SERPINA1 and infection: Seven-day-old C57BL/6 mice were inoculated with B. pertussis or vehicle (PBS), and, at a time point when infants mice begin to succumb to infection (8 days post inoculation (41)), the expression levels of the murine genes that code for α1AT, serpinA1a-e, were determined by quantitative reverse transcription PCR on whole lung homogenates.