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C V Hanson

Publications and source records attributed to C V Hanson.

52 records · Page 3Linked to original sources
PubMed1990

Application of a rapid microplaque assay for determination of human immunodeficiency virus neutralizing antibody titers.

To perform a human immunodeficiency virus (HIV) plaque assay in nonadherent host cells, we developed a novel technique in which HIV-infected MT-2 cells were formed into monolayers by centrifugation through molten agarose. Infection, formation of cell monolayers, and enumeration of plaques all took place in 96-well microtiter plates. When this process was preceded by 18 h of incubation of HIV with patient serum samples, neutralizing antibody titers between 1:10 and 1:5,000 could be accurately determined in patient serum samples. In addition to the determination of neutralizing antibody titers (with the use of various serum dilutions and a constant virus concentration), neutralization indices could also be determined with different virus dilutions and a single dilution of patient serum.

Cell Line↗
PubMed1990

Comparison of Western immunoblot antigens and interpretive criteria for detection of antibody to human T-lymphotropic virus types I and II.

Twenty human T-lymphotropic virus type I (HTLV-I) antibody-positive sera from Japan, Hawaii, and the Marshall Islands and 15 HTLV type II (HTLV-II) antibody-positive sera from intravenous drug users in the United States were tested by immunoblotting with two recombinant HTLV-I proteins and three commercial kits to determine whether there were any differences in reactions between HTLV-I- and HTLV-II-positive sera by the Western immunoblot method and, also, to evaluate the ability of these reagents to detect HTLV-I- and HTLV-II-seropositive individuals by using the recommended Western blot interpretation. These sera were first extensively characterized by immunofluorescence, enzyme immunoassay, radioimmunoprecipitation assay, and Western blot using HTLV-I and HTLV-II viral lysates and an envelope (env) recombinant protein. Although both HTLV-I- and HTLV-II antibody-positive sera reacted with the env protein gp68, reactions with the gp46 env antigens appeared to be specific for HTLV-I. It was found that the use of either p19 or p24 core bands plus an env reaction instead of only the p24 plus env reaction (as presently recommended) increased the number of positive interpretations for HTLV-I but had no effect on the number of HTLV-II-positive interpretations.

Blotting, Western↗
PubMed1990

Inactivated simian immunodeficiency virus vaccine failed to protect rhesus macaques from intravenous or genital mucosal infection but delayed disease in intravenously exposed animals.

Eight rhesus macaques were immunized four times over a period of 8 months with a psoralen-UV-light-inactivated whole simian immunodeficiency virus vaccine adjuvanted with threonyl muramyl dipeptide. Eight unvaccinated control animals received adjuvant alone. Only the vaccinated animals made antibodies before challenge exposure to the viral core and envelope as determined by Western blotting (immunoblotting) and virus-neutralizing antibodies. Ten days after the final immunization, one-half of the vaccinated and nonvaccinated monkeys were challenged exposed intravenously (i.v.) and one-half were challenge exposed via the genital mucosa with virulent simian immunodeficiency virus. All of the nonvaccinated control monkeys became persistently infected. In spite of preexisting neutralizing antibodies and an anamnestic antibody response, all of the immunized monkeys also became persistently infected. However, there was evidence that the clinical course in immunized i.v. infected animals was delayed. All four mock-vaccinated i.v. challenge-exposed animals died with disease from 3 to 9 months postchallenge. In contrast, only one of four vaccinated i.v. challenge-exposed monkeys had died by 11 months postchallenge.

Adjuvants, Immunologic↗
PubMed1989

Effect of dose and immunization schedule on immune response of baboons to recombinant glycoprotein 120 of HIV-1.

To evaluate the immunogenicity of purified recombinant envelope glycoprotein of HIV-1 (rgp120) as a potential vaccine for AIDS, the antibody response of 45 baboons to rgp120 was investigated using an adjuvant (alum) and route of administration (intramuscular) suitable for humans. The primary purpose was to evaluate the effects of different doses and immunization schedules on the antibody response to rgp120 in primates. A secondary objective was to evaluate possible adverse consequences of rgp120 immunization. A liquid-phase radioimmunoprecipitation (RIP) assay for detection of rgp120-reactive antibodies revealed that rgp120 doses of 30-300 micrograms per administration resulted in nearly indistinguishable serum antibody responses. However, significant enhancement of serum antibody titers was observed when the interval between the second and third administrations was increased from 4 to 20 w. Although changing the interval significantly altered the magnitude of resulting peak titers, the kinetics of antibody formation were not changed. Thus, of the three schedules of immunization tested, none resulted in a sustained humoral immune response. The significance of the RIP assay for evaluating immune responses was confirmed by analysis showing that the percentage of immunized baboons that developed in vitro HIV-1 serum neutralizing responses was greatest in groups that also exhibited high anti-rgp120 RIP titers. Immunization with rgp120 had no significant adverse effect on any clinical or laboratory parameter monitored over the course of the study.

Acquired Immunodeficiency Syndrome↗
PubMed1982

Evaluation and reporting of enzyme immunoassay determinations of antibody to herpes simplex virus in sera and cerebrospinal fluid.

Several methods for evaluating and reporting enzyme immunoassay (EIA) determinations of antibody to herpes simplex virus derived from one dilution of single serum samples were studied. An EIA ratio method for serological evidence of current infection from paired serum samples was also evaluated. Optical density (OD) of the reaction at a 1:100 serum dilution and estimated titers obtained by reference of the OD of the serum dilution to a standard curve were compared to the corresponding plotted EIA titer obtained by titration to endpoint. Neither the OD per se nor the estimated titer was completely predictive of the plotted titer (correlation coefficient [r] of 0.824 and 0.817, respectively), and they provided only a semiquantitative measurement of antibody concentration. For an antibody status report, however, OD would be sufficient if related to the cutoff value as an EIA index (OD of sample divided by cutoff OD for positive specimens). The OD of the EIA reaction at a single dilution (1:5) of cerebrospinal fluid, on the other hand, correlated quite well with the titer obtained by titration (r = 0.950). For serological diagnosis of current infection, the OD ratio of convalescence-phase/acute-phase sera was determined at several dilutions. A ratio of greater than or equal to 1.54 was calculated as a reliable index for a significant rise in antibody concentration and compatible with current infection. By determining the convalescent-phase/acute-phase serum ratio at two dilutions, 1:100 and 1:1,000, the EIA ratio method appeared to be a sensitive as or more sensitive than, complement fixation in diagnosing current infection.

Antibodies, Viral↗
PubMed1980

Photoaddition of trimethylpsoralen as a probe for the intracellular organization of Escherchia coli DNA.

It has been previously demonstrated that photoreaction with 4,5',8-tri-methylpsoralen (trioxsalen) can be used as a probe for the in vivo structure of eucaryotic chromatin. We have used this probe to analyze the organization of intracellular Escherichia coli DNA. In contrast to eucaryotic DNA, bacterial DNA within the intact cell is not protected from saturating doses of trioxsalen photoaddition. The final level of covalently bound trioxsalen upon saturation is identical to that found with purified DNA. In addition, the distribution of interstrand DNA cross-links formed by low doses of trioxsalen photoadducts does not exhibit the repeating pattern that has been observed with eucaryotic nucleosomes.

DNA, Bacterial↗
PubMed1979

Photochemical inactivation of deoxyribonucleic and ribonucleic acid viruses by chlorpromazine.

Chlorpromazine, a widely used tranquilizing drug of the phenothiazine group, was found to be a very potent photochemical inactivator of both deoxyribonucleic acid and ribonucleic acid viruses in the presence of long-wave ultraviolet light (320 to 380 nm). Neither the light alone nor chlorpromazine alone caused any appreciable inactivation. The known chlorpromazine photoreactions with nucleic acids are somewhat similar to those of psoralen (furocoumarin) derivatives. As in the case of the psoralens, chlorpromazine is capable of photoinactivating viruses totally within a few minutes under near-physiological or other gentle conditions. The antiviral effects of the chlorpromazine photoreaction could make it valuable for the development of inactivated viral vaccines as well as for use in the photochemotherapy of viral dermatoses.

Chlorpromazine↗
PubMed1978

Photochemical inactivation of DNA and RNA viruses by psoralen derivatives.

Western equine encephalitis virus, and RNA virus, and herpes simplex virus type I, a DNA virus, were efficiently inactivated in less than I min by exposure to long-wave ultraviolet light (320 to 380 nm) in the presence of several psoralen derivatives. The psoralen photochemical reaction was chosen for study due to its known specificity for nucleic acids. Neither the light nor any of the drugs alone caused appreciable inactivation. The inactivation kinetics and dependence on light intensity and on different derivatives of psoralen were studied. The high solubility of a new aminomethyl psoralen derivative was found to be advantageous in the photochemical inactivation of the RNA virus, but was not in the case of the more easily inactivated DNA virus. Within its limited solubility range trimethylpsoralen was superior to its aminomethyl derivative on a molar basis for the inactivation of both types of viruses under most of the conditions studied.

Cell Line↗
PubMed1976

Cross-linking of DNA in situ as a probe for chromatin structure.

The photochemical cross-linking of DNA in situ in chromatin is blocked over short intervals. Electron microscopy of DNA cross-linked in chromatin reveals the lengths of protected regions and provides a map of their sites along the DNA. Protected regions occur most frequently in tandem and have a basic length of 160 to 200 base pairs.

Animals↗
PubMedDate not supplied

Human T-cell lymphotrophic virus in California's injection drug users.

Human T-cell lymphotrophic virus I (HTLV-I) and human T-cell lymphotrophic virus II (HTLV-II) are closely related retroviruses that are highly prevalent in injection drug users (IDUs). The bulk of infection in this group probably occurs with HTLV-II, with a lower prevalence of HTLV-I. HTLV-I is known to cause adult T-cell leukemia/lymphoma and tropical spastic paraparesis. HTLV-II has not been proven to cause any human pathology, but may be immunosuppressive and is almost indistinguishable serologically from HTLV-I. As with human immunodeficiency virus (HIV), infection with these viruses is likely to be lifelong and the disease may have a latent period of many years. Unlike HIV, HTLV-I and/or HTLV-II are not likely to be transmitted from mother to child prenatally, and usually require breast-feeding for vertical transmission. It is likely that HTLV-I and/or HTLV-II has been prevalent in IDUs for far longer than the HIV epidemic. HTLV-I and/or HTLV-II are relevant to the AIDS epidemic in that they may function as biologic markers of behavioral risk status for HIV infection in IDUs or their sexual partners, and they may accelerate the course of HIV infection in persons coinfected with HTLV-I and/or HTLV-II and HIV. Coinfection will be more likely as the HIV epidemic progresses. Pregnant addicts entering outpatient methadone maintenance treatment in San Francisco County or Contra Costa County during 1990 were found to have an HTLV-II prevalence of 21% (n = 24). Important issues in counseling infected methadone patients are described.

Adult↗