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Evolution of Adaptive Immunity: ‘Double-duty’ Dendritic Cells in Cold-blooded Vertebrates

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Air date: Wednesday, June 29, 2016, 4:15:00 PM
Time displayed is Eastern Time, Washington DC Local
Views: Total views: 272 (4 Live, 268 On-demand)
Category: Immunology
Runtime: 01:13:03
Description: Immunology Interest Group

Martin Flajnik earned his Ph.D. at the University of Rochester (NY) under Nicholas Cohen (of comparative- and psychoneuro-immunology fame) and then did his postdoc at the Basel Institute for Immunology under the noted amphibian immunologist Louis Du Pasquier. Flajnik’s first faculty position was at the University of Miami (1988-’98) and he has toiled at The University of Maryland Baltimore ever since. His research has always centered on the evolution of adaptive immunity in the vertebrates and have included studies of: thymic education; MHC biochemistry and genetics; emergence and function of immunoglobulin (Ig) heavy and light chain isotypes; hypermutation of Ig and TCR genes; gamma/delta TCR structure and function; emergence of costimulatory molecules; the advent of lymphoid tissues and their function in selection; mucosal immunity; and single-variable domain antibodies.

The adaptive immune system arose 500 million years ago in ectothermic vertebrates, which include the extant jawless fish (lamprey and hagfish), cartilaginous fish, bony fish, and amphibians (and most reptiles). The definition of canonical adaptive immunity classically has been the RAG-dependent rearranging antigen receptors immunoglobulins (Ig) and T cell receptors (TCR), and the major histocompatibility complex MHC. These molecules/mechanisms are all present in gnathostomes. However, with the discovery of an adaptive immune system in jawless fish based on an entirely different set of antigen receptors (the variable lymphocyte receptors or VLR), the divergence of T cells and B cells goes back even further, to the origins of the jawed and jawless vertebrates; thus, the transcriptional networks governing lymphocyte differentiation are primordial. Certain immune subfeatures, such as the presence of IgM, conventional TCR, thymus, spleen, and MHC, are present in almost all gnathostomes, while other characteristics like IgD and gamma/delta TCR are quite plastic. In this seminar, Dr. Flajnik will focus on the evolution of gamma/delta T cells, where non-mammalian vertebrates have provided evidence for adaptive functions as well as interesting protein structures. The last major advance in vertebrate evolution is the advent of lymph nodes and formation of germinal centers in mammals; the ectothermic vertebrates allow a study of immunity that preceded the emergence of follicular dendritic cells, the major cellular player in mammalian affinity maturation. He will also discuss work in amphibians suggesting that antigen presenting cells have a dual nature, presenting antigen to both B cells and T cells.
NLM Title: Evolution of adaptive immunity : "double-duty" dendritic cells in cold-blooded vertebrates / Martin F. Flajnik ; Immunology Interest Group.
Author: Flajnik, M F.
National Institutes of Health (U.S.). Immunology Interest Group,
Publisher:
Abstract: (CIT): Immunology Interest Group. Martin Flajnik earned his Ph.D. at the University of Rochester (NY) under Nicholas Cohen (of comparative- and psychoneuro-immunology fame) and then did his postdoc at the Basel Institute for Immunology under the noted amphibian immunologist Louis Du Pasquier. Flajnik's first faculty position was at the University of Miami (1988-"98) and he has toiled at The University of Maryland Baltimore ever since. His research has always centered on the evolution of adaptive immunity in the vertebrates and have included studies of: thymic education; MHC biochemistry and genetics; emergence and function of immunoglobulin (Ig) heavy and light chain isotypes; hypermutation of Ig and TCR genes; gamma/delta TCR structure and function; emergence of costimulatory molecules; the advent of lymphoid tissues and their function in selection; mucosal immunity; and single-variable domain antibodies. The adaptive immune system arose 500 million years ago in ectothermic vertebrates, which include the extant jawless fish (lamprey and hagfish), cartilaginous fish, bony fish, and amphibians (and most reptiles). The definition of canonical adaptive immunity classically has been the RAG-dependent rearranging antigen receptors immunoglobulins (Ig) and T cell receptors (TCR), and the major histocompatibility complex MHC. These molecules/mechanisms are all present in gnathostomes. However, with the discovery of an adaptive immune system in jawless fish based on an entirely different set of antigen receptors (the variable lymphocyte receptors or VLR), the divergence of T cells and B cells goes back even further, to the origins of the jawed and jawless vertebrates; thus, the transcriptional networks governing lymphocyte differentiation are primordial. Certain immune subfeatures, such as the presence of IgM, conventional TCR, thymus, spleen, and MHC, are present in almost all gnathostomes, while other characteristics like IgD and gamma/delta TCR are quite plastic. In this seminar, Dr. Flajnik will focus on the evolution of gamma/delta T cells, where non-mammalian vertebrates have provided evidence for adaptive functions as well as interesting protein structures. The last major advance in vertebrate evolution is the advent of lymph nodes and formation of germinal centers in mammals; the ectothermic vertebrates allow a study of immunity that preceded the emergence of follicular dendritic cells, the major cellular player in mammalian affinity maturation. He will also discuss work in amphibians suggesting that antigen presenting cells have a dual nature, presenting antigen to both B cells and T cells.
Subjects: Adaptive Immunity
B-Lymphocytes--immunology
Biological Evolution
Dendritic Cells--immunology
T-Lymphocytes--immunology
Publication Types: Lecture
Webcast
 
NLM Classification: QW 551
NLM ID: 101690002
CIT Live ID: 19377
Permanent link: https://videocast.nih.gov/watch=19377