Effect of IL-5 treatment on anti-PNM Ab isotypes. Comparison of titers taken at day 12 after immunization of anti-PNM Abs in groups treated with IL-5 (●) from day of onset of clinical disease to untreated controls (○; n = 5/group). No significant differences were observed in total Ig (IgFab), IgG1, IgG2a, IgG2b, and IgG2c titers at days 14, 21, 28, and 35 after immunization. Data are expressed as a percentage relative to a control sera from a Lewis rat hyperimmunized with PNM.