Stability of Varicella-Zoster Virus and Herpes Simplex Virus IgG Monoclonal Antibodies

The stability of 3 monoclonal antibodies was analyzed at various temperatures and freeze/thaw cycles. Two varicella-zoster virus (VZV) IgGs (mAb 4F9 and mAb g62) and 1 herpes simplex virus 1 (HSV-1 mAb 1D4) were selected for these studies. IgGs were either incubated at various temperatures (25C, 37C, 45C, and 60C) for different periods of time (0 to 9 weeks) or processed for several freeze/thaw cycles. The reactivities of mAbs 4F9 (IgG1), g62 (IgG1) and 1D4 (IgG2b) were tested by indirect immunofluorescence assay (IFA). The results indicated that: (1) all three mAbs were stable at 25C and 37C for 9weeks; (2) although the reactivities of mAbs g62 and 1D4 were diminished after 5weeks, mAb 4F9 was stable at 45C for 9weeks; and (3) all 3 IgGs lost reactivity after overnight incubation at 60C. In addition, the results showed that the reactivity of mAbs 4F9, g62 and 1D4 was not diminished after 12 freeze/thaw cycles.