Specific antiporin antibody (IgG, IgM, and IgA) response was studied in control, infected, immunized-infected, and immunized mice. The activity of specific IgG immunoglobulins was found to be the highest in immunized and immunized-infected groups in which 87.5% protection had been observed by laboratory potency test in mice; the next-highest activities were those of IgM and IgA immunoglobulins. However, in the infected group the activity of specific IgM and IgG immunoglobulins was almost similar.

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It was proved that three spore coat proteins of 48, 36, and 22kDa (P48, P36, and P22) were the components of the outermost layer (OL) of Bacillus megaterium ATCC 12872 spore by analysis of the isolated OL. And it was indicated that these proteins were deposited not by disulfide bond, but by ionic and/or hydrophobic bonds on the spore. Among them, P36 and P22 were expected to be located on the very surface of the spore by immunological analysis. In the OL deficient mutant of B. megaterium ATCC 12872, MAE05, whose spore was lacking in these OL proteins and galactosamine-6-phosphate polymer, both P36 and P22 were present in the mother cell cytoplasm and deposited on the forespores, but they disappeared with the lysis of mother cells. An OL protein-releasing factor having proteolytic activity was detected in the culture supernatant at the late sporulating stage of both the wild-type and the mutant strains. But the factor could not act on the proteins of the mature spores and the forespores at t₁₀ (t_n indicates n hr after the end of exponential growth) of the wild-type strain. Moreover, P36 and P22 were found in the spores of a revertant of MAE05 which could form galactosamine-6-phosphate polymer, suggesting that this sugar polymer played the role in protecting the OL proteins against the protease-like substance after the deposition.

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In an attempt to clarify the role of cellular immunity in the pathogenesis of acute type B viral hepatitis (AHB), we studied delayed-type hypersensitivity (DTH) skin reaction to hepatitis B surface antigen (HBsAg) and immunohistopathology of livers in patients with AHB. DTH skin reaction to HBsAg developed early in the convalescent phase in all 14 patients with AHB. In contrast, the production of anti-HBs was significantly delayed in these patients, compared with healthy controls immunized with HB vaccine intradermally (P<0.001). These observations suggest that DTH to HBsAg but not anti-HBs may be associated with recovery from AHB. In the biopsied livers obtained from patients with AHB, the proliferation of Kupffer cells was extensive and immunohistopathologic studies revealed an accumulation of CD-4 positive lymphocytes in the portal area, a finding which suggested a DTH reaction in the liver with AHB. CD-8 positive cells had infiltrated the lobule and made contact with affected hepatocytes, thereby indicating that a cytotoxic T cell response is involved in damaging of the infected cells. All these observations taken together, we propose that not only a cytotoxic T cell response but also a DTH reaction may be involved in the pathogenesis of AHB.

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The marked cytopathic effects of human immunodeficiency virus (HIV) for susceptible cells are caused mainly by fusion between cells expressing viral envelope glycoproteins and cells expressing CD4 molecule. In this study, we tested the ability of different clones of HIV to induce syncytia in CD4-positive cells. We have reported marked difference in syncytium-inducing capacity of 2 clones of human T lymphotropic virus type III (HTLV-III_B) isolate despite no detectable difference in expression of viral glycoprotein (gp120). This difference in syncytium induction could be explained by the difference detected in their infectivity and binding activities to CD4-positive cells. Meanwhile we reported difference in syncytium-inducing capacity of 2 clones of lymphadenopathy associated virus (LAV₁) isolate parallel to the different amounts of gp120 and other viral proteins expressed by these 2 clones. These results suggest that viral factors like infectivity and binding affinity of the virus to the susceptible cells and the amount of viral gp120 expressed by the infected cells may interact in a complex manner affecting fusion activity and syncytium induction in CD4-positive cells.

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Eleven hybridoma cell lines producing mouse monoclonal antibodies (mAbs) against human parvovirus B19 were established. Their specificity was as follows. Approximately 5% of fetal erythroid cells inoculated with B19 reacted with all the mAbs and with anti-B19 positive human serum, but not with negative serum by indirect double immunofluorescence staining. All the mAbs recognized both VP-1 (84 kDa) and VP-2 (58 kDa) capsid proteins of B19 virions propagated in vitro and in vivo by Western blotting, and immunoprecipitated B19 virions.

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A sensitive thymocyte co-stimulator assay of IL-1 using a β-D-galactoside specific lectin (allo A) obtained from the beetle (Allomyrina dichotoma) is reported here. Allo A stimulated [³H] thymidine uptake of mouse thymocytes in the presence of IL-1. The allo A assay was more sensitive than the PHA or PNA^- thymocyte assay, especially at low doses of IL-1. Optimal conditions for the allo A assay were as follows: allo A, 2.5-5.0μg/ml; whole thymocytes, 0.5-1.0×10⁶ cells/well; incubation time, 72-96hr. The assay is sensitive and convenient and can easily be performed in any laboratory.

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Human IgG of four subclasses, semi-purified from pooled human serum by a series of DEAE ion exchange and protein A affinity chromatographies, were used as immunogens and initial screening antigens to produce subclass-specific and -restricted monoclonal antibodies (McAbs). These McAbs were bound to CNBr-activated Sepharose 4B and utilized in immunoaffinity chromatography to prepare four polyclonal human IgG subclasses of satisfactory purities, which were then used as final screening antigens. Subclass-specific McAbs thus chosen were further evaluated for subclass- and especially allotype-specificity using a panel of monoclonal IgG myeloma proteins with representative Gm markers for each subclass in micro enzyme-linked immunosorbent assay (ELISA). A total of 10 clones of subclass-specific McAbs (one for anti-IgG₁, three anti-IgG₂, two anti-IgG₃, four anti-IgG₄) were established. Among them, IgG₂-specific clones of HG2-30F and HG2-56F, IgG₃-specific HG3-7C and HG3-32C, and IgG₄-specific HG4-53G McAbs were superior to the corresponding specificity standard McAbs chosen by the Human Immunoglobulins Subcommittee of the WHO/International Union of Immunological Societies (IUIS) in 1985. As allotype-specific McAbs, HG1-1E for G1m(az) and HG3-3B for G3m(b) were obtained. In micro ELISA of this study as well as all protocols of the previous WHO/IUIS collaborative study, antigens (myeloma IgG subclasses) were immobilized or fixed to a solid phase, resulting in possible variations in their epitope expressions. We developed a new assay system, micro radioimmunoassay (RIA), in which reactivities of McAbs against free IgG subclasses in solution can be evaluated. HG2-30F, having extremely high reactivities to coated IgG₂ in micro ELISA, remarkably reduced its reactivities to free IgG₂ in solution in micro RIA. Two other clones also showed some different reactivities in micro RIA and micro ELISA. We believe that this micro RIA is valuable for evaluation of McAbs reactivities against native human IgG subclasses in solution.

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We were able to develop a method with which to successfully and specifically detect virus particles under the electron microscope by using magnetite. This method was devised on the principle that magnetite-labeled antibody or magnetite coupled with protein A selectively bind virus or antibody-treated virus particles on the electron microscope grid by the action of an electromagnet. Another advantage characterizing the technique is the possibility of detection of a small number of virus particles. This is done through a process of concentration and purification of the reaction complexes trapped rigidly by magnetic force.

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Absorption of a pooled human gamma globulin preparation with acetone-treated measles virus-infected cells removed all antibodies to measles virus antigens except a portion of the antibody to the fusion (F) protein. The residual anti-F antibody had hemolysis-inhibiting and virus-neutralizing activities, inhibited spread of infection through cell fusion, and was effective in protection of passively immunized mice from fatal measles encephalitis, providing evidence for the protective role of human antibody to the F protein of measles virus.

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