Interactions between group B streptococci and human cord blood lymphocytes

Area of Science:

• Immunology
• Microbiology
• Neonatal Health

Background:

• Group B streptococci (Streptococcus agalactiae) are a leading cause of invasive infections in neonates.
• Understanding the interaction between Group B streptococci and the neonatal immune system is critical for developing effective prevention and treatment strategies.

Purpose of the Study:

• To investigate the interaction between different Group B streptococcal strains and human mononuclear cells (MNC).
• To analyze the adherence of Group B streptococci to lymphocytes and their effect on lymphocyte proliferation in neonates and adults.

Main Methods:

• Analysis of bacterial adherence to human peripheral lymphocytes.
• Assessment of lymphocyte proliferation in cultured adult and neonatal MNC upon addition of Group B streptococci.
• Measurement of [3H]thymidine incorporation to quantify cellular proliferation.

Main Results:

• Group B streptococcal strains (Ib/c, III/x, B variant) adhered to neonatal cord blood lymphocytes, bound by specific lymphoid cells.
• Neonatal MNC cultures showed an approximately 8-fold increase in lymphocyte proliferation when exposed to Group B streptococci.
• Adult MNC exhibited minimal response in terms of streptococcal binding and proliferation, unlike neonatal cells.

Conclusions:

• Group B streptococci exhibit a common ability to interact with and activate human cord blood lymphocytes.
• The observed interaction and lymphocyte activation are independent of bacterial serotype and origin.
• These findings highlight a unique susceptibility of the neonatal immune system to Group B streptococci.