The relevance to protection of three forms of delayed skin-test response evoked by m. leprae and other mycobacteria in mice. Correlation with the classical work in the guinea-pig

Rapidly Growing Mycobacterium Species: The Long and Winding Road from Tuberculosis Vaccines to Potent Stress-Resilience Agents

Inflammatory diseases and stressor-related psychiatric disorders, for which inflammation is a risk factor, are increasing in modern Western societies. Recent studies suggest that immunoregulatory approaches are a promising tool in reducing the risk of suffering from such disorders. Specifically, the environmental saprophyte Mycobacterium vaccae National Collection of Type Cultures (NCTC) 11659 has recently gained attention for the prevention and treatment of stress-related psychiatric disorders. However, effective use requires a sophisticated understanding of the effects of M. vaccae NCTC 11659 and related rapidly growing mycobacteria (RGMs) on microbiome–gut–immune–brain interactions. This historical narrative review is intended as a first step in exploring these mechanisms and provides an overview of preclinical and clinical studies on M. vaccae NCTC 11659 and related RGMs. The overall objective of this review article is to increase the comprehension of, and interest in, the mechanisms through which M. vaccae NCTC 11659 and related RGMs promote stress resilience, with the intention of fostering novel clinical strategies for the prevention and treatment of stressor-related disorders.

Immunological basis for the introduction of immunotherapy with Mycobacterium vaccae into the routine treatment of TB

An account is given of the immunological investigations carried out in Rosario (Argentina) to identify suitable methods for the assessment of the efficacy of immunotherapy for TB. Some of these were then applied to three small studies: one of a single injected dose of heat-killed, borate-buffered Mycobacterium vaccae administered early in treatment, another of three such doses administered at monthly intervals from the start of treatment, and the third of ten oral doses at frequent intervals throughout short-course chemotherapy. All three displayed better clearance of bacilli from the sputum, faster improvement in clinical symptoms, better radiological resolution of lesions and a return of most immunological parameters towards those of healthy persons. In principle, the immune change achieved is an increase in Th1 mechanisms, notably IL-2 and -12 with downregulation of the tissue damaging aspects of Th2. As an addition to chemotherapy for drug-susceptible or drug-resistant TB, with or without concomitant HIV infection, this immunotherapy offers a safe and effective improvement.

Delayed type hypersensitivity (DTH): studies on necrotising DTH-reactions against listerial antigen in the skin of guinea pigs

Delayed type hypersensitivity (DTH) to facultative intracellular bacteria which leads to destructive skin reactions was so far only investigated against mycobacterial antigens in guinea pigs whereas this work investigates destructive DTH-reactions in the skin of guinea pigs which are directed against listerial antigens. Toxic factors of viable listerias induced an enhancement of destructive skin reactions in non-immunised guinea pigs as compared to immunised ones. In contrast, heat killed listerias (HKL) induced necrotising skin reactions in immunised and non-immunised guinea pigs which were significantly enhanced by DTH in immunised guinea pigs. 5 days after immunisation, necrotising reactivity was maximal and increased in a dose-dependent mode with higher amounts of HKL. Listeria-specific T-cells were able to interact specifically with allogeneic macrophages in vitro. By means of adoptive transfer of listeria-specific T-cells it was possible to transfer successfully Listeria-specific DTH-reactivity from immunised donors to non-immunised recipients.

Delayed type hypersensitivity (DTH): quantitative studies of mycobacteria-induced destructive and non-destructive DTH-reactions in the skin of guinea pigs

Research on delayed type hypersensitivity (DTH) to facultative intracellular bacteria in guinea pigs focused especially on intracutaneous DTH reactions. However, phenomena of erythematous and necrotic skin reactions were only evaluated qualitatively, dose-response relationships not investigated, differences between early and late reactions overlooked and the development of unspecific skin necrosis ignored. In this work, these aspects were investigated by characterisation of DTH-mediated reactions against mycobacterial antigens in the skin of guinea pigs. Intracutaneous injection of mycobacterial antigen into the skin of immunised and non-immunised guinea pigs induced an erythematous reaction which reached its peak after 24 h. On days two and three after challenge, the centre of the erythema blanched and necrotised. During the next days, skin necrosis increased and reached a peak on days six and seven. In immunised guinea pigs, DTH led to a specific enhancement of erythematous and necrotising skin reactions which also appeared in non-immunised guinea pigs. Thus, an early erythematous and a late necrotising DTH-reaction were identified by their morphology and time course. Both types of DTH-mediated allergy revealed dose-dependency from the intracutaneously injected antigen doses. Erythematous and necrotising DTH reactions against viable and killed mycobacteria showed a similar time course and morphology. DTH reactivity which was induced by immunisation with Mycobacterium tuberculosis showed cross-reactivity with antigens of Mycobacterium bovis.

Intracellular iron storage and the pathogenesis of paratuberculosis. Comparative studies with other mycobacterial, parasitic or infectious conditions of veterinary importance

The distribution of iron and mycobacteria was examined in the intestinal tract of ruminants with naturally-occurring M. paratuberculosis infection and compared with mycobacterial infections in several species. This distribution was compared with that of iron in chronic lesions caused by other microbial or parasitic agents. In the clinical form of paratuberculosis in cattle, sheep and goats there was marked lymphangiectasis and a high proportion of the granulomatous lesions contained siderotic macrophages with a high mycobacterial content. In cattle with preclinical lesions of granulomatous enteropathy, the greatest number of acid-fast organisms was present in siderotic, non-differentiated, ileo-caecal macrophages; concurrent mast cell-associated allergic enteropathy was also apparent in the duodenum, proximal and mid-ileum of most animals. In paratuberculosis-affected herds, a high proportion of non-productive cows were without classical granulomatous change but had cultural or immunological evidence of M. paratuberculosis infection and similar allergic catarrhal enteropathy of the upper intestinal tract. Interstitial haemorrhage of the ileocaecal valve, with the accumulation of haemosiderin and ferritin in undifferentiated macrophages was observed in some of these cattle and also in others with experimentally-induced copper deficiency and acute ostertagiasis. Colonisation of the ileo-caecal or caecal glandular crypts by large, apparently saprophytic acid-fast organisms indicated regional tolerance to such organisms in all cattle. In other mycobacterioses such as bovine or avian tuberculosis, undifferentiated, siderotic macrophages containing mycobacteria were also seen in early granulomas, but epithelioid and giant cell differentiation invariably led to the disappearance of intracellular iron and a reduction in mycobacterial numbers. In possums in which epithelioid and giant cells did not occur in response to M. bovis infection, siderosis persisted in many macrophages and overwhelming mycobacterial multiplication occurred. These studies indicate that, in most infections with mycobacteria, differentiation of macrophages radically reverses their iron acquisitive properties, creating an intracellular environment unsuitable for mycobacterial multiplication. It seems likely that allergically mediated microvascular haemorrhage, local tolerance of commensal mycobacteria and attenuation of the macrophage siderosis reversal mechanism provide unique conditions for early, uninhibited, intracellular multiplication of M. paratuberculosis in the ileo-caecal valve of certain mature ruminants.

The use of somatic antigen of Haemophilus influenzae for the monitoring of T cell-mediated skin test reactivity in man

To investigate its usefulness as a skin test antigen, Haemophilus influenzae somatic antigen was tested in 28 healthy individuals, both in soluble and aggregated form. All subjects were found to possess specific antibodies against H. influenzae of both IgG and IgM subclass, thus showing their previous exposure to this commensal micro-organism. The somatic antigen in solution was found to be a poor antigen for eliciting a delayed hypersensitivity skin response: only 2 out of 16 subjects reacted with a positive DTH pattern. In contrast, 25 out of 28 persons showed a positive DTH pattern when somatic antigen was used in aggregated form. Two types of DTH reaction patterns could be detected (in a ratio of approximately 3:2), viz. those with an early (24 h) and those with a late (48 h) maximal swelling. Histology of 3 early and 1 late DTH reaction showed perivascular infiltrates of mainly Thelper/Tinducer lymphocytes. Hardly any basophils were seen. One negative skin test, biopsied at 6 h, showed no signs of Arthus reactivity. It can be concluded that skin tests using the aggregated form of the somatic antigen of H. influenzae are useful for assaying specific T-cell-mediated reactivity in man.

In vitro inhibition of murine B-cell tumor growth by MDP, MDP(D-D) and Vaccin is mediated by macrophages

The effect of two muramyl dipeptides, N-acetylmuramyl-L-alanyl-D-isoglutamine (MDP) and N-acetylmuramyl-D-alanyl-D-isoglutamine (MDP(D-D)), on the in vitro growth of two murine ascitic plasmacytomas, MOPC 173 and TEPC 15, and on an ascitic lymphoma cell line, ABPL2, was studied. The ability of the muramyl dipeptides to inhibit tumor cell growth was compared with a sonicated antigenic preparation of Mycobacterium vaccae (Vaccin), known to have macrophage stimulation activity. The growth of all three ascitic cell lines was inhibited by both muramyl dipeptides and Vaccin. Macrophage-depletion of the ascitic cell populations led to an increase in cell growth of TEPC 15 and MOPC 173, and a decrease in ABPL2. A reduction or loss of the inhibitory activity of the muramyl dipeptides or Vaccin was also observed, and no inhibitory activity was found when the tumor cell lines were cultured in vitro to render them macrophage-free. The inhibitory activity of MDP or MDP(D-D) was restored when purified ascitic macrophages were added to the in vitro cultured cell lines. It was demonstrated that a minimum number of macrophages were necessary for the expression of inhibitory activity. Indomethacin, a PG-synthetase inhibitor, was found to act in a synergistic manner with MDP and MDP(D-D) in inhibiting TEPC 15, but antagonized the effect of these two agents on ABPL2. The lymphoma cell line ABPL2 appeared to be the most sensitive to inhibition by MDP(D-D), a nonpyrogenic, adjuvant-inactive stereoisomer of MDP.

Time course and histological differences between sheep red blood cells and tuberculin DTH reactions in mice

Delayed-type hypersensitivity (DTH) reactions induced with sheep red blood cells (1 X 10(8) SRBC/mouse) or with attenuated viable Mycobacterium bovis (4 X 10(6) BCG/mouse) inoculated subcutaneously and elicited, respectively, with SRBC or protein-purified derivative (PPD), were studied regularly in separate groups of outbred mice and compared during a period of one year following immunization. The present report shows the existence of two distinct types of DTH reactions. The SRBC type consists of a reaction which peaks consistently at 18 h, reaches a maximum 4 days after immunization, and decreases progressively until the fourth month. This local reaction, mediated by specific committed T cells as demonstrated by adoptive transfer experiments, was shown to consist mainly of a polymorphonuclear leukocyte infiltration. The PPD type consists of a local reaction which presents a different time course, the peak shifting from 18 to 42 h during the first two months after immunization, and which persists unchanged over a year after immunization. This second type of DTH reaction consisted of an early phase of polymorphonuclear infiltration followed by an increased number of mononuclear cells. Evidence is also given that the differences in the expression of these two types of DTH reactions depended neither upon the physical characteristics of the two antigens used for elicitation nor upon the nonspecific environmental modulating activity of BCG, since soluble SRBC protein and heat-killed BCG cells elicited the same distinct types, and the two distinct DTH reaction types could be elicited in mice immunized with both BCG and SRBC.

A study of acute-phase reactant proteins in Indonesian patients with pulmonary tuberculosis

The levels of 8 acute phase reactants (alpha 1-antitrypsin, alpha 2-macroglobulin, transferrin, alpha 1-acid glycoprotein, C-reactive protein, ceruloplasmin, haptoglobin and the third component of complement) and immunoglobulin in the IgG, IgM and IgA classes were assayed, by laser nephelometry, in sera from 107 East Japanese patients with smear-positive pulmonary tuberculosis and 144 healthy subjects. These levels were correlated with clinical, haematological and radiological features, the levels of antibody to Mycobacterium tuberculosis, and the diameters of the tuberculin skin test read at various times. Levels of all acute phase reactants increased significantly in tuberculosis except for that of transferrin which was lowered. The correlations between the various acute phase reactants in health and disease were calculated. In general, the correlations were lower in disease than in health, except for the third component of complement and a greatly increased correlation between the levels of alpha 1-antitrypsin and ceruloplasmin. There was a significant correlation between levels of some of the acute phase reactants and those of antibodies to M. tuberculosis, mainly with IgG, less with IgA and least with IgM antibodies. By contrast correlations between acute phase protein and total immunoglobulin levels were most evident in the IgM class, less with IgA and not at all with IgG. Although there were some associations between protein levels and age, sex and weight of controls and patients, these were not great enough to account for the differences between the two groups. There was a tendency for patients, but not controls, with intestinal helminthiasis to have higher levels of total IgM than those without evidence of parasites. In general, the levels of proteins bore very little relation to the clinical and radiological features of disease and were, with the exception of the antimycobacterial antibodies, of no diagnostic value. Likewise, protein levels were not associated with the extent of disease; better correlations were found with the ESR and leucocyte count. Transferrin levels tended to be higher in those with chronic disease and showed a correlation with the diameters of the dermal reactions to tuberculin at 24 hours, which were also significantly larger in chronic disease. Among the haematological findings, the most significant was a negative correlation between the lymphocyte count and haptoglobin levels in disease, suggesting a possible regulatory role for this protein.

The use of a sonicate preparation of Mycobacterium tuberculosis (new tuberculin) in the assessment of BCG vaccination

Six hundred and sixty four children attending elementary schools in and around the town of Butajira in Shoa district of Ethiopia have been skin-tested with a sonicate tuberculin and the responses have been divided into two different types. One of these types is believed to indicate protective immunity and the other tissue damaging hypersensitivity. On the basis of these responses previously administered BCG vaccination has been assessed for its protective efficacy which, it is suggested, is above 80%. This system of assessment also indicated that school entry age would be a very suitable time for BCG vaccination in the region. If the system can be established as useful, its potential value in planning BCG campaigns in developing countries is considerable.

Abnormalities in cell-mediated immune functions to Haemophilus influenzae chronic purulent infections of the upper respiratory tract

Delayed hypersensitivity (dh) skin test reactivity to a somatic antigen of Haemophilus influenzae was studied in 21 patients with unexplained, chronically relapsing, purulent upper respiratory tract infections. Only 2 showed a dh reactivity comparable to that of healthy controls. A majority--15 patients--had a defective dh response, whereas 4 showed exaggerated reactivity leading to necrosis of the test site and general feelings of malaise. Not only was the dh reactivity to somatic H. influenzae antigen affected, but also that to streptokinase/streptodornase and candidal antigen in most cases, though to a lesser extent. Skin test reactivity to the mitogen PHA was normal as were the dh skin test reactivities in 4 out of 5 control patients with mucous atopic rhinitis/sinusitis and 2 cases of nasal suppuration due to disturbed mucociliary transport. Delayed hypersensitivity skin test disorders were associated with elevated ratios of OKT4 + /OKT8 + peripheral lymphoid cells. In addition a high incidence of atopy and thyroid autoimmunity was evident in patients as well as in their first-degree relatives. A negative lymphocyte proliferative response to somatic H. influenzae antigen was found in 3 of our patients. These results suggest that unexplained, chronically relapsing upper respiratory tract infections might be based on restricted T-cell defects to H. influenzae, streptococcal, and candidal antigens. Such defects are reminiscent of the T-cell immune disorders to fungi playing a role in some cases of chronic mucocutaneous candidiasis.

Immunomodulation with P40, an insoluble delipidated fraction of Corynebacterium granulosum. II.--Specific immune responses of the host

Mice immunized subcutaneously in the footpad with P40, an insoluble fraction extracted from delipidated heat-killed Corynebacterium granulosum, developed systemic mechanisms which depended on the generation of a state of systemic cellular hypersensitivity to P40 antigens. An injection of P40 into the footpad resulted in a striking increase in cell division in the draining lymph node, the development of a state of specific systemic delayed type hypersensitivity and a systemic increase in the bacterial capacity of the host macrophages. The footpad containing the immunizing injection of P40 also reflected the generation and decay of host sensitivity. Whereas the expression of 24-h skin sensitivity reactions to the eliciting injection of P40 antigens peaked at about day 6, the maximal increase of the local granuloma reaction peaked at about day 14, the latter representing a cumulative reaction. These local reactions and systemic hypersensitivity did not develop in congenitally athymic Nude mice. Time- and dose-dependent variations were detected in different strains of mice. Systemic hypersensitivity could be transferred to normal recipients with lymph node cells or spleen cells but not with serum from P40-immunized donors. All the results produced in this report indicate the distinct possibility that the systemic hypersensitivity which developed after P40 sensitization was based on cell-mediated responses to P40 antigens.

The role of antibody in primary and reinfection BCG granulomas of rat skin

Primary subcutaneous infection of rats with BCG leads to a three stage local reaction. There is first a short-lived simple granuloma corresponding with high levels of cell mediated immunity (CMI). This is followed by an explosive phase of necrosis and local Mycobacterial multiplication corresponding with low levels of CMI and high levels of circulating anti-BCG antibody. Finally the lesion resolves via an epithelioid cell granuloma as bacteria fall in number and CMI returns. Reinfection with BCG produces quite different lesions when initiated at different stages of the primary infection. Reinfection during the short first stage causes a self-healing epithelioid granuloma. Reinfection during the long second stage produces a florid necrotic, bacilli-laden lesion. Reinfection during the third stage produces only a vestigial, transient granuloma. It is suggested that the evolution of tuberculous lesions depends on the interplay of CMI, bacillary load and circulating antibody. A large antigenic load in the presence of high antibody titres causes necrosis and bacillary multiplication, whereas reduced bacterial numbers plus antibody and high CMI lead to compact granulomas and healing. The first situation may be analogous to immune complex disease in antigen excess and the second to complexes in antibody excess. An analogy is drawn between the reinfection experiments and natural infection after BCG vaccination in humans. It is postulated that BCG vaccination in man may be followed by a phase in which antibody is high relative to CMI. If because of high prevalence rates, natural infection with large doses of bacilli was more likely to occur at this time, the results might help to explain the failure of BCG prophylaxis in India and comparable countries, as opposed to its success in the UK.

The Mantoux test in tuberculosis: correlations between the diameters of the dermal responses and the serum protein levels

The diameters of the skin-test response to tuberculin read at five different times differed markedly in their relationships to the serum levels of albumin, gamma globulin and other globulins and to the haemoglobin levels. The 48 hour response was the most affected by low albumin and haemoglobin levels, both of which were significantly associated with a history of decreasing weight and appetite. In view of strong evidence indicating that the 48 hour skin test response is a measure of an inappropriate, or even antagonistic, immune reaction in tuberculosis it is postulated that a reduction of this reaction under conditions of a low dietary intake of protein is not necessarily indicative of an impairment of the protective immune functions in this disease.

The effect of two distinct forms of cell-mediated response to mycobacteria on the protective efficacy of BCG

The previous paper presents evidence that prior exposure to some environmental mycobacteria enhances the protective efficacy of BCG, whereas exposure to other species opposes it, and suggests that these different species act by evoking one of two types of cell-mediated response of different protective efficacy. This paper reviews past evidence for the existence of these two types of response, and suggests that both can be demonstrated in mice. The type of response evoked in mice by environmental species correlates with their effect on the efficacy of BCG in man, and with the type of proliferative response evoked in human peripheral blood lymphocytes by their soluble antigens in vitro. Preimmunisation of mice to give one type of response can block subsequent induction of the other. We therefore present a model, based on this principle, for the interaction of contact with environmental mycobacteria with subsequent BCG vaccination.

How environmental mycobacteria may predetermine the protective efficacy of BCG

A proposal is made that there are 2 mechanisms of cell mediated response to mycobacteria, both of which produce positive tuberculin tests and that one of them is more protective against mycobacterial infection than is the other. These are referred to respectively as the Listeria-type and the Koch-type of responses. Contact with environmental mycobacteria will induce one or other of these types of response and BCG vaccination will enhance it. Thus in those places where the environmental species prime for the Listeria-type of response subsequent BCG vaccination will afford good protection from both tuberculosis and leprosy. Where the Koch-type of response frequently results from environmental contact BCG will be ineffective. Evidence if presented that a large contact with Mycobacterium scrofulaceum is prejudicial to at least one marker of BCG efficacy in Burma.

Immunological and clinical features of smear-positive pulmonary tuberculosis in East Java

The immunological and clinical features of 90 Javanese patients with smear -positive pulmonary tuberculosis were investigated. Many of the patients had advanced disease at the time of diagnosis and haemoptysis was common, especially in patients with cavitating lesions. Most patients had a significant elevation of one or more non-specific indicators of inflammation (erythrocyte sedimentation rate, third complement component, factor B and C-reactive protein). Rheumatoid factor was detected in 21% of the patients and was significantly associated with high levels of antibodies to M. tuberculosis in the IgM class. Five distinct responses were elicited by tuberculin testing; the most marked occurred at 24 hours. The degree of reaction at 6-8 hours correlated significantly with the levels of specific antibodies in the IgG and IgA classes and the 48 hour response correlated, although less markedly, with specific antibodies in the IgG class. Neither the degree of skin test reactivity nor the level of specific antimycobacterial antibodies correlated with the extent of disease as assessed radiologically. Nine per cent of the patients were skin-test negative at 48 hours but did not differ clinically, as a group, from tuberculin positive patients. It was not possible to place the cases in a spectrum of immunological responses similar to that occurring in leprosy and it is postulated that this is due to differences in the relevance to protection of the various immunological mechanisms in the two diseases. The need to establish more rigorous criteria for assessing the immune responses in tuberculosis and for studying the interactions between the protective and non-protective reactions is stressed.

Recent European research activities in mycobacteriology

The subject of mycobacteriology is becoming an increasingly popular and complex one and the contribution by European scientists has been considerable. The important areas of research include taxonomy and the improvement of identification methods; biochemistry, including enzymology, metabolic regulation, lipid chemistry, iron uptake and metabolism, pigment synthesis and DNA chemistry; genetics and bacteriophages; ecology, including the effect of contact with environmental mycobacteria on the mammalian immune response; immunology; and the association of disease and cell-wall-free mycobacteria and studies on the leprosy bacillus. The European Society of Mycobacteriologists has recently been founded to unite workers in these disciplines and to promote and disseminate knowledge in this subject.