[Effect of Mycobacterium phlei F.U.36 on balance of CD4⁺CD25⁺ regulatory T cells and Th17 cells in asthmatic mice]

OBJECTIVE

To evaluate the effect of early intervention with Mycobacterium phlei F.U.36 injection on the balance of CD4⁺CD25⁺ regulatory T cells and Th17 cells in asthmatic mice, and to investigate the immunomodulatory effect of Mycobacterium phlei F.U.36.

METHODS

Thirty female BALB/c mice were randomly divided into three groups: normal control (n=10), asthma model (n=10) and Mycobacterium phlei F.U.36 treatment groups (n=10). A mouse model of asthma was prepared by injection and aerosol inhalation of chicken ovalbumin in the asthma model and Mycobacterium phlei F.U.36 treatment groups, while mice in the normal control group were given normal saline instead. The treatment group was intraperitoneally injected with Mycobacterium phlei F.U.36 (0.57 μg, once every other day) three times in the first two weeks after the first sensitization. All mice were sacrificed at 24 hours after the last challenge. Left lung tissues of these mice were obtained and made into sections for observation of inflammatory changes. The percentages of CD4⁺CD25⁺ regulatory T cells and Th17 cells in CD4⁺ T cells among splenic mononuclear cells were determined by flow cytometry. The levels of interleukin (IL)-10 and IL-17 in serum and bronchoalveolar lavage fluid were measured using ELISA.

RESULTS

Compared with the normal control group, the asthma model group had significantly decreased percentages of CD4⁺CD25⁺ regulatory T cells and IL-10 levels (P<0.05) and significantly increased percentages of Th17 cells and IL-17 levels (P<0.05). Compared with the asthma model group, the Mycobacterium phlei F.U.36 treatment group had significantly increased percentages of CD4⁺CD25⁺ regulatory T cells and IL-10 levels (P<0.05) and significantly decreased percentage of Th17 cells and IL-17 levels (P<0.05).

CONCLUSIONS

Early intervention with Mycobacterium phlei F.U.36 can promote development of CD4⁺CD25⁺ regulatory T cells and production of IL-10 and inhibit generation of Th17 cells and production of IL-17 in asthmatic mice.

Effects of inhaled inactivated Mycobacterium phlei on airway inflammation in mouse asthmatic models

BACKGROUND

Corticosteroids are the most efficacious anti-inflammatory drugs for asthma therapy; however, steroids are not always completedly effective for asthma. Studies have shown Mycobacterium bovis Bacille Calmette-Guérin (BCG) and other mycobacterial infections suppress airway hyperresponsiveness and inflammation in asthma. We use a murine model of Ovalbumin (OVA)-induced asthma to study whether nebulized inhalation of inactivated Mycobacterium phlei can alleviate asthmatic airway inflammation through influencing cytokine production and determine whether it can prevent and treat asthma.

METHODS

Fifth male Balb/c mice were randomly divided into four groups: normal control group (A), asthma model group (B0, B3, B4, B5), the treatment group (C0, C3, C4, C5), and prevention group (D). Mice were sensitizated and challenged with Ovalbumin to make a murine asthma model. Group C were given treatment of aerosol Mycobacterium phlei once daily after OVA challenge. Groups C3, C4, and C5 were treated for 3 days, 4 days, and 5 days, respectively. Group D inhaled the solution of inactivated Mycobacterium phlei daily before each time of OVA challenge. All the animals were killed and lung tissue and bronchoalveolar lavage fluid (BALF) were harvested. Pathological HE staining and AB-PAS staining were done to measure lung inflammation and mucus production. Total cell numbers and differential cell count in BALF were performed. Cytokines IL-4, IL-10, and IFN-γ levels in BALF were quantified by ELISA.

RESULTS

In groups C4, C5, and D, IL-4 production in BALF was decreased and IL-10 and IFN-γ were increased (p<0.05).The number of total inflammatory cells and the mean percentage of eosinophils and lymphocytes in the BALF of group D, group C4, and group C5 was lower than in the corresponding group B (p<0.05). Histological examination of the lungs showed airway inflammation of group D and group C5 were attenuated.

CONCLUSION

The inhalation of Mycobacterium phlei can reduce airway inflammation in asthmatic mice. This ability was associated with its immunomodulatory effect on regulating IL-4, IL-10, and IFN-γ secretion. Aerosol administration of inactivated Mycobacterium phlei may be accepted as an alternative method with less risk of adverse reactions in treatment of asthma.

[Inhibitory effect of combined bacterin on growth of sarcoma 180 in mice]

BACKGROUND & OBJECTIVE

It was reported that the symptoms of tumor patients may be alleviated markedly and even the tumor may be regressed completely after acute infection. Bacterin OK-432 has notable inhibitory effect on the growth of various tumors in animals. At present, OK-432 has been used in clinical immunotherapy for tumors with no other adverse events besides fever and leucocytosis. This study was to investigate the effects of combined bacterin on the serum level of interleukin 12(p70)[IL-12(p70)] and the growth of sarcoma 180 (S180) in mice.

METHODS

After transplantation of S180, the mice were randomized into 5 groups, and received injection of Staphylococcus aureus, Salmonella typhimurium, Mycobacteria phlei, and combined bacterin containing the 3 bacteria strains, respectively, or received no treatment (blank control). The weight of S180 xenografts, the thymus, and the spleen in mice was measured. The serum level of IL-12(p70) was detected by ELISA.

RESULTS

The mean weight of S180 tumors was 1.39 g in Staphylococcus aureus group, 1.50 g in Salmonella typhimurium group, 1.36 g in Mycobacteria phlei group, 0.62 g in combined bacterin group, and 2.40 g in blank control group; the differences among the 5 groups were significant (F=66.73, P<0.001). The mean weight of S180 tumors was significantly lower in the 4 bacterin groups than in control group, and significantly lower in combined bacterin group than in the 3 single bacterin groups (q test, P<0.001). The weights of the thymus and the spleen among the 5 groups had no significant difference (F=2.36, P>0.05; F=1.89, P>0.05). The inhibition rate of tumor growth was significantly higher in combined bacterin group than in Staphylococcus aureus, Salmonella typhimurium, and Mycobacteria phlei groups (74.17% vs. 42.08%, 37.50%, and 43.33%, P<0.01). The mean serum level of IL-12(p70) was 19.44 pg/ml in combined bacterin group, 12.41 pg/ml in Staphylococcus aureus group, 10.35 pg/ml in Salmonella typhimurium group, 11.68 pg/ml in Mycobacteria phlei group, and 4.45 pg/ml in control group; the difference among the 5 groups was significant (F=15.76, P<0.0001), but the difference among the 3 single bacterin groups was not significant (q test, P>0.05), while the differences between other groups were significant (q test, P<0.01).

CONCLUSIONS

The chosen bacterins in this study can induce the mice to produce IL-12(p70) and suppress the growth of S180. The effect of the combined bacterin is much better than the single bacterins.

The Activity of Milk Leukocytes in Response to a Water-soluble Fraction of Mycobacterium phlei in Bovine Subclinical Mastitis

The effect of a water-soluble fraction (WSF) of a non-pathogenic strain of Mycobacterium phlei was studied in bovine subclinical mastitis (SCM) by measuring the myeloperoxidase and acid phosphatase enzyme levels in the milk leukocytes. Forty-five cows were divided into three equal groups. Group I, consisting of 15 healthy cows, served as the control, whereas groups II and III each contained 15 cows with subclinical mastitis on the basis of a positive reaction in the California mastitis test (CMT). The cows in group II received 100 microg of WSF in 5 ml sterile phosphate-buffered saline, pH 7.4 (PBS) once only, while those in group III received 5 ml sterile PBS daily for 7 days, both treatments being given by the intramammary route. Observations were made up to 30 days after treatment (AT). The CMT of the healthy milk was negative (0), whereas it ranged between 1 and 2 points in SCM. The somatic cell count (SCC) increased significantly (p < 0.05) on day 3, then fell steeply from day 7 up to day 30 AT in the cows in group II. A steady decrease in the total bacterial count (TBC) was observed in the group treated with WSF but the bacterial counts remained high in the groups treated with PBS. The mean acid phosphatase level was enhanced by 119% on day 3 AT in group II but only by 18.7% in the cows in group III. The mean myeloperoxidase level was enhanced by 100% in the cows in group II but only by 18% in those in group III on day 3 AT. This significant reduction in the bacterial load in infected cows caused by intramammary infusion of WSF may be due to activation of the microbicidal activity of the neutrophils, but this requires confirmation.

Evaluation of immune responses of cattle as a means to identify high or low responders and use of a human microarray to differentiate gene expression

An immune response (IR) index to identify cows with high (H) and low (L) antibody-mediated immune responses (AMIR) had been previously devised. High AMIR associated with decreased mastitis and improved response to vaccination. Measurement of cell-mediated immune response (CMIR) was not included in the index; therefore various antigen/adjuvant combinations were evaluated as inducers of DTH to be added to the IR-index. The Bacillus Calmette Guérin (BCG)-induced/purified protein derivative (PPD)-elicited tuberculin skin test is a reliable measure of DTH; however, its use to identify livestock with high CMIR may be confounded due to previous exposure to Mycobacteria tuberculosis. DTH to BCG/PPD was therefore compared with that induced by Mycobacteria phlei (saprophyte) and its derivative phlein as the test antigen. Antibody to OVA was also evaluated. The results indicated that BCG/PPD and M. phlei/phlein induced similar DTH, but cross reaction to PPD was evident following induction of DTH using M. phlei making it a less than ideal alternative for testing livestock. Nonetheless, cows could be ranked for both AMIR and CMIR. RNA from two cows with the highest and lowest IR ranks was then used to probe a human 1.7 kD microarray to determine the ability of a human array to provide information on bovine genes associated with H and L.

Development of short non-CpG phosphodiester oligonucleotides as immune stimulatory agents

We have previously reported that DNA isolated from Mycobacterium phlei (M. phlei) stimulates the synthesis of cytokines by monocytes and macrophages independently of the presence of unmethylated CpG motifs. Oligonucleotides as small as five to six bases isolated from M. phlei DNA have been found to induce cytokine synthesis. In the present study, we have investigated the potential for such CpG-lacking DNA to act as an immune stimulant. A series of six base length phosphodiester oligonucleotides derived from the genome of M. phlei were synthesised and tested for their ability to induce the synthesis of cytokines by murine, non-human primate (rhesus macaques and chimpanzee) and human peripheral blood mononuclear cells. The results show that phosphodiester oligonucleotides with a 5'GGGxGG3' sequence where x is A, C, G or T have the ability to induce the synthesis of IL-1beta, IL-6, IL10 or IL-12 by non-human primate and human PBMC, murine cells being unresponsive. The phosphodiester 5'GGGxGG3' oligonucleotides were shown to be stable in human serum, with a half-life of approximately 72 h. The addition of aluminium hydroxide to these 5'GGGxGG3' oligonucleotides potentiated, in a concentration-dependent manner, the synthesis of IL-12 by human peripheral blood mononuclear cells. These phosphodiester six base length non-CpG motif oligonucleotides may have potential as immunopotentiators for vaccines.

IFN-gamma diagnostic tests in the context of bovine mycobacterial infections in Belgium

In countries where cattle tuberculosis caused by Mycobacterium bovis (Mbov) and paratuberculosis caused by Mycobacterium avium subsp. paratuberculosis (Mptb) are present, testing strategies for the Mbov eradication have to discriminate between these two infections. Present indirect tests are based on the analysis of the specific cellular immune response (DTH, IFN-gamma) against crude mycobacterial antigens (avian and bovine PPD). In this study, we compared the evolution of the IFN-gamma responses of animals experimentally infected with Mbov, Mptb, or inoculated with Mycobacterium phlei. Mbov inoculation induced a strong IFN-gamma response that allows rapid classification of the status of the animals following interpretation criteria set up by us. Experimental inoculation with M. phlei induced sensitisation to mycobacterial antigens as detected by the IFN-gamma test but these reactions were of short duration, therefore, repeated testing allows us to define these animals as aspecific reactors. IFN-gamma response induced after oral inoculation of calves with Mptb was of low intensity and ratio of responses measured against avian versus bovine PPD did not allow a clear diagnostic at least for the six first month of infection.

Mycobacterium phlei as an oral immunomodulator with Newcastle disease vaccine

Experiments were conducted in chickens to understand the effects of oral immunomodulation. Heat inactivated M phlei, a commensal Mycobacterium and a non-specific immunomodulator, was administered orally prior to live Newcastle disease F (ND F) strain vaccination. In experimental birds it lead to an enhanced cell mediated Immune response (CMI) against the vaccine. There was a reduction in the Haemagglutination inhibiting (HI) antibodies. However, it did not affect the protection against a virulent challenge, as the protection percentage was more or less same in vaccinated birds irrespective of the M.phlei administration. M. phlei administration could not enhance the immune response to inactivated ND F vaccine administered orally. The results indicate that M. phlei favours a CMI response to orally administered live ND F vaccine. It may be of potential use in enhancing CMI against vaccines and a cheaper alternative to costlier recombinant cytokines.

The mannose receptor mediates uptake of pathogenic and nonpathogenic mycobacteria and bypasses bactericidal responses in human macrophages

The mannose receptor (MR) is involved in the phagocytosis of pathogenic microorganisms. Here we investigated its role in the bactericidal functions of human monocyte-derived macrophages (MDMs), using (i) trimannoside-bovine serum albumin (BSA)-coated latex beads and zymosan as particulate ligands of the MR, and (ii) mannan and mannose-BSA as soluble ligands. We show that phagocytosis of mannosylated latex beads did not elicit the production of O2-. Zymosan, which is composed of alpha-mannan and beta-glucan, was internalized by the MR and a beta-glucan receptor, but the production of O2- was triggered only by phagocytosis through the beta-glucan receptor. Activation and translocation of Hck, a Src family tyrosine kinase located on lysosomes, has previously been used as a marker of fusion between lysosomes and phagosomes in human neutrophils. In MDMs, Hck was activated and recruited to phagosomes containing zymosan later than LAMP-1 and CD63. Phagosomes containing mannosylated latex beads fused with LAMP-1 and CD63 vesicles but not with the Hck compartment, and the kinase was not activated. We also demonstrate that the MR was unable to distinguish between nonpathogenic and pathogenic mycobacteria, as they were internalized at similar rates by this receptor, indicating that this route of entry cannot be considered as a differential determinant of the intracellular fate of mycobacteria. In conclusion, MR-dependent phagocytosis is coupled neither to the activation of NADPH oxidase nor to the maturation of phagosomes until fusion with the Hck compartment and therefore constitutes a safe portal of entry for microorganisms.

Fusion of azurophil granules with phagosomes and activation of the tyrosine kinase Hck are specifically inhibited during phagocytosis of mycobacteria by human neutrophils

Pathogenic mycobacteria parasitize macrophages and reside within phagosomes, which do not fuse with lysosomal granules. Mycobacteria are also internalized by neutrophils, which possess at least two types of granules, specific and azurophil granules, the latter being specialized lysosomes. Here, we investigated the ability of mycobacteria to inhibit the fusion of these granules with their phagosomes in human neutrophils. It was found that when pathogenic (Mycobacterium kansasii and Mycobacterium avium) or nonpathogenic (Mycobacterium smegmatis and Mycobacterium phlei) mycobacteria were internalized by neutrophils, they induced the inhibition of azurophil granule fusion with phagosomes even when they were serum opsonized. In contrast, secretion of specific granule content and production of O2-, both of which contribute to the neutrophil bactericidal response, were triggered. Hck is a Src family tyrosine kinase associated with azurophil granules. During internalization of zymosan, azurophil granules fused with phagosomes and Hck was activated and translocated to the phagosomal membrane, whereas in neutrophils engulfing mycobacteria, Hck did not translocate and remained unactivated. The activation of the tyrosine kinase Fgr was not affected. These results indicate that 1) pathogenic and nonpathogenic mycobacteria trigger similar bactericidal responses in neutrophils, 2) phagocytosis and fusion of azurophil granules can be uncoupled by mycobacteria, and 3) Hck could be one of the key elements of the azurophil secretory pathway that are altered during phagocytosis of mycobacteria.

Effect of immunostimulation on cytotoxic activity of intestinal intraepithelial lymphocytes of chickens in infectious bursal disease and Eimeria tenella infections

In chickens, intestinal intraepithelial lymphocytes (iIELs) exhibit spontaneous natural killer (NK) cell like activity, by which they are active in the first line of defence on gut epithelial linings. In the present study, the cytotoxic activity of iIELs was found to be drastically suppressed in chickens experimentally infected with infectious bursal disease (IBD) virus at the age of 5 weeks and also in chickens experimentally infected with Eimeria tenella oocysts at the age of 8 weeks (p < 0.01). As nonspecific immunostimulation is gaining importance, immunostimulants such as immunostimulating Mycobacterium phlei (ISMP) and bone marrow culture supernatant (BMCS) were tested for their influence on the functional activity of iIELs of chickens in IBD and E. tenella infections. In chickens primed with ISMP a week prior to respective experimental infections, it was found that the cytotoxic activity of iIELs was restored (p < 0.01) in both IBD and E. tenella infections. At the same time, in chickens primed with BMCS a week prior to respective experimental infections, the cytotoxic activity of iIELs was restored to a certain extent (p < 0.01) in E. tenella but not at all in IBD infection. These results showed that application of immunostimulation helped potentiate and restore the functional activity of iIELs of chickens in IBD and E. tenella infections.

Effect of Mycobacterium phlei on the development of immunity to Babesia bigemina

The immunomodulatory role of Mycobacterium phlei against intracellular blood protozoan Babesia bigemina was demonstrated following experimental immunisation and challenge in bovine calves. A lysate of erythrocytes infected (6 x 10(9)) with B. bigemina was used as a source of dead antigen either with Freund's complete adjuvant (FCA) or with a trypsinised culture of M. phlei as a non-specific immunomodulation (NSI) agent with appropriate controls. Following virulent challenge with B. bigemina infected erythrocytes (1 x 10(7)), the NSI printed calves showed 100% protection, while the dead antigen alone with FCA afforded 75% protection. The protective status of the immunising regimes was studied by clinicopathological parameters and assessment of humoral and cell-mediated immune responses. The role of babesial dead antigen and the effects of M. phlei on the development of immunity to B. bigemina is discussed.

Evaluation of an enzyme-linked immunosorbent assay licensed by the USDA for use in cattle for diagnosis of ovine paratuberculosis

A commercially available Mycobacterium phlei-absorbed enzyme-linked immunosorbent assay (ELISA) approved to detect antibodies to Mycobacterium paratuberculosis in cattle was evaluated for its applicability in sheep. The potential for interference with ELISA results from cross-reacting antibodies to Corynebacterium pseudotuberculosis was also investigated. Serum samples were randomly selected from a collection of samples obtained in 1986-1991 from 6 infected and 5 noninfected sheep flocks varying in breed, age, and geographic origin. Tests were performed on sera from 27 paratuberculous sheep, confirmed by histopathology, bacteriologic culture, and/or acid-fast staining of ileal mucosal smears, and on sera from 246 noninfected sheep. The optical density of each sample was expressed as a percentage of the optical density of a known positive sheep serum sample tested on the same plate. These values were log-transformed to achieve normality of distribution, and sensitivity and specificity estimates were calculated based on 2 and 3 standard deviations above the mean of the percent positive value (PPV) of the noninfected sheep. A cutoff value of PPV > or = 55.74 resulted in an estimated sensitivity of 0.48 and a specificity of 0.95. Sera from 10 noninfected sheep with PPV above the cutoff level of 55.74% were absorbed with heat-treated C. pseudotuberculosis organisms in addition to M. phlei antigens. Sera from 14 ELISA-positive paratuberculous sheep and 23 ELISA-negative noninfected sheep were similarly treated, and results were compared. Absorption with C. pseudotuberculosis resulted in a significant decrease in PPV in all 3 groups of sheep sera, but a greater decrease was observed in the noninfected sheep with PPV above the cutoff level when compared with noninfected sheep with PPV below that level. Results of this study suggest that ELISA may be of value in screening sheep flocks for paratuberculosis, but further experimentation is needed to optimize the sensitivity and specificity of the assay. Exposure to C. pseudotuberculosis may confound results obtained by M. phlei-absorbed ELISA for paratuberculosis.

Immunotherapy of an experimental adenocarcinoma of the prostate

We have developed and tested a fractionated, purified and deproteinized emulsion of a mycobacterial cell wall (MCW) and report on a controlled study of this compound in the treatment of the experimental R3327-H adenocarcinoma of the prostate. The intraperitoneal route of administration was found ineffective at the weekly dose of 500 micrograms. The intratumoral administration of 1000 micrograms of MCW exhibited significant antitumor activity. Tumors larger than 2.2 cm.3 in volume showed evidence of temporary regression, but no cures were recorded in these animals. Complete tumor regression was found in 50% of the rats with tumor volumes less than 2.2 cm.3 at the onset of treatment. The animals in this group not responding initially were treated with a second 3-week course of MCW which resulted in complete tumor regression in one-half of the animals, for a total cure rate, in the smaller tumor cohort, of 75%. Mycobacterial cell wall is an effective biological response modifier in the Dunning R3327-H adenocarcinoma of the prostate in Copenhagen rats. Additional studies to elucidate the effect of the compound in relation to dose and tumor volume are underway.

Safety, immunogenicity, and efficacy of a malaria sporozoite vaccine administered with monophosphoryl lipid A, cell wall skeleton of mycobacteria, and squalane as adjuvant

A Plasmodium falciparum circumsporozoite protein (PfCSP) recombinant fusion protein, R32NS1(81), formulated with monophosphoryl lipid A, cell wall skeleton of mycobacteria, and squalane (Detox) was administered to 12 volunteers. One volunteer had malaise and self-limited painful induration at the injection site after the second dose and declined further immunization. The other 11 volunteers tolerated the three doses of 1,230 micrograms of vaccine, but most complained of sore arms; in five cases the pain or malaise was severe enough to interfere with work or sleep. Two weeks after the third dose of vaccine, four of the 11 immunized volunteers had > or = 14 micrograms/ml of antibodies to the repeat region of the PfCSP in their serum. Two of these four volunteers did not develop P. falciparum parasitemia when challenged by the bite of five mosquitoes carrying P. falciparum sporozoites. The seven volunteers with lower levels of antibodies and 11 of 11 controls developed parasitemia. These data are consistent with other studies, and indicate that vaccine-induced antibodies against the repeat region of PfCSP can prevent effective sporozoite infection of hepatocytes in humans. The challenge is to improve the immunogenicity of PfCSP-based vaccines, and to develop methods for including PfCSP peptides as components of multitarget malaria vaccines.

[Specific antisera to mycobacteria]

Antisera to several Mycobacterium species (M. bovis, M. avium, M. kansasii and M. smegmatis), capable of reacting with homologous antigen diluted not below 1:16000 in the ELISA test, have been obtained. These antisera have been found to cross-react with other Mycobacterium species. Specific antisera to M. bovis, M. avium, M. kansasii and M. smegmatis have been obtained by the multiple exhaustion method on Mycobacterium antigens giving the maximum cross reaction and used for the isolation of antibodies to these Mycobacterium species. In ELISA exhausted antisera produce reactions in the dilution 1:500. Antisera (antibodies) to M. bovis react with the determinant of the antigen with a molecular weight of 25-26 kD, antisera (antibodies) to M. kansasii react with the determinant of the antigen with a molecular weight of 72 kD, those to M. smegmatis react with the determinant of the antigen with a molecular weight of 38 kD and those to M. avium, with the determinant of the antigen with a molecular weight of 16-18 kD.

Diagnostic accuracy of a Mycobacterium phlei-absorbed serum enzyme-linked immunosorbent assay for diagnosis of bovine paratuberculosis in dairy cows

The purpose of this study was to describe the responses of sera from five groups of cattle to an enzyme-linked immunosorbent assay (ELISA) for paratuberculosis by using serum absorbed with Mycobacterium phlei at a single working dilution. The infection status of the cattle was determined by fecal culture. Cattle with different levels of exposure (high versus low prevalence and test negative) and disease manifestation (clinically suspect infection versus subclinical infection) were examined, as follows: (i) two paratuberculosis-negative herds; (ii) a fecal culture-confirmed, clinically suspect cases of paratuberculosis; (iii) cows from a paratuberculosis-infected herd with a high infection rate, as determined by fecal culture, but with no clinical cases at the time of sampling; (iv) cows from three paratuberculosis-infected herds known to have paratuberculosis diagnosed on the farm (low infection rate determined by fecal culture); and (v) one fecal culture-negative herd with known serologically positive cattle. Results generally showed a decreased ELISA response when absorbed rather than nonabsorbed serum from each animal was used. The results of the fecal culture confirmed clinically suspect cases, which were analyzed in relation to the amount of colonies isolated from the animals on fecal culture (0, +, ++,+++ , ++++, and above). There was a significant increase in the ELISA response for animals with heavy Mycobacterium paratuberculosis shedding ( ++++ or above), when both unabsorbed and absorbed sera were used, compared with the response in animals that were fecal culture negative or that shed M. paratuberculosis at lower levels (less than +) (P less than 0.05). The effects on sensitivity and specificity by using different cutoff points for the five groups of cattle with different levels of exposure is described, since sera were not discretely segregated into distinct groups of positive and negative samples. The specificity of the ELISA in the two fecal culture-negative herds was 100% at an ELISA cutoff of an optical density (OD) of 0.1 and above for absorbed serum. For unabsorbed serum the specificity was 62.9% at a similar cutoff value. Similarly, the specificity of the fecal culture-negative, serologically positive herd increased from 37.5 to 72.2 at an ELISA cutoff value of 0.1 to 0.2 (OD) by using absorbed versus unabsorbed serum from 75.0 to 94.4 at an ELISA cutoff value of 0.2 to 0.3 (OD).

Polyclonal B-lymphocyte activation of sheep by Mycobacterium phlei against sheep pox virus

A trypsinized preparation of Mycobacterium phlei, non specific stimulator of immunity (NSI), and Sheep Pox Virus (SPV) were inoculated in different groups of sheep to activate B-lymphocytes and induce SPV neutralizing substance(s). NSI sensitized sheep B-lymphocytes in the presence of NSI or lymphokine elaborated SPV neutralizing substance(s). The SPV sensitized B-lymphocytes also mediated such neutralizing substance(s). Healthy control sheep B-lymphocytes failed to show any appreciable amount of viral neutralizing substance. However, a significant virus neutralizing substance(s) was detected when healthy sheep B-lymphocytes were cultured in presence of NSI antigen along with lymphokines.

Enhanced production of antibody with specific antigen

On inoculation of nonspecific stimulator of immunity (NSI), prepared from Mycobacterium phlei (M. phlei), simultaneously along with sheep pox virus (SPV) in sheep, the recipient has exhibited appreciable level of SPV specific antibody as early as on 10th day which reached at peak level on 20th day and remained unaltered on 30th day of postimmunisation as evinced by serum neutralisation test (SNT), enzyme linked immunosorbant assay (ELISA) indirect, fluorescent antibody technique (FAT) indirect, counter immunoelectrophoresis (CIEP) and finally by virulent SPV challenge. On the contrary, sheep, when immunised with SPV only could not produce appreciable level of antibody on 10th day but did so on 20th day of inoculation. SPV and NSI immunised sheep produced enhanced protection against virulent SPV challenge in comparison with sheep immunised with SPV only. Healthy control sheep, however, could not resist challenge.

Antibody reactivities of Mycobacterium paratuberculosis infected sheep as analyzed by enzyme-linked immunosorbent assay and western blotting

Antibody reactivities in sera from Mycobacterium paratuberculosis (M. ptb) infected and vaccinated sheep were analyzed by enzyme-linked immunosorbent assay (ELISA) and Western (immuno)blotting using a sonicate antigen from M. ptb. Both methods allowed good differentiation between infected/vaccinated animals and noninfected controls. Removal of nonspecific crossreactive antibodies by absorption with a M. phlei sonicate antigen coupled to Sepharose reduced ELISA reactivities of positive sera by 50% and those of noninfected serum by 85%. Immunoblotting analysis revealed that reduction by M. phlei absorption was due to lower reactivities of M. ptb antigens in the range of 30 to 45 kDa. However, one protein with a molecular mass of approx. 27 kDa seemed to be specific for M. ptb since it reacted similarly with nonabsorbed and absorbed serum but not with antibodies which were eluted from M. phlei-Sepharose after absorption. Our findings indicate that M. ptb and M. phlei share a number of common antigens of potential pathogenic importance and that only a smaller part of proteins (i.e. the 27 kDa protein) might be specific for M. ptb.

Pathogenesis of route-related variation in T-suppressor response on immunization with mycobacteria

The route of immunization was observed to play a significant role in deciding the outcome of immunization with killed mycobacterial vaccines. Earlier we reported that the slow growers were immunogenic by both the intraperitoneal (i.p.) and intradermal (i.d.) routes. In contrast, the rapid growers were immunogenic by the i.d. route only. Both rapid and slow growers generated the classical, antigen-specific Lyt-2 positive, T-cell-mediated suppression after i.p. immunization but not after i.d. immunization. Thus, in the case of the slow growers, T-cell-mediated suppression was only a component of the immune response generated after i.p. immunization. In contrast, in the case of Mycobacterium vaccae and the other rapid growers, the T-cell-mediated suppression was the predominant response with i.p. immunization. The T-cell-mediated suppression generated by i.p. immunization exhibited crossreactivity, the spectrum of which was dependent upon the dose of the immunization.

Route-related variation in immunogenicity of mycobacteria

The route of immunization was observed to play a significant role in deciding the T-cell response to immunization with killed mycobacterial vaccines. Slow-growing mycobacteria were found to be immunogenic by both the intraperitoneal (i.p.) and intradermal (i.d.) routes; rapid-growing mycobacteria were immunogenic by the i.d. route only. The nonresponder state following i.p. immunization with Mycobacterium vaccae could be corrected by treatment of the mice with poly I:poly C or indomethacin prior to immunization. Both poly I:poly C, an interferon inducer, and indomethacin, a prostaglandin inhibitor, are known to enhance the expression of major histocompatibility complex glycoproteins. Since they are so important in antigen preparation, it was concluded that the inability of mice to respond to M. vaccae by the i.p. route is likely due to defective presentation of the bacterial antigens by the antigen-presenting cells at the site, namely, the peritoneal macrophages. These findings are significant because M. leprae has been reported to be antigenically similar to M. vaccae, and the response of mice to i.p. immunization with both of these mycobacteria is very similar.

[A comparative study of delayed hypersensitivity due to mycobacteria and their isolated protein fractions]

The role of intracellular protein fractions, isolated from M. tuberculosis virulent strains in the process of the electrophoretic separation, in the development of delayed hypersensitivity reactions has been studied. Low reactogenicity of protein fractions has been established on the basis of the development of faint immunopathological reactions in sensitized animals. High-molecular fraction 1 may be used as a sensitive preparation for the differentiation of individual mycobacterial species.

Induction of cell mediated immune response by nonspecific stimulator of immunity against antigenically unrelated oncogenic virus (Marek's disease virus)

An enzyme treated preparation of Mycobacterium phlei (NSI), induced strong cell mediated immune response (CMIR) against specific as well as against nonspecific oncogenic Marek's disease (MDV) in birds, as evinced by Lymphocyte migration inhibition, (LMIT) lymphocyte transformation test (LT) and Lymphokine (Lymphocyte migration inhibition factor) LyIF assay. Maximum CMIR could be observed towards third week post inoculation. All the three tests exhibited a positive correlation. Such phenomenon of CMIR induction by NSI, nonspecifically to unrelated viral/cancerous diseases (MD) in birds generates hopes for immunoprevention of these maladies by utilizing such phenomenon.

Nonspecific immunoprotection against Rous sarcoma tumor in chicks

An enzyme treated preparation of saprophytic Mycobacterium phlei, referred as NSI, when administered intramuscularly has been found to protect the chicks against Rous Sarcoma Virus induced tumor. A protection level of 35.4%, 24.1% and 21.2% were observed when challenged on 10th, 20th and 30th day post NSI inoculation. The tumor growth inhibitory-activity of NSI was significant (P less than 0.01). Both, systemic and intralesional administration of NSI exhibited significant tumorostatic activity (P less than 0.05). NSI stimulated the cell mediated immune response to specific as well as to nonspecific Rous sarcoma antigen. These studies indicated the immunopreventive activity of NSI against Rous sarcoma tumor which had an immunogenic basis.

Dissection of adjuvant and suppressive effects of mycobacteria in experimental allergic encephalomyelitis production

Dark August rats exhibit clinically and histologically verified experimental allergic encephalomyelitis (EAE) when immunized with appropriate antigen (nervous tissue, myelin basic protein) emulsified in complete Freund's adjuvant (CFA). We provide evidence that 6,6'-trechalose dymicolate (TDM) incorporated in incomplete Freund's adjuvant replaces CFA in EAE induction. The animals that recovered from EAE were resistant to the reinduction of the disease irrespectively whether Mycobacterium tuberculosis or TDM was used as an adjuvant. Finally, pretreatment with CFA alone was sufficient for prevention of disease elicited by challenge with encephalitogen + CFA. However, TDM, despite its adjuvant capacity when applied prior to the induction of the disease with encephalitogen + CFA, did not exhibit any protective effect. Thus, our study implicates that adjuvant and suppressive capacities of M. tuberculosis may be related to the different determinants of the microorganisms, TDM possessing the adjuvanticity only.

Characterization of mycobacterial immunoprecipitates by selective staining of enzymes

Immune precipitation patterns of Mycobacterium intracellulare, M. phlei and M. smegmatis were analysed by selective enzyme staining procedures in order to characterize individual mycobacterial antigens. Enzyme activity was shown in eight precipitinogens of M. intracellulare, seven of M. phlei, and six of M. smegmatis. The identification of mycobacterial precipitinogens as enzymes is important since only a few mycobacterial antigens have been functionally characterized.

Experimental pulmonary cavity formation by mycobacterial components and synthetic adjuvants

An investigation was undertaken to determine the components of mycobacteria responsible for pulmonary cavity formation in tuberculosis. Rabbits received an intrapulmonary injection through the chest wall, of mycobacterial protein, II-p, mixed with either mycobacterial lipids, synthetic adjuvants or Nocardia cell wall skeleton as adjuvant. Six weeks later, they were killed and the lung lesions were examined. Cavities and necrosis were produced by the injection of II-p mixed with cord factor, Nocardia cell wall skeleton or N-acetylmuramyl dipeptide conjugated with long-chain branched fatty acids. Cavities were not produced by either the injection of II-p together with phospholipid, N-acetylmuramyl dipeptide (MDP), MDP-derivatives having no long-chain branched fatty acid, or by the injection of individual components of the mixtures. The results suggest that in tuberculosis a mycobacterial component with a long-chain branched fatty acid such as mycolic acid plays an important role in pulmonary cavity formation by enhancing the antigenicity of mycobacterial protein and helping it induce cell-mediated immunity at the site of the lesion. Passive transfer with sera from rabbits highly sensitized with tubercle bacilli failed to enhance cavity formation in the recipient animals.

Immunological studies with sulpholipids of mycobacteria

Antibodies to sulpholipids of mycobacteria were produced in rabbits when injected as sulpholipid-MBSA complexes and were detected by kaolin agglutination and double diffusion techniques. Sulpholipid antibodies did not cross react with any other lipids of mycobacteria except cord-factor. The antigenicity of sulpholipids appears to be due to alpha-D-trehalose and sulphate groups. Guinea pigs immunized with sulpholipid-MBSA complexes showed partial protection against tuberculous infection with M. tuberculosis H37Rv, as revealed by mortality rate and score of lesions.

Immunotherapy of guinea pigs with a transplanted hepatoma: comparison of intralesionally injected emulsions containing heat-killed Nocardia rubra, Mycobacterium bovis (BCG) and Mycobacterium phlei

Heat-killed cells of Mycobacterium bovis (BCG), Mycobacterium phlei and Nocardia rubra were each tested in emulsified form for their ability to cause regression of established dermal transplants and lymph node metastases of a syngeneic hepatocarcinoma in guinea pigs. On a weight basis, BCG was superior to N. rubra in causing tumor regression. Under the conditions tested N. rubra was inferior to M. phlei in its antitumor activity. M. phlei and BCG were approximately the same in their therapeutic potency. In BCG-sensitized guinea pigs, N. rubra provoked a weaker delayed cutaneous hypersensitivity (DCH) reaction than did BCG. In N. rubra-sensitized guinea pigs, BCG provoked a weaker DCH reaction than did N. rubra. Purified protein derivative of M. tuberculosis was more active in eliciting DCH in BCG-sensitized guinea pigs than in animals sensitized with N. rubra.

Immunotherapy of experimental cancer by intralesional injection of emulsified nonliving mycobacteria: comparison of Mycobacterium bovis (BCG), Mycobacterium phlei, and Mycobacterium smegmatis

Mycobacterium bovis (BCG), Mycobacterium phlei, and Mycobacterium smegmatis were each tested in emulsified form for their potency to cause regression of transplants of a syngeneic murine fibrosarcoma and of a syngeneic guinea pig hepatoma. On a weight basis, M. phlei and M. smegmatis were as effective as BCG in causing tumor regression. M. phlei and M. smegmatis were comparable to BCG in provoking delayed cutaneous hypersensitivity reactions in guinea pigs sensitized to M. phlei or M. smegmatis. In BCG-sensitized guinea pigs, M. phlei and M. smegmatis provoked weaker delayed cutaneous hypersensitivity reactions than did BCG. Purified protein derivative of M. tuberculosis was more active in eliciting delayed cutaneous hypersensitivity in BCG-sensitized guinea pigs than in animals sensitized with M. phlei or M. smegmatis.

Various antigenic reactivities in delayed hypersensitivity among crystalline proteins from Mycobacterium phlei

Comparisons were made of the delayed-type skin reactivity of 6 crystalline proteins purified from the cell extract of Mycobacterium phlei in guinea pigs sensitized with whole cells of the heat-killed bacillus. These highly purified proteins elicited varying degrees of cutaneous reaction. The most active protein had almost the same reactivity as purified protein derivative prepared from the culture filtrate of Mycobacterium phlei. On the other hand, the weakest protein did not elicit a marked cutaneous reaction even after injection of 3,000 times the amount of protein of the most potent one. The other 4 proteins showed moderate reactivities. The difference in antigenic potency between proteins is probably due not to the amounts of the proteins contained in the cells used for sensitization, but to their structure.

Cross-reactions between mycobacteria. II. Crossed immunoelectrophoretic analysis of soluble antigens of BCG and comparison with other mycobacteria

Cross-reactions between Mycobacterium bovis BCG and various other mycobacteria, Nocardia asteroides, Corynebacterium pyogenes and Listeria monocytogenes were studied by incorporating antibodies against these bacteria in the intermediate gel of a crossed immunoelectrophoretic system with BCG antigen and anti-BCG antibodies. In the BCG reference system forty-four distinct antigenic components were recorded, of which thiryt-three cross-reacted with Mycobacterium tuberculosis, twenty-five with M. avium, twenty-one with M. suvalii, eighteen with M. smegmatis, Fifteen with M. nonchromogenicum, twelve with M. phlei, eight with N. anteroides and two with C. pyogenes, whereas no cross-reaction was detected with L. monocytogenes. The value of the method for characterization of mycobacterial antigens is discussed. A taxonomic system based on this method appears particularly valuable for studies of non-cultivativable mycobacteria such as M. leprae. A majority of twenty-one patients with lepromatous leprosy had anti-BCG antibodies of restricted specificity, affecting only four or five BCG antigens, although one patient had twelve anti-BCG specificities. Most of these antibodies reacted with those BCG antigens that cross-react extensively with other mycobacteria.

Immunodiffusion studies of various structural preparations from mycobacterial cells

Various structures and other preparations from mycobacterial cells were analyzed by immunodiffusion. The preparations were obtained from four strains referred to the species Mycobacterium bovis (BCG), Mycobacterium fortuitum, Mycobacterium phlei and Mycobacterium smegmatis. They represented cell walls (CW), culture filtrates (CF), artificially disintegrated cell material (XP), protoplasms (PP), crude ribosomes (CR), ribosomal 50S subunits (50S), ribosomal 30S subunits (30S), ribosomal 16S core particles (16S) and ribosomal-free fractions (UCS). The preparations were analyzed by reference precipitation systems based on CF, CR and 30S preparations. Serological comparisons were made with material from the same species and cross-testing between material from different species was not performed. It was shown that from the precipitinogenic point of view the CF and XP materials were very similar and that they both contained protoplasmic material to a large extent. Furthermore, it was found that ribosomal precipitinogens constitute an important part of the precipitinogens in PP as well as in the CF and the XP preparations. The ribosomal precipitinogens were found to represent the two subunits as well as the 16S core particle. One ribosomal precipitinogen, designated beta, was shown in all preparations except the CW and the UCS.

Immunodiffusion studies of ribosomes in classification of mycobacteria and related taxa

Ribosomal preparations consisting of crude ribosomes (CR), 30S subunits (30S) and 16S core particles (16S) from four strains of the species Mycobacterium bovis (BCG), Mycobacterium fortuitum, Mycobacterium phlei and Mycobacterium smegmatis were analyzed by immunodiffusion technique for taxonomical purposes. The ribosomal preparations tested contained several interspecies cross-reacting precipitinogens. The number of precipitinogens demonstrated at the homologous reactions was generally larger than the number of precipitinogens shown at the heterologous reactions indicating a probable presence of species-specific antigens in ribosomes. The largest number of possible species-specific precipitinogens was demonstrated when crude ribosomal preparations were studied. However, such precipitinogens were also shown in the 30S subunits and they were individually analyzed. The 16S core particles were dominated by cross-reacting precipitinogens. The number of ribosomal precipitinogens shared by M. phlei and M. smegmatis was large indicating a close taxonomical relationship between these two species. Apart from the four mycobacterial strains studied, 15 other strains representing the genera Mycobacterium, Arthrobacterium, Corynebacterium, Kurthia, Nocardia and Rhodococcus were included in the study. The presence of intergenerically cross-reacting precipitinogens in the ribosomal preparations was demonstrated.

Antibody response in rabbits to immunization with Mycobacterium leprae

Mycobacterium leprae purified from liver tissue of an infected armadillo (the A/10 preparation) was tested for antigenic composition by immunization of rabbits and characterization of the antibody response by crossed immunoelectrophoresis. The rabbit antisera detected seven distinct components in the M. leprae preparation. This number is far lower than in similar experiments with other mycobacteria. The M. leprae sonic extract gave far fewer lines after polyacrylamide gel electrophoresis and staining with Coomassie brillant blue than sonic extracts prepared from BCG, M. smegmatis, and M. phlei adjusted to the same protein concentration based on the Folin assay. The seven components detected in M. leprae cross-reacted extensively with M. avium, BCG, M. lepraemurium, M. smegmatis, and Nocardia asteroides. The seven components are involved in immune reactions in leprosy; antibodies against all of them were demonstrated in sera from patients with lepromatous leprosy, but the specificity of the antibodies varied from patient to patient. The reason for the demonstration of so few antigenic components and some of the implications of these findings for the use of armadillo-grown M. leprae to develop specific skin test reagents and in other aspects of leprosy research are discussed.

Macrophage processing of antigen for induction of tumor immunity

Previous studies have indicated, that, after in vitro incubation of antigen with macrophages, the "processed" antigen preferentially induces cell-mediated immunity. To investigate this phenomenon with tumor antigens, mycobacteria-stimulated macrophages were incubated with irradiated syngeneic EMT6 tumor cells for varying lengths of time and injected into normal mice. On subsequent challenge with EMT6, there was a significant increase in protection in mice immunized with macrophage-processed tumor antigen over control animals. Mineral oil-stimulated macrophages were also capable of processing irradiated EMT6, but macrophages induced by thioglycollate or proteose peptone were not. Freeze-thawed mycobacteria-stimulated macrophages were nearly as effective as viable macrophages in processing tumor antigen, but heat-treated macrophages lost this capacity. The immunity generated was specific and could be passively transferred by immune cells but not by immune serum. The results indicate that incubation of tumor antigen with appropriately activated macrophages leads to the enhanced induction of immunity to the tumor. Macrophage enzymes may degrade tumor antigens to fragments with few antigenic determinants that preferentially induce cell-mediated immunity.

Mycobacterial antigens relating to experimental pulmonary cavity formation

Lipid-protein mixtures were obtained from 2 strains of mycobacteria, and their cavity-forming activities were examined in rabbit lungs. The mixtures were separated into lipid and protein fractions by gel filtration on Sephadex LH-20 column. Neither lipid nor protein fraction alone had cavity-forming activity; however, restoration of the cavity-forming activity was observed by recombining the fractions. The activity was also reconstructed by combining the protein fraction with cell walls of bacille Calmette-Guérin. The protein fraction from Mycobacterium phlei was further separated into 2 fragments. The larger molecular fragment with a molecular weight of 10,000 daltons consisted of 60% protein and 40% carbohydrate and had cavity-forming activity in combination with the cell walls. The roles of lipid and protein of mycobacteria in cavity formation are discussed.

The specificity of the fluorescent antibody test using the sera of rabbits inoculated with strains of myocobacteria

Sera from experimentally infected rabbits were used to test the specificity of the fluorescent antibody test. It was possible using mono-specific sera to differentiate antigenically Mycobacterium phlei, M fortuitum, M smegmatis, M avium, M intracellulare, M bovis (BCG) and M johnei. The cross-reactivity within the M avium and M intracellulare group was such that one antigen from these groups would detect infection within that group and exclude M johnei infection. The M phlei growth factor independent strain M johnei 316F was shown to be antigenically distinct from a M phlei dependent strain 9N96. There was loss of specificity when M avium infection was superimposed on a previous M johnei infection and when M johnei infection was superimposed on M avium infection.

Studies on the intergenerical precipitinogen beta with special reference to its presence in mycobacterial ribosomes

Preparations consisting of crude ribosomes and 50S, 30S and 16S ribosomal subunits from strains of the species <i>BCG, Mycobacterium fortuitum, M. phlei </i>and <i>M. smegmatis </i>were analysed by means of immunodiffusion technique for the presence of a precipitinogen designated <i>β. </i>For comparative purposes, mycobacterial cell wall and protoplasm preparations were also analysed regarding <i>β. </i>This precipitinogen has previously been found in culture filtrates and expressed materials from most mycobacterial and several nocardia and rhodochrous strains tested. In addition, antibodies against <i>β </i>have been demonstrated in sera from patients with leprosy. In the present study it was shown that <i>β </i>exists in all of the ribosomal preparations from all four strains tested. It was also demonstrated that <i>β </i>probably is the principle precipitinogen of 16S core particles from mycobacteria. Ribosomal <i>β </i>did not disappear when heated for 15 min at 100 °C. Ribosomal 16S preparations from all the four test strains reacted with sera against culture filtrate or expressed preparations from strains of heterologous mycobacterial species and nocardia and rhodochrous species. The precipitinogen formed could, in several cases, be identified as <i>β. </i>It was therefore postulated that the <i>β </i>precipitinogen which is shared by mycobacterial, nocardia and rhodochrous strains constitutes a part of the ribosomal structure. Furthermore, antibodies against mycobacterial 16S preparations were found in sera from patients with leprosy indicating that ribosomal material from the <i>M. leprae </i>bacilli has stimulated the production of these antibodies.