The
B-cell activating factor (BAFF) is a member of tumour
necrosis factor (TNF) superfamily that specifically regulates B lymphocyte proliferation and survival. Excess BAFF leads to overproduction of
antibodies for secretion,
anti-dsDNA antibodies and a lupus-like syndrome in mice. To investigate whether transgenic overexpression of the zebrafish BAFF leads to
immunoglobulin changes and/or early maturing of the immune system, a Tol2-GFP-2A-BAFF/His recombinant plasmid was constructed by inserting a 2A
peptide between the
green fluorescent protein (GFP) and BAFF sequences. Functional GFP and BAFF
proteins were expressed separately and confirmed in HeLa cells. The relative expression of immune-related genes (IgLC-1, IgLC-2, IgLC-3,
IgD,
IgM and IL-4), early lymphoid markers (Ikaros, Rag-1 and TCRAC), and the protooncogene Bcl-2 were evaluated by quantitative polymerase chain reaction (PCR) in F0 founder of transgenic zebrafish juveniles and adults. Ectopic expression of BAFF in adults was confirmed using Western blots and was shown to upregulate IgLC-1, IgLC-2,
IgD,
IgM, IgZ/T, Ikaros, Rag-1, TCRAC,
IL-4 and Bcl-2 expression in juveniles on day 21 and IgLC-1, IgLC-2,
IgD,
IgM,IgZ/T, Rag-1, TCRAC and Bcl-2 expression in zebrafish three months postfertilization. The relative titers of specific
IgM against Edwardsiella tarda WED were assessed using modified
enzyme-linked
immunosorbent assay (ELISA) with the whole body homogenate of zebrafish and demonstrated a significant increase in BAFF-transgenic group. Therefore, our findings provided novel insight into further exploration of modulating adaptive immunity and studying
autoimmune diseases caused by regulating BAFF.