Background: The cellular immune response to Bordetella pertussis(BP) has not been examined in children with whooping cough in comparison with vaccinated controls.

Subjects: We enrolled two teenage children with recent, laboratory proven, whooping cough and compared them to 3 individuals vaccinated with whole cell pertussis vaccine.

Interventions: Whole mononuclear cells (WMNC) were isolated from heparinzed blood by Ficoll-Hypaque centrifugation. At a density of 105WMNC/well cells were incubated with either wBP. FHA. PT or diphteria toxoid (DT). After 6 days of culture 3H-thymidine was added and proliferation was measured. Additionally, the cytokine secretion of IFN-γ and IL-4 was assessed in the cell culture supernatants by ELISA.

Results: WMNC from the 2 patients with whooping cough proliferated significantly more to wBP (20.9×104 cpm) and PT(3.7×104 cpm) as compared to the controls (5.9×104 cpm and 0.37×104 cpm, respectively). p 0.01. No significant differences could be observed in the proliferation upon FHA(3.6×104 cpm vs. 1.9×104 cpm). The proliferation to DT was 1.1×104 cpm in patients with whooping cough and 0.9×103 cpm in controls. There was no significant difference in the IFN-γ secretion upon stimulation with wBP and FHA in individuals with whooping cough and controls (3.228 vs. 2.605 pg/ml and 862 vs. 584 pg/ml). however. patients with whooping cough secreted significantly more IFN-γ to PT (524 pg/ml) than controls (5.3 pg/ml). p<0.01 IFN-γ secretion to DT was 310 pg/ml and 21 pg/ml in the study and control group. There was no IL-4 secretion in either group.

Conclusion: The main difference in the cellular immune response to BP between individuals with wild type BP infection and vaccinated controls was the response to pertussis toxoid. This may be critical in respect to a life-long immunity against whooping cough.