Adenovirus Type 9 Fiber Knob Binds to the Coxsackie B Virus-Adenovirus Receptor (CAR) with Lower Affinity than Fiber Knobs of Other CAR-Binding Adenovirus Serotypes

The coxsackie B virus and adenovirus (Ad) receptor (CAR) functions as an attachment receptor for multiple Ad serotypes. Here we show that the Ad serotype 9 (Ad9) fiber knob binds to CAR with much reduced affinity compared to the binding by Ad5 and Ad12 fiber knobs as well as the knob of the long fiber of Ad41 (Ad41L). Substitution of Asp222 in Ad9 fiber knob with a lysine that is conserved in Ad5, Ad12, and Ad41L substantially improved Ad9 fiber knob binding to CAR, while the corresponding substitution in Ad5 (Lys442Asp) significantly reduced Ad5 binding. The presence of an aspartic acid residue in Ad9 therefore accounts, at least in part, for the reduced CAR binding affinity of the Ad9 fiber knob. Site-directed mutagenesis of CAR revealed that CAR residues Leu73 and Lys121 and/or Lys123 are critical contact residues, with Tyr80 and Tyr83 being peripherally involved in the binding interaction with the Ad5, Ad9, Ad12, and Ad41L fiber knobs. The overall affinities and the association and dissociation rate constants for wild-type CAR as well as Tyr80 and Tyr83 CAR mutants differed between the serotypes, indicating that their binding modes, although similar, are not identical.     

Expression of human prostate-specific antigen (PSA) in a mouse tumor cell line reduces tumorigenicity and elicits PSA-specific cytotoxic T lymphocytes

 Human prostate-specific antigen (PSA) has a highly restricted tissue distribution. Its expression is essentially limited to the epithelial cells of the prostate gland. Moreover, it continues to be synthesized by prostate carcinoma cells. This makes PSA an attractive candidate for use as a target antigen in the immunotherapy of prostate cancer. As a first step in characterizing the specific immune response to PSA and its potential use as a tumor-rejection antigen, we have incorporated PSA into a well-established mouse tumor model. Line 1, a mouse lung carcinoma, and P815, a mouse mastocytoma, have been transfected with the cDNA for human PSA. Immunization with a PSA-expressing tumor cell line demonstrated a memory response to PSA which protected against subsequent challenge with PSA-expressing, but not wild-type, tumors. Tumor-infiltrating lymphocytes could be isolated from PSA-expressing tumors grown in naive hosts and were specifically cytotoxic against a syngeneic cell line that expressed PSA. Immunization with tumor cells resulted in the generation of primary and memory cytotoxic T lymphocytes (CTL) specific for PSA. The isolation of PSA-specific CTL clones from immunized animals further demonstrated that PSA can serve as a target antigen for antitumor CTL. The immunogenicity studies carried out in this mouse tumor model provide a rationale for the design of methods to elicit PSA-specific cell-mediated immunity in humans. Received: 4 April 1996 / Accepted: 31 May 1996     

Electrocardiography during Manual Dilatation of the Anus

Manual dilatation of the anus was carried out on 50 unpremedicated outpatients under propanidid, nitrous oxide, and halothane anaesthesia with E.C.G.monitoring. About half of the patients received intravenous atropine with the propanidid. The operation induced a variety of changes in heart rate but in the whole experiment only two isolated cardiac arrhythmic complexes were seen—a single defect of conduction and a solitary ventricular extrasystole. Changes in rate were not modified by atropine. It is concluded that manual dilatation of the anus is a safe procedure when carried out under the anaesthetic described and that prior medication with atropine is not necessary. This work supports the view that propanidid protects patients from most abnormalities of heart action which result from intense visceral stimulation.