Abnormal humoral immune response to Staphylococcus aureus in patients with Staphylococcus aureus hyper IgE syndrome.

Patients with the S. aureus hyper IgE syndrome (SAHIGES) have an abnormal IgE response to cell wall and surface antigens of S. aureus. In this paper we describe the detection of IgE antibodies to soluble antigens of staphylococci (S. aureus and S. epidermidis) and qualitative abnormalities of the IgG response to soluble S. aureus antigens in patients with SAHIGES. These findings may be of pathogenetic importance and help to delineate SAHIGES from other diseases.     

Contribution of lymph formation in the popliteal node to efferent lymph flow following stimulation of the sympathetic chain in the sheep

Lymph flow and contraction frequency were measured in popliteal efferent lymphatics. Stimulation of the ipsilateral sympathetic chain resulted in an approximate threefold increase in lymph flow, while contraction frequency increased 28% (n = 6). Occlusion of the metatarsal afferent lymphatics with a pneumatic cuff reduced efferent flow from 18 to 4 microliters/min after 25 min (n = 5), indicating that approximately 80% of popliteal efferent lymph is derived from the foot. After occlusion of the afferent lymphatics, sympathetic stimulation failed to increase efferent lymph flow significantly, while efferent contraction frequency still showed a significant rise. It is concluded that lymph formation in the popliteal node does not contribute to the rise in efferent lymph flow following sympathetic stimulation.     

Cellular immune response to sheep erythrocytes: interrelationship between proliferation of popliteal lymph node cells and footpad swelling

Mice were sensitized with graded doses of sheep erythrocytes by the intravenous or subcutaneous route and challenged for delayed-type hypersensitivity (DTH) at different times thereafter. The DTH response as assessed by footpad swelling (FPS) was compared to the spontaneous proliferative response of the popliteal lymph node cells (PLNC). Proliferation of PLNC was optimal after sensitization regimens resulting in optimal FPS. The same was true for mice sensitized under cyclophosphamide modulation. Proliferation of PLNC induced by SRBC was antigen-specific, although some crossreactivity with horse red blood cells was observed. Proliferation of PLNC could be abrogated by treatment with anti-Thy-1.2 antiserum plus complement demonstrating the T cell nature of proliferating cells. In accordance with published data, FPS of mice presensitized with a high dose of SRBC as well as FPS of recipients of spleen cells from high-dose-sensitized donors was suppressed. In marked contrast, PLNC proliferation was not diminished in these mice. Although proliferation of PLNC did not parallel FPS under all circumstances, it seems to be a correlate of the cellular immune response to SRBC.     

The response of Staphylococcus aureus to benzylpenicillin.

The response to benzylpenicillin of 2 strains of Staphylococcus aureus was investigated in vitro using 3 techniques in parallel: continuous turbidimetric monitoring, continuous microscopic monitoring, and thin-section electron microscopy. Cultures of staphylococci were exposed to several concentrations of penicillin for various intervals of time before terminating the antibiotic activity with penicillinase. Bacterial lysis by penicillin was concentration-dependent and showed an optimal dosage effect which was very marked for one of the strains. The growth and division of cells continued for up to 1 h in the presence of penicillin. A variety of morphological responses was observed at each penicillin concentration. These changes ranged from complete bacterial lysis to apparently normal cells, and included several different types of aberrant morphological forms. On addition of penicillinase to cultures exposed to penicillin, there was a time interval before survivors began to divide. This period was increased by raising the concentration of penicillin or by increasing the period of exposure to penicillin. Bacteria resuming growth after surviving penicillin action exhibited markedly aberrant septation. Most of the survivors were found to originate from clumps of cocci rather than from individual cells or small groups.     

The responsiveness of efferent lymph cells to phytohaemagglutinin during the response of the popliteal node to dinitrophenylated bovine serum albumin.

Cells, recovered from the efferent lymphatics of the popliteal nodes of sheep during in vivo responses to dinitrophenylated bovine serum albumin (DNP-BSA), were examined for their responsiveness to phytohaemagglutinin (PHA) in vitro during the first 4--5 days of the immune response. The response was almost totally depressed when cells collected throughout the response were cultured with supra-optimal doses of the mitogen. Optimal and suboptimal doses of PHA resulted in greatly enhanced responses in cells collected in the first two periods (0--6 h; 6--12h) of the response; the presence of high doses of DNP-BSA in the culture media prevented the enhancement in the second period but had no adverse effects on the cells collected during the first 6 h. Efferent cells collected after 12 h generally showed decreased responses, this depression being maximal in cells collected 2--3 days after antigenic stimulation. Later in the response the cells again exhibited enhanced responses. The possible interpretations of these results in terms of regulation of the response are discussed.     

Staphylococcus aureus strategies to evade the host acquired immune response

Staphylococcus aureus poses a significant public-health problem. Infection caused by S. aureus can manifest as acute or long-lasting persistent diseases that are often refractory to antibiotic and are associated with significant morbidity and mortality. To develop more effective strategies for preventing or treating these infections, it is crucial to understand why the immune response is incapable to eradicate the bacterium. When S. aureus first infect the host, there is a robust activation of the host innate immune responses. Generally, S. aureus can survive this initial interaction due to the expression of a wide array of virulence factors that interfere with the host innate immune defenses. After this initial interaction the acquired immune response is the arm of the host defenses that will try to clear the pathogen. However, S. aureus is capable of maintaining infection in the host even in the presence of a robust antigen-specific immune response. Thus, understanding the mechanisms underlying the ability of S. aureus to escape immune surveillance by the acquired immune response will help uncover potentially important targets for the development of immune-based adjunctive therapies and more efficient vaccines. There are several lines of evidence that lead us to believe that S. aureus can directly or indirectly disable the acquired immune response. This review will discuss the different immune evasion strategies used by S. aureus to modulate the different components of the acquired immune defenses.     

The immune response to influenza vaccines

Specific immunity to influenza is associated with a systemic immune response (serum haemagglutination inhibition antibody), local respiratory immune response (virus-specific local IgA and IgG antibodies in nasal wash), and with the cell-mediated immune response. Both inactivated and live influenza vaccines induce virus-specific serum antibody which can protect against infection with influenza virus possessing the same antigenic specificity. In the absence of serum antibodies, local antibodies in nasal wash are a major determinant of resistance to infection with influenza virus. In comparative studies in humans it was shown that nasal secretory IgA develops chiefly after immunization with live cold-adapted (CA) vaccine, but persistent nasal secretory IgG was detected in both CA live and inactivated vaccines. The origin of nasal wash haemagglutination inhibition (HI) antibodies is not completely known. Recently it was found that cytotoxic T-cells (CTL) play an important role in immunity against influenza and in clearance of influenza virus from the body. In primed humans, inactivated influenza vaccine stimulates a cross-reactive T-cell response, whereas the ability of inactivated vaccine to stimulate such immunity in unprimed humans has not been determined. Data on the T-cell response to live vaccine in humans are limited to the development of secondary T-cell responses in primed individuals vaccinated with a host-range (HR) attenuated vaccine. The data obtained have shown that immunity induced by inactivated influenza vaccines is presumably dependent on the stimulation of serum antibody. Live CA vaccines not only stimulate a durable serum antibody response, but also induce long-lasting local respiratory tract IgA antibody that plays an important role in host protection.     

Immune responses of the ovine lymph node to Chlamydia psittaci. A cellular study of popliteal efferent lymph.

The popliteal efferent lymphatics were cannulated in sheep of two categories, seronegative or immune to Chlamydia psittaci. Following subcutaneous injection of live C. psittaci or control material into the draining area of the popliteal node, sequential samples of efferent lymph were collected and analysed. Both categories of sheep responded to C. psittaci with increased outputs of lymphocytes and blast cells. Numbers of blast cells rose both absolutely and as a proportion of the total. Plasmablasts increased in number only in seronegative sheep. Outputs of total T cells (CD5+), helper T cells (CD4+), cytotoxic/suppressor T cells (CD8+) and non-helper, non-suppressor T cells (T19) were maximal 4 and 7 days after challenge in immune and seronegative sheep, respectively. Proportionally, CD4+ T cells declined, CD8+ T cells increased and T19 cells were unaltered with time after infection. Chlamydial antigens could not be demonstrated in the cells of efferent lymph by an immunoperoxidase method. The results of this preliminary study show that both T and B cell responses are involved in immunity to C. psittaci.     

Immunological response to a Staphylococcus aureus fibronectin-binding protein.

A protein (gal-FnBP), constructed by fusion of the genes encoding beta-galactosidase of Escherichia coli and the binding domains of fibronectin-binding protein (FnBP) of Staphylococcus aureus was used. FnBP is a surface protein responsible for attachment of bacteria to extracellular matrix of various host tissues. Gal-FnBP is more stable and can be produced in larger quantities than native FnBP. The binding specificity of this fusion protein was established in a Western blot analysis. Treatment of gal-FnBP with formalin inactivated the binding capacity of the protein but immunogenicity was retained. Immunisation of mice with formalin-treated gal-FnBP resulted in high antibody titres against the fibronectin-binding part of this fusion protein. These antibodies were measured by their ability to block the specific binding of fibronectin to gal-FnBP in a blocking assay. Sera raised against formalin-treated gal-FnBP and non-treated gal-FnBP blocked this binding to 40 and 25% respectively, thereby indicating the usefulness of gal-FnBP as a vaccine component.     

Effect of Bacillus cereus var. Toyoi and Saccharomyces boulardii on the immune response of sheep to vaccines

In this study we evaluated the effects of Bacillus cereus var. Toyoi and Saccharomyces boulardii on the immune response of lambs to Escherichia coli K88ab and Bovine Herpes Virus type 5 (BoHV-5) vaccines. Thirty, 3-month-old lambs were randomly grouped in three lots of 10 each and vaccinated at days 0 and 30 of the experiment. They grazed on the same pasture and were fed ad libitum twice a day with commercial sheep feed supplemented with either B. cereus var. Toyoi at a concentration of 1×10⁶ viable spores gr^?1, S. boulardii at a concentration of 1×10⁶ CFU gr^?1, or non-supplemented feed. Blood samples were collected at weekly intervals over eight weeks and antibody titres were analysed by ELISA. The mean seroconversions against E. coli and BoHV-5 of the fed probiotics groups were higher (p<0.001) than the controls. Both probiotics enhanced the humoral immune response of lambs to the vaccines.     

Antigen-induced non-specific suppressor factor in sheep efferent lymph is prostaglandin E2.

Efferent lymph from the popliteal node of sheep challenged with antigen was found to suppress the in vitro transformation of sheep peripheral blood lymphocytes to a variety of antigens. The suppressor factor appeared 6-20 hr after challenged of the node and was shown to be prostaglandin E2, probably complexed to albumin.     

The in situ immune response in popliteal lymph nodes of mice after macrophage depletion. Differential effects of macrophages on thymus-dependent and thymus-independent immune responses

Mice were subcutaneously (SC) injected in the left hind footpad with dichloromethylene diphosphonate (Cl2MDP)-containing liposomes to eliminate macrophages lining the subcapsular sinus (SCS) and those in the medulla of draining popliteal lymph nodes (PLN). In order to study the effect of depletion of these macrophages on the in situ immune response in the PLN, liposome-treated mice were SC injected in the same footpad with thymus-independent (TI) type 1 antigen trinitrophenylated lipopolysaccharide (TNP-LPS), TI-type 2 antigen TNP-Ficoll or thymus-dependent (TD) antigen TNP-keyhole limpet haemocyanin (TNP-KLH). No major differences were observed in antibody-serum titers of liposome-treated and control animals. After primary as well as secondary immunization with the TD-antigen TNP-KLH, an increase in the number of antibody-forming cells (AFC) was found and the peak of response was delayed in the PLN of liposome-treated animals. Such differences were not observed with the TI-antigens. These results indicate that macrophages lining the SCS and those in the medulla of the PLN are not essential for the induction of an immune response. The positive effect of macrophage-depletion on the number of AFC may be explained by competition for the antigen by macrophages and other antigen-presenting cells.     

Lymphocyte emigration from lymph nodes by blood in the pig and efferent lymph in the sheep.

Two types of experiment using local labeling of lymph nodes with FITC showed that lymphocytes emigrate from lymph nodes, predominantly in blood in the pig and in efferent lymph in the sheep. In the first type of experiment with the pig, few cells emigrated via the lymph, while the number of labelled cells in the blood increased progressively and the indices in mesenteric blood were always higher than in jugular blood in simultaneously-drawn samples. However, in the sheep, when efferent lymph flowed freely, very low numbers emerged in blood and continuing large numbers of lymphocytes emerged in efferent lymph. In the second type of experiment carried out wholely under anaesthetic on mesenteric lymph nodes in pigs and sheep, and on superficial inguinal lymph nodes in pigs, the lymph node was isolated, the lymph and venous drainage collected and only the arterial supply maintained. Large numbers of FITC+ lymphocytes emigrated via the vein in pigs with either node cannulation (i.e. up to 7% blood lymphocytes were labelled with an emigration rate of approximately 10(8) cells/hr) but in sheep, while lymph contained approximately 30-80% labelled cells and the emigration rate was also approximately 10(8) cells/hr, the mesenteric blood contained very few labelled cells (approximately 0.2%, giving a mean venous emigration rate of 2.7 X 10(6)/hr). Study of the type of lymphocytes emerging from labelled pig lymph nodes and spleen during the phase of major emigration showed that sIg+ B and E rosette-forming T cells, but almost no Null cells, are involved.     

Characteristics of lymphoblasts appearing in efferent lymph in response to immunization with vaccinia virus.

Efferent lymphocytes collected from a cannulated lymphatic draining a single lymph node were studied for their cytotoxic activity following the injection of live vaccinia virus s.c. into the drainage site of the lymph node. Three days after the injection of virus, there was a 40-fold increase in the output of lymphoblasts from the regional lymph node. However, antigen-reactive cells, presumably T-helper cells, cytotoxic T lymphocytes (CTLs) and CTL precursors, were first detectable in efferent lymph during the fifth day after injection of virus. After a secondary challenge with virus, both lymphoblasts and antigen-reactive lymphocytes appeared earlier in efferent lymph, but lymphoblasts were still found well before the antigen-reactive cells. Efferent lymph cells were fractionated into a blast-enriched and a blast-depleted population of cells. Antigen-proliferating cells, CTLs and CTL precursors were each found to coenrich with the lymphoblast population. These findings indicate that much of the initial lymphoblast migration from the regional lymph node into efferent lymph after immunization consists of cells that do not specifically react to the injected antigen in vitro. Previous studies using allogeneic lymphocytes as the antigen have attributed both antigen-proliferating cell and CTL activity to the small lymphocyte population. In contrast, our studies on antigen-proliferating cells, CTLs and CTL precursors, after immunization with virus, suggest that, during the first 10-12 days following immunization, these cells are large lymphoblasts rather than small lymphocytes.     

The T cell-dependent period of the immune response to sheep erythrocytes.

To study the T cell-dependent period of the immune response of mouse spleen cells to sheep erythrocytes the co-operation between T and B cells was abrogated at different times during the in vivo or the in vitro response. The abrogation was performed by killing the T cells with anti-theta serum or anti-H-2 serum. The surviving cells were subsequently cultured in vitro and the number of IgM plaque-forming cells was determined each day. The results indicate that T cells play an important role during the first 3 days of the response in vivo. However, during the in vitro response the presence of the T cells is only required during the first 2 days. The difference between the response in vivo and in vitro is probably due to a synchronous start of the plasma cell development in vitro and a more asynchronous start of this process in vivo.     

Cell-mediated immune responses in Staphylococcus aureus infections in mice.

Delayed hypersensitivity to staphylococcal antigens was shown in mice repeatedly infected with Staphylococcus aureus. It was characterized by footpad swelling at 48 hours with a mononuclear cell infiltrate and could be transferred to non-infected recipients by T lymphocytes from infected animals, but not by serum. Recipients of immune T cells produced very severe necrotic lesions when challenged with staphylococci. This was in contrast to the protection against necrosis in recipients afforded by serum from infected donors. When both serum and cells were transferred into the same mouse the humoral effects overshadowed or perhaps inhibited those mediated by cells with resultant protection against staphylococcal dermonecrosis.     

The role of immune response to Staphylococcus aureus superantigens and disease severity in relation to the sensitivity to tacrolimus in atopic dermatitis

BACKGROUND: Staphylococcus aureus-producing superantigens (SAgs), such as staphylococcal enterotoxin B (SEB) or toxic shock syndrome toxin-1 (TSST-1), are frequently observed in atopic dermatitis (AD). However, little has been done to establish the association of immune responses to SAgs and the therapeutic response to immunosuppressive drugs in AD. Therefore, we investigated the prevalence and role of SAgs in the pathophysiology and immunosuppressive drug sensitivity in AD patients. METHODS: We classified 29 patients into two groups on the basis of their clinical AD scores: a low-score group (n = 14) corresponding to mild to moderate patients and a high-score group (n = 15) corresponding to severe patients. We estimated the plasma anti-SEB or TSST-1 IgE of these patients and healthy subjects by ELISA. We also estimated individual drug sensitivity by determining drug concentrations that would give 50% inhibition (IC(50)) of peripheral-blood mononuclear cell (PBMC) proliferation in vitro. RESULTS: The levels of plasma anti-SEB or TSST-1 IgE in the severe patients were significantly higher than those in the mild to moderate patients (p < 0.05 and p < 0.01, respectively). When stimulated with concanavalin A in vitro, PBMCs in the severe patients exhibited low sensitivity to the suppressive efficacy of tacrolimus (FK506) as compared to the mild to moderate patients (p < 0.01). Furthermore, there was a significant correlation between the IC(50)s of FK506 and plasma anti-TSST-1 IgE levels (p < 0.01). CONCLUSIONS: We showed that PBMCs in severe AD patients exhibited lower sensitivity to FK506, and had higher plasma levels of anti-TSST-1 IgE as compared to the mild AD patients. SAgs appear to be one of the causes of decreased PBMC sensitivity to FK506, and therefore an alternative treatment would be useful based on the individual drug sensitivity data and anti-TSST-1 IgE levels.