Related Experiment Videos
Fc receptors are required in passive and active immunity to melanoma
1Laboratory of Molecular Genetics and Immunology, Rockefeller University, New York, NY, USA. clynesr@rockvax.rockefeller.edu
Abstract:
Effective tumor immunity requires recognition of tumor cells coupled with the activation of host effector responses. Fc receptor (FcR) gamma-/- mice, which lack the activating Fc gamma R types I and III, did not demonstrate protective tumor immunity in models of passive and active immunization against a relevant tumor differentiation antigen, the brown locus protein gp75. In wild-type mice, passive immunization with mAb against gp75 or active immunization against gp75 prevented the development of lung metastases. This protective response was completely abolished in FcR gamma-deficient mice. Immune responses were intact in gamma-/- mice because IgG titers against gp75 develop normally in gamma-/- mice immunized with gp75. However, uncoupling of the Fc gamma R effector pathway from antibody recognition of tumor antigens resulted in a loss of protection against tumor challenge. These data demonstrate an unexpected and critical role for FcRs in mediating tumor cytotoxicity in vivo and suggest that enhancement of Fc gamma R-mediated antibody-dependent cellular cytotoxicity by inflammatory cells is a key step in the development of effective tumor immunotherapeutics.
Insights
Fc receptors (FcRs) are crucial for effective tumor immunity. Blocking FcR gamma signaling in mice abolished protective anti-tumor responses, highlighting FcRs
Area of Science:
- Immunology
- Oncology
- Cancer Research
Background:
- Effective anti-tumor immunity relies on recognizing cancer cells and activating host defenses.
- Fc receptors (FcRs) play a role in immune responses, but their specific function in anti-tumor immunity requires further elucidation.
Purpose of the Study:
- To investigate the role of Fc receptor gamma (FcR gamma) signaling in mediating protective anti-tumor immunity.
- To determine if FcR gamma signaling is essential for antibody-dependent cellular cytotoxicity (ADCC) against tumor cells in vivo.
Main Methods:
- Utilized FcR gamma-deficient mice (FcR gamma-/-) and wild-type littermates.
- Employed passive and active immunization strategies using a tumor differentiation antigen (gp75) and monoclonal antibodies (mAbs) against gp75.
- Assessed the development of lung metastases as a measure of tumor growth and protection.
- Measured IgG antibody titers to confirm intact humoral immune responses in FcR gamma-/- mice.
Main Results:
- Wild-type mice receiving anti-gp75 antibodies or active immunization showed protection against lung metastases.
- This protective effect was completely lost in FcR gamma-/- mice, despite normal IgG antibody production.
- Immune responses were otherwise intact in FcR gamma-/- mice, indicating a specific defect in FcR gamma-mediated effector function.
Conclusions:
- Fc receptor gamma signaling is critical for mediating tumor cell killing in vivo.
- The study demonstrates an unexpected and essential role for FcRs in anti-tumor immunity.
- Enhancing FcR gamma-mediated ADCC represents a potential strategy for developing effective cancer immunotherapeutics.