Most of the cystic fibrosis (CF) patients are or have been pulmonary colonized with bacteria such as Pseudomonas aeruginosa or Staphylococcus aureus. Aim of this study is to detect virulence factor neutralizing antibodies in the sera of the study population followed by B cell repertoire analyses to design B cell-derived neutralizing monoclonal antibodies. The functionality of neutralizing antibodies rests on inhibition of virulence factors by binding of crucial epitopes rather than merely the induction of opsonization. Focusing on patients with bacterial colonization/chronic infections or a history of an acute infection in the past, will increase the likelihood for identification of serum with neutralizing activity as in vivo antigen contact is a prerequisite for antibody development and maturation. Since virulence factors are essential for infection, dissemination and tissue damage, inhibition of these factors by developed neutralizing antibodies might contribute to a favorable outcome of life-threatening infections.

Inclusion Criteria:

• Age ≥ 18 years
• Ability to give consent
• Normal vital signs including:
• Blood pressure systolic value 150 - 100 mmHg, diastolic value < 90 mmHg
• Respiratory rate < 20/min
• Oxygen saturation >92%
• Heart rate 50 - 110/min
• Body temperature <38°C

Exclusion Criteria:

• Cytopenia (leukocytes < 1.500/µl, thrombocytes < 50.000/µl, Hemoglobin < 12 g/dl)
• Heart disease or pulmonary hypertension
• Body weight <50 kg (exclusion of blood sampling for B cell isolation)
• Blood donation, larger blood loss and/or major surgery in the last 8 (male) or 12 (female) weeks
• Any decline of the general state of health in the last 3 month including weight loss > 2kg, pulmonal exacerbation or increased impairment of pulmonary function (FEV1 < 50%)

Patients of the University Hospital Cologne