Chicken lines differ in production of interferon-like activity by peripheral white blood cells stimulated with phytohemagglutinin

Interferon (INF) activity was evaluated in the supernatants from peripheral white blood cells (WBC) of chickens from six lines. The WBC were cultured in flasks or 24-well plates with medium or medium and phytohemagglutinin (PHA). After 2 to 5 d, duplicate supernatant samples were tested for INF activity, i.e., the 1092 titer inhibiting 50% destruction of the cytopathic effect of vesicular stomatitis virus on primary chick embryo fibroblasts. Also triplicate WBC samples were tested for proliferation by [H-3]-thymidine labeling and scintillation counting. In the absence of PHA, INF was significant for only two lines, i.e., 72 (two trials) and C (one trial). With PHA the level of INF produced was similar if flasks were sampled daily or on successive days. The INF levels were highest using 10 or 20 mug/mL PHA, but line differences were best distinguished using 5 or 10 mug/mL. In three trials there was a low correlation between PHA-stimulated WBC proliferation and INF titer (r greater than or equal to 0.30; P < 0.05). It was concluded that supernatants from chicken WBC stimulated with 10 mug/mL PHA contain INF, and inbred Lines 7(2) and C repeatedly produce more INF than inbred Lines 6(3) and 15I(5). This is the first evidence for line differences in INF production in chickens, and these lines may be useful for characterization of the relevant genes and their importance in immune response(s) and disease resistance.