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Biomedical subjects

K C Hsu

Publications and source records attributed to K C Hsu.

16 recordsLinked to original sources

An unlabeled antibody macromolecule technique using hemocyanin for the identification of type B and type C retrovirus envelope and cell surface antigens by correlative fluorescence, transmission electron, and scanning electron microscopy.

The present resolution (75-100 A) of the conventional scanning electron microscope (SEM) and its ability to image the surfaces of large numbers of whole cells in situ permit the approach of problems such as viral and cell surface antigen localization by immunological labeling with visual markers. Identification of virus and cell surface antigens in situ has been accomplished in indirect reactions by unconjugated markers. Hemocyanin (Hcy) from whelk, Busycon canniculatum, has been developed as an immunospecific marker for virion and cell surface labeling in the electron microscope. Its size (30 x 50 nm) and distinct cylindrical shape permit easy visualization in the SEM and the transmission electron microscope (TEM). The Hcy method involves the preparation of antisera to Hcy in appropriate hosts for use in an unlabeled antibody macromolecule procedure based exclusively on antigen-antibody affinity to couple the macromolecule to the antigen site. Further correlative data from fluorescence microscopy can be obtained from similarly labeled samples by binding fluorescein to the bridging antibodies used in the Hcy technique. The usefulness of the Hcy marker system was demonstrated by employing highly specific antisera to the major envelope and cell surface glycoprotein (gp70) of Rauscher murine leukemia virus (R-MuLV), a type C retrovirus. The antiserum was shown to bind to the virion and cell surfaces of virus-infected cells in the homologous virus-infected cell system. It also demonstrated the expression of R-MuLV gp70-related antigens on a murine cell line Mm5mt/c1 which produces mouse mammary tumor virus (MuMTV), a type B retrovirus. Furthermore, when used in the Hcy marker system the anti-gp70 serum was able to distinguish type B from type C budding virus on the same cell. Methods for the preparation of immunoreagents and labeling of cells are discussed.

Animals

Immunologic techniques for the identification of virion and cell surface antigens by correlative fluorescence, transmission electron and scanning electron microscopy.

The present resolution (75-100 A) of the conventional scanning electron microscope (SEM) and its ability to image the surfaces of large numbers of whole cells in situ permits the approach of problems such as viral and cell surface antigen localization by immunological labeling with visual markers. Identification of virus and cell surface antigens in situ has been accomplished in indirect reactions by conjugated and unconjugated markers. Hemocyanin (Hcy) from whelk, Busycon canniculatum, has been developed as an immunospecific marker for virion and cell surface labeling in the electron microscope. Its size (approximately 30 x 50 nm) and distinct cylindrical shape permit easy visualization in the SEM and TEM. The Hcy method involves the preparation of antisera to Hcy in appropriate hosts for use in an unlabeled antibody macromolecular procedure based exclusively on antigen-antibody affinity to couple the macromolecule to the antigen site. Further correlative data from fluorescence microscopy can be obtained from similarly labeled samples by binding fluorescein to the bridging antibodies used in the Hcy technique. The usefulness of the Hcy marker system was demonstrated using antisera to the major envelope and cell surface glycoprotein (gp70) of Rauscher murine leukemia virus (R-MuLV), a type C retrovirus. The antiserum was shown to bind to the virion and cell surfaces of virus-infected cells in the homologous virus-infected cell system. It also demonstrated the expression of R-MuLV gp70-related antigens on a murine cell line Mm5mt/c1 which produces mouse mammary tumor virus (MuMTV), A type B retrovirus. Furthermore, when used in the Hcy marker system this antiserum was able to distinguish type B from type C budding virus on the same cell. Examples of other marker systems (ferritin, peroxidase, colloidal gold, and latex) used to show anti-gp70 serum reactivity will be presented to demonstrate their applicability to cell surface labeling studies. Methods for the preparation of immunoreagents and labeling of cells are discussed.

Animals

Susceptibility of human skeletal muscle culture to influenza virus infection. Part 2. Ultrastructural cytopathology.

Cultured post-fused human skeletal muscle monolayers exposed to WSN influenza A virus were analyzed by scanning and transmission electron microscopy. At 12-14h post-inoculation (p.i.), affected mononuclear cells retracted from the cell surface, but remained anchored to the substrate by taut filar processes. Retraction was accompanied by shortening of microvilli, appearance of hemispherical cytoplasmic protrusions and corrugation of the surface proper. These changes were more pronounced at 24 and 48h p.i. The rounded, moribund mononuclear cells eventually detached from the substratum. Surface alterations were accompanied by the intracellular appearance of electron-dense nuclear inclusions (often associated with the nucleolus) and paracrystalline ribosomestudded cytoplasmic bodies, which increased in size and number with time. In myotubes, distinct surface alterations appeared later (24h p.i.). Early myotube retraction was accompanied by accentuation of the longitudinally oriented surface pleats and appearance of "blebs" followed by cell-rounding. At 48-72 h, many myotubes detached from the substratum. The surfaces of those still adhering appeared corrugated. Intranuclear and cytoplasmic inclusions accumulated, and budding virions, often filamentous, could be demonstrated at the plasmalemma of mononuclear cells and myotubes. Late (end-stage) cytopathic effects included clumping of chromatin, breakdown of the nuclear envelope, disappearance of cortical and endoplasmic cytofilaments, mitochondrial swelling, and vesiculation of surface membranes. The lesions leading to cell injury and cell death appeared to be due to massive accumulation of virus-induced products that altered cellular metabolism, with physical and functional abnormalities of surface membranes.

Autoradiography

Counter immunoelectrophoresis for detection of human prostatic acid phosphatase.

An immunochemical method for detection of prostatic acid phosphatase is described. Acid phosphatase was obtained from benign human prostatic tissue. A specific antiserum to this enzyme was produced in rabbits. A counter immunoelectrophoretic method utilizing the specific antiserum with a chemical staining technique has been developed. Clinical trials have indicated the usefulness of this method for the specific determination of prostatic acid phosphatase.

Acid Phosphatase

Ultrastructural localization of anaplasmal antigens (Pawhuska isolate) with ferritin-conjugated antibody.

Antibodies from a cow with an experimentally induced infection of the Pawhuska isolate of bovine anaplasmosis were conjugated with ferritin and used to label antigenic sites in preparations of parasitized erythrocytes. Intact erythrocytes did not label on the extracellular surface. Ferritin-conjugated antibody did not pass through the intact erythrocyte to label the parasite, probably due to the large molecular size of the antibody. Damage to erythrocytic plasmalemma and inclusion body in the hemolyzed erythrocytes and complement-fixation antigen allowed labeling of anaplasmal inclusion structures. The positively labeled structures were outer surface of the pellicle, chromatin of the initial body, and inclusion appendage. Unlabeled structures included inner organismic membrane of the initial body, inclusion membrane, fibrillar protoplasmic network of the initial body, and small electron-dense bodies derived from the initial body.

Anaplasma

Novel method for estimating the labeling index in clinical specimens with the use of immunoperoxidase-labeled.

The labeling index determined by [3H]thymidine autoradiography in cells from clinical specimens was compared with the percentage of the cells showing nuclear reactivity to immunoperoxidase-labeled antinucleoside antibodies. This nuclear immunoreactivity is specific for denatured or single-stranded DNA's and is detectable almost exclusively during DNA synthesis. Results with the two methods showed excellent agreement. The new method allowed rapid accurate assessment of S phase in the tumor cells from freshly isolated aspirated specimens as well as frozen sections, suggesting general applicability to estimation of the labeling index without autoradiography.

Adenocarcinoma

Angiotensin-converting enzyme: vascular endothelial localization.

Fluorescein-labeled antibody to rabbit pulmonary angiotensin-converting enzyme localized in the vascular endothelium of rabbit lung, liver, adrenal cortex, pancreas, kidney, and spleen. Epithelial cells of the renal proximal tubules were the only parenchymal cells among the organs studied that demonstrated immunoreactivity.

Adrenal Cortex

Immune complex orchitis in vasectomized rabbits.

The results of the present study show that bilaterally vasectomized rabbits with high levels of antibodies to sperm antigens frequently develop an orchitis associated with granular deposits of rabbit IgG and C3 in the basement membranes of seminiferous tubules. The immune deposits correspond in location to electron-opaque deposits seen by electron microscopy. The "membranous orchitis" is characterized by thickening of tubular basement membranes, acc-mulation of macrophages and a few polymorphonuclear leukocytes, and destruction of the basal lamina, of the Sertoli and spermatogenetic cells. The pathogenetic role of the immune deposits and the possibility that they contain antigen-antibody complexes is indicated by: (a) selective accumulation of IgG and C3 granular deposits along the basement membranes of seminiferous tubules in rabbits producing high and persistent levels of antibodies to sperm antigens; (b) the elution of immunoglobulins from tissues with chaotropic ion-containing buffers, acid buffers, or heat; (c) the observation that the immuno-globulins accumulated in the testis contain antibody to sperm antigens; and (d) the demonstration of sperm antigens in a location similar to that of IgG and C3. It is postulated that sperm antigen-antibody complexes are formed in the basement membranes of seminiferous tubules when antigens leaking out of the tubules react with specific antibody coming from the circulation. In two rabbits with higher levels of circulating antisperm antibodies and severe orchitis, granular deposits of IgG and C3 were also present in renal glomeruli. Immunoglobulins eluted from the kidneys contained antibody with antisperm activity. These findings are consistent with the hypothesis that in some vasectomized rabbits extratesticular lesions may develop by a mechanism comparable to that of chronic serum sickness.

Animals

Natural antibodies in sera from healthy humans to antigens on surfaces of type C RNA viruses and cells from primates.

Sera from healthy humans contained naturally occurring antibody against group- or subgroup-specific antigen on the envelope of the following type C viruses isolated from primates: gibbon ape leukemia virus, simian (woolly monkey) sarcoma virus, baboon endogenous type C virus, and putative human type C viruses [HL23V isolated from blood cells of a patient with acute myelogenous leukemia (HL23) and HEL-12V from human embryonic diploid cells (CIH-32)]. Two sera also reacted with C57BL/6 mouse leukemia induced by Friend virus. These results were obtained by indirect immunoelectron microscopy with various virus-producing cells and by absorption tests using as targets gibbon lymphosarcoma cells that release gibbon ape leukemia virus. In a previous report, the presence of natural antibody in sera from healthy gibbon apes was demonstrated. When the specificities of the human and gibbon natural antibodies were compared, the human natural antibody reacted with two nonproducing culture cell lines of human lymphocytic leukemia (CEM-A and MOLT) and with human embryonic diploid (CIH-1(V-) cells [which became type C virus-producing CIH-32(V+) cells after many passages], but did not react with normal gibbon spleen monolayer cells. In contrast, gibbon natural antibody showed no reaction with CEM-A, MOLT, and CIH-1(V-) cells but reacted with gibbon spleen monolayer cells. Neither human nor gibbon natural antibody that was reactive with gibbon ape leukemia virus crossreacted with feline leukemia virus and mouse wild-type AKR leukemia virus. The gibbon lymphosarcoma cells releasing gibbon ape leukemia virus were used in a screening study of sera from healthy humans. Out of 72 sera screened by indirect immunoelectron microscopy using this system, 55 were positive (76%), i.e., 26 out of 35 males (74%) and 29 out of 37 females (78%). The highest incidence of antibody production was in 1- to 10-year-olds and 31- to 40-year-olds, with the adults exhibiting higher levels. Differences in incidence of natural antibody were not found to be sex-linked. These findings suggest that type C RNA viruses related to the gibbon ape leukemia virus and simian (woolly monkey) sarcoma virus family as well as the baboon endogenous type C virus family may be widespread in humans.

Animals

Relationship between A-type and C-type particles in cells infected by Rous sarcoma virus.

Chicken cells infected with avian RNA tumor virus often contain small cytoplasmic A-type particles which commonly exist as clusters of 50--100 particles when viewed in thin sections. These particles were found more consistently in Rous sarcoma virus-infected than Rous-associated virus-infected cultures, but were generally present in only a small fraction of the total infected cells. The results of the survey of cells infected with various strains of leukosis-sarcoma viruses led to the hypothesis that the A particles develop in cells undergoing cytopathological degeneration. The hypothesis explains also the evanescent nature of the appearance of these particles in infected cells. The application of immunoelectron microscopic methods using monospecific antisera against viral internal proteins revealed that the A particles contain components immunologically related to the proteins of C-type virus.

Animals

Association of fibrinogen and microfibrils with trophoblast basement membrane.

Two non-collagenous placental antigens have been detected both in membranes isolated from terminal villi by sieving and sonication and in acetic acid extracts of the villi. One of the antigens is apparently fibrinogen based on immunologic and chemical data. The second, detectable with anti-membrane antiserum after absorption with fibrinogen remained with the fibrinogen-like antigen during isoelectric precipitation at pH 4.7, electrophoresis at pH 8.6 and chromatography on DEAE cellulose. Fractions of villi in which the two antigens occur comprise more than a third of the weight of the villi. The fibrinogen-related antigen was concentrated in placental basement membranes compared to kidney and lung basement membranes. A third antigen common to the membranes, to glomerular basement membrane and to alveolar basement membrane was also detected.

Amino Acids