Identification of B-cell linear epitopes in domains 1-3 of pyolysin of Trueperella pyogenes using polyclonal antibodies

Trueperella pyogenes is an important opportunistic pathogen. Pyolysin (PLO) makes important contributions to the pathogenicity of T. pyogenes. However, the structure and function of PLO has not been well documented. In the current study, epitopes in domain 1-3 of PLO have been mapped using rabbit anti-recombinant PLO (rPLO) polyclonal antibodies, and then the results were re-checked by using mouse and chicken anti-rPLO polyclonal antibodies, respectively. The results indicated that the region of aa 281-393 in PLO could not elicit antibodies against linear epitopes. A total of six B cell linear epitopes have been found in domain 1 of PLO. Two of the six epitopes (EP1 and EP2) were used to immunize mice and chicken. Chicken anti-EP1 and anti-EP2 serum and mouse anti-EP2 serum could react with rPLO and corresponding epitope polypeptide in western blot assay; however, only mouse anti-EP2 serum shows weak anti-hemolysis effect in the rPLO and sheep red blood system. Our results provide some new information to the research field of PLO structure and function.

Functional and structural properties of CbpA, a collagen-binding protein from Arcanobacterium pyogenes

Arcanobacterium pyogenes, an opportunistic pathogen of economically important food animals, is the causative agent of liver abscesses in feedlot cattle, osteomyelitis in turkeys, and pneumonia and arthritis in pigs. Previous studies identified the first A. pyogenes adhesin, CbpA, a protein located on the bacterial surface which has the ability to bind collagen and promotes adhesion to the host cells. The protein has an N-terminal ligand-binding region (region A) and a C-terminal repetitive domain (region B). In this study we found that CbpA bound to almost all the collagen types tested but not to other proteins, and it displayed a propensity to interact with several collagenous peptides derived by CNBr cleavage of type I and II collagens. The K(D) values of CbpA for type I and II collagens and collagen peptides determined by solid-phase binding assay and intrinsic tryptophan fluorescence were in the range of 1-15 nM. It was also found that CbpA and its A region bound fibronectin, and that collagen and fibronectin interacted with distinct subsites. Anti-CbpA antibodies were effective at inhibiting both binding of isolated CbpA and bacterial adhesion to immobilized collagen, suggesting that CbpA is a functional collagen-binding adhesin. Analysis of the immunological cross-reactivity of CbpA with antibodies against other bacterial collagen-binding proteins indicated that CbpA is immunologically related to ACE from Enterococcus faecalis but not to CNA from Staphylococcus aureus or Acm from Enterococcus faecium. Far-UV and near-UV circular dichroism spectra showed that full-length CbpA and its region A are mainly composed of beta-sheet with only a minor alpha-helical component and that both the proteins have a well-defined tertiary structure.

Perinatal exposure to low doses of PCB 153 and PCB 126 affects maternal and neonatal immunity in goat kids

Pregnant does (10 goats/group) were dosed orally either with polychlorinated biphenyl (PCB) 153 (98 microg/kg body weight/d) or PCB 126 (ng/kg body weight/d) dissolved in corn oil or with corn oil only (control group) from gestation day (GD) 60 until delivery. An additional group (n = 5) of pregnant does received the synthetic estrogen diethylstilbestrol (DES; 0.4 microg/kg body weight/d) by intramuscular injection using the same treatment schedule as for the PCB groups. Blood samples for immune analysis were collected at wk 0, 1, 2, 4, 6, and 8 of age. The effects of perinatal PCB exposure on postnatal humoral immune responses were examined by assessing the levels of total immunoglobulin G (IgG) and immunoglobulins to specific microbes at wk 0, 1, 2, 4, 6, and 8 of age, and immune responses following immunization of kids at 2 wk of age. PCB 153 exposure suppressed maternal and neonatal immunity, as demonstrated by reduced transfer of maternal IgG and specific antibodies to the environmental microbes Arcanobacterium pyogenes, Mannheimia haemolytica, and reovirus (REO-1). Furthermore, PCB 153 reduced the level of maternal antibodies to Mycobacterium avium paratuberculosis and equine influenza virus (EIV-1) in the newborn kids. The antibody response against EIV-1 was significantly higher in PCB 153-exposed kids 2 wk following immunization. PCB 126 exposure reduced the levels of maternal antibodies to REO-1. In contrast, gestational exposure to PCB 126 increased the concentrations of maternal antibodies to tetanus toxoid. No differences from controls in plasma total IgG levels at birth or colostrum IgG concentrations were observed in the PCB 126-treated does. However, a significant reduction in IgG levels from GD 60 until delivery was found in this group. Gestational exposure to DES reduced the concentrations of maternal antibodies against A. pyogenes, M. haemolytica, M. avium Paratuberculosis, and REO-1. These results suggest that perinatal exposure to low doses of PCB 126 and PCB 153 affects the maternal immunity in kids. The difference in responses between PCB 126 and PCB 153 treatment groups may strengthen the hypothesis that PCBs mediate immunotoxic effects through both AhR-dependent and -independent mechanisms. The observation that the effects produced by PCB 153 resembled those produced by DES raises the question of whether this congener may modulate immunity by estrogenic mechanisms.

The Arcanobacterium pyogenes collagen-binding protein, CbpA, promotes adhesion to host cells

Arcanobacterium pyogenes is an opportunistic pathogen associated with suppurative diseases in economically important food animals such as cattle, pigs, and turkeys. A. pyogenes adheres to host epithelial cells, and adhesion is promoted by the action of neuraminidase, which is expressed by this organism. However, a neuraminidase-deficient mutant of A. pyogenes only had a reduced ability to adhere to host epithelial cells, indicating that other factors are involved in adhesion. Far Western blotting revealed the presence of an approximately 120-kDa A. pyogenes cell wall protein that binds collagen type I. The 3.5-kb gene that encodes the 124.7-kDa CbpA protein was cloned, and sequence analysis indicated that CbpA contains a typical MSCRAMM protein domain structure. Recombinant, six-His-tagged CbpA (HIS-CbpA) was capable of binding collagen types I, II, and IV but not fibronectin. In addition, CbpA was involved in the ability of A. pyogenes to adhere to HeLa and 3T6 cells, as a cbpA knockout strain had 38.2 and 57.0% of wild-type adhesion, respectively. This defect could be complemented by providing cbpA on a multicopy plasmid. Furthermore, HIS-CbpA blocked A. pyogenes adhesion to HeLa or 3T6 cells in a dose-dependent manner. cbpA was only present in 48% of the A. pyogenes strains tested (n = 75), and introduction of plasmid-encoded cbpA into a naturally cbpA-deficient strain increased the ability of this strain to bind to HeLa and 3T6 cells 2.9- and 5.7-fold, respectively. These data indicate that CbpA, a collagen-binding protein of A. pyogenes, plays a role in the adhesion of this organism to host cells.

Immunization with genetic toxoids of the Arcanobacterium pyogenes cholesterol-dependent cytolysin, pyolysin, protects mice against infection

Pyolysin (PLO), a cholesterol-dependent cytolysin expressed by Arcanobacterium pyogenes, is an important host-protective antigen. However, this molecule is toxic and requires inactivation prior to its use as a vaccine. Three genetically toxoided, nonhemolytic PLO molecules, HIS-PLO.F(497), HIS-PLO.Delta P(499), and HIS-PLO.A(522), were found to be nontoxic, and vaccinated mice were protected from infection, indicating the potential of these toxoids as vaccines. Furthermore, in a mouse model of infection, A. pyogenes carrying the F(497) mutation was as attenuated as a PLO-deficient strain, indicating that the cytolytic activity of PLO is important in virulence.

Progesterone increases susceptibility of gilts to uterine infections after intrauterine inoculation with infectious bacteria

In cattle and sheep, a progestogenated uterus is susceptible to infections, but this is not well documented for pigs. Therefore, the effects of day of the estrous cycle and progesterone on the susceptibility to uterine infections were evaluated. Gilts (n = 5 per group) were assigned to treatments in 2 x 2 factorial arrays. In Exp. 1, day of cycle and bacterial challenge were main effects. On d 0 or 8, uteri were inoculated with either 70 x 10(7) cfu of Escherichia coli and 150 x 10(7) cfu of Arcanobacterium pyogenes in PBS or with PBS. In Exp. 2, ovariectomy (OVEX) and progesterone treatment were main effects. On d 0, gilts were ovariectomized or a sham procedure was performed. After surgery, gilts received i.m. injections of progesterone (10 mg/5 mL) or 5 mL of safflower oil diluent twice daily. On d 8, gilts were inoculated with the same doses of bacteria as in Exp. 1. In Exp. 1 and 2, vena caval blood was collected for 4 d, after which uteri were collected. Sediment and ability to culture E. coli and A. pyogenes from uterine flushings were used to diagnose infections. Differential white blood cell counts and lymphocyte response to concanavalin A (Con A) and lipopolysaccharides (LPS) were used to measure lymphocyte proliferation. Progesterone, estradiol-17beta, prostaglandin F2alpha, (PGF2alpha), and prostaglandin E2 (PGE2) were measured in vena caval blood. In Exp. 1, d-8 gilts receiving bacteria developed infections, but d-0 gilts receiving bacteria did not. Daily percentages of neutrophils and lymphocytes changed (P < 0.05) with cycle day and bacterial challenge. Basal- and Con A-stimulated lymphocyte proliferation were greater (P < 0.05) for d-0 than for d-8 gilts. Concentrations of PGF2, (P < 0.01) and PGE2 (P < 0.05) increased after bacterial challenge, regardless of stage of the estrous cycle at the time of inoculation. In Exp. 2, OVEX decreased (P < 0.001) and progesterone treatment increased (P < 0.001) progesterone concentrations, and OVEX decreased (P < 0.01) estradiol-17beta. Gilts with ovarian and/or exogenous progesterone developed infections. Daily percentages of neutrophils and lymphocytes changed in response to OVEX, and neutrophils changed (P < 0.05) in response to endogenous and exogenous progesterone. Lymphocyte proliferation in response to Con A and LPS increased (P < 0.05) with OVEX and decreased (P < 0.05) with progesterone treatment. We conclude that endogenous and exogenous progesterone reduce the ability of the uterus in gilts to resist infections.

Effect of amino acid substitutions in the epitope regions of pyolysin from Arcanobacterium pyogenes

Pyolysin (PLO), secreted by Arcanobacterium pyogenes, is a novel member of the thiol-activated cytolysin (TACY, cholesterol-dependent cytolysin) family of bacterial toxins. Recently, we demonstrated that the epitopes of monoclonal antibodies (mAbs) S, H, C, and G lie in the regions of amino acids regions 55-73, 123-166, 482-506, and 482-506 of PLO, respectively, by the reaction of mAbs with truncated PLOs. In this study, we substituted the amino acids in these epitope regions of PLO by site-directed mutagenesis and examined the effect of these amino acid substitutions. Mutants I70S/R71A/L73S, Y131S/P132S, and L163S/P164S for mAbs H or S completely lost the hemolytic activity of the proteins, but these mutants still bound to erythrocyte membranes. Mutants L495S/W497S and W500S/W501S for mAbs C and G also completely lost their hemolytic activity, but still bound to erythrocyte membranes. In the undecapeptide region of PLO, the cysteine residue required for thiol activation is replaced with alanine. Therefore, we substituted Ala-492 of the undecapeptide region for Cys. The hemolytic activity of this mutant A492C decreased by adding hydrogen peroxide or storing at 4 degrees C, and the decreased hemolytic activity was restored by adding L-cysteine.

Molecular characterization of the pore-forming toxin, pyolysin, a major virulence determinant of Arcanobacterium pyogenes

Arcanobacterium pyogenes is a common inhabitant and opportunistic pathogen of domestic animals. The pathogenesis of this organism in a range of suppurative diseases is not well understood. However, the development of genetic techniques to study this organism has allowed advances in the analysis of A. pyogenes virulence factors. A major step in this analysis was the identification and cloning of the A. pyogenes hemolytic exotoxin, pyolysin (PLO). PLO is the most divergent member of the cholesterol-binding pore-forming family of toxins. PLO is also divergent in a C-terminal undecapeptide motif which is almost invariant among other members of the family. This divergent undecapeptide motif is required for the full cytolytic activity of PLO and is also responsible for its oxygen-resistant nature. Insertional inactivation of the plo gene results in a significant reduction in virulence in an intraperitoneal mouse model of infection. The virulence of the plo mutant can be restored by providing PLO in trans, suggesting that PLO is a major virulence factor in A. pyogenes pathogenesis in mice. Results of previous vaccination trials with crude antigens against A. pyogenes infection in domestic animals and mice have been equivocal at best. However, a recombinant PLO-based subunit vaccine protected mice from experimental A. pyogenes infection, indicating that PLO is also an important host protective antigen. These results provide promise that the dogma that domestic animals are recalcitrant to vaccination against A. pyogenes infection may prove false.

Analysis of the functional domains of Arcanobacterium pyogenes pyolysin using monoclonal antibodies

Pyolysin (PLO), secreted by Arcanobacterium pyogenes, is a novel member of the thiol-activated cytolysin (TACY) family of bacterial toxins. Four monoclonal antibodies (mAbs) to PLO were prepared for the analysis of functional domains of this toxin. Two (mAbs S and H) of these markedly inhibited the hemolytic activity of PLO, but the inhibiting activity of the other two antibodies (mAbs C and G) was weaker. Subsequently, nine truncated PLOs were derived from recombinant Escherichia coli by various deletions from the N-terminus. Strong hemolytic activity was recognized in truncates of PLO following the deletion of 30 or 55 amino acids, but not in the truncate with deletion of 74 residues. Truncated PLOs were used in immunoblotting experiments to locate the epitopes for the mAbs. The epitope for mAbs C and G lies within the undecapeptide region (amino acids 487-505) of the C-terminus of PLO, which seems to be the binding site to erythrocytes. In contrast, the epitopes for mAbs S and H, which showed strong neutralizing activity, were found to lie in the N-terminal regions of the PLO ranging from 55 to 73 and 123 to 166 amino acids, respectively. From these results, it seems that the N-terminal region of PLO, in particular, the region of amino acids 55-74 is important for hemolytic activity.

Immunostimulatory effect of Rothia dentocariosa in mice

In mice killed Rothia dentocariosa cells in doses of about 1.5 mg dry weight activated anti-infection immunity to Listeria antigens and anti-tumour immunity to the ascitic form of mouse sarcoma S-180. Their probable target site is the macrophage. The Rothia-activated macrophages in human gingiva may take part in the pathogenesis of periodontal disease. Three models were employed to verify the immunostimulating properties of preventively administered Rothia dentocariosa bacterin-1) a spleen macrophage migration test, using mice immunized with Listeria innocua, with the soluble listeria Ei antigen as the antigenic signal, 2) determination of the increase in the Listeria monocytogenes LD50 for mice and 3) the prolongation of survival of mice carrying the S-180 tumour. In all three cases, the administration of Rothia bacterin stimulated the immune response to the later administration of other antigens. Furthermore, in the macrophage migration inhibition test, the chemotaxis of non-immune mouse macrophages was found to be stimulated. This gives evidence of the fact that Rothia bacterin has an activating effect on these macrophages.

Comparison of polyclonal and monoclonal antibodies to Actinomyces and Arachnia species

Polyclonal (PoAbs) and monoclonal (MoAbs) antibodies were produced to Actinomyces israelii serotypes 1 and 2, to Actinomyces naeslundii, and to Arachnia propionica, and their specificities were studied by an enzyme immunoassay (EIA). All PoAbs except those to A. propionica reacted also with at least one other Actinomyces species. Only the MoAb to A. naeslundii proved to be more specific than the corresponding PoAbs. This MoAb did not crossreact with other Actinomyces or Arachnia species, nor with any other anaerobic or aerobic bacteria studied by inhibition EIA. Immunoblotting studies indicated that the antibody specific to A. naeslundii is directed against a large molecular weight antigen (greater than 150 kd), probably polysaccharide in nature. The produced PoAbs and MoAbs can be used for further analyses of the antigenic determinants of different Actinomyces and Arachnia species.

Immunocytochemical demonstration of Actinomyces species and Arachnia propionica in periapical infections

Immunocytochemical methods were used for the demonstration of Actinomyces israelii, Actinomyces naeslundii and Arachnia propionica in bacterial colonies found in 7 routine biopsies from periapical inflammatory lesions. All 3 species were found in one specimen, both A. israelii and A. propionica in 3 specimens, and one of each species in the remaining 3 biopsies. Specificity controls by enzyme immunoassay showed that antiserum to A. israelii reacted also with A. odontolyticus, and that to A. naeslundii with A. viscosus, while antiserum to A. propionica did not show any cross-reactions with Actinomyces species. The results indicate that immunocytochemical methods can be used for the diagnosis of periapical actinomycosis at the species level. Actinomyces and Arachnia species seem to have an important role in the pathogenesis of complicated periapical infections.

Synergistic effect of concanavalin A and Bu-WSA on DNA synthesis in human peripheral blood lymphocytes

Butanol-extracted water soluble adjuvant (Bu-WSA) obtained from Bacterionema matruchotii was not mitogenic for human peripheral blood mononuclear cells (PBM) but was capable of enhancing (3H) thymidine uptake of T cells stimulated by concanavalin A (Con A) in the presence of B cells or macrophages (M phi) in vitro. The mechanisms of the synergy of Con A and Bu-WSA were studied by using separated cell populations from PBM. Both subfractioned OKT4+ and OKT8+ cells were responsive to co-stimulation by Con A and Bu-WSA in the presence of an accessory cell population. Allogeneic B cells and M phi as well as autologous cells had helper function as accessory cells. Heavy irradiation with gamma-rays did not affect the function of the accessory cells, but previous treatment of B cells with anti-Ig serum plus complement (C) or treatment of M phi with anti-M phi serum plus C deprived them of their function. The treatment of accessory cells with anti-HLA-DR serum, regardless of the presence or absence of C, resulted in loss of their helper function. Cultures in Marbrook-type vessels showed that a mixed cell population of T cells and accessory cells in the lower chamber produced some active factor(s) after co-stimulation with Con A and Bu-WSA, and by passing through the membrane filter separating the chambers, the factor(s) enhanced the proliferation of the Con A-activated T cell population in the upper chamber. The factor(s) was presumed to be interleukin 2 (IL 2), because it supported the growth of IL 2-dependent CTLL cells. These results indicate that the synergy of Con A and Bu-WSA on the proliferative response of human PBM is due to the elevation of growth factor production from T cells stimulated by those mitogens.

Blastogenic response of human lymphocytes to antigens of Rothia dentocariosa

Peripheral blood lymphocytes were isolated from 20 individuals with varying degrees of periodontal health and classified as either normal, having acute gingivitis (GV), or chronic periodontitis (PD). Crude cell wall and cytoplasmic antigens were derived from Rothia dentocariosa (RD), were applied to lymphocyte microcultures, and subjected to radioactive thymidine; the resulting lymphocyte blastogenesis (LB) was surveyed with a scintillation counter. All three groups displayed statistically similar levels of stimulation (F = 0.71), demonstrating that crude antigens of RD are not appreciably active in vitro studies of cell-mediated immunity (CMI), as measured by LB.

In vitro proliferative response and polyclonal antibody production in spleen cells of immunologically defective CBA/N and C3H/HeJ mice by water-soluble adjuvant (Bu-WSA) extracted from Bacterionema matruchotii

Mitogenicity and the polyclonal plaque forming cell (PFC)-inducing property of a water soluble-adjuvant extracted from Bacterionema matruchotii by butanol (Bu-WSA) were examined in vitro in the spleen cells of hybrid (CBA/N female X BALB/c male)F1 mice and C3H strain of mice. The hybrid F1 male cells which expressed a CBA/N-defect were unable to respond to Bu-WSA, when assessed by the incorporation of [3H]thymidine into the cells and the generation of anti-trinitrophenyl (TNP)-PFC or autoantibody PFC defined by the anti-bromelain-treated mouse erythrocyte PFC assay. However, hybrid F1 female cells with normal traits responded to Bu-WSA. Cultured spleen cells of bacterial lipopolysaccharide (LPS)-nonresponsive (C3H/HeJ mice responded to Bu-WSA as in the case of cells of LPS-responsive C3H/He mice, and the [3H]thymidine-uptakes and the numbers of PFC in these culture cells increased. Re-extraction of Bu-WSA by phenol did not affect its activities, while the activity of butanol-extracted LPS and C3H/HeJ cells decreased after re-extraction by the same procedure with phenol.

Role of surface fimbriae (fibrils) in the adsorption of Actinomyces species to saliva-treated hydroxyapatite surfaces

We studied the adsorption, morphological, and serological characteristics of selected Actinomyces and related species. Evaluation of uranyl acetate-stained cells by electron microscopy revealed wide variations among strains in the frequency of surface fimbriae. These variations did not always correlate with the percent adsorption to saliva-treated hydroxyapatite of the various Actinomyces strains. However, two strains of Rothia dentocariosa possessing no surface fimbriae and five strains of A. israelii possessing very few surface fimbriae exhibited feeble adsorption to saliva-treated hydroxyapatite. Although the calculated number of adsorption sites on saliva-treated hydroxypatite did not vary widely among the strains tested, significant differences were observed in the affinities calculated for some species or serotypes. The mean affinities for strains of A. viscosus serotype 2 and A. naeslundii serotype 3 were similar, and these strains adsorbed well to saliva-treated hydroxyapatite. The mean adsorption and affinity for the A. naeslundii strain serotype 1 and all strains of A. israelii tested were significantly less than those determined for the A. viscosus serotype 2 or A. naeslundii serotype 3 strains. Adsorption inhibition activity of antiserum to strain T14V, previously shown to be solely related to antibodies in immune serum directed against the VA1 fimbria (fibril) antigen, was removed by preadsorption of the antiserum with most A. viscosus and A. naelundii strains, but not with A. israelii strains. This suggests some cross-reactivity among strains of A. viscosus and A. naeslundii but not A. israelii. Adsorption to saliva-treated hydroxyapatite of all A. viscosus and A. naeslundii strains tested was strongly inhibited by fimbriae isolated from A. viscosus strain T14V. Collectively, these data suggest that the adsorption of certain A. viscosus and A. naeslundii strains is mediated by surface fimbriae, many of which appear serologically cross-reactive with strain T14V fimbriae.

[Characteristics of the soluble antigens of bifidobacteria]

The immunological study of aqueous buffer extracts obtained from 45 strains of bifidobacteria belonging to the species B. bifidum, B. longum, B. adducens, B. breve, B. infantis and B. parvulorum was made. This study revealed 3 levels of the immunological specificity of soluble bifidobacterial proteins: common to the genus Bifidobacterium, common to a limited number of strains belonging to one or several species of bifidobacteria and strain-specific.

Detection of proteinases in electrophoretograms of complex mixtures

A simple, sensitive technique for detecting proteolytic enzyme zones on electrophoretograms by making contact print zymograms is described. The method is applicable to electrophoretograms prepared on a variety of support media, immunoelectrophoretograms or isoelectric focusing patterns on various media. The contact print zymograms are prepared by placing unfixed, unstained electrophoretograms in contact with a thin film of casein which has diffused into a layer of agarose supported by a hydrophilic polyester film. After staining the casein film with Coomassie blue, the proteolytic zones are detected as clear zones against a blue background. The method can detect as little as 9 ng of trypsin. The utility of the method is illustrated by detection of the proteinase enzymes in thermophilic actinomycete antigen preparations separated by polyacrylamide electrophoresis, crossed immunoelectrophoresis and isoelectric focusing on agarose and granulated dextran supports.

Mitogenic activity of water-soluble adjuvant obtained from Bacterionema matruchotii

A butanol-extracted water-soluble adjuvant (Bu-WSA) obtained from Bacterionema matruchotii, a gram-positive oral bacterium, is a potent B-cell mitogen for murine lymphocytes in vitro. [(3)H]thymidine uptake of cultured spleen cells of BALB/c mice and nude athymic mice was greatly enhanced by the presence of Bu-WSA. Spleen cells which had been treated previously with rabbit anti-mouse thymocyte serum and guinea pig complement responded to Bu-WSA, whereas thymocytes and nylon wool column-filtered spleen cells were unresponsive to it. It was necessary for the adjuvant to be in the culture for at least 24 h in order to obtain significant lymphocyte activation. As macrophage-depleted spleen cells still responded to Bu-WSA, the proliferative response of lymphocytes seems to be independent of the presence of macrophages. The degree of response of spleen cells stimulated by a mixture of Bu-WSA and lipopolysaccharide (LPS) was very close to the sum of the responses stimulated by Bu-WSA and LPS individually. Spleen cells of LPS-injected mice, which were refractory to LPS, responded to Bu-WSA. On the other hand, the spleen cells of Bu-WSA-injected mice responded to LPS but not to Bu-WSA. Furthermore, the cells obtained from the spleens of mice which had been heavily cobalt 60 irradiated and bone marrow reconstituted 3 weeks in advance responded to LPS but not to Bu-WSA. Therefore, it appears that the cells responding to Bu-WSA were not identical to those responding to LPS.

Preliminary quantification of immunological relationships among the transaldolases of the genus Bifidobacterium

The immunological relatedness among the transaldolases (dihydroxyacetone transferase, E.C. 2.2.1.2) of twenty species of the genus Bifidobacterum has been tested by the microcomplement fixation method, using B. thermophilum (B. ruminale) RU326 (= ATCC 25866), B. cuniculi RA93 (= ATCC 27916) and B. 'minimum' (DNA homology group) F392 (= ATCC 27916) as references. Based on the serological relationships of the transaldolases, expressed either as indices of dissimilarity or as immunological distances, the twenty species of the genus Bifidobacterium were arranged into clusters. These clusters generally coincided with the immunological groups obtained previously by the immunodiffusion method (Sgorbati and Scardovi, 1979).

Immunological relationships among transaldolases in the genus Bifidobacterium

Antisera were prepared against electrophoretically homogeneous transaldolase (dihydroxyacetone transferase, E.C. 2.2.1.2.) of Bifidobacterium thermophilum (B. ruminale) RU326 (ATCC25866), B. cuniculi RA93 (ATCC27916) and B. 'minimum' (homology group) F392 (ATCC 27538). Crude extracts of eighty six strains previously assigned to twenty one species of the genus Bifidobacterium on the basis of deoxyribonouclelic acid (DNA) homology (DNA-DNA hybridization), were compared by double diffusion tests on Ouchterlony plates. Eight groups of identical antigenic specificity were recognized. By analysis of the spur formation, the groups of identical specificity were arranged in preliminary sequences of decreasing similarity to each of the three homologous transaldolases used as reference points. The relationships between immunological data and the genetic similarity among the species of the genus measured by means of DNA-DNA hybridization were discussed together with some relevant points of bifidal ecology.

Water-soluble adjuvant obtained from Bacterionema matruchotii

The adjuvant effect of a butanol-extracted water-soluble adjuvant (bu-WSA) obtained from Bacterionemia matruchotii, a gram-positive oral bacteria, was studied on the antibody response at the plaque-forming cell (PFC) level in murine spleens. Intraperitoneal injection of Bu-WSA caused significant increase in direct PFC numbers in spleens 1 to 3 days after the antigenic stimulation with sheep erythrocytes (SRBC). Injection of 100 to 800 microgram of Bu-WSA was effective, and 400 microgram of Bu-WSA seemed to be the optimum for induction of the adjuvant effect. The adjuvant effect was strongest when Bu-WSA was injected at the same time as the SRBC, but some effect was still observed when Bu-WSA was injected 7 days before or 1 day after the immunization. The adjuvant effect of Bu-WSA was greatest at high dose of antigen. The mice injected with Bu-WSA at the time of priming SRBC and then immunized with trinitrophenylated SRBC showed greater anti-trinitrophenyl PFC response than controls without the injection of Bu-WSA. These findings suggest that a part of the adjuvant effect of Bu-WSA depends on thymic cell function and another part does not.

Levan production by a strain of Rothia: activation of complement resulting in cytotoxicity for human gingival cells

An extracellular polysaccharide identified as a levan has been isolated from Rothia dentocariosa, strain 477 serotype 2. The levan produced by strain 477 has been found to activate the complement cascade in the absence of specific antibodies. This activation was found to be cytotoxic for human gingival cells in tissue culture.

Longitudinal studies of immunological parameters in Farmer's lung

A group of patients with serum precipitins against M. faeni culture filtrate antigens and with clinically proven farmer's lung disease was examined. A group of precipitin-negative farmers with comparable antigen exposure and with unrelated forms of pulmonary disease served as control. Immunoglobulins G and A were elevated at first consultation in the majority of the acute cases of farmer's lung. Immunological parameters normalized during corticosteroid medication and antigen avoidance. Autologous complement (C) consumption by M. Faeni antigens proved valuable for diagnostic purposes. Despite normalizing immunological factors and subsiding symptomatology, C-consuming antibody levels remained constant.

Experimental production of granulomatous pneumonitis. Comparison of immunological and morphological sequelae with particulate and soluble antigens administered via the respiratory route

Rabbits were sensitized with either a soluble protein antigen (BSA) or a particulate thermophilic actinomycete antigen (Micropolyspora faeni) via the respiratory route, followed by monitoring of sequential morphologic changes and the humoral plus cellular immunologic response. Primary respiratory tract sensitization with BSA resulted in a humoral anti-BSA response, Arthus and delayed skin reactivity, and in some cases specific antigen-induced alveolar macrophage migration inhibition, all in the absence of pulmonary lesions. Lesions characterized by mild multifocal perivascular mononuclear cell infiltrates in the lungs developed only after secondary BSA aerosol challenge. In contrast to these findings, "primary" respiratory tract sensitization with M. faeni particulate antigen in saline solution resulted in the gradual development of extensive and progressive pulmonary interstitial and alveolar mononuclear cell infiltrates. These lesions were uniformly associated with specific serum precipitating antibody and delayed skin reactivity. Alveolar macrophage migration was significantly inhibited by Micropolyspora faeni in virtually of these animals. These results, while not excluding a primary irritant effect or Type II or III alergic tissue injury, suggest a role for delayed (cell-mediated) hypersensitivity in the pathogenesis of particulate actinomycete-induced pulmonary lesions. They also indicate that primary immunization with soluble purified protein antigens via the respiratory route can lead to systemic humoral and cell-mediated immunity without production of pulmonary lesions.