The role of IL-10 in crossregulation of TH1 and TH2 responses

The identification of helper T (TH)-cell subsets has greatly improved understanding of the regulation of immune effector functions. In addition to controlling humoral and delayed-type hypersensitivity responses, these subsets crossregulate by secreting mutually inhibitory cytokines. In this review, Tim Mosmann and Kevin Moore examine these phenomena and in particular the role of interleukin 10, a cytokine secreted by TH2 cells that inhibits TH1-cell function.

Dendritic cells in the murine dermis in delayed-type contact hypersensitivity. An ultrastructural and immunocytochemical study

Dendritic cells within the dermis in the later stages of delayed-type contact hypersensitivity were examined ultrastructurally and immunohistochemically. The immunohistochemical observations were done using monoclonal antibody M1-8, which reacts specifically with murine Langerhans cells and interdigitating cells. Seventeen hours after challenge, infiltrating cells in the dermis included dendritic cells, possibly so-called indeterminate cells, monocytoid cells and Langerhans cells. Immunohistochemically, the indeterminate cells and some monocytoid cells were M1-8-positive. These findings suggest that indeterminate cells are intimately related to Langerhans cells, and that they belong to the mononuclear phagocyte system. M1-8 is a very useful marker for studies on the kinetics of Langerhans cells or indeterminate cells.

Early cellular events in evolving cutaneous delayed hypersensitivity in humans

The delayed-type hypersensitivity reaction (DHR) in human skin is prototypic for many inflammatory dermatoses. However the cellular events that precede gross lesion formation are unknown. In this study, inflammatory cell populations and adhesion molecule expression in early phases of DHR elicited by 2,4-dinitrochlorobenzene were evaluated. The first discernible event (at 1 hour) was mast cell degranulation, followed by induction of endothelial leukocyte adhesion molecule (ELAM-1) expression on dermal postcapillary venules at 2 hours. Endothelial leukocyte adhesion molecule expression peaked at 24 hours and declined by 48 hours. In contrast, endothelial expression of intercellular adhesion molecule-1 (ICAM-1) remained at constitutive levels. Intrafollicular T-cell migration occurred independent of ICAM-1 expression and commenced as early as 4 hours after challenge. Mature, activated CD4-positive lymphocytes that expressed a helper-inducer/memory phenotype predominated in early lesions. These results demonstrate in vivo that mast cell degranulation, ELAM-1 expression, and memory T-cell-follicular interactions are key events in subclinical evolutionary stages of cutaneous DHR.

Catecholamine- and endotoxin-influenced cutaneous basophil hypersensitivity in chickens

1. Catecholamines suppress cutaneous basophil hypersensitivity (CBH) to intradermal phytohemagglutinin (PHA-P) challenge in chickens. 2. E. coli 0127:B8 endotoxin, reserpine, and propranolol prevented a norepinephrine-induced suppression of CBH. 3. PHA-P induced CBH appeared to be mediated through a beta-adrenergic receptor mechanism associated with plasma corticosterone in chickens.

Double hapten challenge in guinea pigs undergoing an ocular late-phase reaction

Clinical and histological profiles of guinea pig conjunctiva undergoing late-phase reaction (LPR) were evaluated before and after additional antigenic challenge. Four groups of animals were passively sensitized with IgG1 antibodies, challenged with the specific hapten di-DNP-lysine, and rechallenged during LPR either with di-DNP-lysine, or with PBS, or with an aspecific antigen to characterize the reactivity of the inflamed conjunctival tissues. The course of the clinical anaphylactic responses was modified slightly only by challenge with a specific hapten during LPR. However, no significant changes in the inflammatory cell profile were observed in conjunctiva undergoing LPR after an additional challenge. This suggests the participation of mechanisms which may mediate the attenuation of the anaphylactic response in physiologic conditions of persistent antigen provocation.

Sympathetic auricular chondritis in rats: a model of autoimmune disease?

Following the unilateral implantation of metal ear tags in female Crl:CD(SD)BR-rats, chronic inflammatory lesions were observed in both auricles in 7% and 24% of the animals after 30 and 60 weeks, respectively. Involvement of the collateral auricles was identified only after diffuse inflammation of the ear tag-marked pinnae had developed. Histological examination revealed a multifocal granulomatous chondritis, characterized by progressive destruction of the cartilaginous plate and excessive regeneration of cartilaginous tissue. IgG and complement deposits were present in the matrix of the marginal area of regenerating cartilage and at the destruction sites of autochthonous cartilage. It is likely that the pinally-restricted chondritis was due to an autoimmune response initiated by a chronic inflammatory process at the insertion site of the ear tag. Since the response was not due to immunity to type II collagen, this pathologic phenomenon in rats may provide a useful animal model to study autoimmunity involving other cartilaginous matrix molecules.

Potentiation of delayed-type hypersensitivity response to syngeneic tumors in mice prevaccinated with cells modified by hydrostatic pressure and crosslinking

Delayed-type hypersensitivity (DTH) to the chemically induced EL4 and virally induced ARadLV 136 leukemia cells was determined by the radioactive ear test. Prior to the DTH test, mice were prevaccinated with cells treated either with hydrostatic pressure or with the membrane-impermeant crosslinker adenosine dialdehyde or with a combination of these. For both tumor cells, DTH against unmodified cells was markedly potentiated by prevaccination with cells treated with hydrostatic pressure combined with adenosine dialdehyde. In vitro cytotoxicity data indicated that maximal lysis of target cells is induced by vaccination with adenosine-dialdehyde-treated cells, as well as by pressure in combination with adenosine dialdehyde treatment. In addition, increased [3H]thymidine uptake was observed in effector T cells induced by prevaccination with tumor cells modified by adenosine dialdehyde or pressure or both. This novel and innocuous potentiation of an antitumor immune response may have a practical utility in the treatment of human cancer.

Predominantly indurated reactions to sensitizers may not cause keratinocytes to express HLA-DR

Dermal reactions to primary intradermal or appendageal sensitization are compared to predominantly dermal reactions to standard patch tests and to intradermal antigen tests. In contrast to epicutaneous spongiotic contact dermatitis, HLA-DR was only seen on skin appendages and nearby basal keratinocytes in indurated tissue reactions with the exception of the reactions with focal basal cell layer disruption and an indurated patch test performed one week post angry back syndrome. Other intradermal skin tests showed only minimal epidermal HLA-DR expression despite spongiotic epidermal changes. Predominantly dermal hypersensitivity reactions can be induced by intradermal or epicutaneous routes. They can evoke hypersensitivity responses which do not cause most epidermal keratinocytes to express HLA-DR.

[Histologic characterization of late asthmatic response in guinea pigs]

We examined lung tissues in a guinea pig model actively sensitized by inhalation of aerosolized ovalbumin (OA) and found reproducible late bronchial responses (LBR) 7 h and 24 h after OA challenge. Light microscopic examination revealed bronchoconstriction, damage to the epithelium, eosinophil infiltration in both the epithelium and subepithelium, retention of mucous in the pulmonary bronchial lumens and a decrease in the mucous content of Periodic Acid-Schiff (PAS) stain positive cells in the bronchial epithelium in LBR. An increase in the number of PAS-stain positive cells of in the bronchial epithelium was also observed in LBR. Electron microscopic examination revealed eosinophil migration around mast cell at 7 hs after OA challenge. Two different mechanisms of degranulation of eosinophil specific granules were observed in LBR. In one mechanism, the granule core changes after its matrix has changed. In the other mechanism, the granules were exocytosed as a whole, accompanied by the cell membrane and densely clumped chromatin, suggesting burst of eosinophil.

Psoriasiform intradermal test reaction to ABPC in a patient with psoriasis and ABPC allergy

We experienced a case of psoriasis with ABPC allergy which showed a psoriasiform intradermal test reaction to ABPC. A 22-year-old man with a history of psoriasis since the age of 17 was admitted to our department because he developed erythrodermic psoriasis after oral administration of ABPC. About 1 year later, he again developed erythroderma after administration of ABPC. Intradermal testing with 2% ABPC was performed. We found infiltrating erythema at day 2, followed by a gradually increasing psoriasiform reaction at 6 days on the site of ABPC skin test. We examined the infiltrating cells in the skin test reaction immunohistochemically. Most of the infiltrating cells in the dermis were activated helper/DTH-type T cells. Among the infiltrating cells in the epidermis, we observed more cytotoxic/suppressor-type T cells than helper/DTH-type T cells. A possible role of a DH reaction to ABPC in inducing the psoriatic lesion is discussed in relation to the pathomechanisms of psoriasis.

Lipid metabolism in the inflammatory lesion of a mouse model of delayed type hypersensitivity. I. Increased acylCoA:cholesterol acyltransferase activity as an integral component of the inflammatory response

Lipid metabolism was studied in a normal model of delayed type hypersensitivity to methylated bovine serum albumin (MBSA). Following initial sensitization to a single injection of MBSA, MBSA-soaked millipore filter disks (10 mm diam) were implanted in subcutaneous pockets and the course of development and the resolution of the inflammatory lesions were followed biochemically for 35 days. Of particular interest were our observations that the activity of the cholesterol esterifying enzyme, which is attributed to acyl-CoA:cholesterol acyltransferase (ACAT; EC 2.3.1.26) was increased up to 38-fold in the developing inflammatory lesion and represented the single most dramatic alteration in lipid metabolism to occur. As the lesions began to show histological evidence of resolving (between 21 and 35 days), ACAT activity declined toward basal levels. The data suggest the possibility that the ACAT reaction is an important component of the inflammatory response and, as such, offers the possibility of a novel approach to controlling the inflammatory process through ACAT inhibition.

Eczematous infiltrated plaques to subcutaneous heparin: a type IV allergic reaction

Two patients are described who had delayed reactions with eczematous plaques to subcutaneous injections of heparin. Subcutaneous challenge with high and low molecular weight heparin compounds were positive in both patients. Patch and intradermal tests with heparin were positive in one subject. Histological and immunohistochemical studies indicated that it was a type IV allergic reaction.

Orofacial granulomatosis associated with delayed hypersensitivity to cobalt

Orofacial granulomatosis is a distinct clinical and pathological entity characterized by swelling of the lips and lower half of the face. Ulceration of the oral mucosa may also occur. Granulomas are seen histologically. Orofacial granulomatosis may occur in the Melkersson-Rosenthal syndrome, granulomatous cheilitis of Miescher, oral Crohn's disease, sarcoidosis and focal dental sepsis. The increased prevalence of atopy in patients with orofacial granulomatosis and the association with food intolerance suggests the possibility of a role for allergy in at least some cases.

The immunobiological properties expressed in vitro and in vivo of Salmonella enteritidis-induced murine T cell lines

Splenic T lymphocytes from two strains of mice, BALB/c and B10.BR, infected with an attenuated strain of Salmonella enteritidis were cloned by the double-layer soft agar technique in the presence of interleukin 2 (IL 2), formalin-killed S. enteritidis (FKS) and syngeneic feeder cells. One Salmonella-reactive T cell line was established from each strain of mice. Both T cell lines bore Thy-1+, Lyt-1+ and L3T4+ surface markers as demonstrated by cytofluorography. Biological properties of the T cell lines were studied with respect to their ability to proliferate and produce lymphokines such as IL 2 and gamma-interferon (IFN-gamma) in response to Salmonella antigens, and to transfer adoptively protection against infection and delayed-type hypersensitivity (DTH). As the result of the present study, the T cell lines were proliferated specifically against several Salmonella and other bacteria, which belong to species of Enterobacteriaceae. Their proliferation required the presence of the specific antigen(s) and the compatibility in the I-A region of the H-2 complex between the T cell lines and feeder cells. The T cell lines could be proliferated with resultant production of IL 2 and IFN-gamma by in vitro culture in the presence of syngeneic feeder cells and Salmonella antigens. The protective activity assessed by the number of recoverable bacteria in spleens and livers after challenge with virulent S. enteritidis and DTH reactions to Salmonella antigen were exhibited by the T cell lines when transferred adoptively to naive syngeneic mice. These results suggested that different biological functions of cell-mediated immunity to Salmonella could be mediated by a single phenotype of T cell population.

[Delayed hypersensitivity to Candida albicans]

Conditions and factors influencing the formation of delayed hypersensitivity (DH) to yeast-like fungi of the species C. albicans under experimental conditions have been studied. The intensity of this reaction has been found to depend on the dose and method used for infecting mice, the time of the test and the qualitative state of fungal cells. As the result of this study, the infectious model of DH to C. albicans has been proposed. This model may be used for the study of the influence of different exogenous and endogenous factors of cell-mediated immune response to candidiasis.

A comparison of the relative sensitivity of two types of Heaf gun

A total of 696 secondary school children were given a Heaf test in one forearm with a magnetic head Heaf gun and in the other forearm with a fixed head gun. One week later the results were read blind. In 333 (48%) children the fixed head gun gave a more strongly positive result than the magnetic head gun, while in only 27 (4%) children did the magnetic head gun gives a more strongly positive result. These findings are statistically highly significant (p less than 0.001).

How well do the general public read Heaf skin tests?

The ability of 550 consecutive patients attending a tuberculosis clinic to grade their own Heaf skin test reaction, using an illustrated card designed for such self-reporting, was assessed. Individuals were asked to grade their own Heaf skin reaction and at the same attendance the reaction was formally graded by a respiratory health visitor. There was overall excellent agreement with only 58 (10.5%) disparate gradings. We conclude that self-reporting of Heaf skin tests using an illustrated card is simple, usually accurate and may preclude an otherwise unnecessary early reattendance. This study also validates an often used system of self-reporting.

Histologic study of delayed reactions to coelenterates

We studied by immunohistochemistry three cases of delayed envenomation by coelenterates. The most prominent features were the grouping of human leukocyte antigen-DR-positive cells with Langerhans cells (S-100 positive) and helper/inducer T lymphocytes (Leu-1+, Leu-3+, and Leu-4+). This indicates the possibility of a type IV immunoreaction in the delayed cutaneous lesions caused by coelenterates.

[Microbiologic and histomorphologic characteristics of experimental Mycoplasma-pneumococcus infection]

The specific features of the development of Mycoplasma pneumoniae and Streptococcus pneumoniae infections in mice have been studied in cases of mixed and monoinfections. As shown in this study, mixed infection is characterized by the mutual inhibition of the proliferation of both pneumococci and mycoplasmae in the lungs, the liver and the spleen of the animals, while the associative interaction of these infective agents in isolated mouse lung tissue is characterized by the inhibition of pneumococcal proliferation only. In mixed infection the early activation of cells of the immunocompetent system is observed, which is accompanied by the development of mainly cell-mediated immune processes manifested as delayed hypersensitivity with the late formation of fibrillogenesis. During the development of mixed mycoplasmal-pneumococcal infection the histopathology of mycoplasmal infection prevails, which is probably due to the early formation of delayed hypersensitivity to M. pneumoniae in the animals.

Evidence that neutrophils do not participate in the late-phase airway response provoked by ovalbumin inhalation in conscious, sensitized guinea pigs

Inhalation of ovalbumin by conscious, sensitized guinea pigs induced two phases of airway obstruction measured at 2 h (EAR) and at 17 h (LAR), respectively. In addition to causing airway obstruction, allergen challenge induced an accumulation in the bronchial lumen of eosinophil and neutrophil polymorphonuclear leukocytes at 17 h. Intraperitoneal injection of guinea pigs with a specific rabbit anti-guinea pig neutrophil serum 24 h before challenge reduced the number of circulating neutrophils by 94% and the airway neutrophilia after challenge by 90%, but it had no effect on the magnitude of either the EAR or the LAR. The observation that the LAR was not effected by neutropenia supports previous conclusions derived from experiments using the anti-allergic drugs, cromolyn sodium and nedocromil sodium, and the beta 2-adrenoceptor stimulant, albuterol, that, although there is a temporal relationship between neutrophil accumulation in the airways and the peak of the LAR, this polymorphonuclear leukocyte does not play a central role in the pathophysiologic processes that give rise to the late-phase response to guinea pig airways.

Effect of cyclosporin A on suppressor T cells

The effect of cyclosporin A (CsA) on suppressor T cells (Ts) was evaluated by in vitro incubation with afferent-phase Ts (Ts-aff) and efferent-phase Ts (Ts-eff). 2,4-Dinitro-1-fluorobenzene (DNFB) and hen egg-white lysozyme (HEL) were used as antigens. Both Ts-aff and Ts-eff were resistant to high- and low-dose CsA treatments. However, T cells associated with delayed type hypersensitivity (DTH) [TDTH] to DNFB or HEL were sensitive to these CsA treatments. These results indicate that the effect of CsA treatment on contact sensitivity and DTH influences TDTH and not Ts.

Experimental oral candidosis in the mouse: microbiologic and histologic aspects

A model of oral candidosis was developed in order to investigate histologic and microbiologic aspects of this host-parasite interaction under controlled experimental conditions. Normal adult CD-1 mice were inoculated by the topical application of 10(8) Candida albicans blastospores, and oral colonization was monitored by the quantitative culturing of saliva samples and of digested oral mucosa. Tissue sections of the mucosa were examined in a kinetic study ranging from 2 h to 13 days postinoculation. We report here that oral colonization by C. albicans can be induced in normal adult mice without the use of any compromising agent and that the animals recover from this mucosal infection following a reproducible pattern. Temporal analysis of the oral histopathology showed that distinct patterns of inflammation are associated with particular stages in the development of the infectious foci. This experimental model offers a means of further investigating the host-parasite interactions involved in the onset and development of oral candidosis.

A role for T cells in the induction of airway hyperreactivity

In this study we investigated a possible relationship of delayed type hypersensitivity (DTH), as a model for cellular IgE-independent immunity, with the induction of airway hyperreactivity. In PC1 (picryl chloride) sensitized BALB/c mice DTH-like lung infiltrates were found that were maximal 48 hr after intranasal hapten challenge. During the elicitation of this DTH-like reaction tracheal hyperreactivity to the cholinergic agonist carbachol could be detected from 2 hr after challenge with the homologous hapten and that was maximal after 48 hr.