A neutralizing monoclonal antibody against Coxsackievirus B4 cross-reacts with contractile muscle proteins.

A panel of Coxsackievirus B4 (CVB4) neutralizing monoclonal antibodies (mAbs) were tested against a panel of normal mouse tissues. One mAb, 356-1, reacted specifically with murine heart tissue. Immunohistochemical studies revealed an A band pattern of staining of the heart. Examination of sequential differential extracts of heart by Western immunoblotting showed that 356-1 predominantly reacted with the murine cardiac myosin heavy chain. A rather weak cross-reaction was found with actin. These observations were confirmed by the binding of 356-1 to purified cardiac myosin and actin. This antibody showed a higher affinity for murine cardiac muscle myosin than for skeletal muscle myosin. Examination of the reactivity of 356-1 with CVB4 polypeptides using Western immunoblotting revealed that 356-1 binds to the VP-1 capsid protein. These studies imply that molecular mimicry is one mechanism by which autoimmunity could develop during CVB4 induced myocarditis.

Plasma nicotine and cotinine in tobacco smoke exposed beagle dogs.

Nicotine and cotinine have been determined in plasma samples from 87 beagle dogs chronically exposed to cigarette smoke with three different levels of nicotine. An additional 18 sham-exposed animals were included in the study as controls. Smoke was administered to the animals through permanent tracheostomas via cuffed tracheostomy tubes and was generated from reference cigarettes under standard puffing parameters by ADL-II smoking machines. The dogs were exposed for an average of 2 years prior to sample collection. The results from blood samples collected at specific intervals in the daily exposure schedules indicate that nicotine may be useful as a relative index of smoke exposure. At elevated exposure levels, average blood concentrations were related to the number of cigarettes smoked as well as the nicotine delivery of the cigarette. Cotinine was found to increase more slowly than nicotine and was also metabolized more rapidly than in humans. Overall, the study affords an examination of the relationship of plasma nicotine and cotinine with estimated nicotine exposure.