In comparison with the canine rabbit-anti-IgG antibody, the canine goat-anti IgG antibody caused significantly less pinkish background, which facilitated detection of faint bands (Figures 2A,B) and made the evaluation in general easier, which is reflected by the higher agreement between the examiners when evaluating the quantity of bands (as mentioned above)

In comparison with the canine rabbit-anti-IgG antibody, the canine goat-anti IgG antibody caused significantly less pinkish background, which facilitated detection of faint bands (Figures 2A,B) and made the evaluation in general easier, which is reflected by the higher agreement between the examiners when evaluating the quantity of bands (as mentioned above). rabbit-anti-IgG antibody (Jackson ImmunoResearch) vs. a canine goat-anti-IgG antibody (Bio-Rad). The method was performed according to the instructions of the commercial kit used. The canine goat-anti-IgG antibody showed a better performance than the canine rabbit-anti-IgG antibody. The availability of the technique of OCB detection in the dog paves the way for further studies, especially in the field of inflammatory diseases of the canine central nervous system, and comparison between specific human and canine diseases. Keywords: canine (doggie), cerebrospinal fluid (CSF), inflammation, immunoblot, isoelectric focusing (IEF) Introduction The analysis of cerebrospinal fluid (CSF) is an important diagnostic test for various neurological diseases in both human and veterinary patients. Besides the standard macroscopic, biochemical, and cytological analyses, the assessment of IgG oligoclonal bands (OCBs) is routinely performed in human medicine. B cells and plasma cells involved in an inflammatory process are responsible for the production of oligoclonal immunoglobulin within the CNS; the term oligoclonal means the immunoglobulin is derived from few antibody clones (1). OCBs that are present in CSF but not in the paired serum sample are representing a local humoral response in the CNS (2). They are found in various infectious, autoimmune, and inflammatory diseases in human medicine (1, 3), with multiple sclerosis (MS) being the disease with the highest incidence of OCBs. Although there is a lack of understanding of the precise role of OCBs in MS, their presence is tightly coupled with the disease: up to 95% of human MS patients show two or more OCBs exclusively in the CSF, which 1G244 are absent in the paired serum sample (2). OCB analysis is the most sensitive method for qualitative assessment of intrathecal IgG synthesis (4). Different methods for their analysis have been used and investigated; isoelectric focusing (IEF) on agarose gel followed by immunoblotting for IgG using paired CSF and serum samples is most widely used in clinical routine for the detection of OCBs (2, 5C7). Polyacrylamide gel electrophoresis and IEF combined with silver staining of proteins may be more sensitive, but is used less commonly in clinical routine since the method is usually more time-consuming, costly and dependent on elaborate expertise (1). According to the 2017 McDonald criteria for 1G244 the diagnosis of MS, the presence of CSF-specific OCB may substitute for the requirement for demonstration of dissemination of time in relapsing-remitting MS and is one of three additional criteria for the diagnosis of primary progressive MS (2, 6, 8, 9). In veterinary medicine, OCBs in CSF and serum so far have only been investigated in six German Shepherd dogs diagnosed with degenerative myelopathy using a altered IEF and immunofixation method (10). The purpose of the present study was to describe a altered method for OCB detection in dogs as well as to compare two different canine anti-IgG antibodies for detection of OCBs in CSF and serum samples of dogs. For this purpose, isoelectric focusing followed by immunoblotting used in human medicine was investigated in a clinical laboratory specialized in human CSF diagnostics. Materials and Methods The experimental procedures used in this study were approved by the Ethical Committee of the Veterinary Support, Cantone of Bern (BE121/2020). Inclusion of Dogs Dogs included in the study were presented for diagnostic purposes to the Small Animal Clinic, Division of Clinical Neurology, Vetsuisse Faculty Bern, as well as to the Neurology Department, Clinic of 1G244 Small Animal Medical procedures, Vetsuisse Faculty Zurich and CD38 were diagnosed with different neurological diseases [meningoencephalitis of unknown origin (MUO) = 8, idiopathic epilepsy (IE) = 2, intracranial neoplasia (IN) = 1, intervertebral disc herniation (IVDH) = 2, steroid-responsive meningitis-arteritis (SRMA) = 3, eosinophilic meningoencephalitis = 1], as well as three dogs that did not receive a final diagnosis. The medical records including signalment of all dogs were available. Moreover, all dogs included received a complete diagnostic work-up with physical and neurological examination, as well as CSF analysis. The further diagnostic work-up differed according to the suspected underlying disease and included one or more of the following examinations: hematology, biochemistry, infectious disease testing, urine analysis, thorax and/or abdominal radiographs, MRI of the brain and/or spinal cord. The samples used for this brief research report were investigated to describe the method and compare two different canine anti-IgG antibodies. The description of CSF-specific OCBs in neurological and non-neurological diseases and a statistical comparison among different groups are not objects of this communication..