THE FLORIDA MANATEE (TRICHECHUS MANATUS LATIROSTRIS) IMMUNOGLOBULIN HEAVY CHAIN SUGGESTS THE IMPORTANCE OF CLAN III VARIABLE SEGMENTS IN REPERTOIRE DIVERSITY

14 Jun 2017
10:15 - 10:30

THE FLORIDA MANATEE (TRICHECHUS MANATUS LATIROSTRIS) IMMUNOGLOBULIN HEAVY CHAIN SUGGESTS THE IMPORTANCE OF CLAN III VARIABLE SEGMENTS IN REPERTOIRE DIVERSITY

Breanna Breaux, Texas A&M

Authors: Breanna Breaux1, Thaddeus C. Deiss1, Patricia L. Chen1, Maria Paula Cruz- Schneider2, Leonardo Sena3, Margaret E. Hunter4, Robert K. Bonde4, Michael F. Criscitiello1,5

1. Department of Veterinary Pathobiology, Texas A&M University, College Station, TX;
2. Laboratory of DNA Polymorphism, Federal University of Pará, Belém, Pará Brazil;
3. Laboratory of Medical and Human Genetics, Federal University of Pará, Belém, Pará Brazil;
4. Wetland and Aquatic Research Center, U.S. Geological Survey, Gainesville, FL 32653 USA;
5. Department of Microbial Pathogenesis and Immunology, Texas A&M Health Science Center, College Station, TX

Manatees are a vulnerable, charismatic sentinel species from the evolutionarily divergent Afrotheria. Manatee health and resistance to infectious disease is of great concern to conservation groups, but little is known about their immune system. To develop manatee-specific tools for monitoring health, we first must have a general knowledge of how the immunoglobulin heavy (IgH) chain locus is organized and transcriptionally expressed. Using the genomic scaffolds of the Florida manatee (Trichechus manatus latirostris), we characterized the potential IgH segmental diversity and constant region isotypic diversity. We then used 5’ RACE PCR on peripheral blood leukocytes to perform the first Afrotherian repertoire analysis. The Florida manatee has low V(D)J combinatorial diversity (3744 potential combinations) and few constant region isotypes. They also lack clan III V segments, which may have caused reduced VH segment numbers. However, we found productive somatic hypermutation concentrated in the complementarity determining regions. In conclusion, manatees have limited IGHV clan and combinatorial diversity. This suggests that clan III V segments are essential for maintaining IgH locus diversity.