We present an immunocompetent patient with transfusion-associated graft-versus-host disease (GVHD), in which chimaerism of peripheral blood lymphocytes was demonstrated by analysis of a highly polymorphic genome. The patient was treated successfully with anti-CD3 monoclonal antibody, OKT3 and cyclosporin A. Although it is undoubtedly important to prevent transfusion-associated GVHD by irradiation of cellular blood components, intensive therapy with OKT3 and cyclosporin A in the early phase of onset may be effective for treatment of this potentially fatal condition. The mechanism of the effectiveness of this treatment for transfusion-associated GVHD is discussed.

Monoclonal antibodies against etiological agents of Weil's disease were produced by cell fusion technology. Twenty hybridomas were produced through the fusion of P3×63Ag8.653 cells with spleen cells from BALB/c mice immunized against Leptospira interrogans serovar icterohaemorrhagiae RGA strain and serovar copenhageni Shiromizu and M20 strains. Reactivities of the antibodies produced by the hybridomas were determined by the microscopic agglutination test. Among the five hybridoma antibodies to the RGA strain, two reacted specifically to serovar icterohaemorrhagiae, two reacted to serovar icterohaemorrhagiae at a high titer and serovar copenhageni at a low titer, and one reacted to serovars icterohaemorrhagiae, copenhageni, pyrogenes, and canicola. Of the ten hybridoma antibodies to the Shiromizu strain, one reacted specifically to serovar copenhageni, seven reacted to both serovars copenhageni and icterohaemorrhagiae at almost the same titer, and two exhibited intermediate properties. Of the five hybridoma antibodies to the M20 strain, three reacted to both serovars copenhageni and icterohaemorrhagiae at almost the same titer, one reacted to serovar copenhageni at a low titer and serovar icterohaemorrhagiae at a high titer, and one reacted to serovars copenhageni, icterohaemorrhagiae, and pyrogenes. The results revealed that each serovar has its own antigen(s) and their common antigens. In addition, 20 strains of leptospires were recently isolated and tested with three monoclonal antibodies characterized by different reactivities. Twenty strains were clearly identified by their antibodies, i.e., 16 strains were identified as serovar icterohaemorrhagiae and three strains were identified as serovar copenhageni. The remaining strain, which was not agglutinated by three antibodies, was identified as serovar autumnalis by an agglutination test with immune rabbit sera.

Leptospira interrogans serovar icterohaemorrhagiae strains Ictero No. I and RGA and serovar copenhageni strains M20, Shiromizu and Shibaura were examined by restriction endonuclease DNA analysis. Fifteen endonucleases (AluI, BamHI, BglII, EcoRI, HaeIII, Hhal, HindIII, KpnI, PstI, SacI, SaiI, SmaI, StyI, XbaI and XhoI) were used as the digesting enzymes.Strain Ictero No. I showed endonuclease cleavage patterns which differed from those of the other four strains only when it was digested with enzymes Kpnl and HindIII. When digested with Kpnl, an extra band of about 5 .4 kb was clearly produced, and when digested with HindIII, an extra band of about 25 kb was produced. When the other 13 enzymes were used, no differences were found between the endonuclease cleavage patterns among the five strains. Moreover, strains RGA, M20, Shiromizu and Shibaura could not be distinguished by the restriction endonuclease DNA analysis using all 15 endonucleases. In addition , six newly isolated leptospires from patients with leptospirosis and from Rattus norvegicus were compared with the Ictero No. I and M20 strains, by restriction endonuclease DNA analysis using enzymes KpnI and HindIII. Three leptospires belonging to serovar icterohaemorrhagiae showed the same endonuclease cleavage patterns as the M20 strain. The other three strains, which belong to serovar copenhageni, showed almost the same endonuclease cleavage patterns as the M20 strain; only the Kaijima 702 strain produced an extra band which was not identical to the Ictero No. Ispecific extra band when digested with HindIII. The leptospiral restriction endonuclease DNA analysis has revealed taxonomic structures that are unrecognized by serology alone.

Hybridoma cells were produced by fusing P3X63Ag8.653 mouse myeloma cells with spleen cells from BALB/c mice immunized with Japanese encephalitis (JE) virus, Nakayama-RFVL strain. The resulting 26 clones produced hemagglutination inhibition antibodies against the homologous strain. The hemagglutination inhibition reactivity of each clone was tested against six flaviviruses: JE, Murray Valley encephalitis (MVE), Egypt 101 strain of West Nile (WN), St. Louis encephalitis (SLE), Russian spring summer encephalitis, and dengue type 1. The 26 monoclonal antibodies fell into four groups: 14 JE species-specific antibodies, 6 antibodies reactive to JE and MVE viruses, 3 antibodies to three or four viruses in the JE-MVE-WN-SLE subgroup, and 3 antibodies to all six flaviviruses. Furthermore, antigenic comparison of 27 strains of JE virus was carried out by using five JE species-specific monoclonal antibodies. Of these, 24 strains were isolated in various parts of Japan, and 3 strains came from Southeast Asia. In reactivity, the 27 strains were classified into at least four antigenic groups. The results showed that the Nakayama-Yakken strain is a mutant strain which lacks the Nakayama strain-specific antigen and that the recently isolated strains are immunologically different from Nakayama and JaGAr 01 strains. One clone (NARMA 13) produced a JE species-specific antibody which showed almost the same titer against 26 JE virus strains, whereas one clone (NARMA 5) produced a Nakayama strain-specific antibody which reacted only to the Nakayama-RFVL and Nakayama-Yoken strains.

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