclonal antibodies

Five murine monoclonal antibodies (MAbs) against the NADL strain of bovine viral diarrhea (BVD) virus were developed, identified, and characterized. Four of the MAbs were directed against a 53-kilodalton (kDa) viral protein, and one was specific to a 47-kDa polypeptide. Competitive radioimmunoassay showed that two MAbs were specific to related epitopes of the 53-kDa protein, and the other three MAbs were each specific to a different epitope. The MAbs were used to study heterogeneity among BVD virus strains. Various degrees of reactivity of cytopathic and noncytopathic virus isolates were detected by virus neutralization and immunofluorescence assays. The virus isolates were divided into six groups based on the neutralization test. The results indicated that the 53-kDa glycoprotein of BVD virus is the major protein involved in virus neutralization and that only a few epitopes of the protein contribute to the neutralization. None of the MAbs neutralized all the BVD virus isolates tested in this study, suggesting antigenic variations among BVD virus isolates.

Investigation of atypical western blot (immunoblot) reactivity involving core proteins of human immunodeficiency virus type

Serum specimens which originally exhibited a narrow (indeterminate) 24-kilodalton core protein (p24) or p24/p55 pattern of reactivity with human immunodeficiency virus (HIV) in the Western blot (immunoblot) test were studied to gather information on antibody specificity. A total of 12 specimens were initially reevaluated with an indirect immunofluorescence assay (IFA), three enzyme-linked immunosorbent assays (ELISAs), and Western blot analyses. Five of the specimens were IFA positive and contained anti-gp160/gp120 antibodies which were observed only when an HIV Western blot antigen rich in gp160 and gp120 was used. The remaining seven serum specimens were nonreactive by IFA and showed variable reactivity in HIV antibody ELISAs. The specimens did not cross-react with core antigens for human T-cell leukemia virus types 1 and 2 or contain detectable levels of HIV p24 antigen. The p24/p55 reactivity of six of the seven indeterminate specimens could be reduced or eliminated by preincubating the specimens with disrupted, HIV-infected H9 cells but not with uninfected H9 cells. The six specimens also exhibited discernible reactivity with recombinant HIV p24 antigen. When an additional 23 indeterminate specimens were assayed, all of the serum specimens were nonreactive by IFA while 65% (15 of 23) showed various degrees of reactivity with the recombinant p24 protein. There was no indication that any of the HIV core antibody reactivity was caused by HIV infection. Indeterminate results for five patients with specific p24 reactivity, who were retested after a period of weeks or months, remained indeterminate for HIV antibody with no significant change in ELISA or Western blot reactivity.

Swine Monoclonal Antibodies of High Affinity and Specificity to Carcinoembryonic Antigen

To avoid the exclusive use of rodent monoclonal antibodies (MAbs) in patients for the detection of tumors by immunoscintigraphy and for radioimmunotherapy, swine MAbs were produced that are directed against carcinoembryonic antigen (CEA). Spleen cells from 2 pigs immunized with purified colon carcinoma CEA were fused with a nonsecreting mouse myeloma cell line by conventional methods, except that a particularly long immunization protocol and large amounts of spleen and myeloma cells were used. Of 1,200 growing hybrids tested, 20 were found initially to produce antibodies binding to radiolabeled CEA. Seven stable clones producing anti-CEA MAbs for more than 6 months were derived from these hybrids by repeated subcloning. The pig origin of the seven MAbs was demonstrated in a solid-phase CEA enzyme immunoassay where anti-pig immunoglobin (Ig) antibodies coupled to peroxidase gave a positive reaction while anti-mouse Ig antibodies were entirely negative. All swine MAbs were of the IgG isotype. Three anti-CEA MAbs showed no cross-reactivity with granulocytes, while four others gave various degrees of reactivity with different granulocyte glycoproteins. Competitive binding to CEA performed for two purified swine MAbs showed that they recognized two different epitopes. The affinity constants measured for these two MAbs by Scatchard plot on purified CEA were high (1.2 X 10(9) and 1.2 X 10(10) liter/mol). One of the MAbs was tested in vivo for tumor localization by injection, after radiolabeling, in nude mice bearing human colon carcinoma xenograft. High ratios of tumor to normal tissue were obtained with mean values of 10.5 for intact MAbs and of 26.8 for F(ab')2 fragments of the porcine MAb. The results showed that heterofusion with this particular protocol can be used to produce swine MAbs of high affinity and specificity for a well-defined tumor marker. These reagents may have an important clinical utility, particularly in patients who became sensitized to mouse immunoglobulins.

Osmium impregnation of the endoplasmic reticulum correlates with the functional status of prostatic secretory cells.

The ultrastructure of prostatic secretory cells was studied with the osmium impregnation technique in order to determine if the ER reactivity, or its absence, and its three-dimensional organization correspond to specific functions possibly hormono-dependent. Thick sections (0.3 micron) of rat ventral prostate were made after a five-day impregnation with osmium tetroxide and examined by standard transmission electron microscopy at 80 kV. Studies were performed in normal adult rats, between the 3rd and 26th day following castration and in castrated rats treated with 5-alpha-dihydrotestosterone. In normal rats the impregnation technique delineated three secretory cell types (dark, greyish and clear), representing various degrees of reactivity in ER cisternae; however, despite this quantitative variation, they had similar morphological characteristics. In a longitudinal section, the ER network appeared to be made of saccules running parallel along the length of the cell and forming whorl-like patterns around the nucleus. Comparison of sections taken at various angles suggests that the ER network is made of concentric parallel saccules extending from the base to the apex of the cell and encircling the nucleus and the Golgi apparatus like a large multilayered cylinder. Whereas in dark cells the Golgi apparatus contained mostly clear vesicles, it was always heavily impregnated in clear cells. Noteworthy, osmium deposits were rarely observed on the nuclear envelope of secretory cells but were always present in basal cells. After castration, secretory cells became progressively cubic and the most conspicuous cytoplasmic change was observed in association with the ER. The Golgi apparatus decreased markedly in volume and became heavily stained with metallic osmium.(ABSTRACT TRUNCATED AT 250 WORDS)

A hybridoma monoclonal antibody which reacts with cells carrying the HLA-A2 antigen: evidence for heterogeneity in the expression of HLA-A2.

A monoclonal antibody, FMC 5, has been prepared against human lymphocytes and its reactivity examined. FMC 5 behaves, for the most part, as an anti-HLA-A2 typing serum. However, three small groups of discrepant types were identified, and each provides additional insight into the complexity of the MHC antigens. A small number (5/60) of donors typed as HLA-A2 did not react with FMC 5. A further group (6/35) were HLA-A2 and did react with FMC 5, but lysis was always incomplete in this group. Finally, 13/39 non-A2 donors gave various degrees of reactivity with FMC 5. Lysis in this group was usually incomplete and required a high antibody concentration.

41] Assay of soluble immune complexes using radiolabeled rheumatoid factor

This chapter discusses the assay of soluble immune complexes (IC), using radiolabeled rheumatoid factor. The measurement of the circulating IC presents a number of problems that are relatively infrequently encountered in enzymology or biochemistry. The experiments, leading to the development of a radiolabeled monoclonal rheumatoid factor binding (RFB) assay for IC, are described in this chapter. IgG was isolated from serum, containing a high concentration of the monoclonal IgG, by repeated precipitation, with 18% saturated sodium sulfate. The final washed precipitate was dialyzed extensively in phosphate-buffered saline and adjusted to a protein concentration of 20 mg/ml. Aggregation was achieved by heating at 63° for 12 min, followed by rapid cooling in ice. Rheumatoid factors have been shown to exhibit the various degrees of reactivity with monomeric IgG, as opposed to the complexed or aggregated IgG. Soluble IC, consisting of bovine serum albumin, and an IgG isolate of hyperimmune rabbit antibovine serum albumin serum were prepared in vitro. The studies undertaken in human diseases have shown that the RFB assay gives results similar to a number of other systems.

Histochemical and ultrastructural identification of neurotensin cells in the dog ileum.

In the dog ileum, neurotensin cells stained with immunofluorescence or immunoperoxidase proved distinct from argentaffin (EC) cells, glucagon immunoreactive (GLI) cells and pancreatic peptide immunoreactive (PP) cells. Neurotensin cells showed various degrees of reactivity with Grimelius' silver. With electron microscopy, besides EC cells, large granule cells with a thin peripheral rim of Grimelius-reactivity (L cells) and large granule cells with variable Grimelius-reactivity of the core (N cells) were found. On distributive grounds, L cells were identified with GLI cells and N cells were interpreted as neurotensin cells.