An easy, fast and "low-tech"-equipment-requiring alternative method to optimize immunolabelling conditions for pre-embedding immunogold electron microscopy and to correlate light and electron microscopical immunogold labelling results.

Correlating light microscopic immunolabelling results with electron microscopic data is of great interest in many fields of biomedical research but typically requires very specialized, expensive equipment and complex procedures which are not available in most labs. In this technical study, we describe an easy and "low-tech"-equipment-requiring pre-embedding immunolabelling approach that allows correlation of light microscopical immunolabelling results with electron microscopic (EM) data as demonstrated by the example of immunolabelled synaptic ribbons from retinal rod photoreceptor synapses. This pre-embedding approach does not require specialized embedding devices but only commonly available equipment. The cryostat section-based procedure allows optimization of the pre-embedding immunolabelling conditions at the less laborious and time-consuming light microscopic (LM) level before the ultrastructural analyses of the immunolabelled structures can be performed on the same sample after ultrathin sectioning without further modification. The same photoreceptor synapse that has been first studied at the light microscopic level can be subsequently analyzed with this approach at the electron microscopic level at individual ultrathin sections or serial ultrathin sections from individual, identical synapses. Higher resolution EM analyses of the immunolabelled synapses can be performed with only minor modifications of the combined LM/EM procedure. The detergent-free procedure is applicable even for weakly fixed cryostat sections which is a relevant aspect for many antibodies that do not work with more strongly fixed biological samples.

Immunology of stiff person syndrome and other GAD-associated neurological disorders.

Antibodies against glutamic acid decarboxylase (GAD), the rate-limiting enzyme for the synthesis of GABA, are associated with an array of distinct, mostly autoimmune, neurological conditions. In all associated syndromes, namely stiff person syndrome, cerebellar ataxia, epilepsy, limbic encephalitis or abnormal eye movements, anti-GAD antibodies are detected at high titers and play a fundamental role in diagnosis, but do not correlate with disease severity, diversity of symptomatology or response to therapies. Despite considerable efforts, including in vitro (enzymatic assays) and in vivo (animal models) systems, the pathogenicity of anti-GAD antibodies has not been unequivocally proven for any specific condition. The search for the responsible autoantigen has revealed a few other antigenic targets, particularly for SPS, localized in the pre- or post-synaptic inhibitory neuronal synapses. Cumulative clinical and laboratory evidence indicates that anti-GAD and related antibodies define a novel group of syndromes, collectively known as 'hyperexcitability disorders'.

Complement in animal development: unexpected roles of a highly conserved pathway.

The complement pathway is most famous for its role in immunity, orchestrating an exquisitely refined system for immune surveillance. At its core lies a cascade of proteolytic events that ultimately serve to recognise microbes, infected cells or debris and target them for elimination. Mounting evidence has shown that a number of the proteolytic intermediaries in this cascade have, in themselves, other functions in the body, signalling through receptors to drive events that appear to be unrelated to immune surveillance. It seems, then, that the complement system not only functions as an immunological effector, but also has cell-cell signalling properties that are utilised by a number of non-immunological processes. In this review we examine a number of these processes in the context of animal development, all of which share a requirement for precise control of cell behaviour in time and space. As we will see, the scope of the complement system's function is indeed much greater than we might have imagined only a few years ago.