Tsunehisa Suto

Immunoblotting Analysis of Anti‐Rickettsial Antibodies Produced in Patients of Tsutsugamushi Disease

The reactivity of sera from patients of Tsutsugamushi disease (scrub typhus) with the antigenic polypeptides of Rickettsia tsutsugamushi was analyzed by the immunoblotting method. The reactivity varied greatly among the sera of individual patients tested. IgG and IgM antibodies of most patients reacted with the 54–56 kilodalton (54–56K) polypeptide located on the rickettsial surface, suggesting that this polypeptide is a predominant antigen in the infection. Other polypeptides of 60K, 50–52K, 46–47K, 35K, and 21–25K were reactive with some but not all sera. From the reactivity of these polypeptides, it was suggested that the 54–56K polypeptide is both strain‐specific and group‐specific, the 60K polypeptide is group‐specific, and the 35K and 21–25K polypeptides are subgroup‐specific. IgG antibodies seem to be more cross‐reactive with polypeptides of multiple strains than IgM antibodies and have a tendency of increased cross‐reactivity that was observed in the sera obtained at the later stage of illness.

Serological Reactivity of Sera from Scrub Typhus Patients against Weil-Felix Test Antigens

Sera from 17 patients of scrub typhus in the acute and convalescent phases were tested by indirect immunoperoxidase test, Weil‐Felix (WF) test, enzyme‐linked immunosorbent assay (ELISA), and immunoblotting. In the comparison of antibody titers between acute‐ and convalescent‐phase sera, we recognized a parallelism of increment between the titers in WF test and titers of immunoglobulin M (IgM) in ELISA against Proteus mirabilis strain OXK‐whole cells and OXK‐lipopolysaccharides (Proteus OXK‐LPS). Furthermore, IgM antibodies from almost all of WF test‐positive sera recognized LPS from Proteus OXK in immunoblotting. Based on these results, it was concluded that IgM antibody rather than IgG may participate in WF test, and that Proteus OXK‐LPS may have one of antigenic epitopes common to the components of R. tsutsugamushi.

Immunological Characterization of Lipopolysaccharides from Proteus Strains Used in Weil-Felix Test and Reactivity with Patient Sera of Tsutsugamushi Diseases

Immunological analyses of lipopolysaccharides (LPS) isolated from Proteus strains OX2, OX19, and OXK used as antigens of Weil‐Felix (WF) test, were performed by quantitative agglutination, enzyme‐linked immunosorbent assay (ELISA), and immunoblotting. Antisera against LPS and whole cells (WC) of the three Proteus strains reacted with homologous LPS but not with heterologous LPS. and the reaction was inhibited by the O‐polysaccharide fraction isolated from the homologous LPS except OX19‐LPS. which lacked O‐polysaccharide moiety. The immunological data support the findings that the O‐polysaccharide moieties of LPS from OX2 and OXK strains possess different chemical composition (Mizushiri, Amano, Fujii, Fukushi, and Watanabe, Microbiol. Immunol. 34: 121 133, 1990). Antisera against Proteus strains reacted weakly with WC of Rickettsia prowazekii, Rickettsia typhi, and Rickettsia tsutsugamushi. Antisera from patients with tsutsugamushi disease reacted with OXK‐WC by WF test when the sera were obtained 13 days after onset of fever. The immunoperoxidase (IP) test titers of these antisera began to rise 6 days after the onset of fever. By ELISA tests these antisera reacted with OXK‐WC and OXK‐LPS independently of the titers of WF or IP tests.

Electron Microscopic Studies on the in vitro Proliferation of Spotted Fever Group Rickettsia Isolated in Japan

Rickettsia was isolated from a patient with Japanese spotted fever, and its proliferation in cultured green monkey kidney cells was observed by electron microscopy. In the course of this study, we observed fusion of infected cells to uninfected cells which may be a way of spreading the rickettsiae from a cell to another. On the other hand, whirlpool‐like, multilayer membranous structures, similar to the mesosomes of gram‐negative bacteria, were sometimes seen in the rickettsial cells. The other profiles common to the other rickettsiae in spotted fever group were observed, such as the electron‐lucent halo zone around the rickettsiae, and external fibrous materials on their surface, but intranuclear multiplication was rarely observed.

Improved production of a chromophore component of antitumor antibiotic neocarzinostatin (NCS) by addition of threonine in a chemically defined medium

Abstract Production in a chemically defined medium of a free chromophore component (free NCS-chr) of an antitumor antibiotic neocarzinostatin (NCS) by Streptomyces carzinostaticus var. F-41 was improved by the use of l -threonine or l -asparagine as a sole nitrogen source. Under the conditions established, the yield of free NCS-chr was comparable to that obtained in a control medium containing casamino acids.

マウス乳仔下痢症から分離された新コロナ様ウイルス (DVIM) の形態学的特性について

近年, マウス乳仔下痢症から分離されたウイルス (Diarrhea virus of infant mice: DVIM) をBALB/c-3T3培養細胞により増殖させ, その形態学的性状を検討し以下の結果を得たので報告する.1. DVIMは直径100nm, 厚さ10nmのエンベロープをもつRNA型の球形ウイルスでありHA能をもち, 粒子表面に長さ20nm, 幅10nmの突起を有するコロナ様ウイルスである.2. 粒子表面の突起は既知のコロナウイルスとは異なり, 形態的に長さ20nmの大突起と長さ5nmの小突起の2つの形を認める. 大突起は精製の過程や sonication により容易に脱落するが, 小突起は粒子表面に強固に保持される. 小突起は大突起の基部をなすものと思われ, HA能は小突起に担われている可能性が大きい.3. DVIMはBALB/c-3T3細胞に感染しシンシチウムを形成する. 増殖は細胞質内で行なわれ, 増殖周期は約6時間である.4. マウス赤血球はシンシチウムに吸着し, その表面微細構造の観察から, DVIMの細胞外への遊出はシンシチウム細胞膜表面からの出芽による.以上の結果からDVIMは従来のコロナウイルスに似ているが細部では際立った差異が認められる.

マウス乳仔下痢症から分離されたコロナ様ウイルス (DVIM) の赤血球凝集能について

BALB/c-3T3細胞により増殖させたマウス乳仔下痢症ウイルス (Diarrhea virus of infant mice: DVIM) の赤血球凝集能 (HA) の特性をインフルエンザ-AおよびHVJとの対比のもとに検討して以下の結果を得た.1. DVIMはマウスおよびラットの赤血球を4℃において凝集し, 37℃で解離する.2. HAの至適pHは6.5付近である. HA能は37℃24時間後でもまったく失活しないが, 56℃20分, またはエーテル処理等で失活する.3. マウス赤血球のDVIM-レセプターはインフルエンザA-レセプターとは別個に存在し, RDE (コレラ菌558株培養濾液) およびインフルエンザAのノイラミニダーゼでは破壊されない.