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An enzyme-linked immunosorbent assay (ELISA) using biotin-labelled oligo-dT primer and digoxigenin (Dig)-dUTP was designed to measure the reverse transcriptase (RT) activity of human immunodeficiency virus type 1 (HIV-1). The ELISA system involves the selective detection step of a newly synthesized cDNA by two specific bindings, biotin-streptavidin binding and alkaline phosphatase (AP)-conjugated anti-Dig-Dig binding, and the enzymatic amplification step to increase coloring generated by AP. This method was used to measure the activity of RT in the culture supernatants of peripheral leukocytes obtained from four anti-HIV-1-positive persons cocultivated with those from four anti-HIV-1-negative persons. RT activity was detected in all of four anti-HIV-1-positive culture supernatants but not in those cultivated with anti-HIV-1-negative supernatants alone. Thus, our improved ELISA for detection of HIV-1 appears to be sensitive enough and useful for routine laboratory work. This non-radioactive method will also be useful for detecting other retroviruses and for screening of RT inhibitors.

Examination was made of the in vitro response of human peripheral blood mononuclear cells (PBNMCs) to phytohemagglutinin (PHA) following treatment with varicella zoster virus (VZV) or herpes simplex virus type 1 (HSV 1). Cell proliferation was determined by colorimetric assay using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide. The response to PHA was depressed in all cases by virus infection of PBMNCs prior to PHA treatment. When the infection with the viruses was after PHA treatment, PHA response differed. For VZV infection, the response increased in four out of six samples, but was reduced in the other two. The response to PHA was depressed in all six samples by HSV 1 infection.

An enzyme-linked immunosorbent assay (ELISA) for the purpose of detecting the albumin receptor on hepatitis B virus surface antigen (HBsAg) particles was developed. Patient sera with moderate to high receptor values demonstrated significant correlations with serum DNA-polymerase activity (p less than 0.005), but not with HBeAg titer. Within one year of the study of 47 HBeAg-positive patients, only in the group of 12 patients with the moderately high values and 9 with low values, did 2 (16.7%) and 6 cases (66.7%) sero-convert, respectively. These results suggest that the albumin receptor might be a useful marker of HBsAg-positive patients.

<p>Murine sarcoma virus, CS-Moloney substrain, was inoculated intracranially into 2 litters of newborn Syrian hamsters within 24 h of birth. Seven of 12 hamsters which survived more than 30 days developed brain tumors in the cerebral cortex 104 to 153 days, 139 days on the average, after the virus inoculation. The tumors consisted of spindle-shaped, round or polygonal astrocytes which showed a positive reaction for glial fibrillary acidic protein by the immunoperoxidase method.</p>

In 144 cases of hepatocellular carcinoma (HCC), 166 cases of cirrhosis without HCC and 142 cases of chronic hepatitis, we examined HBsAg, anti-HBs and anti-HBc in sera and compared the following factors between hepatitis B virus marker-negative and -positive patients: age, sex, alcohol consumption, family clustering of liver diseases, and histories of blood transfusion and post-transfusion hepatitis. Results of this study demonstrated several distinct differences in clinical backgrounds between non-B (negative for HBsAg, anti-HBs and anti-HBc) and B (positive for HBsAg) patients with HCC. Non-B patients were significantly older, had a lower frequency of familial tendencies for liver diseases, and more frequently had cancers other than HCC in their families. Some of these differences were also observed between non-B and B patients with cirrhosis and chronic hepatitis. Among patients with chronic hepatitis, the non-B patients had received blood transfusion or had post-transfusion hepatitis more frequently than the B patients. However, this difference was not apparent in patients with liver cirrhosis or HCC, suggesting that progression of non-A, non-B post-transfusion hepatitis to cirrhosis and HCC may not be as frequent as progression to chronic hepatitis.

An enzyme-linked immunosorbent assay (ELISA) for the detection of serum blocking factors (BF), or antibodies to the albumin receptor on HBsAg particles, was developed, and its clinical usefulness was examined in healthy persons and patients with liver diseases. Thirteen of 80 anti-HBs-positive female (16.3%) had BF, but all 25 male anti-HBs-positive, 41 female and 32 male anti-HBs-negative subjects were negative for BF. The activity of BF in BF-positive cases was not associated with the positive reciprocal hemagglutination titer of anti-HBs. For a neutralization test of BF, the BFs from 5 cases were absorbed with IgG-immunobeads. It was determined that these IgG-BFs were antibodies to the albumin receptors on HBsAg particles. No significance between positive-BF and abnormal S-GPT levels was recognized. These results suggest that the present test for the detection of BF, or anti-albumin receptor antibody, different from anti-HBs, might be useful for diagnosis of hepatitis B and as a marker for HB virus.

To search for lymphocyte marker antigens on the surface of human T-cell leukemia virus (HTLV), an immunoelectron microscopic study was performed on a HTLV-producing human T-cell line, MT-2, using monoclonal antibodies, such as anti-Leu-1, -Leu-2b, -Leu-3a, -Leu-5, -Leu-10 and -HLA-DR and OKIal. The reactivity of each antibody with MT-2 cells was tested by the immunoperoxidase method at the light microscopic level. OKIal, anti-HLA-DR and -Leu-10 gave positive results. At the ultrastructural level, the surface of HTLV as well as the plasma membranes of MT-2 cells were labeled with ferritin by the monoclonal antibodies OKIal, anti-HLA-DR and -Leu-10, but not by anti-Leu-1 and -Leu-3a. These findings suggest that HLA-D region -associated antigens are common antigenic determinants shared by the surface of HTLV and the plasma membranes of MT-2 cells. These antigens on the virus surface are probably picked up selectively from the plasma membranes and may play an important role in the interaction of HTLV and target T-cells.

Simian virus 40 (SV40) large T antigen was partially purified from small amounts of SV40-infected and SV40-transformed cells by immunoaffinity chromatography with high recovery. T antigen, in both crude and partially purified states, was detected rapidly by a sensitive and quantitative enzyme-linked immunosorbent assay (ELISA). Stability of the partially purified T antigen was found to increase by addition of 0.01% bovine serum albumin (BSA).

<P>The effect of P³² in the experimental Japanese B Encephalitis infection was investigated. A remarkable delay of infection was observed, when a therapeutic dose of P³² was administered intraperitoneally to the mouse which had been inoculated intracerebrally with the virus suspension at the concentration of about LD50. Almost equal results were obtained by intraperitoneal administrations to the mice when they had deen inoculated intravenously or intraperitoneally.

HST virus which was isolated in 1950 from the roshida ascites tumor by Hamazaki and his associates is a pantropic virus which creates a unique inflammatory granulation in mice. When virus of an acute infections disease was inoculated on embryonated eggs, not only the egg membrane but also the chick embryo were infected more or less, and when the number of virus increased the chick embryo died, terminating the development of the egg. However, the tumor inducing virus which represents the Rous virus does not cause heavy disturbances in the embryo and it is well known that chick hatched from this egg can long maintain health unless it is subjected to a provocative factor. HST virus is no exception to this example and though it is inoculated on an embryonated egg it does not cause any serious disturbance on the embryo. The tissue changes of the chorio allantois infected by the "Virus were the focal proliferation and necrosis of ectodermal epithelium, the proliferation of the mesenchymal cells of the mesodermal layer adjacent to these foci, accompaning infiltration of lymphoid cells and leukocytes with edema, especially eosinophilic leukocytes. By these tissue changes a terrace-shaped thickening of the membrane was the result. In the viscera of the chick embryo a special change in the liver was seen, i. e., along the edge of the liver greyish white nodules submacroscopic to miliary in size appeared. The principal pathologic change of the foci is the coagulation necrosis of the liver parenchyma and only a slight infiltration about the periphery of the foci was observed. Moreover, proliferation of mesenchymal cells occurred next to the walls of the large blood vessels of the liver (principally, the portal veins) and with the added infiltration of a small number of lymphoid cells and leukocytes sharply defined nodular foci were formed. Though this was a rare instnace, similar pathologic changes were seen also in the walls of the blood vessels of the cerebrum stem of the embryo and along the periphery local gliosis was observed.