Tracing the Evolution of Adaptive Immunity

Air date: Wednesday, February 04, 2015, 3:00:00 PM

Category: WALS - Wednesday Afternoon Lectures

Runtime: 00:55:45

Description: NIH Director's Wednesday Afternoon Lecture

A search for the origin of our adaptive immune system has revealed that the jawed vertebrates and jawless vertebrates (lampreys and hagfish) use different strategies for generating large repertoires of lymphocyte receptors for antigens. Whereas lymphocytes in jawed vertebrates undergo RAG-mediated recombinatorial assembly of immunoglobulin V, D, and J gene segments to generate diverse T-cell receptor (TCR) and B-cell receptor (BCR) repertoires, lymphocytes in jawless vertebrates employ leucine-rich repeat (LRR) gene segments as templates to complete the assembly of variable lymphocyte receptor (VLR) genes. Three VLR loci (VLRA, VLRB and VLRC) undergo independent assembly during the differentiation of three distinct lymphocyte lineages. The VLRA-bearing and VLRC-bearing lymphocytes have genetic programs and phenotypic characteristics that resemble those of certain T cells of jawed vertebrates, whereas the VLRB-bearing cells resemble B cells. Dr. Cooper’s lab concludes that the basic genetic programs for the T- and B-cell lineages were already present in a common vertebrate ancestor more than 500 million years ago, prior to the convergent evolution of different types of anticipatory receptors.

Author: Max D. Cooper, M.D., Eminent Scholar, Georgia Research Alliance; Professor, Department of Pathology and Laboratory Medicine, Emory University School of Medicine

Permanent link: http://videocast.nih.gov/launch.asp?18835