Question

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.

Answer 1

The clonal selection theory proposed by Frank Burnet suggests that individuals have multiple types of T cell clones based on their receptors. During an immune response, specific clones are selected and undergo clonal expansion.

Step-by-step explanation:

The clonal selection theory, first proposed by Frank Burnet in the 1950s, posits that individuals have a multitude of different types of T cell clones based on their receptors. Each clone is present in low numbers and shares the same antigen receptor. The theory suggests that during an immune response, certain clones are selected and undergo clonal expansion, leading to a larger population of specific lymphocytes.