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Cytimmune ANTI- INTERFERON SERA Cytimmune ANTI- INTERFERON SERA are whole antisera raised in long- term immunization regimens in New Zealand white rabbits, heat- inactivated and diluted, where appropriate, with PBS buffer (p. 5) to give the stated neutralizing titer. The sera are supplied in sterile lyophilized form to be rehydrated in 1 mL sterile water. No preservatives have been added. The antisera have been raised against the corresponding tissue culture- derived, nonrecombinant interferons purified to 3 to 7 x 10^7 IU/mg (human and rat interferons) or 2 to 3 x 10^8 IU/mg (mouse interferons), except for Cat. 10135 and 10136, which have been raised against pure, recombinant human betaSer interferon under agreement with CETUS Corporation, and which are therefore designated as monospecific in the sense of pure protein antigen. Except for Cat. 10135 and 10136, the interferon immunogens contain trace amounts of bovine serum proteins remnant from growth of the cell cultures, noninterferon proteins secreted by the cultures during accumulation of interferon, and chick chorioallantoic fluid and Newcastle disease virus proteins remnant from the induction phase. The antisera may be reactive with any of these, but only at significantly higher concentrations (10^3- to 10^5- fold) than for specific interferon neutralizing activity. The antisera are extremely specific with regard to cross- reactivity toward heterologous interferon species (cross- reactivities are generally less than 0.02%). The sole specification for Cytimmune ANTI- INTERFERON SERA is biological activity, that is, the neutralizing titer. The principal application of Cytimmune ANTI- INTERFERON SERA, therefore, is the immunochemical identification of interferons and their effects by specific neutralization of biological activity. The anti- human and anti- mouse interferon sera are standardized using the respective anti- human interferon beta (code G028- 501- 568) and anti- mouse interferon alpha + beta (code G024- 501- 568) reference reagents provided by the Antiviral Substances Program, NIAID, NIH. For our own manufacturing control as well as for other laboratories, we routinely assay anti- interferon serum or immunoglobulin activity by vital dye uptake and microtest assays (described on p. 27). Fig. 1 (p. 13) and Fig. 6 (p. 30), respectively, illustrate results typical of each type of assay. As a rough guide each neutralizing unit will result in complete neutralization of 3 to 10 units of the corresponding interferon activity. Please note the distinction between neutralizing titer, on the one hand, and units of interferon neutralized, on the other. The neutralizing titer is defined as the reciprocal of the dilution of antiserum which gives 50% neutralization of 10 IU/mL interferon activity [17]. The sera generally have less than 0.02% cross- reactivity against heterologous interferon species. It is anticipated that the polyclonal antisera, unlike certain monoclonal anti- interferons, will also neutralize other activities associated with various interferon molecules. The anti- interferon sera are of sufficient specificity and avidity to be useful in immunohistochemical and cytochemical staining applications. It is assumed that such assays would be of the indirect type, for which we suggest that anti- interferon serum dilutions in the range 10^- 2 to 10^- 5 will be found useful. Electron microscopic immunocytochemical localization of murine interferon beta, using Cytimmune anti- mouse interferon beta serum (Cat. 20031) has been described [28]. In addition to their neutralizing activity, Cytimmune ANTI- INTERFERON SERA are useful as sources of material for affinity purification of small amounts of interferons or anti- interferon immunoglobulins, anti- idiotype studies, conjugation and other manipulations. It should be recognized that the anti- interferon sera are neither immunologically nor chemically purified immunoglobulins, but contain nonimmunoglobulin serum proteins and also noninterferon- specific immunoglobulins. Purified immunoglobulin G’s corresponding to the anti- interferon sera are listed on p. 18. Access Biomedical currently does not offer specific anti- mouse interferon alpha. Instead, we routinely infer the identity and quantity of mouse alpha interferon as that acid- stable activity which is neutralized by anti- mouse alpha + beta serum (Cat. 2103X) but not by the highly specific anti- mouse beta serum (Cat. 2003X) or monoclonal anti- mouse gamma immunoglobulin (Cat. 25001). We are pleased to provide quotations for manufacturing quantities of Cytimmune ANTI- INTERFERON SERA
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