Herceptin is an antibody that is used to treat certain forms of breast cancer by binding to a class of estrogen receptors. What is the basis for its effectiveness in treating certain forms of breast cancer?

To study the immune responses that provide protection against tumor growth in mice, some investigations have used the EL4 mouse thymoma line. This tumor cell line was derived from a C57BL/6 mouse, and represents a type of T cell lymphoma. When transplanted into Rag-deficient mice, the mice rapidly succumb to the tumor. This is also the case when the mice receive wild-type C57BL/6 T cells the day before tumor cell injection. However, Rag-deficient mice were protected when the transferred T cells came from mice that lacked expression of one cytokine receptor, as shown in the fugure below.  Name one likely candidate for the cytokine receptor that is knocked out in the T cells that are able to protect the mice.

When T cells are activated by recognizing peptide:MHC complexes on dendritic cells in the lymph node, they up-regulate the receptor CD69. For T cells expressing a given T-cell receptor, the initial strength of the T-cell receptor signal can be modulated by varying the number of peptide:MHC complexes on the dendritic cells, or by varying the affinity with which the T cell-receptor binds to the peptide:MHC complexes. As a result, T cells stimulated with stronger T-cell receptor signals will maintain high expression of CD69 for one or two days longer that if those same T cells were stimulated with weaker T-cell receptor signals. Therefore, T cells stimulated with weaker T-cell receptor signals are likely to: Die by apoptosis Undergo more rounds of proliferation that T cells stimulated with stronger T-cell receptor signals Migrate to the B-cell zones of the lymph node Have reduced effector functions, such as cytokine production Egress from the lymph node 1–2 days earlier than T cells…

Which proteins involved in the activation of T cells have the capacity for transduction without the need to be activated by a family of kinases?