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BRAIN BOUND ANTIBODIES IN NZB/W F 1 HYBRID MICE, Patr ic ia M. Moore, Dept. of Neurology~ Vanderbil t University Medical Center, Nashville, TN 37212

NZB/W F 1 hybrid mice, an autoimmune model of systemic lupus erythematosus, develop circulat ing autoantibodies to mult iple antigens. Neuron reactive antibodies occur but their access to the CNS has not been established. In the present study, antibodies in PBS washes and acid eluates of 10 NZB/W F 1 hybrid and 10 ~alb/c control mouse brains were compared. The in i t ia l PBS wash and the acid eluates were precipi tated wi th ammonium sulfate and evaluated for protein content and presence of antibody. Both IgG and IgM were detected in the in i t ia l PBS washes of NZB/W and Balb/c brains, IgG alone was present in the acid eluates of NZB/W brains, and no antibody was present in acid eluates of ~lalb/c brains. Samples of the in i t ia l PBS wash and the acid eluate were passed over anti-mouse IgG sepharose columns and the quantity, subclass~ and binding af f in i ty of the IgG compared. A tota l of 9.5 ug of igG was present in the PBS wash end 3.7 ug in the acid eluate of the NZB/W mice. Subclasses G 1, G2a, and G2b were present in PBS wash but only G 1 in the acid eluate. When adjusted for equivalent immunoglobulin concentration, the antibody in the PBS wash bound to DNA, neuroblastoma cells, and l iver cells in an Elisa assays the acid eluted antibody bound prominently to neuroblastoma ceils, only slightly to l iver cells, but not to DNA. This study shows antibody bound to CNS tissue reacts with fewer targets than that found in serum and demonstrate$these antibodies do cross the blood/brain barr ier and potent ial ly may affect neuronal function.

This was supported by Grant #l-RO1-NS22270

NEURONAL CELL SURFACE PROTEINS REACTIVE WITH SPONTANEOUSLY OCCURING ANTIBODIES IN NZB/W MOUSE SERA~ Patr ic ia M. Moore, Thomas Oeitman9 Depts. of Neurology and Medicine, Vanderbii t University Medical Center, Nashville~ TN 37212

Antineuronal antibodies occur in NZB/W F l hybrid mice, an autoimmune model of SLE, but the antigenic targets of these antibodies are not yet delineated. On the basis of histologic studies neuron react ive antibodies b i rd to nuclear, cytoplasmic and ceil surface structures in a variety of neuronal tissue. Antibodies react ive wi th cel l surfaces may mediate changes in neuronal function. Focusing on cell surface antigens we investigated whether there was tissue specif ici ty associated with antibody binding. Murine neuroblastoma 2A and l iver cell lines were radiolabeled wi th 125I-iodosulfanilic acid. A solubil ized membrane preparation was mixed with Balb/c IgG-sorb to remove non-specif ically birding proteins. The supernatants were treated wi th NZB/W F]. hybrid serum samples and IgG-sorb. Af ter centr i fugat ion the pellets were resuspended m detergent and the IgG-serb removed. Solubilized radiolabeled proteins were applied to a 12% acrylemide gel. Autoradiography identi f ied several proteins shared between the neurobiastoma and l iver cells and 2 proteins (66K and 501<) present only in the neuroblastoma cells.

Using this technique we have ident i f ied two unique proteins on the ceil surface of 2A cells. These may be target antigens in this autoimmune process and may be important in the neurologic manifestat ion of the disease.

This was supported by Grant #l-ROI-NS22270