Overview

Studies of the immune system in elasmobranchs have been conducted on the Atlantic sharp-nosed ray, the cownose ray, catsharks, dogfish, and the nurse shark. Many of these animals have been used primarily as laboratory models for research into the evolution of the human immune system. Elasmobranchs are one of the earliest groups of vertebrates to exhibit a fully functional innate and adaptive immune system comparable to those found in mammals. Both innate and adaptive components of the shark immune system have now been described in the literature in detail and many of the pathways for immune reactivity are well known. However, much of this information has been derived from only a few species–primarily smaller, benthic species because of the ease with which they are kept in captivity or worked with in a lab. Little is known about larger coastal or pelagic shark species in terms of their immune system and immune reactivity. Some evidence suggests that there is a high degree of variation in the immune systems of different shark species, which is not surprising given the long evolutionary timelines between divergences among various shark lineages.

One of the challenges for studying the immune system of sharks is the ability to collect tissue samples and conduct field immune assessment. Current monitoring programs that include tagging studies present an opportunity to investigate immune status and gain further understanding of the immune system of wild sharks. An important consideration is whether we can use immune status to evaluate the well-being of wild sharks under various stresses, in diverse habitats, or at different levels of maturity. Several examples of this have popped up in the literature where investigators have sought to measure well-being in sharks in polluted and non-polluted habitats by measuring an immunological parameter such as inflammation. However, such studies require baseline data for various immunological parameters. Once baseline information about immune reactivity for each species is established, a methodology can be developed to apply these immune assessments to current monitoring protocols and maximize information regarding wild shark immune status. The purpose of current research is to conduct preliminary immune assessments on wild sharks caught off the coast of South Florida as part of an on-going ecological study and use these data as a baseline to determine whether measures of immune status can be applied to global conservation efforts.