BIOINFORMATICS ANALYSES OF B-CELL REPERTOIRE EXPRESSION IN THE GRAY SHORT-TAILED OPOSSUM (MONODELPHIS DOMESTICA)
Andrea Schraven, Western Sydney University
Andrea L. Schraven1, Robert D. Miller2, Hayley J. Stannard3,4, Oselyne T.W. Ong5, Victoria L. Hansen2, Kimberly A. Morrissey2, Julie M. Old1
1School of Science and Health, Western Sydney University, Penrith, New South Wales, Australia
2Center for Evolutionary and Theoretical Immunology, Department of Biology, University of New Mexico Albuquerque, New Mexico, USA
3School of Life and Environmental Sciences, and Charles Perkins Centre, The University of Sydney, Sydney, New South Wales, Australia.
4Charles Sturt University, School of Animal and Veterinary Sciences, Wagga Wagga, New South Wales, Australia
5QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
B-cells are key to humoral immunity, are found in multiple lymphoid organs, and have the unique ability to mediate the production of antigen-specific antibodies in the presence of pathogens. Marsupial B-cell investigations have become increasingly important in understanding an adaptive immune system that develops primarily postnatally. In comparison to eutherians and monotremes, marsupial B-cells have four Immunoglobulin (Ig) heavy (H) chain isotypes (IgA, IgG, IGM and IgE), defined by their constant regions (Cα, Cγ, Cμ and Cε respectively), and two light (L) chain isotypes; lambda (λ) and kappa (κ). Preliminary bioinformatics of single cell RNA sequencing results indicated a high diversity of repertoire expression between the spleen and peripheral blood of the Gray short-tailed opossum (Monodelphis domestica). High expression levels of IgM were consistently observed in both tissues; IgG were expressed more so in the spleen whereas IgA had a higher expression in the peripheral blood. Analysis of the B-cell light chain revealed a Igλ to Igκ ratio of 2:1 in both tissues. Annotation of the gene segments show Igλ and Igκ have highly diverse variable (V) gene families suggesting a higher rate of complexity than the IgH loci and therefore has a greater contribution to the overall antibody repertoire.