Figure 5. In vivo expression of vaccine-candidate genes.
Naïve adult female BALB/c mice (n = 4) were infected intranasally with B. pertussis strain B1917 or B1920. After 7 days, bacteria were collected through broncho-alveolar lavage and used for in vivo transcriptional analysis using antigen-specific primers as described in the text. The transcription data is expressed as 40-ΔCt value, which is a measure of expression relative to the recA household gene (ΔCt = Ct target – Ct recA). The number 40 represents the number of PCR cycles. A 40-ΔCt value of 40 indicates that the gene is expressed at equal levels as recA, while higher values correspond to higher expression.