FIG. 6.

Detection of rPtAPI-specific IgG isotypes in llama sera by ELISA. (A) Llamas from a P. tenuis-endemic area (New York State). Sera from diseased llamas, confirmed to be P. tenuis infected, contained predominantly IgG1 specific for rPtAPI. No antigen-specific IgG isotypes were detected in the uninfected llama serum. Polyclonal goat anti-llama IgG (H+L) did not distinguish infected from uninfected llamas. (B) Llamas from P. tenuis-free area (Washington State). Cross-reactive IgG1 as well as IgG3 and/or IgG2 were detected in sera from uninfected llamas. The polyclonal goat antibodies yielded consistently high readings for all seven sera. Columns represent mean optical densities of sera diluted 1:100 (tested in triplicate) ± standard deviations (T bars).