Humoral immune responses in loggerhead (Caretta caretta ) and Kemp's ridley (Lepidochelys kempii) sea turtles.

摘要

Sea turtles are a unique group of marine organisms that live in tropical and temperate waters across the globe. They are one of just a few groups of marine reptiles that currently inhabit oceanic environments, and therefore fill an important and distinct role in marine ecosystems. Though much research has been conducted on sea turtle nesting and ecology, comparatively little research has been done on sea turtle immunology, especially in turtles other than green sea turtles (Chelonia mydas). Using a simple technique, immunoglobulin Y (IgY), which is found in reptiles, birds, and amphibians, was purified. Using standard techniques, polyclonal antisera and monoclonal antibodies were made against two forms of IgY (known as IgY and IgY(DeltaFc)) for both loggerhead (Caretta caretta) and Kemp's ridley (Lepidochelys kempii) sea turtles. Following antibody production, serum samples from 60 loggerhead and 30 Kemp's ridley individual turtles were examined to look for antibodies specific to 9 marine bacterial species (Escherichia coli, Vibrio cholera, V. parahaemolyticus, V. anguillarum, V. vulnificus, Mycobacterium marinum, Erysipelothrix rhusiopathiae, Streptococcus agalactiae, and Brevundimonas vesicularis). It was found that serum titer levels against these bacteria can vary significantly in regards to factors such as gender and year of serum collection. In addition, some correlations were found between total serum protein levels and serum titers against bacteria, and between straight carapace length and serum titers against bacteria. Measurements taken from these individual turtles (packed cell volume, glucose, and total protein) are similar to measurements seen in other wild, healthy turtles of the same species. This indicates that the bacterial data is not reflective of special or unusual circumstances (such as disease or injury), but is what can be expected from healthy, wild turtles from these populations. This is the first study of its kind to examine serum titers against marine bacteria, and therefore offers clues to the species of bacteria that sea turtles may be exposed to in their natural environments. Moreover, this study lends insight into the nature and function of the truncated form of IgY, known as IgY(DeltaDeltaFc).