Natural killer cell activity during murine Schistosomiasis mansoni

Area of Science:

• Immunology
• Parasitology
• Infectious Diseases

Background:

• Schistosoma mansoni is a parasitic worm causing significant global health issues.
• Natural killer (NK) cells are crucial innate immune cells involved in host defense.
• The impact of chronic Schistosoma mansoni infection on NK cell activity requires further elucidation.

Purpose of the Study:

• To investigate the functional activity of NK cells in mice infected with Schistosoma mansoni.
• To determine how NK cell activity changes over the course of infection.
• To assess the responsiveness of NK cells to activation during chronic infection.

Main Methods:

• Assessing NK cell activity using 51Cr-labeled YAC-1 target cells in spleen cells from infected and control mice.
• Comparing NK activity at various time points post-infection (1-18 weeks).
• Evaluating NK cell responsiveness to polyinosinic-polycytidylic acid stimulation in vivo.

Main Results:

• NK cell activity showed no significant difference between infected and control mice from 1 to 4 weeks post-infection.
• From 8 to 18 weeks, NK cell activity per cell was significantly reduced in infected mice compared to controls.
• Chronic infection led to splenomegaly, increasing the total NK activity per spleen despite reduced per-cell function.
• NK cells from chronically infected mice remained responsive to in vivo activation.

Conclusions:

• Schistosoma mansoni infection modulates NK cell activity in a time-dependent manner.
• While chronic infection impairs individual NK cell function, the overall splenic NK cell capacity is enhanced due to increased cell numbers.
• NK cells retain their responsiveness to activation even during chronic schistosomiasis.