Choi et al [102] have exploited the finding that increased produ

Choi et al. [102] have exploited the finding that increased production of IFN-γ is the hallmark of in vivo anti-4-1BB administration [103] to treat EAU: treatment of C57BL/6 mice with IRBP peptide (an EAU-inducing agent) and anti-4-1BB led to expansion of IFN-γ+ CD11c+CD8+ T cells and indoleamine 2,3-dioxygenase (IDO)+ DCs and these, in combination, led to deletion of autoreactive CD4+ T cells [102]. Taken together, these various findings indicate that targeting CD137 is an attractive strategy for preventing the symptoms associated with various autoimmune diseases (Table 1, Fig. 1e). The Fas (Apo-1/CD95) and Fas ligand (FasL) are one of the extensively studied TNF superfamily members. The

Fas was described originally as a cell surface molecule capable of inducing apoptosis when stimulated by Fas ligand (FasL) or agonistic

anti-Fas mAb [104–106]. However, there are reports that ligation of Fas on freshly isolated T cells co-stimulates cellular activation and proliferation [107], an attribute that is somewhat conflicting with its proposed role in apoptosis. The Fas is expressed in most tissues [108] and is up-regulated further during inflammation [109,110]. selleck At the cellular level, Fas expression is low on freshly isolated lymphocytes but is up-regulated on activated T cells [111]. Also, proportions of Fas-positive cells in peripheral T and B cells have been reported to increase in humans with Etofibrate advancing age [112]. Conversely, the expression of FasL is governed tightly and is expressed, among others, by activated T cells [113]. The Fas and FasL have been shown to play critical roles in various diseases including fulminant hepatitis [114,115], graft-versus-host disease [116] and tissue-specific autoimmune disease [117]. Fas–FasL interactions also are important in T cell-mediated cytotoxicity [118], immune privilege tissues [119–121], activation-induced cell death (AICD) [122,123] and transplant tolerance [124]. The Fas- and FasL-deficient mice develop autoimmune diseases and lymphadenopathy

due to the inability to delete the autoreactive T and B lymphocytes [125,126]. The importance of the Fas–FasL pathway has been underscored in a number of autoimmune diseases, including lupus [118], SLE [127], autoimmune lymphoproliferative syndrome (ALPS) [128,129], Canale–Smith syndrome [130], type 2 autoimmune hepatitis [131], Hashimoto’s syndrome [132], insulin-dependent diabetes mellitus [133,134], MS [135], Sjögren’s syndrome [136], myasthenia gravis [137], EAE [138] and RA [139]. Increased Fas+ and FasL+ cells were observed on the glial cells, macrophages and infiltrating lymphocytes in the white matter of MS brains [135,140]. Also, acinar cells of salivary glands of Sjögren’s syndrome patients show high expression of Fas and FasL and were shown to die by apoptosis [141]. While patients with Hashimoto’s disease showed decreased sFas, increased levels were noted in Graves’ thyroiditis and SLE patients [142,143].

4D) This qualitative change might be due to better differentiati

4D). This qualitative change might be due to better differentiation of effector/memory T cells in tumor sites after depletion of Treg. This result might not be readily explained by the disappearance of simple competition for IL-7 between pmel-1 cells and CD122+ cells. Rucaparib manufacturer However, our data did suggest that a large amount of exogenous IL-7 (1 μg×10 times, Fig. 5) could mimic certain aspects of CD25 and CD122 depletion. The administration of

a super-physiological amount of IL-7 could have also resulted in other qualitative changes in pmel-1 cells. Together with recent findings that CD122+CD8+ Treg can suppress autoimmunity in the murine Graves’ hyperthyroidism and EAE model independent of lymphopenia-driven proliferation 31, 32, our results indicate that, like CD25+CD4+ Treg, CD122+CD8+ Treg are in fact another group of bona fide natural Treg, whose immune regulatory functions and suppressive mechanisms are waiting to be exploited in the near future. Mice were purchased from the Jackson Laboratory Talazoparib (Bar Harbor, Main)

and from Charles River Laboratories (Wilmington, MA). Pmel-1 transgenic mice, Pmel-1 and GFP double transgenic mice, and IL-15 knockout mice (IL-15−/−) were described before 6. All animal protocols were approved by the Earle A. Chiles Research Institute Animal Care and Use Committee. DC were generated and isolated as described previously 6. Briefly, bone marrow cells were isolated and cultured in complete media supplemented with murine GM-CSF (50 ng/mL) Etofibrate for 8–10 days. Expanded cells were harvested and frozen in mulitple aliquots in LN2. Frozen DC were rapidly thawed at 37°C and pulsed for 2–4 h at 37°C with 10 μg/mL of the appropriate peptide in complete medium. In all experiments, the H-2Db-restricted human gp100 (KVPRNQDWL; hgp-9) was used. Loaded DC were washed with

PBS before injection. The detailed immunotherapy protocol has been described elsewhere 6. Briefly, C57BL/6 mice subcutaneously injected with B16F10 melanoma were subjected to whole body irradiation (500 Gy) on day 5, and adoptively transferred with naïve spleen cells from mice as indicated. In some experiments, CD25+ cells alone or together with NK cells or CD122+ cells (including T cells and NK cells) were depleted using biotin-conjugated anti-CD25, anti-CD122, or anti-NK1.1 antibodies and strepavidin-conjugated MACS MicroBeads (Milenyi Biotec) before adoptive transfer into tumor-bearing mice (n=5–8 per group). Adoptive transfer was followed immediately by s.c. vaccination with 1∼2×106 DC pulsed with hgp-9 peptide. In some experiments, additional DC vaccinations were administrated at indicated intervals. Tumor size was measured three times a week, and mice were sacrificed when one diameter exceeded 150 mm. All experiments were carried out in a blinded and randomized fashion. In some experiments, IL-7 was blocked by injection of mice with 1 mg purified monoclonal anti-IL-7 antibody (clone M25).

Moreover, even different strains or mutants of particular Lactoba

Moreover, even different strains or mutants of particular Lactobacillus species stimulated very different immunological outcomes in mice [16,17]. Recent evidence demonstrates that colonization of germ-free mice with complex microbiota orchestrated a broad spectrum of Th1, Th17 and Treg responses. Whereas most tested individual bacteria failed to stimulate intestinal T cell responses efficiently, a

restricted number of individual bacteria can control the tonicity of the gut immune system [18]. The key commensal organisms in immune system development have been identified very recently as segmented filamentous bacteria [18,19]. A further reflection of how the make-up of the intestinal flora can impact upon systemic responses is found in studies of non-obese diabetic (NOD) mice, which succumb spontaneously see more to type 1 diabetes (T1D); it has been known for some time that higher microbial exposure militates against development of this autoimmune disease [20], but it was shown recently not only that conventionally housed myeloid differentiation primary response gene 88 (MyD88)−/− mice are resistant to T1D, but that resistance to disease is due to the distinct microbial

combination with which they are colonized. Hence, MyD88−/− mice develop T1D under germ-free conditions, while wild-type mice given the microbial population from MyD88−/− animals had reduced susceptibility to disease [21]. It is tempting

to speculate that alteration of Treg homeostasis mediated by TLR signalling, either because of Histone Methyltransferase inhibitor genetic polymorphism or because of changes in gut flora composition, could also have consequences on development of gut inflammatory disorders. Indeed, gut flora bacteria are not equal in their capacity to stimulate TLR-9 and do so with various levels of efficiency that correlate with the frequency of cytosine–guanine dinucleotides. Thus, control of the Treg ratio and effector T cell function in the GI tract is likely to be regulated differentially by specific gut flora species. An illustration of how the presence of defined bacterial species can influence the outcome of an infection comes from the observation that mice fed Bifidobacterium Celecoxib infantis are protected from the pathogenic effect and translocation of Salmonella[22]. Activation of Tregs by the probiotic microorganism contributed to this protective effect. The proposition that certain commensal species may act in a counterinflammatory manner has led to extensive investigation of potential probiotic regulation of immunopathology. Promising results have been obtained with probiotics in the treatment of human inflammatory diseases of the intestine and in the prevention and treatment of atopic eczema in neonates and infants, but mechanism(s) of action remain to be elucidated [23].

Importantly, these in silico investigations could be used to desi

Importantly, these in silico investigations could be used to design experiments distinguishing between the two explanations above. In summary, the virtual NOD mouse was built to reproduce untreated

pathogenesis and responses to interventions (internal validation). The virtual NOD mouse also predicted most responses accurately to interventions not used in model construction (external validation). In the few instances where the virtual NOD mouse did not match the reported therapeutic response, a closer examination highlighted potential conflicts within the published data, in some cases providing a basis for clarifying laboratory experiments. The model as described DAPT concentration is ready for in silico research. It can be updated to accommodate new data or to address additional biology not currently within the model scope. Model updates may include new validation tests to ensure Erastin price that the modifications are consistent with the reported biology. The Type 1 Diabetes PhysioLab platform is a physiologically based mathematical model of type 1 diabetes pathogenesis in a NOD mouse, designed to facilitate type 1 diabetes research and accelerate development of human therapies. The model has a graphical user interface and incorporates much of the known biology in the PLN and islets, which sets the stage for its use as an educational and research tool to illustrate complex biological relationships at

these important sites. Because data are used to define qualitatively or quantitatively the biological relationships that are embedded in the model, the model can also be used as a data archive or continuing repository.

Beyond these applications, the model simulates the represented biology, providing a mathematically integrated description which is consistent with published experimental data. Generating this description was an intensive and iterative process, which refined our understanding and interpretation of the published literature. Protein Tyrosine Kinase inhibitor For example, the initial modelling exercise did not include the representation of a distinct tolerogenic DC phenotype. With the initial representation, late and transient LipCl2MDP-mediated depletion of macrophages and DCs reduced the cellular infiltrate and delayed disease onset but did not provide sustained protection despite the presence of Treg cells. Briefly, when LipCl2MDP was cleared from the system, phagocyte populations recovered and re-established a diabetogenic environment and a corresponding destructive cellular infiltrate. With no data to suggest a direct effect of LipCl2MDP on Treg cell populations, the next plausible scenario was an effect mediated through phagocytes. The representation of tolerogenic DCs was based largely on data from outside the NOD mouse literature (e.g. [99–101]), and included regulation by cytokines and cell contact.

To assess VIP production in endometrial CD4 lymphocytes, cells re

To assess VIP production in endometrial CD4 lymphocytes, cells recovered from endometrium after mechanical disruption were cultured with GolgiStop™ for 4 h in a flat-bottomed plate. In both situations, after washing in PBS, cells were fixed and permeabilized with the Fix/Perm kit (at the manufacturer’s recommended concentrations; Becton Dickinson). After washing, permeabilized cells were incubated for 30 min with rabbit anti-VIP antibody (Peninsula-Bachem Inc.), then washed and incubated with fluorescein isothiocyanate (FITC)-conjugated anti-rabbit antibody (Santa Cruz Biotechnology). Cells were then washed with PBS–2% FCS to allow membrane closure

and finally surface-stained with phycoerythrin cyanin5 (PECy5)-conjugated anti-CD4 antibody (Becton Dickinson). Ten thousand events were acquired in a FACS Aria II cytometer® and results were analysed using WinMDI software®. Negative control samples were incubated in parallel Selumetinib chemical structure with an irrelevant, isotype-matched antibody. Results for positive cells are expressed as a percentage of the respective population and the quadrant was set using irrelevant isotype-specific antibody.

The percentage of CD25+FoxP3+ or VIP+ cells was obtained inside the electronically gated CD4+ cell population using WinMDI software®. Determination of VIP, VPAC1 and VPAC2 expression levels was performed in PBMCs from RSA and fertile women after co-culture with trophoblast cells for 24 h by RT–PCR and real-time RT–PCR. Briefly, maternal PBMC total RNA was isolated with TRIzol reagent (Life Technologies, Grand Island, NY, USA), followed by reverse transcription according to the manufacturer’s instructions (Promega). For amplification Dimethyl sulfoxide of the resulting

cDNA, 1 or 2 μl of the RT mixture were used. The sample volume was increased to 25 μl with 0·2 mM deoxynucleotide triphosphates (dNTPs), 0·25 uM specific primers, 3 mM MgCl2, 2 U Taq DNA polymerase and 1:30 000 dilution of Sybr Green. Real-time PCR reactions were performed in a DNA Engine Opticon (MJ Research, Inc., Waltham, MA, USA) after a predenaturation step at 95°C for 5 min; we used a denaturation step at 95°C for 30 s, an annealing step at 58°C for 30 s and elongation step at 72°C for 30 s for a total of 40 cycles. An additional extension step at 72°C for 10 min was carried out. PCR products were quantified in Opticon Software® and normalized to endogenous glyceraldehyde 3-phosphate dehydrogenase (GAPDH). The primers and thermal profiles were selected with the software Primer-3, as described previously [20]. PCR products were electrophoresed through a 2% ethidium bromide-stained agarose gel, visualized by transillumination and photographed. As a positive control for VIP and VPAC receptors we used human neuronal cell line SH-SY5Y, cultured as described previously [27].

g Figure 3b) The degranulation

of MCs and neutrophils w

g. Figure 3b). The degranulation

of MCs and neutrophils was characterized by free granules that were frequently seen close to the capilliform filitriches (Figure 4b) or adjacent to and/or between the coniform spinitriches of the scolex (Figure 4b) (see 39 for cestode microtriche terminology). In some grids, because of the plane of the section, the free granules from neutrophils and MCs were found in contact with the scolex tegument (respectively, Figure 4c,d). Several glandular cytons within the syncytial tegument along the anterior and lateral parts of the M. wageneri scolex were observed (not shown). No discharge from these glands or the presence of an adhesive layer in the interface region between the tench intestine and the tapeworm was evident. Cyprinids are the main group of freshwater fish that have a global importance as a source of food in many PD-0332991 concentration countries. The study of

disease in cyprinids held in captivity and in semi-wild stocks is essential for Public Health Authority. The pathological alterations to the intestine of cyprinids due to cestodes have been detailed in several PD0325901 in vitro papers (3,4,40). Among gross effects of tapeworms on fish hosts, intestinal occlusion and rupture are infrequent and extreme consequences of cestode infection (41). Such phenomena are among the most serious impacts induced by intestinal tapeworms, which have been associated with debilitation, nutritional disturbance and even the death of heavily parasitized fish (42). Generally, infection of the gastrointestinal tract by parasites has detrimental effects on digestion function (5,7).

Most intestinal pathology associated with tapeworm infections results from the deep penetration of the scolex into the gut wall (43). The organs used by intestinal helminths during the process of attachment to their host’s gut frequently induces inflammation of the alimentary canal (5,10). This is the case in M. wageneri that induces marked pathological changes, penetrating the muscularis layer (41, current study), causing a significant inflammatory Resveratrol response in all layers of the intestine in both light and heavy infections. M. wageneri is a caryophyllidean cestode and it was reported that the tegumentary glands of this group of tapeworms release neutral glycoproteins which protect the parasite against host cellular responses (44). This interpretation, however, does not appear plausible given that no discharge from these glands nor the presence of an adhesive layer between the tench intestine and M. wageneri was evident in the material studied here. The presence of abundant immune cells at the site of M. wageneri attachment and presence of free granules discharged from MCs and neutrophils in close contact with the scolex microtriches rule out earlier interpretations (44). Rodlet cells (23) and two type of granulocytes, MCs (23,24,30,45) and neutrophils (20,31), have been repeatedly shown to play an essential role in the immune system of fish.

In addition, Th17 cells can be converted into Th1 cells in differ

In addition, Th17 cells can be converted into Th1 cells in different animal

models 21, 22. Furthermore, human CD4+ Tregs can be converted to a Th2 cell lineage subsequent to decreased FOXP3 expression 23. More recent studies have shown that CD4+ Tregs can also differentiate into IL-17-producing Th17 cells (IL-17+FOXP3+), and Th17 cells can co-express FOXP3 and RORγt (RoRγt+FOXP3+) 24, 25. Although these studies have focused on Th17 and Treg commitment and plasticity, whether Th17 cells can reciprocally convert into Tregs has not been described. In addition, the majority of studies demonstrating the plasticity of T-cell development have been based on observations in mixed cell populations without clear proof that this occurs buy PF-02341066 at the single-cell level. Further precise investigations of

plasticity and the intimate links between T-cell lineages at a homogeneous cell clonal level will be critical for better understanding of T-cell-mediated immunity. To further explore the phenotypic and functional features of human Th17 cells, we have recently generated Th17 clones from tumor-infiltrating T lymphocytes (TILs) which were characterized by their transcriptional factor expression, cytokine and chemokine receptor expression profiles, and their effector function. During the course of procedures intended to maintain the stability of Th17 clones for future studies, we

unexpectedly found that these Th17 clones could differentiate into IFN-γ-producing and Ivacaftor chemical structure FOXP3+ cells after in vitro stimulation with OKT3 and allogeneic peripheral blood mononuclear cells (PBMCs). Further studies showed that this Th17-to-Treg differentiation was specifically due to T-cell receptor (TCR) stimulation and was associated with FOXP3 demethylation and reprogramming of gene expression signatures, including lineage-specific transcriptional factor and cytokine genes, in Th17 cells following TCR stimulation and expansion. In addition to the expression of IFN-γ and FOXP3, these Th17 clones exhibited potent suppressive function following three rounds of repetitive stimulations and expansions with OKT3 and allogeneic PBMCs, suggesting their differentiation into Tregs. We also demonstrated that these Th17-derived Tregs RAS p21 protein activator 1 were resistant to Th17 reconversion in the presence of Th17 differentiation cytokines, including IL-2, IL-1β, IL-6 and IL-23. These results further indicate the substantial developmental plasticity of human Th17 cells and provide the first evidence that human Th17 cells can differentiate into Tregs at a T-cell clonal level. In the course of studies to examine the role of TIL subsets in anti-tumor immunity, we observed increased numbers of CD4+ Th17 cell populations in tumors of melanoma, ovarian, breast and colon cancers 26, 27.

Measurements of BWT and DWT, and ultrasound estimated bladder wei

Measurements of BWT and DWT, and ultrasound estimated bladder weight (UEBW) are potentially noninvasive clinical tools for assessing the lower urinary tract. Quantification of bladder wall hypertrophy seems useful for the assessment of diseases, prediction of treatment outcomes, and longitudinal anti-PD-1 antibody studies investigating disease development and progression.However, lack of data in healthy asymptomatic subjects creates disparity between studies and hampers the use of ultrasound in routine practice.

If methodological discrepancies can be resolved, BWT, DWT and UEBW will be valuable in assessing LUTS. Studies clearly demonstrate a need for standardized techniques and criteria. The International Consultation on Incontinence-Research Society recommended all future reports should provide information about frequency of the ultrasound probe; bladder filling volume at measurement; if BWT, DWT, or UEBW were measured; enlargement factor of the ultrasound image; and one ultrasound image

with marker positioning.94 Only under these quality controls, ultrasonic measurements of urinary bladders can be considered suitable to quantify bladder wall hypertrophy due to BOO, DO, or neurogenic bladder dysfunction in adult men or women and in children. Although recent investigations found several potential biomarkers for OAB, there is no satisfactory one for diagnosis and treatment of OAB. Based L-gulonolactone oxidase on the recent investigations, OAB mightcomprise several subtypes caused by different pathophysiologies. It is not likely to use one single biomarker to fit all types of OAB. However, in the future, with further investigations of urine, serum and bladder tissue biomarkers from patients with OAB subtypes, potential molecules which give rise to urgency sensation might be discovered and serve as suitable biomarkers for OAB assessment. No conflict of interest has been declared by the author. “
“Objectives: The current study aimed to characterize

comparatively the binding of imidafenacin to muscarinic receptors in the human bladder mucosa and detrusor muscle and parotid gland. Methods: The muscarinic receptor in homogenates of human tissues (bladder mucosa and detrusor muscle and parotid gland) was measured using a radioligand binding assay with [N-methyl-3H]scopolamine methyl chloride ([3H]NMS). Results: Imidafenacin competed with [3H]NMS for binding sites in the bladder mucosa and detrusor muscle and parotid gland, and its affinity was significantly (2.6–8.7 times) higher than that of oxybutynin. Also, the affinity of imidafenacin for muscarinic receptors was approximately two-fold higher in the parotid gland than bladder tissue. The affinity of imidafenacin in the mucosa was similar to that in the detrusor muscle, suggesting that this agent exhibits therapeutic effects by blocking muscarinic receptors in the mucosa as well as detrusor muscle.

DCs from GLA-SE but not SE-treated mice became active stimulators

DCs from GLA-SE but not SE-treated mice became active stimulators of the allogeneic mixed leukocyte reaction, inducing robust proliferation of both CD4+ and CD8+ T cells (Fig. 5C). To further evaluate the capacity of DCs to become immunogenic following antigen capture in vivo, mice were injected with anti-DEC-HIV gag and either GLA-SE or SE. After 4 h, splenic DCs were purified by cell sorting and injected into naïve mice i.v. In addition, to check that antigen presentation was performed by the transferred and not recipient DCs, MHCII−/− DCs were used as negative controls. Only WT DCs, after targeting with anti-DEC-gag and stimulated with GLA-SE in vivo, were capable

of inducing gag-specific T-cell immunity (Fig. 5D). These data indicate that GLA induces the full maturation of spleen and lymph node Tamoxifen DCs in vivo. The discovery of receptors

responsible for stimulating innate immunity, such as the TLR and RIG-like receptor pattern recognition receptors, makes it possible to test chemically defined agonists as new adjuvants to trigger the DC link between innate and adaptive immunity. To understand adjuvant action, these agonists need to be characterized in vivo at the level of antigen presenting DCs. Our experiments at this direct level indicate that a synthetic TLR4 agonist, GLA-SE, serves as an effective adjuvant and enhances Barasertib clinical trial the capacity of DCs in vivo to immunize against protein antigens. The adjuvant role of GLA-SE was dependent on TLR4. Similar results have been reported by Baldwin et al. where GLA induced production of IL-6 by Montelukast Sodium monocyte-derived DCs in culture, and this was blocked with anti-TLR4 but not TLR2 antibodies 27. Our results extend prior research by showing a complete dependency of TLR4 stimulation for the induction of adaptive responses in vivo by GLA-SE. DCs are the major link between the innate and the adaptive immune system, and its appropriate activation and maturation by agonists for innate signaling receptors should allow for the induction of

an adaptive response 41, 42. However, much of the evidence involves studies of DCs stimulated in cell culture with adjuvants 43. In the current study, we demonstrated that GLA-SE injection together with a protein antigen allows the antigen-capturing DCs to quickly become immunogenic in vivo. Enhanced T-cell responses were detected when antigen was targeted to DCs. We did not detect qualitative difference in adaptive responses between untargeted or targeted protein. However, lower doses of antigen were required using anti-DEC-HIV gag p24 to achieve detectable responses. This finding highlights the importance of DCs for initiating adaptive T-cell immunity. After showing that DCs were essential for the generation of T-cell responses in lymph nodes to an s.c.

Additionally, several independent laboratories reported that resp

Additionally, several independent laboratories reported that respiratory viral infections such as influenza could subvert the generation of protective ‘inhalation Poziotinib tolerance’ to aeroallergens (for example) [2,3], a process described originally by our laboratory as the respiratory tract equivalent of oral tolerance (reviewed in [4]). More recently, signals such as enterotoxins from skin-dwelling bacteria

have been invoked as important contributors to the pathogenesis of atopic dermatitis [5]. However, it was also clear from other observations that microbial exposure per se could not be considered in generic terms as ‘pro-atopic’. For example, other microbial-derived agents exemplified by the components of Freund’s adjuvant displayed atopy-antagonistic activity [6], and stimuli derived from normal gut flora were demonstrated to be necessary to facilitate the expression of oral tolerance

to fed allergen [7,8], and also inhalation tolerance to aeroallergen [4]. These observations suggested that microbial-derived stimuli had potential to modulate the aetiology and pathogenesis of atopic diseases in dichotomous ways, their AZD3965 concentration ultimate effects perhaps being context-dependent. A limitation of these ideas was their universal derivation from experimental models, leaving open the question of applicability to corresponding human disease. In order to bridge this conceptual gap, some creative epidemiology was required. While it was not the first observation noting the inverse relationship between risk for allergic disease in humans and microbial exposure/infection frequency, the insightful publication by Richard Strachan in 1989 [9] first articulated this concept Florfenicol in a way that caught the attention of the immunology community, who were focusing upon underlying

sensitization mechanisms. The core observations in the initial Strachan study and subsequent follow-ups pointed to a series of related factors, notably family size, socio-economic class and birth order, as important determinants of allergy risk in the United Kingdom. In particular, the lowest risk was seen in children with multiple older siblings, from relatively poor families [9,10]. These ‘low-risk’ children grew up typically experiencing a relatively high frequency of gastric and respiratory infections contracted from their older siblings, and the concept developed that these robust early microbial exposures helped to educate the immune system in some way to the dangers of inappropriate immune responses against non-pathogenic antigens.