Article

Robert, J. & Ohta, Y. Comparative and developmental study of the immune system in Xenopus. Dev. Dyn. 238, 1249-1270

Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York, USA.
Developmental Dynamics (Impact Factor: 2.67). 06/2009; 238(6):1249-70. DOI: 10.1002/dvdy.21891
Source: PubMed

ABSTRACT Xenopus laevis is the model of choice for evolutionary, comparative, and developmental studies of immunity, and invaluable research tools including MHC-defined clones, inbred strains, cell lines, and monoclonal antibodies are available for these studies. Recent efforts to use Silurana (Xenopus) tropicalis for genetic analyses have led to the sequencing of the whole genome. Ongoing genome mapping and mutagenesis studies will provide a new dimension to the study of immunity. Here we review what is known about the immune system of X. laevis integrated with available genomic information from S. tropicalis. This review provides compelling evidence for the high degree of similarity and evolutionary conservation between Xenopus and mammalian immune systems. We propose to build a powerful and innovative comparative biomedical model based on modern genetic technologies that takes take advantage of X. laevis and S. tropicalis, as well as the whole Xenopus genus. Developmental Dynamics 238:1249-1270, 2009. (c) 2009 Wiley-Liss, Inc.

Download full-text

Full-text

Available from: Jacques Robert, Aug 28, 2015
0 Followers
 · 
114 Views
  • Source
    • "Xenopus has been and still is one of the top model systems for the study of fundamental questions related to development, immunology, toxicology, neurobiology, embryology and regenerative biology (Du Pasquier et al., 1989; Khokha, 2012; Robert and Ohta, 2009). More recently Xenopus has also been increasingly used as a model for understanding tumor biology, transplantation biology, self tolerance and autoimmunity [reviewed in (Edholm and Robert, 2013). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Tumors have the ability to grow as a self-sustaining entity within the body. This autonomy is in part accomplished by the tumor cells ability to induce the formation of new blood vessels (angiogenesis) and by controlling cell trafficking inside the tumor mass. These abilities greatly reduce the efficacy of many cancer therapies and pose challenges for the development of more effective cancer treatments. Hence, there is a need for animal models suitable for direct microscopy observation of blood vessel formation and cell trafficking, especially during early stages of tumor establishment. Here, we have developed a reliable and cost effective tumor model system in tadpoles of the amphibian Xenopus laevis. Tadpoles are ideally suited for direct microscopy observation because of their small size and transparency. Using the thymic lymphoid tumor line 15/0 derived from, and transplantable into, the X. laevis/gilli isogenic clone LG-15, we have adapted a system that consists in transplanting 15/0 tumor cells embedded into rat collagen under the dorsal skin of LG-15 tadpole recipients. This system recapitulates many facets of mammalian tumorigenesis and permits real time visualization of the active formation of the tumor microenvironment induced by 15/0 tumor cells including neovascularization, collagen rearrangements as well as infiltration of immune cells and melanophores.
    Developmental Biology 01/2015; DOI:10.1016/j.ydbio.2015.01.003 · 3.64 Impact Factor
    • "Although wood frogs usually begin reproduction at 2 years of age (Duellman & Trueb, 1994) and our experimental subjects were only 1 year old, most were sexually mature (oogenesis or spermatogenesis evident histologically in 19/20 frogs examined) and thus representative of the anatomy and immunophysiology of adult individuals. Our findings can probably also apply to postmetamorphic juveniles as immune system maturation occurs at metamorphosis or soon afterwards (Robert & Ohta, 2009). Extrapolations to other experimental or to natural infections should be made cautiously if environmental conditions are different from those reported here since habitat characteristics, particularly temperature, are known to influence the immune function of amphibians "
    [Show abstract] [Hide abstract]
    ABSTRACT: Amphibian populations suffer massive mortalities from infection with Frog virus 3 (FV3, Ranavirus, Iridoviridae), a pathogen also involved in mortalities of fish and reptiles. Experimental oral infection with FV3 in captive-raised adult wood frogs, Rana sylvatica [Lithobates sylvaticus], was performed as the first step in establishing a native North American animal model of ranaviral disease to study pathogenesis and host-response. Oral dosing was successful; LD50 was 10^2.93 (2.42-3.44) pfu for frogs averaging 35 mm in length. Onset of clinical signs occurred 6-14 days post-infection (dpi) (median 11 dpi) and time-to-death 10-14 dpi (median 12 dpi). Each ten-fold increase in virus dose increased the odds of dying by 23-fold and accelerated onset of clinical signs and death by approximately 15%. Ranavirus DNA was demonstrated in skin and liver of all frogs that died or were euthanized because of severe clinical signs. Shedding of virus occurred in feces (7-10 dpi; 3-4.5 d before death) and skin sheds (10 dpi; 0-1.5 d before death) of some frogs dead from infection. Most common lesions were dermal erosion and hemorrhages, hematopoietic necrosis in bone marrow, kidney, spleen and liver, necrosis in renal glomeruli and in tongue, gastrointestinal tract, and urinary bladder mucosa. Presence of ranavirus in lesions was confirmed by immunohistochemistry. Intracytoplasmic inclusion bodies (probably viral) were present in the bone marrow and the epithelia of the oral cavity, gastrointestinal tract, renal tubules and urinary bladder. Our work describes a Ranavirus-wood frog model and provides estimates that can be incorporated into ranavirus disease ecology models.
    Journal of General Virology 01/2015; 96(Pt_5). DOI:10.1099/vir.0.000043 · 3.53 Impact Factor
  • Source
    • "Afterwards, as metamorphosis starts, lymphocyte function becomes severely impaired with a consequent downregulation of the adaptive immune response. Finally, adult frogs show efficient immune response and antigen recognition (Robert and Ohta, 2009). Although the adaptive immune response has been thoroughly characterized during Xenopus development , the immune and inflammatory responses after injury have not been well studied. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Unlike mammals, regenerative model organisms such as amphibians and fish are capable of spinal cord regeneration after injury. Certain key differences between regenerative and non-regenerative organisms have been suggested as involved in promoting this process, such as the capacity for neurogenesis and axonal regeneration, which appear to be facilitated by a favorable astroglial, inflammatory and immune response. These traits provide a regenerative-permissive environment that the mammalian spinal cord appears to be lacking. Evidence for the regenerative non-permissive environment in mammals is given by the fact that they possess neural stem/progenitor cells, which transplanted into permissive environments are able to give rise to new neurons, whereas in the non-permissive spinal cord they are unable to do so. We discuss the traits that are favorable for regeneration, comparing what happens in mammals with each regenerative organism, aiming to describe and identify the key differences that allow regeneration. This comparison should lead us towards finding how to promote regeneration in organisms that are unable to do so. © 2013 Wiley Periodicals, Inc.
    genesis 08/2013; 51(8). DOI:10.1002/dvg.22406 · 2.04 Impact Factor
Show more