Home

New Role for the CIgW Website

The CIgW was established to provide investigators with information on the repertoire and nomenclature of Igs in species of interest to veterinary and comparative immunology. Of equal importance is information on the availability of reagents for measuring Ig levels and specific antibody responses. Commercial suppliers list polyclonal antibodies for the major isotypes in the most frequently-studied species e.g. cattle and swine. For applications like ELISA and Western blotting these are generally adequate and in some cases preferred. The difficulties that arise when using polyclonal reagents concern the subisotypes and when antibodies are needed for flow cytometry and immunochemistry. In these applications mAbs are needed to reduce ambiguity caused by non-specific binding.  To better serve investigators, the CIgW Website starting in 2009 will begin to offer information on available mAb to species Igs of the most frequently studied vertebrates (other than those to mouse, human or other lab animals). This will include: (a) listings of available mAbs for each major species (b) the source of these mAbs and (c) results of specificity tests as they become available.

Monoclonal antibodies available from the USDA Center for Veterinary Biologics (CVB)

A Toolkit grant from the National Porkboard is making it possible to supply investigators with regents for veterinary immunology. The program was initiated by offering two anti-porcine Ig monoclonal antibodies (mAbs).  Monoclonal antibodies M160 (anti-porcine IgM) and M1458 (anti-porcine IgA) have been successfully used for a decade in a variety of porcine immunoassays and these are now available for non-commercial use by investigators. The reagents are produced and managed by the USDA Center for Veterinary Biologics (CVB) and can be ordered from the National Veterinary Services Laboratory  (NVSL) for the cost of shipment and processing. A maximum of four 2 ml vials can be order at one time. The two mAbs currently available can be used in ELISAs at a 1:4000 to 1:6000 dilution so one 2 ml vial is enough for 400 microtiter plates. The shipment cost per order form is $50 for a domestic USA request and $200 US for an international request. Instructions for using the order forms can be found on the following website: <http:/www.aphis.usda.gov/vs/nvsl/reagentsorderforminfo.html>. The attached pdf file contains a sample of the order form.

The Emergence of Large Animal Models

Compared to mainstream immunology, research on veterinary species has been “at the poverty level”. However, when a certain species is shown to be a better model for human disease than a mouse, the opportunity for veterinary immunology to rise above the poverty level increases. 2007-2009 was witness to several developments that can indirectly benefit veterinary immunology. One example was the generation of the CFTR knockout pig. Realizing that disrupting the CFTR gene in mice (the gene associated with cystic fibrosis in humans) did not result in CF, researchers turned to the pig. CFTR knockout pigs develop many of the same major symptoms of CF as is known from young children. (Roger et al  Science 321:1837; 2008). These animals are now under study at the University of Iowa supported by an NIH Program Project Grant.

A spin-off of this project is Exemplar Genetics which is a new Iowa-based biotechnology company focused on developing porcine models of human disease. They are combining gene targeting and somatic nuclear transfer (cloning) to generate knockout, knockin and transgenic pigs. Together with academia, industry, and disease-focused foundations, Exemplar Genetics is pursuing other disease models where existing models fail to accurately reflect the human disease. Exemplar Genetics maintains a herd of Yucatan miniature swine that are commonly used in the biomedical research market. Therefore, they can generate new models in either domestic or miniature pig breeds. Also, Exemplar Genetics has the ability to reproduce pigs by cloning, allowing for replication of certain genetic traits and decrease variability among animals. In addition to producing models of disease, Exemplar Genetics also has extensive animal research infrastructure. Biosecure housing and research facilities are located near both Iowa City and Sioux Center in Iowa and near Flandreau, South Dakota. More information can be found at http://www.ewxemplargenetics.com or at 712-722-2767.

Another example of a large animal model for medical immunology is the neonatal lamb model of respiratory syncytial virus infection. Respiratory syncytial virus (RSV) is a prominent viral pathogen whose tropism for the lower respiratory tract causes severe bronchiolitis and pneumonia. Infants and young children are most susceptible to the virus and reinfections are common due to an ineffective immune response to the virus. Disease is most severe in premature infants (< 35 weeks) and in infants with underlying pulmonary disease, congenital heart disease or immunodeficiencies. A collaboration involving Randy Sacco of the National Animal Disease Center, Mark Ackermann of Iowa State University and Kim Brogden of the University of Iowa employs an NIH-funded lamb model of RSV infection that includes Caesarean-derived premature lambs or neonatal lambs less than 7 days of age. As in humans, disease is more severe in premature lambs and neonates compared to older animals.  Moreover, RSV-infected lambs exhibit many of the pathologic features of RSV infection in human infants. Gross lesions consist of multifocal atelectasis and consolidation with hyperinflation. Histologically, there are multifocal areas of brochointerstitial consolidation with mononuclear infiltrates and congestion in alveolar septa. Intralesional bronchioles are characterized by epithelial sloughing, necrosis, and hyperplasia with neutrophilic infiltrates (Meyerholz et al. Microbes Infect 6:1312; 2004). The progression of RSV disease is associated with a type II cytokine response (Fach et al., Viral Immunol 20:119-130; 2007) and this type of cytokine response after RSV infection predisposes children to future pulmonary problems. Advantages of the lamb model compared to the mouse model of RSV for studies of immunopathogenesis are that: (a) RSV naturally infects lambs (b) the mouse model lacks many of the pathologic features of RSV infection in human infants, (c) adult BALB/c mice are more susceptible than neonatal mice, (d) studies of premature mice are relatively more difficult and (e) mice lack bona fide IL-8, a CXC chemokine, whose expression is correlated with severe RSV infection.

Veterinary species like rabbits, goats, sheep and chickens have long been used to produce polyclonal antibody reagents for medical research and diagnostic immunoassays. However this application of veterinary species did little to advance our understanding of the immune system of these species, with exception of the rabbit. Furthermore, federal grants are traditionally not awarded for reagent preparation. The first use of a veterinary species to produce a therapeutic product for human medicine that sequestered medical research funding was use of transgenic sheep. However these therapeutic products involved primarily endocrinology not immunology.  A change occurred in 2000 when cattle were selected as the species for transgenic studies designed to produce humanized antibodies for therapy.  While this work continues (Kuroiwa et al 2009) the B cell knockout pig has also been developed ultimately for a similar purpose (Mendicino et al 2009). Even before these pigs are made transgenic for human antibody production, they are potentially valuable in their own right in veterinary research for determining whether protective immunity to certain viruses is primarily B- or T cells dependent.

If in the future additional large animal models replace the mouse or large animals transgenic for features of the immune system are developed that benefits human medicine, it can be a means to infuse more research dollars into veterinary immunology which has downstream implications in both educational and research programs. The emergence of these “non-traditional” animal models has stimulated interest within the Howard Hughes supported center at the University of Iowa which has now organized a forum in which the use on non-mouse model of human disease is being discussed.