Immunity amphibians

Gantress J, Maniero GD, Cohen N, Robert J. Development and characterization of a model system to study amphibian immune responses to iridoviruses. Virology. 2003 311 254-62. 

Amphibians. Amphibians are highly susceptible to endocrine disruption during development of the larval form and during metamorphosis. The action of metamorphosis is triggered and controlled by the thyroid gland via an increase in triiodothyronine and a decrease in thyroxine, and differs greatly between oviparous and viviparous species. Experimentally, it has been shown that disruption during this sensitive period can lead to malformations and adverse impacts on immune and reproductive functions. 

Amphibians. Immunosuppression has been shown to occur during metamorphosis in several amphibians, and appears to be hormonally regulated. The disappearance of 11 populations of toad from Colorado was associated with immune suppression, and frog mortalities have been associated with infection by a commonly occurring bacteria, Aeromonas hydrophila the cause of the immunosuppression in these animals has not been elucidated. " ... 

In addition to these well-characterized adaptive immune defenses, amphibians have an array of innate immune defenses. These include complement-mediated defenses [13], Natural Killer cells (NK) [14], phagocytic cells [15], and antimicrobial peptides secreted into the gut and skin mucosa [16, 17],... 

Rollins-Smith, L.A. Neuroendocrine-immune system interactions in amphibians. Implications for understanding global amphibian declines. Immunologic Res., 2312 3, 273, 2001. 

Over the next few decades, researchers learned that melatonin had many other effects in addition to influencing pigmentation in amphibians. Most current research has studied its influence on promoting sleep. Other studies have linked this hormone to other processes such as reducing jet lag, boosting the immune system, and fighting cancer. 

Three isotypes, IgM, IgD and IgT (also called IgZ in zebrafish) have been identified in almost all studied species belonging to the main orders of teleost fish. The main exception is that IgT has not been found thus far in the channel catfish (I. punctatus) (Edholm et al, 2010,2011). IgM is the most ancient and the only isotype functionally conserved in all jawed vertebrates. IgD has been found in all jawed vertebrate groups except birds, indicating that it is also a primordial antibody class despite its highly plastic structure and unclear function in evolution (Edholm et al, 2010, 2011). Other Ig isotypes have evolved to play specialized roles either within mucosal or systemic compartments. In mammals and birds, the IgM, IgG and IgY isotypes have major roles in systemic responses, while IgA is the main player in mucosal areas. In amphibians, IgM and IgY play a prevalent role in systemic immunity whereas IgX is an isotype chiefly expressed in the gut (Flajnik, 2010). The fish IgT is a mucosal-epithelial Ig preferentially... 

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