Preventive Anti-CD2 Treatment does not Impair Parasite Control in a Murine Toxoplasmosis Model

Area of Science:

• Immunology
• Infectious Diseases
• T cell biology

Background:

• Monoclonal antibody (mAb) CB.219 targets human CD2 on T cells and reduces intestinal inflammation.
• The safety of CB.219 regarding infection control is not well understood.

Purpose of the Study:

• To investigate the effects of CB.219 treatment on controlling Toxoplasma gondii infection in mice expressing human CD2 on T cells (huCD2tg).

Main Methods:

• huCD2tg mice were infected with T. gondii and treated with CB.219 preventively.
• Intestinal parasite loads, ileal inflammation, immune cell infiltration, and cytokine levels were assessed.
• Regulatory T cell (Treg) populations were quantified in the ileum and liver.
• In vitro studies using human peripheral blood mononuclear cells were conducted.

Main Results:

• CB.219 treatment did not alter intestinal T. gondii loads or ileal inflammation.
• Protein levels of interferon-γ, TGF-β, and IL-6 were reduced in the ileum, while IL-18 mRNA increased.
• Neutrophil, macrophage, and T cell infiltration remained unchanged.
• CB.219 treatment decreased Treg numbers in the ileum and liver, confirmed in vitro.

Conclusions:

• Targeting CD2+ T cells with mAb CB.219 does not compromise immune responses essential for controlling T. gondii infection.
• Further research is needed to explore gut specificity, mechanisms, and broader applications of CB.219.