12-Cell Mediated Effector Responses Chpt. 14 2023 (5)

What is the primary function of cell-mediated immune responses?

They are effective against virus-infected cells, tumor cells, grafted tissues, fungi, intracellular parasites, and some intracellular bacteria.

What are the two main types of T cells in the cell-mediated immune response?

CD4+ T helper cells and CD8+ cytotoxic T cells.

CD45RA is expressed on which type of T cells?

Naïve T cells.

CD45RO enhances the signaling of which two types of receptors?

T cell receptor (TCR) and B cell receptor.

What key cytokine do activated helper T cells secrete to stimulate cytotoxic T cells?

Interleukin 2 (IL-2).

What are the two major pathways CTLs use to kill target cells?

Perforin/granzyme pathways and Fas/FasL pathways.

How do natural killer (NK) cells recognize infected cells?

By the absence of MHC class I on the target cells.

What are the distinguishing features between naïve and effector T cells?

Naïve T cells require co-stimulation for activation, while effectors have higher expression of adhesion molecules and can be activated with minimal co-stimulation.

What role do dendritic cells play in T cell activation?

They present antigens on MHC molecules and provide co-stimulation necessary for T cell activation.

What is the main function of NKT cells in the immune system?

They bridge innate and adaptive immune systems, recognizing glycolipids and can act as helper or killer cells.