Suppressor cells in Trypanosoma congolense-infected mice

Area of Science:

• Immunology
• Parasitology
• Cell Biology

Background:

• Trypanosoma congolense infections can lead to immunosuppression.
• Understanding the mechanisms of immunosuppression is crucial for developing effective treatments.

Purpose of the Study:

• To investigate the nature of spleen cells responsible for suppressing lymphocyte stimulation in mice infected with T. congolense.
• To characterize the cell types and properties involved in this immunosuppressive activity.

Main Methods:

• Spleen cells from infected mice were co-cultured with normal spleen cells and mitogens or allogeneic cells.
• Cell dilution studies were performed to assess suppressor activity.
• Spleen cell populations were treated with mitomycin-C, anti-Thy.1 sera and complement, carbonyl iron, or nylon columns to identify suppressor cell characteristics.

Main Results:

• Spleen cells from T. congolense-infected mice strongly suppressed lymphocyte stimulation.
• Suppressor activity was extremely potent, as shown by cell dilution studies.
• Mitomycin-C treatment significantly reduced suppressor activity, suggesting a role for proliferating cells.
• Treatment with anti-Thy.1 sera and complement did not affect suppressor activity.
• Removal of carbonyl iron-binding cells or nylon-adherent cells partially reduced suppressor activity, but did not abolish it.

Conclusions:

• T. congolense infection induces potent immunosuppression mediated by spleen cells.
• The suppressor cells are likely not T cells (Thy.1 positive).
• The suppressor cells may involve proliferating cells (sensitive to mitomycin-C) and potentially include cells with characteristics of both adherent and non-adherent populations.