The extracts having diverse immunostimulating activities were obtained as a water-phase fraction from four bacterial species representing the 4 genera (Mycobacterium, Nocardia, Gordona, and Rhodococcus) of Mycobacteriaceae by the phenol-water method, which is commonly used for extraction of endotoxic lipopolysaccharides (LPS) from gram-negative bacteria and amphipathic substances from gram-positives. These fractions, especially those of G. aurantiaca and R. terrae, showed strong stimulatory effects on murine splenocytes, macrophages of mice and guinea pigs, the immunoadjuvant activities in guinea pigs and mice, and the distinct activities inducing a tumor necrosis factor and interferons α/β and γ in primed mice. The fractions from G. aurantiaca and R. terrae exhibited potent pyrogenicity and the ability to activate the clotting enzyme cascade of the horseshoe crab (Tachypleus tridentatus). Some of these biological activities were not very different from the potency of the reference endotoxic LPS derived from Escherichia coli or Fusobacterium nucleatum. But the test fractions neither showed the activity to prepare rabbit skin to the local Shwartzman reaction, nor reacted with anti-lipid A conventional and monoclonal antibodies. Furthermore, unlike LPS, these fractions stimulated the splenocytes of C3H/HeJ mice (LPS-Nonresponder). Although the fractions showing the above biological activities have not yet been adequately purified, they contained polysaccharides, whose main constituent sugar is mannose with a smaller amount of arabinose, fatty acids consisting primarily of palmitic, stearic, and tuberculostearic acids, and small amounts of peptides and amino sugars. Since components characteristic of known immunomodulators of bacterial origin, namely endotoxins (lipid A's), cell wall peptidoglycans, lipoteichoic acids, cord factors (trehalose dimycolates), or deoxyribonucleic acids, were practically not detected in these fractions, the agent responsible for the above bioactivities is considered to be a novel substance different from the known, bacterial immunomodulators.

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Leukotoxic activity in Actinobacillus(Haemophilus) actinomycetemcomitans isolated from patients with rapidly progressive periodontitis (RP), gingivitis (G), and juvenile periodontitis (JP), and several oral bacteria, was determined by observation of morphological changes in polymorphonuclear leukocytes (PMNs). Many A. actinomycetemcomitans isolates yielded both rough-surfaced and umbonate-shaped colonies (A-type), and smooth-surfaced and convex-shaped colonies (B-type), when stock cultures were streaked on agar medium. Both types of cells were identical in terms of Gram stain, cell morphology, sugar fermentation profile, nitrate reduction and cellular fatty acid composition. Sonic extracts were prepared from 32 A. actinomycetemcomitans strains isolated from patients and from 3 American Type Culture Collection (ATCC) strains. Sonic extracts from 8 isolates and 2 ATCC strains induced sphering of PMNs during a 45-50min period of incubation at 37C. Extracts from the other oral bacteria had no effects on PMN morphology. The sphered PMNs were found by their fluorochromatic-negative reactions to be damaged cells. The leukotoxic substance was heat-sensitive (56C, 30min), trypsin-sensitive and did not induce sphering of PMNs at 4C. There was no clear correlation between colony type and leukotoxicity. Among 8 leukotoxic strains, 5 were isolates from an RP patient.

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By the introduction of Sabin oral poliovirus vaccine, the circulation of wild type polioviruses has virtually disappeared in Japan. However, an outbreak of poliomyelitis associated with sporadic transmission of type 1 wild strain occurred in Nagano in 1980. Furthermore, we found that some type 1 wild strains were introduced into Japan from abroad in 1981. In recent surveys, the two poliovirus type 1 isolates which have non-vaccine-like antigenic character were detected in Aichi. Then, an investigation to trace the origin of these strains was performed, by using intratypic serodifferentiation and biochemical techniques. Electrophoretic migration patterns of their structural polypeptides were quite different from the vaccine virus. In the oligonucleotide mapping, however, one of them gave patterns very similar to those of the vaccine virus. We could conclude that one originated most probably from wild strains, and the other was an antigenic variant derived from the vaccine virus. It showed that oligonucleotide mapping was a very useful method for identification of antigenic modified Sabin type 1 derivatives.

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A follow-up study of type C influenza in a children's home was made where the first outbreak of type C influenza occurred in March, 1981. During the survey period of 2 years, 2 additional outbreaks occurred in April and October, 1982 and 4 cases of the secondary and 2 cases of the tertiary infections were serologically confirmed. All of the children exposed to the outbreaks, except 2 particular cases who were suffering from German measles, showed similar mild respiratory symptoms characterized by fever and long-lasting nasal discharge, irrespective of primary, secondary, and tertiary infections. No case of inapparent infection was observed. Incubation period was estimated to be not longer than 5 days and the period of virus shedding, to be longer than 22 days. Antibody response in the sera of patients to type C influenza virus was equally good after every infection, although it was not efficient to prevent the succeeding infection. Factors involved in the repeated infections of type C influenza were discussed.

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Ultrasonicated Toxoplasma gondii (RH strain) tachyzoite extract was chromatographed on Sephadex G-200, and one main peak (93, 000M.W.) and three small peaks (>160, 000M.W., 110, 000M.W., and 20, 000M.W.) were eluted. Toxoplasma-specific proliferative T cell responses of peripheral blood leukocytes (PBL) from a patient with acute toxoplasmosis caused by accidental injection of tachyzoites of the protozoa were sequentially examined by using these fractioned antigens. As early as one week after the accidental injection of the protozoa, significant proliferative responses of PBL could be detected. The reaction of proliferative T cells was observed occurring mainly with Fr. II antigen. Then T cells began to respond to Fr. I and III in addition to Fr. II 3 weeks after the injection. Thus, expansion of antigen specificity in Toxoplasma-specific T cell responses was observed at the initial stage of acquired acute toxoplasmosis.

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The mechanism by which polymorphonuclear leukocytes (PMNs) kill ingested Bacteroides fragilis was examined using PMNs from patients with chronic granulomatous disease (CGD) which is an inherited disease characterized by the defect of their PMNs in oxygen-radical generation. The phagocytosis of B. fragilis by PMNs from CGD patients was comparable to that by normal PMNs. Although CGD cells killed B. fragilis to some extent, they did so less effectively than the normal PMNS. B. fragilis was killed by a xanthine oxidase system that generates oxygen radicals. When PMNs were incubated with opsonized B. fragilis, B. fragilis triggered the release of O₂^- and H₂O₂ from normal PMNs. Thus, normal PMNs appear to kill B. fragilis by both oxygen-dependent and oxygen-independent mechanisms.

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The present study investigates some of the immunogenetic bases for tolerance of anti-allo-delayed type hypersensitivity (DTH) responses as induced by pre-inoculating allogeneic cells via portal venous (p.v.) route. BALB/c mice were injected with totally allogeneic C57BL/6 or H-2 incompatible BALB.B spleen cells via p.v. route. These mice not only failed to exhibit anti-H-2^b DTH responses, but also abrogated the potential to generate H-2^b-specific DTH responses as induced by the subsequent immunization with H-2^b spleen cells via subcutaneous (s.c.) route. The p.v. presensitization with allogeneic spleen cells differing at either class I or class II of major histocompatibility complex (MHC) resulted in the tolerance induction of DTH responses to the respective allogeneic class I or class II MHC antigens. Moreover, the p.v. administration of the class I-positive allogeneic cell fraction depleted of class II-positive component into recipients differing at both class I and class II was capable of inducing anti-class I DTH tolerance. These results indicate that anti-allo-class I or class II DTH tolerance can be induced independently and that the existence of class II antigens on p.v.-presensitized cells is not necessarily required for the tolerance induction of anti-alto-class I DTH response.

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