Antibodies in multiple sclerosis oligoclonal bands target debris

Abstract

IgG oligoclonal bands (OCB) are detected in the cerebrospinal fluid (CSF) of more than 90% of multiple sclerosis (MS) patients and are considered the immunological hallmark that supports MS diagnosis. OCB are not unique to MS but are also observed in chronic CNS infections, where they target their causative agents (1⇓–3). However, the target specificities of the IgG within OCB in MS have remained a mystery. Identification of those antigens recognized by OCB antibodies is thought to hold fundamental clues to the pathogenesis of MS. In a recent PNAS publication, Brandle et al. (4) provide evidence that OCB in MS target ubiquitous intracellular antigens released in cellular debris. In 1942, Kabat et al. (5) established the diagnostic value of quantitative determinations of CSF gamma globulins in clinical neurology, and particularly in MS. They observed that changes in CSF IgG were independent of those in serum, suggesting that this Ig production was compartmentalized to the CNS. Advances in CSF analytics and gel electrophoresis led to the identification of OCB in 1959 (6). CSF OCB in MS patients are persistent, which is thought to be a reflection of both ongoing CNS inflammation and immunologic memory. Understanding the specificity of OCB has since captivated the interest of clinical neurologists and scientists alike. It has been assumed that the OCB target antigens are relevant to MS pathogenesis. The most popular theory contends that IgG within OCB target myelin autoantigens and/or viruses that may elicit CNS damage directly or indirectly via molecular mimicry. Some earlier studies that evaluated whole CSF IgG from MS patients identified antibodies to several different viruses, such as measles, varicella zoster, human T-lymphocytic virus 1, and … [↵][1]1To whom correspondence should be addressed. Email: zamvil{at}ucsf.neuroimmunol.org. [1]: #xref-corresp-1-1