Unraveling the Arthus Mystery: Fc Receptors and the Holy Grail of Inflammation

This Pillars of Immunology article is a commentary on “Fc receptors initiate the Arthus reaction: redefining the inflammatory cascade,” a pivotal article written by D. L. Sylvestre and J. V. Ravetch, and published in Science, in 1994. https://www.science.org/doi/10.1126/science.8066448.

Experimental serum disease; a pathogenetic study

The intravenous injection of one large dose of serum into rabbits caused a variety of changes of considerable complexity. 1. There was an immediate proliferation of mesenchymal cells, including plasma cells, particularly in heart, lungs, and spleen. 2. The signs of serum disease developed only at the time of abundant antibody formation, before significant quantities of antibody were laid down in the vascular connective tissue. 3. Allergic arteritis, marked glomerular nephritis, myocardial necrosis, and Aschoff body-like structures were seen only after hypersensitivity had developed. It appears that most, if not all, of these pathological alterations were true Arthus phenomena. 4. There were at least two distinct varieties of allergic arteritis and glomerular nephritis, namely a proliferative one, following the first injection, and a a necrotizing one, seen only after 2 injections. It appears that the first was a subacute Arthus phenomenon, while the latter was an acute Arthus phenomenon superimposed on a subacute one. The subacute experimental glomerular nephritis resembled the intracapillary glomerulonephritis in man, while the acute variety was like human extracapillary glomerular nephritis.

A clinical evaluation of definitive and clinical allergic bronchopulmonary mycosis

OBJECTIVE

The present study aims to overcome problems associated with the early diagnosis of allergic bronchopulmonary mycosis (ABPM) using the current criteria.

PATIENTS AND METHODS

Clinical features including radiographic findings from 10 patients with definitive ABPM based on the diagnostic criteria of Rosenberg-Patterson were compared with those from 9 patients with ABPM clinically diagnosed by respiratory allergy specialists.

RESULTS

ABPM should be considered in patients with peripheral blood eosinophilia and pulmonary infiltration and/or central bronchiectasis when serum total IgE is elevated. Complication by bronchial asthma suggested ABPM, but was not essential. The expectoration of sputum containing solid components was a critical factor in patients with a history in ABPM. Evaluation of sputum cultures, serum specific IgE antibodies, skin tests and precipitating antibodies were required to establish a diagnosis, but the positive rate of these tests remained low.

CONCLUSIONS

Even when a definitive diagnosis cannot be established, systemic corticosteroid therapy should be initiated for clinically diagnosed ABPM to prevent irreversible pulmonary dysfunction.

The mechanism of action of 17-hydroxy-11-dehydrocorticosterone (compound E) and of the adrenocorticotropic hormone in experimental hypersensitivity in rabbits

The concurrent administration of compound E at a daily dosage of 2 mg. per kg. to rabbits receiving daily intracutaneous injections of crystalline egg albumin markedly inhibited the development of anaphylactic hypersensitivity of the Arthus type. ACTH, when given at a similar dosage, produced a much less marked effect. Both hormones suppressed circulating antibody and as with the Arthus reaction, the suppression produced by compound E was much greater than that obtained with ACTH. When treatment with compound E was started following sensitization, there was a rapid decline in circulating antibody and, if the pretreatment serum antibody was low, there was also a progressive decrease in skin reactivity, becoming negative after 5 days of treatment. When the pretreatment serum antibody concentration was great, so that by the termination of treatment the antibody concentration was still above the level ordinarily sufficient for a maximal skin response, the Arthus reaction was unaffected by treatment. These considerations as well as the failure of compound E to inhibit the systemic passive Arthus reaction suggest that the inhibitory effect of compound E and ACTH on the development of experimental hypersensitivity results from the hormonal reduction of circulating antibody. Treatment with compound E had no effect on the rate of disappearance of circulating antibody in the passively immunized rabbit. This finding suggests that ACTH and compound E reduce circulating antibody by inhibiting antibody formation rather than by promoting antibody destruction. The question is raised as to whether the marked lymphoid atrophy produced by these hormones may be related to the interference with antibody production.

Similarities in the mechanisms determining the Arthus and Shwartzman phenomena

The intradermal injection of ovalbumin in rabbits sensitized to this antigen, under circumstances resulting in the elicitation of the Arthus phenomenon, causes a systemic reaction involving alterations in leucocytes and platelets, and results in cellular thrombosis of capillaries and veins in the injected skin areas. An abnormal metabolic process develops in the injected skin areas and may be the cause of the vulnerability of these vessels to leucocyte-platelet thrombosis. The form of vascular damage determining the Arthus phenomenon is similar to that already observed in the case of the Shwartzman phenomenon, and the results of various metabolic, hematologic, and histologic studies indicate that the mechanisms resulting in both phenomena are closely related.

Vaccine allergy and pseudo-allergy

Allergic and pseudo-allergic reactions to vaccines frequently involve the skin, and can be generalized systemic symptoms (urticaria/angioedema, serum sickness, flares of eczema) or localized at the sites of vaccination (persistent nodules, abcesses, granulomas). Diagnosis of Arthus-type reactions is based on clinical history and specific IgM/IgG anti-toxoid determination. For other local reactions, diagnostic value of non-immediate responses in skin tests varies with clinical symptoms and substances involved. Immediate responses in skin tests and specific IgE determination have good diagnostic and/or predictive value in anaphylaxis and immediate/accelerated urticaria/angioedema to toxoid-, pneumococcus-, and egg- and gelatin-containing vaccines. Diagnosis of reactions to dextran in BCG is based on specific IgM/IgG determination. Most non-immediate generalized reactions result from non-specific inflammation, except for gelatin-containing vaccines, but the diagnostic value of immuno-allergological tests with the vaccines and gelatin are controversial. Withholding booster injections is advised if specific IgM/IgG levels are high. If the levels are low, sequential injections of vaccines containing a single vaccinating agent are usually tolerated. However, injections of the vaccine should be performed using a " desensitization " procedure in patients reporting anaphylaxis and immediate/accelerated urticaria/angioedema.

Humoral immune-mediated acute, antigen-induced arthritis in rats is suppressed by the inducing antigen administered orally before, but not after, immunization

Acute ovalbumin-induced arthritis (OIA), which is mediated by Arthus reaction to ovalbumin (OVA) in the joint space, can be induced by immunization of rats with OVA followed by the intraarticular injection of OVA. Because oral administration of antigen induces immunological unresponsiveness, we studied for the first time the effects of oral administration of OVA on acute OIA. The oral administration of OVA before immunization significantly suppressed the development of acute OIA, in accordance with decreases in both the anti-OVA IgG antibody production and in vitro lymphocyte proliferative responses to OVA. However, the oral administration of OVA after immunization did not show any decrease in antibody production or in vitro lymphocyte proliferation to OVA, or in the severity of acute OIA. These results indicate that the induction of oral tolerance to OVA in OIA is possible by oral administration of OVA before, but not after, immunization with the antigen. This supports the concept of using antigen feeding as a treatment for certain humoral immune-mediated diseases.

[Suppressive effects of lanoconazole on arthus phenomenon in vivo and on production and functions of TNF in vitro]

The anti-inflammatory effect of lanoconazole (LCZ) was investigated in vivo and in vitro. The effect of LCZ was evaluated on the inflammatory reactions elicited by intradermal injection of ovalbumin to ovalbumin-immunized rabbits, as an Arthus phenomenon. A one or two % cream preparation of LCZ was topically applied on the lesion daily after challenging injection until the inflamation had diminished. By macroscopic observation and measuring the diameter of edema, erythema, hemorrhage and necrosis, the effects of LCZ on the reactions were compared with the reactions of the sites administered withcream vehicle as reference agent. Two % LCZ showed an anti-hemorrhagic effect. The in vitro effect of LCZ on production and functions of an inflammatory cytokine, TNF was also examined. LCZ suppressed the production of TNF by murine peritoneal macrophages at 20 micro g/ml and the adhesion of neutrophils at 100 micro g/ml. Moreover, LCZ significantly suppressed the growth inhibitory activity of TNF against L929 fibroblasts at 0.5 micro g/ml. A very low concentration of LCZ might protect the fibroblasts from immunological cytotoxicity in vivo. These findings suggest that LCZ has a suppressive activity to inflammatory responses and this suppressive action may be due to its protective activity to cells like fibroblasts.

The cutaneous reaction to soluble antigen-antibody complexes; a comparison with the Arthus phenomenon

The in vivo activity of soluble antigen-antibody complexes was tested by a single intradermal injection in rabbits. Skin reactions were obtained marked by erythema, induration, and occasionally hemorrhage and necrosis. Microscopically, diffuse inflammation and occasional vascular necrosis could be found at all dosages. This indicates that soluble antigen-antibody complexes are phlogogenic and provides support for the suggestion that complexes are responsible for the lesions seen in serum sickness. The reactions were similar in severity to local passive Arthus (LPA) reactions at equal dosages of antibody in the dosage range studied. BSA antigen could be found in large concentrations in affected vessel walls of both reverse passive Arthus (RPA) and active or classical Arthus reactions. It is suggested that this predominantly vascular localization of antigen might bring about the relative severity of the RPA and active Arthus reactions, as contrasted to the complex and LPA reactions. The finding of affected vessels in the complex and LPA reactions containing little or no antigen and antibody, while these components were present in adjacent areas, suggests that the antigen-antibody combination may cause vascular reaction and damage by the release of physiologically active mediators from the tissue or tissue fluid.

Altered reactivity to epinephrine in the hypersensitive rabbit

A series of experiments are reported which illustrate and characterize an altered state of reactivity of the skin of the hypersensitive rabbit to epinephrine (and norepinephrine). The requirements for the production of the lesion are: a state of hypersensitivity, circulating antigen and antibody and focal deposition of epinephrine or norepinephrine. The size and intensity of the reaction appear to be directly related to the amount of epinephrine injected (within certain limits) and to the degree of hypersensitivity as measured by the Arthus reaction. Although circulating antigen is required, the precise quantity does not seem to be as critical as does the amount of circulating antibody; a certain minimum amount is necessary, however. Experimental evidence is given which indicates the utilization of antigen in the production of the lesion. Data tending to identify this lesion with the Arthus reaction are given. The possibility of an analogous relationship between the mechanism of this experimental lesion and the necrotizing arteritis of the collagen diseases is postulated.

The specificity of allergic reactions. I. Delayed versus Arthus hypersensitivity

Guinea pigs sensitized with either hen, duck, or goose egg albumin showed delayed hypersensitivity followed by Arthus reactions to the homologous antigen, but tended to have much weaker delayed responses and slower antibody formation to heterologous antigens. Guinea pigs with delayed hypersensitivity to one of the avian antigens had a slower antibody response to a secondary injection of heterologous antigen than to one of the homologous antigen. Sensitization with a protein conjugated with a hapten such as picryl chloride (Pi) or dinitrofluorobenzene (DFB) resulted in delayed hypersensitivity to the homologous conjugate, the homologous protein, and the homologous protein with a heterologous hapten. Circulating antibody and Arthus reactions occurred subsequently to the homologous conjugate, as well as to the homologous hapten attached to a heterologous protein. Delayed hypersensitivity thus seemed associated with the protein moiety, and Arthus responses with the hapten. Anamnestic responses followed injection of an antigen causing delayed hypersensitivity, but not of a hapten not causing delayed reactions. Thus, animals sensitized initially with Pi·HEA, DFB·HEA, or HEA produced antibodies sooner after a secondary injection of Pi·HEA than did unsensitized animals. No anamnestic response resulted when animals sensitized to Pi·BGG were injected with Pi·HEA. Thus, delayed hypersensitivity is indicated to be a preliminary and immature step in the immune process, with specificity directed against broad, more general features of the protein antigen. This intermediate step is followed by production of circulating antibody to any antigen having a similar basic structure, with the specificity of the antibody also directed against smaller immunologically active sites on the antigen molecule.

Hypersensitivity in newborn guinea pigs

Neonatal guinea pigs during the first 2 weeks of life did not indicate the presence of delayed hypersensitivity intradermally, after sensitization with purified soluble antigens in dose levels that induced detectable delayed hypersensitivity in the skin of adults. Although Arthus type allergy was detectable in newborns, circulating antibody frequently preceded its appearance by several days. Passive Arthus reactions were not produced in newborns as readily as in adults. Contact hypersensitivity and allergic encephalomyelitis were induced in newborns, but corneal reactions were not. Total body irradiation with 200 r inhibited antibody formation in newborns, as in adults. In addition, the induction period for anamnestic responses in newborns and the antigen elimination rate were the same as in adults. Passive transfer of delayed hypersensitivity from sensitized newborns to normal adults was accomplished.

Properties of guinea pig 7S antibodies. III. Identification of antibodies involved in complement fixation and hemolysis

Guinea pig 7Sγ₂ antibodies were demonstrated to fix complement in the presence of antigen and to sensitize antigen-coated, tanned erythrocytes for lysis in the presence of complement; guinea pig 7Sγ₁ antibodies did not participate in these reactions. Gamma-2 antibodies were more efficient in provoking hemorrhagic necrosis in reverse passive Arthus reactions than equal amounts of non-complement-fixing gamma-1 antibodies. Unlike anaphylaxis in the guinea pig, both guinea pig 7Sγ₁ and 7Sγ₂ antibodies provoked passive cutaneous anaphylactic reactions in the rat. Efficient hemolytic activity attributable to 7S guinea pig anti-sheep erythrocyte antibodies migrated faster than the peak of complement-fixing activity, but slower than the peak of PCA activity in starch block electrophoresis. It is uncertain whether this activity is a function of a third type of antibody produced in response to the particulate property of the antigen or whether it is due to the antigenic heterogeneity of the erythrocyte cell membrane.

Some effects of proteolytic inhibitors on tissue injury and systemic anaphylaxis

A study was made of the development of various forms of local and systemic injury in animals treated with inhibitors of proteolytic activity. The agents used were tosylarginine methyl ester (TAME), epsilon aminocaproic acid (EACA), and soybean trypsin inhibitor (SBTI). 1. Hemorrhagic necrosis in the skin of the rabbit following intradermal epinephrine in combination with bacterial endotoxin (either intravenous or local) was clearly suppressed by EACA, TAME, and SBTI, given systemically. Tosylarginine (TA) was ineffective. 2. No effect was observed on the classical Shwartzman reaction, the local Arthus phenomenon, or inflammation induced by xylene. 3. The lethal effects of systemic anaphylaxis in the mouse, acute endotoxemia in the rat and mouse, and drum shock in the rat are suppressed by EACA and TAME. 4. There was no effect on the generalized Shwartzman phenomenon in the rabbit and on anaphylaxis in the guinea pig. 5. The effects of EACA or TAME on the injury reactions under investigation were not due to a pharmacological or chemical action on vascular behavior per se. 6. The data provide corroborative evidence for a proteolytic step in injury phenomena which may be mediated through some common activation system. 7. The working hypothesis is advanced that local or systemic stress through the release of epinephrine may result in an increase of a circulating activator of proteolysis and that this in turn may give rise to the release of vasoactive substances,-possibly histamine, serotonin, or a polypeptide.

The specificity of allergic reactions. III. Contact hypersensitivity

Intradermal injection of a simple hapten (e.g., 1-fluoro-2,4-dinitrobenzene) in water-in-oil emulsion results in contact hypersensitivity to surface application of the homologous hapten and, after appearance of circulating antibody, in Arthus type hypersensitivity to a conjugate of homologous hapten with guinea pig serum. Intradermal administration of this conjugate induces delayed and subsequently Arthus hypersensitivity to the conjugate, but no evidence of a contact reaction to the hapten alone. When a conjugate of hapten plus solubilized guinea pig skin is used as the sensitizing antigen, both contact hypersensitivity to the hapten and delayed and/or Arthus reactions to the conjugate develop. These observations are consistent with the hypothesis that the specificity of contact sensitivity is directed toward some particular protein of the skin which has been modified by combination with hapten.

The use of specific "lymphocyte" antisera to inhibit hypersensitive reactions of the "delayed" type

Rabbit antisera against normal guinea pig lymph node, when injected into guinea pigs, produced transient depression of the level of blood lymphocytes. It had no effect on other circulating cellular elements. Repeated injection over several days produced lymphopenia, which became progressively less marked with continued treatment, and clear-cut depletion of small lymphocytes in lymph nodes, whether draining an inoculation site or remote. In guinea pigs treated with lymphocyte antiserum, there was marked suppression of the tuberculin and contact allergic reactions and the "delayed" skin reaction to purified diphtheria toxoid, and a relative suppression of allergic encephalomyelitis and the rejection of first set skin homografts. There was a slight effect on second set graft rejection and no effect on PCA or the reversed passive Arthus reaction. Non-specific reactions to intradermal turpentine or to concentrated dinitrochlorobenzene placed on the skin were moderately reduced. The suppression of these reactions (except allergic encephalomyelitis) was closely correlated with the degree of lymphopenia. Lymphocyte antiserum absorbed with normal blood white cells lost both its lymphopenic effect and its ability to suppress the tuberculin reaction. It is tentatively concluded that a circulating mononuclear cell, probably the small lymphocyte, is the primary reactant in the various types of delayed hypersensitive reactions.

Rational approaches to reduce adverse reactions in man to vaccines containing tetanus and diphtheria toxoids

Adverse reactions to routine vaccines are obstacles to the mass vaccination campaigns. Though the absolute safety of any injectable vaccine cannot be guaranteed, the adverse side effects to vaccines can be minimized by practicing existing scientific knowledge. Adverse side effects to tetanus and diphtheria toxoids have been known for many years and there have been ways to minimize these reactions. These procedures did not get wide acceptance, because the current partially purified tetanus and diphtheria vaccines meet the regulatory requirements and the manufacturers are reluctant to change the established procedures of production due to the amount of work involved in the regulatory issues under the current Good Manufacturing Practices (GMP). Due to the recent epidemic of diphtheria in the independent states of the former Soviet Union, and its potential for spread to other European Countries, vaccination campaigns with tetanus and diphtheria vaccines received a new boost with several international agencies. In this report, we review the causes for adverse reactions to tetanus and diphtheria vaccines and offer practical suggestions for minimizing these reactions. The major issues in minimizing adverse reactions to these vaccines include: (1) purifying the toxins before detoxification as the reactogenic accessory antigens get covalently bound to the toxins during detoxification; (2) either using well-tolerated adjuvants which do not elicit the production of antigenic specific IgE antibodies responsible for adverse reactions or by using non-adjuvanted highly immunogenic polymerized antigens; (3) checking the status of immunity by recently developed rapid serological methods or by the Schick skin-test for diphtheria to avoid allergic or Arthus-type reactions. These approaches are applicable to industrial scales and would result in a pure, less reactogenic and better characterized toxoids antigens which would be more suitable for combined vaccines comprising highly purified acellular pertussis components, polysaccharide-protein conjugates and other antigens.

Streptococcal and staphylococcal superantigen-induced lymphocytic arteritis in a local type experimental model: comparison with acute vasculitis in the Arthus reaction

Many pathogenic bacteria produce superantigenic exotoxins. To study their pathogenetic role, in particular to test whether these toxins are able to induce vasculitis, we developed a local-type experimental model in rabbits. Toxins were injected along the intermediate auricular artery of the ear. The histology of ear skin, including the artery, was examined after single or repeated injections. Repeated injections of streptococcal erythrogenic toxins produced chronic-type arteritis characteristic of lymphocytic infiltration, whereas single injection induced no acute-type vasculitis. Staphylococcal enterotoxin B and toxic shock syndrome toxin-1 also induced the same type of arteritis, although weaker in degree. In human patients these lesions are similar to those of Kawasaki disease, a systemic vasculitis with unknown etiology. The Arthus reaction to human serum albumin in immunized rabbits included acute-type vasculitis similar to polyarteritis nodosa when examined in this model. Microvasculitis lesions similar to leukoclastic vasculitis were combined in the Arthus reaction but not in the superantigen-induced lesions. Our experimental model described here is widely applicable to the study of the etiology and pathogenesis of human diseases involving vasculitis lesions.

Comparison of the reversed passive Arthus and local Shwartzman reactions of rabbit skin: effects of the long-acting PAF antagonist UK-74,505

1. By using the selective, potent and long acting platelet-activating factor (PAF) antagonist, UK-74,505, we investigated the role of PAF in a local Shwartzman reaction (LSR) and a reversed passive Arthus (RPA) reaction in rabbit skin. For comparison, we also studied the effect of the PAF antagonist on neutrophil aggregation in vitro and on acute inflammatory responses induced by intradermally (i.d.) injected lipopolysaccharide (LPS), PAF, bradykinin and zymosan-activated plasma. 2. Neutrophil aggregation was assessed photometrically. Haemorrhage, oedema formation, platelet deposition and neutrophil accumulation were quantified in rabbit skin by measuring the accumulation of i.v. injected 51Cr-labelled red blood cells (RBC), 125I-labelled human serum albumin, 111In-labelled platelets and 111In-labelled neutrophils respectively. 3. UK-74,505 inhibited in vitro neutrophil aggregation induced by PAF but not by leukotriene B4. When injected i.v. into rabbits UK-74,505 suppressed oedema formation in response to i.d. PAF for up to 4 h but had no effect on oedema induced by bradykinin or zymosan-activated plasma. 4. Oedema formation, but not neutrophil accumulation, produced during the RPA reaction was significantly inhibited by i.v. UK-74,505. The PAF antagonist also suppressed 111In-platelet but not 111In-neutrophil accumulation in response to i.d. LPS. UK-74,505 did not affect haemorrhage or oedema formation produced during the LPS-mediated LSR. 5. The results demonstrate that PAF is an important mediator of oedema formation, but not neutrophil accumulation, in the immune-complex mediated RPA reaction in rabbit skin. PAF also appears to be required for platelet, but not neutrophil, accumulation in response to locally injected LPS. Our studies do not suggest a role for PAF in the LPS-mediated LSR.

Humoral and cell-mediated immune responses following lesions of the nucleus basalis magnocellularis in the rat

The present study was undertaken to elucidate whether electrolytic lesions of nucleus basalis magnocellularis--NBM (an animal model of Alzheimer's disease--AD) may influence humoral and cellular immune responses in adult male Wistar rats. For this purpose intact control (IC), sham-operated (SO) and NBM-lesioned rats were divided into two main groups: (1) rats immunized with sheep red blood cells (SRBC) for plaque-forming cell (PFC) response and anti-SRBC agglutinins, and (2) rats immunized with bovine serum albumin in complete Freund's adjuvant (BSA-CFA) for anti-BSA antibody production, Arthus and delayed hypersensitivity skin reaction to BSA. PFC responses and anti-SRBC agglutinins as well as diameter and expression of edema/induration of Arthus/delayed skin reaction and titer of anti-BSA antibody were significantly lower in NBM lesioned rats (compared to IC and SO). The results showed that in NBM-lesioned rats both the humoral and cellular immune responses were suppressed.

IMMUNOLOGIC TOLERANCE IN THYMECTOMIZED, IRRADIATED RATS GRAFTED WITH THYMUS FROM TOLERANT DONORS

Lewis rats, thymectomized at 5 weeks of age and irradiated at 8 weeks, received grafts of adult thymus and marrow, one or both grafts being derived from donors tolerant to bovine gamma-globulin. Challenge 3 or 6 weeks after grafting showed that delayed sensitization could not be induced in animals which received a tolerant thymus or tolerant thymus and marrow, though sensitization to a heterologous antigen (chicken ovalbumin) occurred normally. Arthus reactivity was regained slowly in animals receiving normal thymus and marrow and, to an equal extent, in those receiving grafts from tolerant donors.

STUDIES ON THE LOCALIZATION OF CIRCULATING ANTIGEN-ANTIBODY COMPLEXES AND OTHER MACROMOLECULES IN VESSELS. I. STRUCTURAL STUDIES

A short term model in which circulating antigen-antibody complexes and host complement localized in vessel walls of guinea pigs was analyzed. Localization was accomplished by subjecting the animals to anaphylactic shock. The circulating macromolecules, such as antigen-antibody complexes, appeared to localize by being trapped in the vessel wall along the basement membrane that acted as a filter during a state of increased permeability of the vessel. It was suggested that this point of localization between the endothelial cell and the basement membrane may well represent the earliest focus of inflammation in diseases caused by the deposition of injurious macromolecules such as soluble antigen-antibody complexes from the blood stream. Complexes localized in the vessel walls did not provoke Arthus-type vasculonecrotic reactions even though in both these vessels and in cutaneous Arthus reactions antibody, antigen, and host complement (C'3c) were deposited in the vessel walls. The possibility was presented that since circulating macromolecules and probably complexes deposited in (a) relatively small amounts, and (b) in a position beneath endothelial cells, they were not strongly chemotactic toward circulating polymorphonuclear leukocytes. Vasculonecrotic reactions, therefore, were not observed. It was brought out that this may be similar to the situation in glomerulonephritis induced by localized immune complexes, in which severe necrosis is not observed. In the Arthus vascular reaction, host complement was found microscopically accumulated with the immune reactants in affected vessel walls.

BOUND COMPLEMENT AND IMMUNOLOGIC INJURY OF BLOOD VESSELS

Rats and guinea pigs were depleted of complement (C') by treatment with heat aggregated human γ-globulin (agg HGG), zymosan, anti-β1C globulin, and carrageenan. Although antigen and antibody were bound to vascular structures, Arthus reactions were inhibited. This inhibition was characterized by the lack of C' binding to walls of vessels, the lack of polymorphonuclear (PMN's) cellular infiltrates, and the lack of significant vascular damage. When the same animals were followed for several hours thereafter, levels of serum C' began to rise, C' was bound in tissues, PMN infiltrates appeared, and immunologic vasculitis developed. Blood counts, chemotaxis of PMN's induced by lysates of PMN granules, together with studies on motility and phagocytosis by PMN's obtained from C' depleted rats, failed to establish any abnormality in these cells which would account for inhibition of Arthus reactions. The specificity of C' depletion in terms of effects in the first four reacting components of guinea pig C' was studied. Treatment with agg HGG led to loss of activity in all components, whereas zymosan and anti-β1C globulin predominately affected the third component (C'3c). Carrageenan mainly affected the first two reacting components of C'. Thus, the availability of the 3c component, or a subsequently reacting component, correlated with the attraction of PMN's to immune reactants in vivo. Various antibodies with different C' fixing capacities in vitro were tested for their ability to induce immunologic vasculitis in normal animals. In rats, only those antibodies which fixed C' in vitro possessed biological activity, whereas in guinea pigs, all antibodies tested, regardless of C' fixation in vitro, induced Arthus reactions. For a given antibody in rats the vasculitis-inducing property was reflected in its ability to bind C' in vascular structures. Rats depleted of circulating PMN's by specific antibody were tested for Arthus activity. Although concentrations of immune reactants and C' were readily detected in vascular structures, no PMN infiltration occurred and significant vascular damage was averted.

STUDIES ON DELAYED HYPERSENSITIVITY. I. INFERENCES ON THE COMPARATIVE BINDING AFFINITIES OF ANTIBODIES MEDIATING DELAYED AND IMMEDIATE HYPERSENSITIVITY REACTIONS IN THE GUINEA PIG

Experiments carried out with several well defined antigenic systems (hapten conjugates of poly-L-lysine and guinea pig serum albumin) in guinea pigs demonstrated that: 1. Arthus reactions also manifest carrier specificity, although to a smaller extent than do delayed hypersensitivity reactions. 2. Desensitization by injection of minute doses of antigen results in moderate specific desensitization of delayed hypersensitivity without desensitization of Arthus reactivity to the same antigenic determinant. 3. Insoluble antigen-antibody complexes prepared from high affinity guinea pig antibodies can elicit specific delayed skin reactions in sensitized guinea pigs. 4. Homologous conjugates of structurally similar haptens show considerably less cross-reactivity in delayed reactions than in immediate hypersensitivity reactions to the same antigenic determinant. These experimental results are interpreted as indicating that delayed hypersensitivity reactions in the guinea pig are mediated by "antibodies" of comparatively high binding affinities. High binding affinities are achieved for these antibodies more likely by closer structural adaptation between antigen and antibody than by a larger area of specific contact.

ANTIGEN-ANTIBODY REACTION: NATURE OF COMPLEX INITIATING DELAYED HYPERSENSITIVITY

Two homologous lightly coupled dinitrophenyl conjugates of poly-L-lysine of differing average molecular sizes were compared with regard to their abilities to elicit in guinea pigs specific delayed hypersensitivity skin reactions, passive cutaneous anaphylaxis, and active Arthus reactions. Equal concentrations by weight (but not equimolar concentrations) of the two conjugates elicited equally intense delayed hypersensitivity reactions and Arthus reactions, whereas equimolar concentrations (but not equal weightconcentrations) elicited equally intense passive cutaneous anaphylaxis reactions. These results suggest that delayed hypersensitivity reactions are initiated by the reaction of antigen with antibody molecules in true solution, and not by the simple bridging by antigen of a small number of antibody molecules firmly fixed to cell membrane surfaces. Whether "sensitized cells" or circulating "delayed hypersensitivity antibodies" are the specific mediators of the delayed hypersensitivity reactions is discussed.

A dominant role for mast cell Fc receptors in the Arthus reaction

Antibody-antigen complexes are central to the inflammatory response and are implicated in the development of such diverse diseases as systemic lupus erythematosis, rheumatoid arthritis, immune glomerulonephritis, and vasculitis. We recently demonstrated that experimental immune complex-mediated injury in mice, as modeled by the cutaneous Arthus reaction, requires receptors for the Fc portion of the antibody and is unaffected by deficiencies in complement components. However, the responsible cell type(s) and Fc receptor(s) were not known. We now demonstrate by differential reconstitution in vivo that Fc gamma RIII on mast cells is necessary for this inflammatory response. We propose a general model of antibody-mediated diseases as an immunopathologic spectrum whose specific manifestations are determined by the Fc receptor and cell type engaged.

Amelioration of lupus-like autoimmune disease in NZB/WF1 mice after treatment with a blocking monoclonal antibody specific for complement component C5

New Zealand black x New Zealand white (NZB/W) F1 mice spontaneously develop an autoimmune syndrome with notable similarities to human systemic lupus erythematosus. Female NZB/WF1 mice produce high titers of antinuclear antibodies and invariably succumb to severe glomerulonephritis by 12 months of age. Although the development of the immune-complex nephritis is accompanied by abundant local and systemic complement activation, the role of proinflammatory complement components in disease progression has not been established. In this study we have examined the contribution of activated terminal complement proteins to the pathogenesis of the lupus-like autoimmune disease. Female NZB/W F1 mice were treated with a monoclonal antibody (mAb) specific for the C5 component of complement that blocks the cleavage of C5 and thus prevents the generation of the potent proinflammatory factors C5a and C5b-9. Continuous therapy with anti-C5 mAb for 6 months resulted in significant amelioration of the course of glomerulonephritis and in markedly increased survival. These findings demonstrate an important role for the terminal complement cascade in the progression of renal disease in NZB/W F1 mice, and suggest that mAb-mediated C5 inhibition may be a useful approach to the therapy of immune-complex glomerulonephritis in humans.

Interleukin 8 and mast cell-generated tumor necrosis factor-alpha in neutrophil recruitment

In the reverse passive Arthus reaction in mouse skin and immune injury of mouse dermal basement membrane, neutrophil (PMN) infiltration in mast cell deficient WBB6F1-W/Wv (W/Wv) mice was only 40% of that in WBB6F1-(+)/+ (+/+) mice that had a normal mast cell repertoire. An anti-tumor necrosis factor-alpha (TNF-alpha) monoclonal antibody (mAb) decreased PMN infiltration by 35-80% in +/+ but not W/Wv mice. In addition, an anti-human interleukin-8 (IL-8) MAb, DM/C7, inhibited PMN infiltration of the skin induced by either intradermal administration of recombinant human IL-1 beta or immune complex deposition. In both models of immune complex injury, DM/C7 reduced PMN infiltration by 40-60% in +/+ mice but not W/Wv mice. PMN infiltration and the sensitivity of this infiltration to anti-TNF-alpha or DM/C7 MAb in W/Wv mice whose mast cell population had been restored was indistinguishable from the influx observed in +/+ mice. These data suggest that TNF-alpha, IL-8, and mast cells play a fundamental role in PMN recruitment following immune complex injury.

Melanin can deplete immunosuppressive substances from the aqueous humor

Heavily pigmented eyes tend to experience greater inflammation than lightly pigmented eyes following trauma and surgery. The purpose of these studies was to test the possibilities that: (i) melanin augments T cell-responses by depleting or neutralizing anti-inflammatory substances that are normally present in the aqueous humor, and (ii) melanin augments extraocular T cell-mediated inflammatory responses. Two types of experiments were performed. First, the capacity of melanin-adsorbed and non-adsorbed rabbit aqueous humor to inhibit the proliferative response of the T cell line D10.G4.1 to IL-1 was tested. Non-adsorbed aqueous humor inhibited T cell proliferation to the background level in unstimulated cultures, whereas melanin-adsorbed aqueous humor enhanced the proliferation of stimulated, but not resting T cells. Next, mice were sensitized to the antigen conalbumin, and challenged in the ear pinna with conalbumin alone, conalbumin + melanin, or melanin alone and delayed-type hypersensitivity (DTH) was measured. Challenge with melanin alone caused some ear swelling, and melanin increased the DTH response to conalbumin. Our findings are consistent with the notion that melanin can augment intraocular inflammation by depleting or neutralizing the inhibitory components of normal aqueous humor, possibly exposing stimulatory components that are normally masked.

Delayed hypersensitivity to beta-lactams

We present nine patients with delayed allergic reactions to beta-lactams. Four of them developed reactions to ampicillin; the diagnostic studies suggested the involvement of a type IV hypersensitivity mechanism to an antigenic determinant in the side-chain structure, with intradermal and patch tests positive to ampicillin but good tolerance to benzylpenicillin. Three patients showed delayed hypersensitivity reactions to benzylpenicillin (positive delayed skin tests and/or challenges). Arthus-type reactions were seen in two other patients. Specific IgE of uncertain relationship to benzylpenicillin and ampicillin was later detected in four cases.

Experimental hypersensitivity pneumonitis in mice induced by Trichosporon cutaneum: histologic and immunologic features and effect of in vivo depletion of T cell subsets

An animal model of hypersensitivity pneumonitis (HP) was developed in C57Black/6J mice by repeated intratracheal inoculations with particulate Trichosporon cutaneum, a causative agent of Japanese summer-type HP. We observed severe alveolitis and bronchiolitis with infiltration of lymphocytes, macrophages, and neutrophils in the lung lesions. Granuloma formation was occasionally seen. Bronchoalveolar lavage (BAL) of the experimental animals showed an increase in the number of lymphocytes, macrophages, neutrophils, and in the total cell yield. Phenotypic analysis of the BAL lymphocytes by flow cytometry revealed that 43.1 +/- 3.1% of lymphocytes were Thy1.2+ (CD3+) cells and that the L3T4+ (CD4+) cells (36.3 +/- 3.5%) predominated over the Lyt2+ (CD8+) cells (18.5 +/- 1.2%). As for the humoral immune response, the specific IgA antibody activities in the BAL fluids well reflected the specific pulmonary inflammatory responses. Studies of lymphocyte depletion were performed by in vivo administration of anti-CD4 and anti-CD8 monoclonal antibodies. Depletions of CD4+ cells and of both CD4+ and CD8+ cells diminished the pulmonary lesions and specific IgA antibody activities in the BAL fluids. These results indicate that CD4+ cells may play a major role in the inflammatory process of this animal model.

Effect of aristolochic acid on arachidonic acid cascade and in vivo models of inflammation

Recently, it has been reported that aristolochic acid inhibits phospholipase A2 (PLA2) in vitro and also decrease either oedema induced by snake venom and human synovial fluid PLA2. The aim of this research was to study the antiinflammatory activity of aristolochic acid and to investigate the effect of the alkaloid on the enzymes involved in the release of eicosanoids. Our results demonstrate that aristolochic acid is able to inhibit inflammation induced by immunological, immune complexes, and nonimmunological agents such as carrageenan or croton oil. We suggest that one mechanism of the antiinflammatory activity of alkaloid may be by directly blocking PLA2 catalyzed release of arachidonic acid. Moreover, this study demonstrates that aristolochic acid could also inhibit other steps involved in eicosanoids release such as cyclooxygenase and lipooxygenase pathways.

Delayed (footpad) hypersensitivity and Arthus reactivity using protein-rich antigens and LPS in mice immunized with live attenuated aroA Salmonella vaccines

Footpad reactions to protein-rich salmonella extracts and lipopolysaccharide (LPS) were studied in BALB/c mice 2 and 8 months after immunization with the Salmonella typhimurium SL3261 aroA live vaccine. T-cell depletion in vivo and adoptive serum transfer showed that protein-rich antigens induced T-cell dependent delayed hypersensitivity reactions, whereas LPS only elicited Arthus reactions. The footpad reactions to crude protein extracts were not always T-cell mediated, but depended on the nature and the dose of the antigen. Selective depletion of CD4+ T cells alone had a greater effect than depletion of CD8+ T cells alone, but neither was as marked as simultaneous depletion of both CD4+ and CD8+ T cells, which abolished the delayed type hypersensitivity (DTH) response. Crude protein-rich extracts subjected to alkaline hydrolysis (which removes some ester-linked fatty acids and causes disaggregation of LPS resulting in decreased toxicity while conserving O-specificity) still gave positive T-cell dependent reactions, but with reduced T-cell independent reactivity. Purified phenol-water LPS (2.5 micrograms) produced Arthus reactivity which could be confused with DTH. LPS induced positive reactions which still occurred in T-cell depleted mice and were transferable by immune serum. Arthus reactions did not occur when using alkali-treated LPS, which showed reduced complement fixation in vitro when using serum from immunized mice. The results indicate that footpad testing using salmonella antigens containing LPS elicit DTH but can also produce toxic reactions, some of which are T-cell independent and not necessarily a true measure of DTH. Arthus reactivity to LPS can be confused with DTH. Alkaline hydrolysis of the antigens can eliminate non-specific reactogenicity while retaining the ability of the (protein-rich) antigen to elicit a true T-cell dependent footpad response, which requires the participation of both CD4+ and CD8+ T cells.

Brain self-stimulation and immunity: effect on humoral and cell-mediated immune responses

This study was designed to evaluate the effect of intracranial self-stimulation (ICSS) on specific immunological reactivity in the rat. Male Wistar rats were implanted with stimulating electrodes in the lateral hypothalamus (LH) and ventral tegmental area (VTA). After recovery from surgery and screening procedure, animals were allowed to self-stimulate 30 minutes daily during different periods of time before or after immunization with sheep red blood cells (SRBC) and bovine serum albumin (BSA). We report here on the in vivo immunoregulating effects of ICSS on plaque-forming cell (PFC) response, hemagglutinin production to SRBC, and antibody titer and hypersensitivity skin reactions to BSA. The effects produced were dependent on the brain area which was stimulated, time relationship of ICSS and immunization, type of immune reaction, and antigen used for immunization. Therefore, ICSS appears to be a significant tool in the regulation of the immune system function, and thus provides further evidence of the interconnections between the immune system and behavior.

[Difference of immunogenicity evoking in rabbits after immunization with a low-molecular antigen by various routes]

The present studies were undertaken to clarify the difference of the immunogenicity evoked in rabbits immunized with a low-molecular chemical antigen (TNBS) alone, by four administration routes. Rabbits were divided into four experimental groups: TNBS sc group, i.v. group, im group and ip group (3 times/week, 10 times in total), and immune responses to TNBS were estimated by the assay systems of humoral immunoreactions (HA.PCA.Arthus) and cellular immunoreaction (DTH). The highest evoking of the immunogenicity to TNBS was noted in the sc group in the case of humoral immune response, whereas the lowest evoking in the i.v. group. The intermediate degree of the immunogenicity was elicited in the im and ip groups. On the other hand, only the sc group displayed positive cellular immune response (DTH), while such immune response was never recognized in the i.v., im and ip groups. These results were indicated that the immunogenicity to the low-molecular antigen (TNBS) was evoked exceedingly in rabbits by sc sensitization route from view of humoral and cellular immune responses.

The damaging potential of leukocyte activation in the microcirculation

Traditionally leukocytes have been regarded as beneficial cells, owing to their immunologic and antimicrobial activity. Recent evidence suggests, however, an additional role of granulocytes and monocytes as mediators of cardiovascular complications, such as ischemia, reperfusion, diabetes, physiologic shock, venous ulceration, and other conditions. Granulocytes and monocytes have a large volume, and stiff cytoplasm; they have the ability to adhere to endothelium and to other substrates; and they exert several forms of cytotoxicity. Granulocytes and monocytes may be trapped in the microcirculation, may obstruct capillaries and thereby induce a no-reflow phenomenon, and may initiate organ dysfunction via oxygen free radical production and proteolytic cleavage. Few organs seem to be spared from the potential destructive actions of these cells, and novel approaches are required to interfere with leukocyte accumulation in local regions of the peripheral circulation.