mRNA expression analysis

Protein expression analysis

Strain specific IL2RA expression analysis in homozygous B-hIL2RA mice by flow cytometry. Splenocytes were collected from WT and homozygous B-hIL2RA (H/H) mice stimulated with anti-CD3ε in vivo, and analyzed by flow cytometry with species-specific anti-IL2RA antibody. Mouse IL2RA was detectable in WT mice. Human IL2RA was exclusively detectable in homozygous B-hIL2RA but not WT mice.

Analysis of spleen leukocytes cell subpopulations in B-hIL2RA mice

STAT-5 Phosphorylation is blocked by hIL2RA Ab1, non-blocked by hIL2RA Ab2. Splenocytes were isolated from C57BL/6 and B-hIL2RA mice (n=3), treated with 100 U/mL mouse IL2 and then analyzed by flow cytometry. STAT-5 phosphorylation is blocked by hIL2RA Ab1, but not hIL2RA Ab2.

In vivo efficacy of anti human IL2RA antibodies  

Antitumor activity of anti-human IL2RA antibodies in B-hIL2RA mice. (A) Anti-human IL2RA antibodies inhibited MC38 tumor growth in B-hIL2RA mice. Murine colon cancer MC38 cells were subcutaneously implanted into homozygous B-hIL2RA mice (female, 6-7 week-old, n=5). Mice were grouped according to body weight differences, at which time they were treated with anti-hIL2RA Ab4 and Ab5 with doses and schedules indicated with red arrows in panel A. (B) Body weight changes during treatment. As shown in panel A, anti-human IL2RA antibodies were efficacious in controlling tumor growth in B-hIL2RA, demonstrating that the B-hIL2RA mice provide a powerful preclinical model for in vivo evaluation of anti-human IL2RA antibodies. Values are expressed as mean ± SEM. (All antibodies were made in house)

Ratio of blood lymphocytes

Flow cytometry analysis of tumor infiltrating lymphocytes (TILs). Tumor cells were harvested at the endpoint of experiment (n=5). Flow cytometry analysis of the lymphocytes were performed to assess cell number and proportion changes compared to the group with no anti-hIL2RA antibody treated. CD4+ T cells, Treg cells and hCD25+mFoxP3+ T cells were significantly reduced when treated with anti-hIL2RA antibodies, while the ratio of CD8+ T cells/Treg cells were significantly increased in the all groups treated with anti-hIL2RA antibodies compared to the hIgG1. Values are expressed as mean ± SEM.

In vivo efficacy of anti-human IL2RA antibodies