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     

Randomised,double blind,placebo controlled trial of penicillin V and amoxycillin in treatment of acute sinus infections in adults.

OBJECTIVES--To compare the effectiveness of penicillin V and amoxycillin with placebo in treatment of adult patients with acute sinusitis. DESIGN--Randomised, double blind, placebo controlled trial. SETTING--Norwegian general practice. SUBJECTS--130 adult patients with a clinical diagnosis of acute sinusitis confirmed by computed tomography. MAIN OUTCOME MEASURES--Subjective status after three and 10 days of treatment, difference in clinical severity score between day 0 and day 10 as evaluated by the general practitioner, difference in score from computed tomography on day 0 and day 10, and duration of sinusitis. RESULTS--Amoxycillin and penicillin V led to significantly faster and better recovery than placebo. By day 10, 71 patients receiving antibiotic treatment- (86%) considered themselves to be recovered or much better compared with 25 (57%) receiving placebo. The mean (95% confidence interval) reductions in clinical severity scores by day 10 were 5.4 (5.0 to 5.8) for penicillin V, 5.5 (4.9 to 6.0 for amoxycillin, and 3.4 (2.8 to 4.0) for placebo. For the antibiotic groups combined the number of patients with the greatest degree of improvement on computed tomography (scale 0-16)-that is, score 5-16 on day 10-was 31/83 (37%) compared with 10/44 (23%) receiving placebo. The median duration of the sinusitis was nine days in the amoxycillin group, 11 days in the penicillin V group, and 17 days in the placebo group. CONCLUSION--Penicillin V and amoxycillin are significantly more effective than placebo in the treatment of acute sinusitis.     

Mapping the extracellular topography of the α-chain in free and in membrane-bound acetylcholine receptor by antibodies against overlapping peptides spanning the entire extracellular parts of the chain

The extracellular surface of theα-chain ofTorpedo california acetylcholine receptor (AChR) was mapped for regions that are accessible to binding with antibodies against a panel of synthetic overlapping peptides which encompassed the entire extracellular parts of the chain. The binding of the antipeptide antibodies to membrane-bound AChR (mbAChR) and to isolated, soluble AChR. was determined. The specificity of each antiserum was narrowed down by determining the extent of its cross-reaction with the two adjacent peptides that overlap the immunizing peptide. With mbAChR, high antibody reactivity was obtained with antisera against peptidesα1–16,α89–104,α158–174,α262–276, andα388–408. Lower, but significant, levels of reactivity were obtained with antibodies against peptidesα67–82,α78–93,α100–115, andα111–126. On the other hand, free AChR bound high levels of antibodies against peptidesα34–49,α78–93,α134–150,α170–186, andα194–210. It also bound moderate levels of antibodies against peptidesα262–276 andα388–408. Low, yet significant, levels of binding were exhibited by antibodies against peptidesα45–60,α111–126, andα122–138. These binding studies, which enabled a comparison of the accessible regions in mbAChR and free AChR, revealed that the receptor undergoes considerable changes in conformation upon removal from the cell membrane. The exposed regions found here are discussed in relation to the functional sites of AChR (i.e., the acetylcholine binding site, the regions that are recognized by anti-AChR antibodies, T-cells and autoimmune responses and the regions that bind short and long neurotoxins).