Further assessment of the binding properties of proteins A, G, and chimeric protein AG to immunoglobulins of multiple host species of marine mammals.

Detection of infectious diseases in marine mammals is crucial to reduce the risk of transmission of zoonotic pathogens to humans. Although serodiagnostic tests such as enzyme-linked immunosorbent assay (ELISA) can detect antibodies against such pathogens, commercial secondary antibodies specific to marine mammal species are limited. Proteins A and AG have been previously found to react strongly to the immunoglobulins of pinnipeds and cetaceans. However, the binding properties of immunoglobulins of other marine mammals remain unclear to these proteins. Using ELISA, this study further assessed the binding properties of proteins A, G, and AG in detecting immunoglobulins in marine mammals such as marine fissipeds and sirenians (grouped together ecologically but not taxonomically). Sera/plasmas from two marine fissipeds (polar bears and sea otters), one sirenian (manatees), one pinniped (grey seals), and four cetaceans (Commerson's dolphins, false killer whales, finless porpoises, and pantropical spotted dolphins) were collected. The results revealed that the immunoglobulins of these marine mammals bound more strongly to proteins A and AG than to protein G, indicating a strong signal intensity in ELISA and a strong antibody-protein complex reaction. This study thus suggests that proteins A and AG can be used as secondary antibodies to detect immunoglobulins against infectious agents in multiple host species of marine mammals in serodiagnostic tests, thereby preventing the transmission of infectious agents from marine mammals to humans.