title: Quantitative assay for testing susceptibility of HIV isolates to zidovudine and sCD4 (178)-PE40.
abstract: A quantitative coculture assay is described for determining susceptibility of HIV-1 isolates to zidovudine and sCD4 (178)-PE40 (a 60 kDa hybrid protein consisting of the gp120 binding region of CD4 linked to the translocation and ADP-ribosylation regions of Pseudomonas aeruginosa exotoxin). The assay was relatively simple to perform and gave highly reproducible results often within three to five days. IC50 values of zidovudine for HIV-1 strains isolated from two AIDS patients and an asymptomatic seropositive individual were in the range 0.001-0.002 mumol. Isolates obtained after six months of zidovudine treatment had zidovudine IC50 values of 0.01-0.5 mumol. All isolates were equally sensitive to sCD4 (178)-PE40 (IC50 1-5 micrograms/ml). HIV-1 activation in the chronically infected cell line U-1 was inhibited by sCD4 (178)-PE40 but not by zidovudine.
authors.affiliation: Laboratory for Medical Microbiology, University Hospital, Utrecht, The Netherlands.
authors.forename: J
authors.initials: J
authors.lastname: Verhoef
authors.forename: G
authors.initials: G
authors.lastname: Gekker
authors.forename: A
authors.initials: A
authors.lastname: Erice
authors.forename: P K
authors.initials: PK
authors.lastname: Peterson
authors.forename: H H
authors.initials: HH
authors.lastname: Balfour
mesh_terms: D000998:Antiviral Agents / Q000494:pharmacology*; D002460:Cell Line; D005098:Exotoxins / Q000494:pharmacology*; D015658:HIV Infections / Q000382:microbiology; D015497:HIV-1 / Q000187:drug effects*; D006801:Humans; D000922:Immunotoxins / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests / Q000379:methods; D011994:Recombinant Proteins / Q000494:pharmacology*; D015215:Zidovudine / Q000494:pharmacology*
chemical_list: D000998:Antiviral Agents; C057689:CD4-Pseudomonas toxin; D005098:Exotoxins; D000922:Immunotoxins; D011994:Recombinant Proteins; D015215:Zidovudine