In vitro stimulation of human lymphocytes by Bordetella Pertussis

Area of Science:

• Immunology
• Microbiology
• Cell Biology

Background:

• Bordetella pertussis (B.p.) is the causative agent of whooping cough.
• Lymphocyte transformation is a key indicator of immune response.
• Pertussis vaccines utilize various B.p. strains and components.

Purpose of the Study:

• To investigate the capacity of Bordetella pertussis to induce lymphocyte blast transformation in humans.
• To compare the efficiency of whole killed B.p. versus sonication extracts in stimulating lymphocytes.
• To explore the role of specific B.p. components like Protective Antigen and Histamine-Sensitizing Factor in lymphocyte activation.

Main Methods:

• Human lymphocytes were exposed to whole killed B.p. and sonication extracts.
• Purified fractions of B.p. supernatants, including Lymphocytosis Promoting Factor, were tested for mitogenic activity.
• Lymphocyte transformation responses were assessed in various human populations: normal adults, cord blood, postpartum women, and children with whooping cough.

Main Results:

• Whole killed B.p. induced significant lymphocyte transformation, more so than sonication extracts.
• B.p. strains used in the Danish vaccine elicited similar responses.
• Purified fractions containing Lymphocytosis Promoting Factor demonstrated T-lymphocyte mitogenic activity.
• Lymphocytes from all normal individuals, including cord blood, responded to B.p.
• Postpartum women and children with whooping cough exhibited depressed lymphocyte responses to B.p.
• A strong correlation was found between B.p. and E. coli responses in adults and newborns.

Conclusions:

• The majority of lymphocyte transformation induced by B.p. is a non-specific immune response.
• Specific B.p. components may contribute to lymphocyte activation, but non-specific mechanisms are predominant.
• Immune status, such as in postpartum women or during active infection, can modulate lymphocyte reactivity to B.p.