Method validation and reference range values for a peripheral blood immunophenotyping assay in non-human primates

A peripheral blood immunophenotyping assay was developed and validated for determination of total T-lymphocytes, helper T-lymphocytes, cytotoxic T-lymphocytes, B-lymphocytes, and natural killer cells in cynomolgus monkeys. Validation parameters included assessment of precision, linearity, antibody optimization, stability of peripheral blood samples, and stability of fixed immunophenotyping samples. Total lymphocyte populations were determined using a heterogeneous lymphocyte gating strategy consisting of CD45 fluorescent staining and side-scatter demarcation. Relative lymphocyte subset values were determined using antigen-specific gating strategies. Absolute subset concentrations for each lymphocyte subset were subsequently determined using a dual-platform methodology wherein relative lymphocyte subset values (via flow cytometry analyses) were multiplied by the absolute total lymphocyte (via hematology analyses) values. Reference ranges are presented for cynomolgus monkey, rhesus monkey, and baboon. Additional 1-year longitudinal immunophenotyping values are presented for the cynomolgus monkey. The method validation and reference ranges presented in this research provide a robust analytical methodology for determination of peripheral blood lymphocyte subsets in various non-human primate species.