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Human-human hybridomas producing monoclonal antibodies (MoAbs) specific for five major serotypes of Pseudomonas aeruginosa were developed by fusing P. aeruginosa primed and Epstein-Barr virus-transformed cells with human myeloma P109 cells using polyethyleneglycol. The MoAbs which were produced by the hybridomas were protective against lethal intraperitoneal (i.p.) challenge of P. aeruginosa (10 LD50) in mice. The 50% effective dose (ED50) values of MoAbs ranged from 0.5 to 10.2 micrograms/mouse and were 26 to 240 times more protective than a commercial human IgG preparation. MoAb administration to mice promoted bacterial clearance in peritoneal cavity, and prevented bacterial invasion into blood in the way of increasing both the number of bacteria trapped by a macrophage and the ratio of macrophages that trapped bacteria. MoAbs also showed protective effects against lethal infection of P. aeruginosa in the mice which were decreased in polymorphonuclear cells (PMN) by cyclophosphamide (CY). All MoAbs showed serotype-specific binding to the clinical isolates of P. aeruginosa as well as to the immunized strains. The hybridoma cell lines maintained their capacity to produce MoAb continuously for more than 12 months and produced 10 to 60 micrograms MoAbs per 10(6) cells in 24 hr. It is practicable to use these cell lines for large-scale production of anti-P. aeruginosa MoAbs and such MoAbs must be useful for the therapeutics of patients with P. aeruginosa infection.

Duck hepatitis B virus (DHBV) replication in primary duck hepatocytes was monitored by examining the synthesis of both DHBV DNA and DHBV core antigen. Several nucleoside analogs which were previously shown to inhibit the replication of DNA viruses (i.e., herpesviruses) and retroviruses were examined for their inhibitory effects on the synthesis of DHBV core antigen in primary duck hepatocytes. (S)-9-(3-Hydroxy-2-phosphonylmethoxypropyl)adenine [(S)-HPMPA], 9-(2-phosphonylmethoxyethyl)-2,6-diaminopurine, 2',3'-dideoxyadenosine, and 2',3'-dideoxycytidine inhibited DHBV core antigen synthesis at concentrations that were significantly lower than those found to be toxic to the primary hepatocytes. Of all the compounds tested, (S)-HPMPA showed the lowest 50% effective concentration (0.5 micrograms/ml). The selectivity index or ratio of the 50% cytotoxic concentration to the 50% effective concentration of (S)-HPMPA was greater than 300. (S)-HPMPA not only inhibited DHBV core antigen but also DHBV DNA synthesis in DHBV-infected hepatocytes.

Ten samples of antiserum against Pseudomonas cepacia were prepared by the intravenous immunization of rabbits with heat-killed organisms. Ten P. cepacia strains used for immunization were proven unique antigenic strains. Using these antisera, we serogrouped 127 strains of P. cepacia, and 114 strains (89.8%) fell under one of the ten serogroup. The most prevalent serogroup was C (26.8), the second most prevalent being D (18.1%). When we compared our serogroups with the serogroups of Monteil et al. (H. Monteil, C. Richard, and A. Heidt, Med. Mal. Infect. 11:544-547, 1981) and Heidt et al. (A. Heidt, H. Monteil, and C. Richard, J. Clin. Microbiol. 18:738-740, 1983), five out of seven of their serogroups were represented by our antisera.

Adult rabbits were immunized with nine Achromobacter xylosoxidans strains by intravenous injection of Formalin-killed organisms. Antisera thus obtained were reciprocally titrated with the nine A. xylosoxidans strains, and seven sera were defined as serologically distinct. Three of nine antisera possessed one common antibody while also each having their own specific antibody. Ninety-five strains of A. xylosoxidans were examined for serotyping by a microtiter agglutination test with the nine antisera, and the strains were divided into seven serogroups. The distribution of the 95 strains among the serogroups was as follows: serogroup A, 15 strains; B, 17 strains; C, 43 strains; D, 2 strains; E, 4 strains; G, 8 strains; F, 2 strains. Four strains were not agglutinated with any of the antisera. Serogroups A, B, and F had the ability to reduce nitrate to nitrogen gas and to grow in heart infusion broth at 41 degrees C, although there were some exceptions. In contrast, most strains of serogroups C, D, and E could not produce nitrogen gas from nitrate, although they did produce nitrite. The strains of serogroup C could not grow at 41 degrees C, whereas those of serogroups D and E could. Thus, we concluded that serogroups A, B, and F referred to biotype IIIb described by Tatum, and serogroups C, D, and E referred to biotype IIIa. The serotyping of A. xylosoxidans may be useful for the analysis of nosocomial infections caused by these organisms.