The clonal selection theory was first proposed in the 1950s, decades before the molecular details of B and T lymphocyte development and lymphocyte antigen recognition responses were elucidated. Nonetheless, Burnet, who proposed this theory, correctly inferred several key aspects of adaptive immune responses. One key postulate that Burnet proposed was that:
A) Cells of the innate immune system are distinct from those of the adaptive immune system.
B) Cells of the adaptive immune system are generated from a pluripotent hematopoietic stem cell that resides in the bone marrow.
C) B and T lymphocytes are closely related cells that have distinct properties from myeloid cells.
D) Circulating antibodies are generated by many different antibody-secreting cells, each of which expresses a single type of antibody on its surface as a receptor.
E) Antibodies binding to pathogens lead to efficient pathogen clearance by phagocytic cells.

Question

Quizplus · Accepted Answer

Burnet's clonal selection theory primarily posits that each lymphocyte bears a single type of receptor with a unique specificity and that the binding of a foreign molecule to this receptor selects that lymphocyte for clonal expansion. This concept underlies the generation of specific antibodies by plasma cells, which are derived from B cells that have been activated by their specific antigen.

The Clonal Selection Theory Was First Proposed in the 1950s