Murinization and H Chain Isotype Matching of the Anti-GITR Antibody DTA-1 Reduces Immunogenicity-Mediated Anaphylaxis in C57BL/6 Mice

• Published in: The Journal of immunology (1950) Vol. 198; no. 11; pp. 4502 - 4512
• Main Authors: Belmar, Nicole A, Chan, Sarah W, Fox, Melvin I, Samayoa, Josue A, Stickler, Marcia M, Tran, Ninian N, Akamatsu, Yoshiko, Hollenbaugh, Diane, Harding, Fiona A, Alvarez, Hamsell M
• Format: Journal Article
• Language: English
• Published: United States American Association of Immunologists 01.06.2017
• Subjects: Anaphylaxis; Anaphylaxis - immunology; Animal models; Animals; Antitumor activity; Body temperature; Cancer immunotherapy; CD8 antigen; CD8-Positive T-Lymphocytes - immunology; Cell Line, Tumor; Drug development; Glucocorticoid-Induced TNFR-Related Protein - immunology; Glucocorticoids; Immune response; Immunogenicity; Immunoglobulin E; Immunoglobulin G; Immunoglobulin Isotypes - immunology; Immunoregulation; Interleukin 4; Interleukin-4 - immunology; Lymphocytes; Lymphocytes T; Mice; Mice, Inbred C57BL; Oncology; Proteins; Rats; Receptors, IgG - immunology; Strain; T-Lymphocytes, Regulatory - immunology; Tumor necrosis factor receptors
• DOI: 10.4049/jimmunol.1601512
• ISSN: 0022-1767

Recent advances in immuno-oncology have shown that the immune system can be activated to induce long-term, durable antitumor responses. For immuno-oncology drug development, immune activation is often explored using rat Abs in immunocompetent mouse models. Although these models can be used to show efficacy, antidrug immune responses to experimental protein-based therapeutics can arise. Immunogenicity of surrogate Abs may therefore represent an important obstacle to the evaluation of the antitumor efficacy of immunomodulator Abs in syngeneic models. A recent publication has shown that anti-glucocorticoid-induced TNFR family-related protein agonistic Ab DTA-1 (rat or murinized IgG2a) can induce the development of anaphylaxis in C57BL/6 mice upon repeated i.p. dosing because of an anti-idiotypic anti-drug Ab immune response. This study was undertaken to address the impact of the immunogenicity derived from the Fc and variable domains. To this end, chimerized (rat V domains/mouse constant regions) and murinized (95% mouse sequence) DTA-1-based surrogate Abs with a murine IgG2c H chain isotype were created. Chimerization and murinization of DTA-1 did not affect receptor binding and glucocorticoid-induced TNFR family-related protein-induced T cell agonistic properties. Similar in vivo antitumor efficacy and intratumoral CD8 /regulatory T cells were also observed. Finally, treatment of C57BL/6 mice with the chimerized and murinized DTA-1 Abs on a C57BL/6-matched IgG2c isotype resulted in reduced development and severity of anaphylaxis as measured by decline of body temperature, behavioral effects, serum IL-4, IgE, and anti-drug Ab levels. These results suggest that careful murinization and selection of a strain-matched H chain isotype are critical to generate ideal surrogate Abs for testing immuno-oncology mechanisms in vivo.