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A dot-blot assay with the specific monoclonal antibody entails preparation of a diluted
solution or suspension of a mixture of the life cycle form(s) of the lutjanid of interest. This is
“dotted” onto nitrocellulose paper and incubated first with the specific mouse monoclonal
antibody and second with a peroxidase-conjugated second antibody directed against the first
mouse antibody. The peroxidase activity is assayed with H,O, and 4-chloro-1 -naphthol color
development reagent. A positive reaction is visualized as a colored dot against the white
nitrocellulose paper, and a negative reaction is colorless. The protein-dotted filter may be stored
dry for several weeks without any loss of activity. Thus, specimens collected from many
different sites could be stored and screened at the same time. Positive reactions are confirmed
later in the laboratory on field- collected specimens using immunofluorescence in which the
primary antibody is conjugated with a fluorochrome such as fluorescein and the bound antibody
is visualized with a fluorescence microscope. A second procedure is to further test the diluted
solution or suspension in an ELISA (1). Sarver et al. (10) has used the polymerase chain
reaction to amplify portions of two mitochondrial genes to examine phylogenetic relationships of
species of the Family Lutjanidae, but the-relationships of some of the members are still unclear.
In summary, immunological methods were employed for two major research projects
currently under investigation in our laboratories: 1) predation of hatchery-reared, juvenile red
drum (S. ocellatus) following a program of reestablishing and enhancing the populations in
Biscayne Bay, Florida, and 2) specific species identification of early life history stages (eggs and
larvae) and the source of recruits of western Atlantic snappers (family Lutjanidae). After the
development of immunoassays for these studies, the specificity and sensitivity of the methods
have resulted in significant progress.
Immunological detection methods have also been valuable for many aspects of seafood
science. Recently, Huang et al (4) distinguished the commercially valued red snapper (L.
campechanus) from less valuable substitutes using ELISA with two monoclonal antibodies
raised to a red snapper protein. To ensure quality and safety of seafood products, immunology
offers powerful methods for these goals.
Acknowledgements. We are grateful to M.E. Clarke, Ph.D., who contributed to the initial
predator-prey studies of red drum.
References
1. Arnold, P-I., Serafy, J.E., Clarke, M-E., et al. 1995. An immunological study of
predation on hatchery-reared, juvenile red drum (Sciaenops ocellatus, Linnaeus):
description of an ELISA, and predator-prey studies in nature. J. Exp. Marine Biol. Ecol.,
in press.