We have developed 18 hybridoma cell lines which secrete murine monoclonal strain‐specific antibodies to prototype strains of Rickettsia tsutsugamushi: nine anti‐Gilliam, four anti‐Karp and five anti‐Kato antibodies. All the monoclonal antibodies reacted only with their homologous strains in direct and indirect immunofluorescence (IF), or indirect immunoperoxidase (IP) test. By IF and IP tests with the monoclonal antibodies, 22 strains of R. tsutsugamushi, which were newly isolated from mites, field rodents and patients with Tsutsugamushi disease (scrub typhus) in Japan, were all clearly identified as either Gilliam or Karp type. Analysis by polyacrylamide gel electrophoresis and immunoblotting techniques revealed that the monoclonal antibodies recognized primarily the polypeptides of an apparent molecular weight of 54 to 56 kilodaltons of the homologous rickettsial surface. The monoclonal antibodies produced in the present study should enhance the serotyping and further analytical investigation of the rickettsial antigens since they recognize the strain‐ or type‐specific polypeptides and do not show any cross‐reaction among strains.

Upon stimulation with antigen, naive CD4+ cells can differentiate into distinct subsets defined by their cytokine secretion pattern. Human allergen-specific Th cells generally belong to the Th2 phenotype and produce IL-4, which are generally implicated in cellular immune re

Cytostatin has been identified as a novel inhibitor of cell adhesion to components of extracellular matrix (ECM) in cultured broth of Streptomyces sp. MJ654-NF4. Though cytostatin did not inhibit EL-4 cell adhesion to ECMcomponents such as laminin and fibronectin,* it inhibited the adhesion of B16 melanoma cells to laminin and collagen type IV but not to fibronectin. It exhibited antimetastatic activity on B 1 6 melanoma cells in mice. The cytotoxicity ofcytostatin are also reported.

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