T Cell Activation Notes

Exogenous vs. Endogenous Antigens & MHC Molecules

• Exogenous Antigens:

  • Associated with MHC class II molecules.
  • Recognized by CD4 T cells.
  • Require professional antigen-presenting cells (APCs).

• Endogenous Antigens:

  • Associated with MHC class I molecules.
  • Recognized by CD8 T cells.

T Cell Activation Signals

• Full Activation:

  • Requires Signal 1 and Signal 2.

• Differentiation (CD4 T cells):

  • Requires Signal 3, which involves cytokines received during the activation process.
  • Cytokines released during differentiation shape the immune response.

Cytokines Role

• Cytokines are important in the context of T cell activation.

Exam Tips

• Use word association to remember key pathways.
• Diagrams or pictures can be used to illustrate points, alongside words, to effectively communicate understanding and differentiate between immune responses. Focus on key, top-line information in responses.