Editing Tasuku Honjo (section)

== Major Scientific Contributions ==

=== Immunological Research ===
Honjo's research has made fundamental contributions to immunology, particularly in understanding the mechanisms of immune regulation and antibody diversity. His major scientific achievements include:

# '''PD-1 Discovery''': In 1992, Honjo identified Programmed Cell Death Protein 1 (PD-1), a breakthrough that laid the foundation for modern cancer immunotherapy. This discovery was instrumental in developing PD-1 blockade-based cancer treatments.
# '''Cytokine Research''': He successfully conducted molecular identification of several crucial cytokines:
#* Interleukin-4 (IL-4)
#* Interleukin-5 (IL-5)
#* Interleukin-2 receptor alpha chain
# '''Antibody Diversification''': Honjo established the basic conceptual framework of class switch recombination and discovered Activation-Induced Cytidine Deaminase (AID), which plays a vital role in:
#* Class switch recombination
#* Somatic hypermutation

=== Class Switch Recombination Model ===
Between 1980 and 1982, Honjo developed and verified a model explaining antibody gene rearrangement in class switch by elucidating its DNA structure. This work significantly advanced our understanding of immune system mechanisms.