Suppressor cells in mice infected with Trypanosoma brucei

Area of Science:

• Immunology
• Parasitology
• Cell Biology

Background:

• Trypanosoma brucei infection leads to significant immune dysregulation.
• Understanding the mechanisms of immunosuppression during infection is crucial for developing effective treatments.

Purpose of the Study:

• To investigate the cellular mechanisms underlying the suppression of antibody responses during Trypanosoma brucei infection.
• To identify the cell types responsible for immune suppression and the potential triggers.

Main Methods:

• In vitro culture of spleen cells from infected CBA mice.
• Cell mixture experiments to detect suppressor cell activity.
• Assessment of antibody responses to thymus-dependent (SRBC) and thymus-independent (DNP-Ficoll) antigens.

Main Results:

• Spleen cells from infected mice showed a profound reduction in primary antibody response to SRBC.
• Suppressor cell activity was identified in T cells and adherent cells, but not B cells.
• Antibody responses to the thymus-independent antigen DNP-Ficoll were also significantly reduced.
• The trypanosome itself did not directly cause suppression, nor was it antigenic competition.

Conclusions:

• Trypanosoma brucei infection induces suppressor T cells and adherent cells that impair both T-dependent and T-independent antibody production.
• The findings support a model where trypanosome antigens stimulate T cells, leading to the release of suppressive factors.
• This immune suppression impacts both B cell and T cell responses, contributing to disease pathogenesis.