Psoralen inactivation of influenza and herpes simplex viruses and of virus-infected cells

Abstract

Psoralen compounds covalently bind to nucleic acids when irradiated with longwavelength ultraviolet light. This treatment can destroy the infectivity of deoxyribonucleic acid and ribonucleic acid viruses. Two psoralen compounds, 4'-hydroxymethyltrioxsalen and 4'-aminomethyltrioxsalen, were used with long-wavelength ultraviolet light to inactivate cell-free herpes simplex and influenza viruses and to render virus-infected cells noninfectious. This method of inactivation was compared with germicidal (short-wavelength) ultraviolet light irradiation. The antigenicity of the treated, virus-infected, antigen-bearing cells was examined by immunofluorescence and radioimmunoassay and by measuring the capacity of the herpes simplex virus-infected cells to stimulate virus-specific lymphocyte proliferation. The infectivity of the virus-infected cells could be totally eliminated without altering their viral antigenicity. The use of psoralen plus long-wavelength ultraviolet light is well suited to the preparation of noninfectious virus antigens and virus antigen-bearing cells for immunological assays. Cells. Rabbit kidney (RK13) cells were obtained from

Antibodies to coronaviruses are higher in older compared with younger adults and binding antibodies are more sensitive than neutralizing antibodies in identifying coronavirus‐associated illnesses

“…Mock antigen was prepared, in the same way, from uninfected cells. 17,18 HCoV-HKU1 has not been grown using standard tissue culture techniques, so His 6 -tagged recombinant nucleoprotein (N) of HCoV-HKU1 and mock antigen that was produced from the same plasmid DNA vector without the N protein gene were used as antigens to detect antibody to -HKU1, as described. 7,8,16 Viral and mock antigens, the same stocks throughout the assays, were used to coat flat-bottom 96-well Maxisorp Immunoplates (Nalge-Nunc International, Rochester, NY) followed by the sequence of serum in serial dilutions, mouse antihuman IgG conjugated with horseradish peroxidase (Accurate Chemical and Scientific, Westbury, NY) and peroxidase substrate (KPL, Gaithersburg, MD).…”

“…The concentrated virus was inactivated by psoralen compound (Sigma, St Louis, MO), followed by irradiation by long-wavelength UV light, as described. 17,18 This method of viral inactivation does not affect viral antigenicity. Mock antigen was prepared, in the same way, from uninfected cells.…”

Coronavirus and Other Respiratory Illnesses Comparing Older with Young Adults

“…The 4 coronavirus antigens for the antibody assay were produced as described. 30,36,37 Viral and mock antigens were used to coat flat-bottom 96-well Maxisorp Immuno-plates…”

Prevalence of Antibodies to Four Human Coronaviruses Is Lower in Nasal Secretions than in Serum

“…Virus-infected cells were frozen and thawed three times, the supernatant fluid was cleared of cell debris by centrifugation, the virus was concentrated by overnight centrifugation, and the virus pellet was resuspended in phosphate-buffered saline (PBS). The concentrated virus was inactivated by a psoralen compound (Sigma, St. Louis, MO), followed by irradiation by long-wavelength UV light, as described previously (34). Mock antigen was prepared, in the same way, from uninfected cells.…”