We have therefore updated the 2006 diagnostic protocol, using the IUIS 2009 paper

and its references as the basis for clinical disease entities of PIDs. Additionally, a PubMed search was performed from 2007 onwards; several papers discussing the recognition of potential PID in everyday practice were found [3–13], and all were based mainly on expert opinion. All ESID members received an invitation to participate check details in this effort. [Searchstrategy, papers selected for algorithms designed for identification of potential PID patients in everyday clinical practice published in English in international papers: 1. ‘Related citations’ for the original paper [1] (three relevant hits, references [3–5]); ‘Immunologic Deficiency Syndromes/*classification[MeSH] NOT HIV NOT AIDS NOT HTLV NOT Simian’ (no additional relevant hits); ‘Immunologic Deficiency Syndromes/*diagnosis[MeSH] NOT HIV NOT AIDS NOT HTLV NOT Simian’ (eight additional

relevant hits, including the original ESID paper, references [1,4,6–11]); two additional papers suggested by contributors (references [12,13]).] While the general outline of the diagnostic protocol has remained the same, novel PIDs have been incorporated. Gemcitabine supplier The body of knowledge concerning PIDs has expanded considerably; therefore, possible diagnoses are now presented separately from the clinical protocols. Because evidence supporting diagnostic decisions is still limited, the protocols Dapagliflozin are based largely on consensus of expert opinions. Considering the possibility of a PID is the key to the diagnosis. Unfortunately,

the awareness of PIDs among professionals is low, as PIDs are considered rare and complex diseases. However, the incidence of PIDs ranges – depending on the disease – from 1:500 for often asymptomatic immunoglobulin (Ig)A deficiency to 1:500 000 [14,15]; all PIDs taken together may be as frequent as 1:2000 [16]. Like any other diagnostic process, symptoms from the history (Table 1a), signs on physical examination (Table 1b) and baseline blood tests (Table 1c) should alert any physician to the possibility of PID in children and adults, even though they are unfamiliar with the precise possible diagnosis. This is important, as successful treatment of a child with severe PID such as severe combined immunodeficiency (SCID) is dependent upon rapid recognition [17]. Non-immunologists such as general paediatricians play a vital role. Leucocyte differential and immunoglobulin isotype levels enable detection in most cases; these can be performed in many hospitals. Less urgent, but still important if future organ damage and decreased quality of life and life-span are to be prevented, is the timely recognition of late-onset as well as less pronounced forms of PID in older children and adults [18].

In unimmunized mice, 4–1BBL is expressed on CD11c+ MHC II− cells, however, only a small fraction of adoptively transferred CD8+ memory phenotype cells were found in contact with CD11c+ cells, making it difficult to evaluate their importance. We also detected 4–1BBL on Gr1lo CD11b+ F4/80+ MHC-IIlo CD11c− cells from the BM of unimmunized mice, thus this population could be the radiosensitive cell that contributes 4–1BBL to the CD8+ T cells. Previous studies have established that 4–1BBL is required for the maintenance of influenza-specific CD8+ T cells between find more 3 and 6 weeks post infection with influenza A/HKx31 virus, a time when this virus has been fully cleared

from the host [28]. Further studies, using adoptive selleck transfer of TCR transgenic CD8+ OT-I memory T cells confirmed this role for 4–1BBL in the antigen-independent maintenance of memory CD8+ T cells and inferred that this was likely due to effects of 4–1BB signaling on survival rather than trafficking or cell division [29]. Here, we have provided evidence that an αβ T-cell must express 4–1BB for maximal recovery of CD8+ memory T cells. As 4–1BBL affects the CD8+ but not the CD4 response to influenza virus [28, 40] and 4–1BB is expressed on resting CD8+ memory but not CD4+ memory T cells

in the BM of unimmunized mice (Fig. 2), these data argue that the effects of 4–1BBL are likely through direct effects on CD8+ T cells in the BM. The association of transferred Red fluorescent memory T cells with the stromal IMP dehydrogenase cells was not affected by 4–1BBL-deficiency. Thus, although 4–1BBL affects the number of T cells recovered in the BM when assayed after 3 weeks [29], it does not appear

to affect the positioning of the memory T cells in these short-term assays. This is not surprising, as 4–1BBL is not known as a cell adhesion molecule, and its effects on T-cell survival would not be expected to affect T-cell recovery within the 24 h of our microscopy study. PCR analysis of sorted VCAM-1+ and VCAM-1− stroma showed preferential expression of CCL19 on the VCAM-1+ as compared with VCAM-1− stroma, consistent with a role for chemokines in attracting the CD8+ T cells to the VCAM-1+ stroma in the BM [7]. We also found CXCL12 in the cultured stromal cells. The association of the memory T cells with the VCAM-1+ cells in the BM is also consistent with the observation that memory T cells express three to four times the level of VLA-4 as compared with that of naïve T cells [41]. A caveat to these experiments is that VCAM-1+ cells are highly abundant in the BM and we have not shown that the proximity of the VCAM-1+ cells to the adoptively transferred memory T cells results in a productive interaction. Nevertheless, these data indicate that it is plausible that 4–1BBL+ VCAM-1+ cells could provide a signal to the CD8+ 4–1BB+ memory cells found in the BM.

“
“Although haemolytic factor is known to be a putative virulence factor contributing to pathogenicity in Candida species, its production by Candida tropicalis is poorly understood. In this study, we analysed the culture conditions under which C. tropicalis can display haemolytic

factor on plate assay and the secretion of haemolytic factor in liquid medium by clinical isolates obtained from different specimens. All the tested isolates exhibited an internal translucent ring, resembling beta-haemolysis, surrounding by a peripheral greenish-grey halo on sheep blood agar medium. Similar PF01367338 haemolytic pattern was observed on human blood enriched medium. Furthermore, incubation either under normal atmosphere or under increased CO2 had no effect on haemolysis. Overall, no differences were observed on beta-haemolytic activities (P > 0.05) among tested isolates of C. tropicalis. In glucose-limited medium

(RPMI 1640 with 0.2% glucose), none of the isolates induced haemolysis on red blood cells. Similarly to found on plate assays, there were no significant differences (P > 0.05) in the activity of secreted haemolytic factor in liquid medium among C. tropicalis isolates. However, after growth, the number of yeast Proteasome inhibition assay cells varied among isolates revealing different efficiencies of haemolytic factor production. Haemolytic activity was neither inhibited by heat treatment (100 °C) nor by the addition of pepstatin A. The obtained results extend our knowledge about haemolytic factor production by Candida species. “
“The lungs are common sites for the occurrence of saprophytic or invasive mycosis as well as hydatid cysts. The two diseases seldom coexist, and the manifestation is seen as a fungal ball (usually aspergilloma) formed in the cavity

left behind after hydatid cystectomy. Active invasion and proliferation of the fungi in the laminated ectocyst or sometimes the pericyst of the hydatid is very unusual. We report such a unique coexistence identified in two of the Nutlin-3 in vitro six surgically excised pulmonary hydatid cysts in the past 2 years. Both were immunocompetent males, who had presented with non-specific symptoms of cough, haemoptysis and chest pain. The septate slender hyphae of the invading fungus resembled those of Aspergillus. “
“The purpose of this study was to evaluate a preemptive approach with serum 1,3-beta-d-glucan (BDG) as a marker for treatment stratification of systemic antifungal (AF) therapy in patients with clinical suspected invasive fungal infections (IFI) at intensive care units (ICU), and the impact of surgical procedures. A total of 66 ICU patients with clinical suspected IFI were included in this retrospective analysis. Serum BDG testing was performed prior to initiation of AF treatment and in addition to routine diagnostic measures. Based on the BDG results the initial clinical decision whether or not to start systemic AF therapy was re-evaluated.

Allergen, adjuvant and anaesthetics.  Chicken egg ovalbumin (OVA), grade VII, was from Sigma-Aldrich, St. Louis, MO, USA. The Al(OH)3 adjuvant (Alhydrogel) was from Brenntag Biosector, Denmark. Two different types of anaesthetics were used; Isoflurane (Isoba vet; Intervet/Schering-Plough Animal Health, Lysaker, Norway) and a cocktail named ZRF, consisting of Zoletil Forte (Virbac International, Carros Cedex, France), Rompun (Bayer Animal Health GmbH, Leverkusen, Germany) and Leptanal (Janssen-Cilag International NV, Beerse, Belgium) and isotonic saline. Isoflurane gas was administered as a 3.5% mixture with

medical O2 in a coaxially ventilated open mask to effect. BAY 57-1293 order The ZRF cocktail contains 18.7 mg BMS-777607 purchase Zolazepam, 18.7 mg Tiletamine, 0.45 mg Xylazine and 2.6 μg fentanyl per ml and was administered to effect with a nominal dose of 0.1 ml/10 g i.p. Intraperitoneal sensitization study.  Groups of mice received first sensitization at ages 1, 6 and 20 weeks and are hereafter referred to as 1-, 6- and 20-week-old mice. The mice were sensitized by i.p. administration of 0, 0.1, 10 or 1000 μg OVA in 1 mg Al(OH)3 in Hank’s balanced salt solution (HBSS) in a 0.1-ml bolus. Two weeks later, they were boosted i.p. with the corresponding dose, but without Al(OH)3 in 0.1 ml. All mice in the

1000-μg groups suffered from severe anaphylactic chock and died or were killed upon booster administration. One week later, a blood sample ZD1839 purchase was taken from the remaining groups, which

were then anaesthetized with isoflurane and challenged by i.n. instillation of 10 μg OVA in 35 μl HBSS per day for 3 days. Three days after the last challenge, the mice were anaesthetized with ZRF before the chest was opened and blood drawn by heart puncture. Lung-draining mediastinal lymph nodes (MLNs) were collected, lungs lavaged and the lymph nodes and bronchoalveolar lavage fluid (BALF) kept on ice. Intranasal sensitization study.  Groups of 1-, 6- and 20-week-old mice were sensitized i.n. [13] with 10 μg OVA with 120 μg Al(OH)3 in HBSS on days 1, 2 and 3 (Table 1). On days 22, 23 and 24, they were boosted i.n. with 10 μg OVA in HBSS. All i.n. exposures were performed under isoflurane anaesthesia. On day 27, blood was drawn by heart puncture. Nose- and lung-draining lymph nodes [superficial cervical (SLNs) and MLNs, respectively [14]] were collected and kept on ice; lungs were lavaged and thereafter collected for histopathology. The BALF was also kept on ice. In a concurrent study, control groups of age- and sex-matched mice were immunized i.n. with OVA alone without Al(OH)3 (Table 1). This OVA-only exposure did not induce sensitization or any significant responses, when compared with OVA + Al(OH)3-treated mice. For clarity, the OVA-only groups are not presented, except for a few observations. Determination of instillation volumes in the intranasal sensitization study.  The mice of the different age groups were exposed according to Table 1.

The emerging literature in several areas points to complex interactions between exposure to microbial pathogens and susceptibility to the induction and expression of allergic diseases exemplified by atopic asthma. Earlier notions that infections protect against allergy by enhancing Th1-associated immunity have been supplanted by a broader understanding of the relevance of issues, such as timing, type and intensity of infections, to the underlying disease process. Many issues BIBW2992 remain to be resolved, and this will remain a ‘hot topic’ in the allergy field for some time

to come. The authors have no conflicts of interest to declare. “
“Immunoglobulin (Ig) replacement therapy has substantially changed the life of patients with primary antibody deficiency (PAD). In the majority of cases, patients with common variable immunodeficiency (CVID) or X-linked agammaglobulinaemia (XLA) now live to lead a near-normal life. Modern Selleckchem DAPT production facilities, a series of safety measures and a choice of several ways of

administration make Ig replacement a safe and relatively easy therapy to use. The well-known presentations of PAD, such as pneumonia, septicaemia and other invasive bacterial infections [1], would continue to occur in PAD patients without regular replacement therapy. In this paper, we comment on the success and limitations of our present Ig replacement therapy in PAD. We also speculate how further improvement can be achieved in the treatment of complications from which PAD patients continue to suffer. IgG replacement effectively prevents pneumonia and invasive bacterial infections, as shown in several large cohorts.

For instance, in a large Italian cohort of CVID patients, the prevalence of pneumonia was reduced from 49·0 to 20·5% upon initiation of Ig therapy [2]. Prevention of pneumonia by Ig replacement therapy appears to be possible in a dose-dependent fashion. In a meta-analysis on IgG trough levels of 676 patients, the risk of pneumonia declined by 27% with each 0·1 g/kg body weight increment in the monthly IgG dose [3], although other factors, such as individual IgA levels, may determine the risk of pneumonia even more Plasmin strongly [4]. However, the effect of IgG replacement therapy on bacterial bronchitis and sinusitis in PAD patients is less clear. In the Italian CVID cohort, prevalence of chronic bacterial airway infections rose markedly from time at diagnosis through an observation period of a mean of 11 years of performed IgG replacement therapy. Frequency of both chronic bronchitis and sinusitis increased from 33·9 to 46·4% and from 36·6 to 54·0%, respectively [2]. The increase of these conditions during Ig therapy was described similarly in XLA patients [1, 4]. Chronic bronchitis and sinusitis in PAD is due almost exclusively to chronic bacterial infection.

3A). In chimeric mice, we found that γcKO bone marrow-derived PI3K inhibitor thymocytes (identified by CD45.1+/2+ congenic markers) were still developmentally arrested in DN cells, specifically at the DN2 stage (Fig. 3B, left). However in the same mice, the development of Pim1TgγcKO bone marrow-derived thymocytes (identified by CD45.1−/2+ congenic markers) proceeded normally through the DN compartment and effectively generated both CD4SP

and CD8SP mature thymocytes (Fig. 3B, middle). Strikingly, the vast majority of chimeric thymocytes were reconstituted from Pim1TgγcKO, and not γcKO-derived cells, suggesting that Pim1 provides a survival advantage to developing thymocytes under competing conditions (Fig. 3B, top). Along this line, peripheral T cells were also mostly reconstituted from Pim1TgγcKO-derived cells, and only few γcKO T cells survived in the absence of transgenic Pim1 (Fig. 3C). Importantly, survival of Pim1TgγcKO T cells was independent of T-cell activation as click here CD69 expression was comparable to γcKO T cells (Fig. 3C). Collectively, these results indicate that Pim1 promotes thymopoiesis and T-cell survival in a cell intrinsic manner. To further assess the effect of Pim1 on T-cell survival, next, we analyzed Pim1TgγcKO LN

cells (Fig. 4A). Compared with γcKO LN, Pim1TgγcKO LN contained both increased percentages and numbers of TCRβ+ T cells (Fig. 4A and Supporting Information Fig. 3A). Moreover, we observed a dramatic increase in CD8+ T-cell percentages compared with γcKO LN cells (Fig. 4A). Such increase was specific to LN cells because transgenic Pim1 did not increase CD8SP percentages in thymocytes (Fig. 2B, bottom). Thus,

Pim1 improves peripheral survival of CD8+ T cells but does not promote their generation in the thymus in the absence of γc signaling. Despite increased survival, Pim1 failed to restore the peripheral CD8+ LN T-cell pool as Pim1TgγcKO CD8+ LN T-cell numbers were still severely reduced compared with those in WT mice (Fig. 4B, right). In striking contrast, we observed a pronounced increase in CD4+ LN T-cell numbers (Fig. 4B, left). In fact, transgenic Pim1 restored CD4+ T-cell numbers in Pim1TgγcKO mice close Adenosine to the levels in WT mice. Notably, such increased cellularity was not because of increased proliferation. Both intranuclear Ki-67 staining and in vivo BrdU labeling did not show any differences between γcKO and Pim1TgγcKO LN T cells (Fig. 4C–E), suggesting that Pim1 did not affect cell cycling or proliferation. Instead, we found that Pim1TgγcKO T cells were metabolically more active and more resistant to apoptosis than γcKO T cells, because cell size of CD69neg resting T cells were larger and caspase-3 activity was significantly lower in Pim1TgγcKO mice compared with that in γcKO mice (Fig. 4F and Supporting Information Fig. 3B and C). Thus, Pim1 increases peripheral T-cell numbers by promoting cell survival.

5-HT can regulate inflammation by acting on signalling pathways in inflammation,

production of inflammatory mediators from immune cells and promoting interaction between innate and adaptive immune response. Recently we have investigated the role of 5-HT in colonic inflammation in two different models of colitis (DSS and DNBS) using tryptophan hydroxylase1-deficient (TPH1−/−), mice, which have significantly reduced amounts of 5-HT in gut, and in mice treated with 5-HT synthesis inhibitor parachlorophenylalanine (PCPA) [37]. Delayed onset and decreased severity of colitis were observed in TPH1−/− mice compared to wild-type mice and in PCPA-treated mice after induction of colitis by DSS. This was associated with down-regulation of macrophage infiltration and production of proinflammatory cytokines. Restoration of 5-HT amounts in TPH1−/− mice by administration

of 5-HT precursor 5-HTP enhanced the severity RG7204 price of DSS-induced colitis. We also observed a significant reduction in severity of colitis in TPH1−/− mice after induction of DNBS-colitis. Our data complement the recent study published by Bischoff et al., which demonstrated that TNBS-induced colitis is increased in severity when coupled with the 5-HT-enhancing effects by knock-out of SERT gene [51]. Recent studies from our selleck inhibitor laboratory also demonstrate that dendritic cells from TPH1−/− mice in DSS-colitis produced reduced IL-12 compared to TPH1+/+ mice and

stimulation with 5-HT restored IL-12 production from the dendritic cells from naive TPH1−/− mice [52]. Taken together, these studies show a critical role of 5-HT in the pathogenesis of inflammation Molecular motor in gut by influencing proinflammatory cytokine production in experimental colitis and provide new insights into the mechanisms of gut inflammation. In a wider context, a beneficial effect with treatment with 5-HT receptor antagonist has been shown in both clinical and experimental arthritis [53], implicating a role of 5-HT in the pathogenesis of non-GI-inflammation in addition to GI inflammation. As presented above, 5-HT is present throughout the GI tract and plays an important role in the regulation of the development of gut inflammation and various physiological activities in the gut. In addition to 5-HT, enteric endocrine cells produce the granins family [40] of biologically active products, which include Cgs A/B [54] and secretogranin, which can also contribute to various GI functions including immune modulation and inflammation. The granin family consists of single-polypeptide chains of 185–657 amino acid residues. The numerous pairs of basic amino acids indicate a potential site for cleavage by prohormone convertases PC1/3 and PC2 in the secretory granules [55]. More than 10 different proteolytic sites have been identified in the CgA.

To get reference values, the determinations were done on samples of healthy blood donors (n = 100). In univariate analyses, the patients had higher MMP-8 (P < 0.001), TIMP-1 (P = 0.045), and MMP-8/TIMP-1 (P < 0.001), and lower MPO (P < 0.001) when compared with the blood donors. All three subgroups had higher MMP-8 (P < 0.001) and MMP-8/TIMP-1 (P < 0.001), and lower MPO (P < 0.01,

except AOD) levels when compared with the references. In multiple logistic regression analyses, the male gender (P < 0.01), age (P < 0.001), Dasatinib research buy elevated MMP-8 (P < 0.001) and decreased MPO (P < 0.001) concentrations associated significantly with the risk for arterial disease, and provided an area under curve (AUC) of 0.97 in the Receiver operating characteristics analyses. In multiple linear regression analyses, HNE correlated with both MMP-8 (P < 0.001) and MPO (P = 0.008) concentrations. Combination of high MMP-8 and low MPO level in serum eventually reflecting selectively modified

neutrophil degranulation may indicate increased risk for arterial disease. Arterial diseases are a heterogeneous group of diseases with a wide range of clinical presentations and outcomes. Inflammation plays a key role in the pathogenesis of atherosclerotic and aneurysmal diseases in various locations [1, 2]. The Staurosporine prevalence of peripheral arterial disease increases with age and is 10–25% in people over 55 years of age. Seventy to eighty per cent of affected individuals are asymptomatic. Abdominal aortic aneurysm (AAA) is a common and potentially life-threatening condition closely associated with atherosclerosis and aging [3]. Inflammation in vascular wall is characterized by accumulation of inflammatory cells, increased expression of cytokines and chemokines, matrix remodelling, oxidative stress, and depletion of smooth muscle cells. The terminal stage of aneurysmal disease

is characterized by intraluminal thrombus formation and rupture of arterial wall. The proportions and degradation rates of elastin and collagen play a key role in the formation and development of aneurysm [4, 5]. Carotid acetylcholine artery stenosis is the narrowing of the carotid arteries caused by plaque formation leading to the increased risk of cerebral ischaemic events because of plaque rupture and distal embolization. Stenosis of carotid arteries is a common sign of advanced systemic atherosclerosis. Aorto-occlusive disease (AOD) is a form of peripheral arterial disease (PAD) where occlusive atherosclerosis involves the infrarenal aorta. Long-term survival of these patients is substantially decreased despite operative and medical management [6]. Matrix metalloproteinases (MMPs) are a family of structurally related but genetically distinct zinc-containing enzymes capable of degrading almost all extracellular matrix and basement membrane components as well as in processing serpins, growth factors, and pro- and anti-inflammatory cytokines.

To study the association between pulmonary function and the SNPs in the ALOX5AP gene in a healthy and general population, the predicted values for forced expiratory volume in one second (FEV1; FEV1_%PRED) and the proportion of the FVC exhaled in the first second (FEV1/FVC; FEV1/FVC_PRED) in the KARE database were used. The 662 subjects with asthma, chronic lung disease (pneumoconiosis and silicosis), tuberculosis, or a previous diagnosis of respiratory-related

disease were excluded. In addition, 4553 subjects Proteases inhibitor without diagnosis, treatment, FEV1, FEV1/FVC, height and smoking status information were also excluded. Therefore, 3627 subjects without respiratory disease were included and defined as a healthy population in this study. The average age of this population was 52.4 ± 8.9. The specific characteristics of Ansan and Ansung cohorts are described in Table 1. Total subjects including healthy population and with respiratory diseases or no information on medical history selleck chemical were described as a general population in this study. Genotyping.  The genotype data regarding the SNPs in the ALOX5AP gene, which are available to the research community through the KARE project from KoGES, were analysed. The study protocol was approved by the Institutional Review Board of KNIH. Affymetrix Genome-Wide Human SNP Array 5.0 (Affymetrix Inc., Santa Clara, CA, USA) was used to genotype the samples from the Ansan and Ansung

cohorts. The Bayesian Robust Linear Model with the Mahalanobis distance algorithm was used to determine the genotypes at each SNP of Affymetrix 5.0. The SNPs were excluded if any of the following criteria were met: (1) a call rate lower than 95%, (2) a minor allele frequency lower than 0.05 or PRKACG (3) a significant deviation from the Hardy–Weinberg equilibrium that was lower than 0.05. Among SNPs filtered by the criteria, only tagging SNPs were used for all analysis in this study. Statistical analyses.  The associations between the ALOX5AP SNPs and diplotypes of the 3627 subjects without asthma or respiratory

disease and the two pulmonary function measures FEV1 and FEV1/FVC were evaluated by performing a linear regression. A permutation test was performed for multiple comparisons in the association analysis. Interactions between SNPs in the ALOX5AP and smoking status on FEV1 and FEV1/FVC were analysed using linear regression. For the analysis of general population, 8535 subjects excluded 307 subjects without FEV1, FEV1/FVC, height and smoking status information was used for linear regression without consideration for the medical history of respiratory-related diseases. Only tagging SNPs were used for analysis. Every analysis on combined data was adjusted for residence area, sex, age, height and ever/never smoking status. All analysis on Ansung and Ansan data was adjusted for sex, age, height and ever/never smoking status.

Interestingly, this website the avidity of response to the OVA was similar (1.7×10−9 M) to the response to TRP2 (1.3×10−9 M) suggesting that there is no deletion of the

repertoire to this self Ag. However responses to both epitopes could be increased over 100-fold, by using an Ab–DNA vaccine compared to peptide immunization. These results suggest that at the each peptide MHC complex interacts with a defined number of TCR within the repertoire playing an important role in determining the original avidity 28 but this can then be further modulated at the clonal level. The range of avidities observed in the mice analyzed spans five logs, yet within individual experiments this variation is less. This probably reflects the plasticity of the avidity to any given TCR:MHC/peptide combination with optimal immunization leading to a high avidity. The avidity with DNA vaccination depends upon the degree of direct v cross presentation, Ixazomib concentration which may vary between experiments. However this does not explain the reduced variability within one

experiment. Our explanation is that despite careful operating procedures, this is related to the efficacy of immunization/monitoring of the response. We are aware that timing for harvesting the splenocytes to plating into an assay is a key parameter and endeavor to keep this constant. Finally experiments were performed over a 2-year period and factors such as subtle changes in mice, environment and batches of DNA have to be considered. Within the small groups these factors would be more consistent. The avidity of the responses to the TRP2/HepB human IgG1 DNA vaccine varied from 5×10−13 M to 5×10−8 M in different mice but was on average

5×10−10 M. Is this avidity sufficient to result in effective immune response? An elegant study by Dutoit et al. demonstrated that T cells cloned from cancer patients exhibited an exponential increase in killing with T-cell avidity greater than 10−9 M PLEK2 2. A similar study with T-cell clones showed that only high-avidity clones adoptively transferred caused tumor rejection in mice 1. The avidity resulting in tumor killing will depend upon the expression level of the Ag/MHC. Our study is in agreement with these demonstrating that selective vaccination can increase avidity to a level sufficient for therapy. The frequency and avidity of the responses from human IgG1 DNA immunization was significantly higher than that observed from peptide immunization. Initially unlinked peptides were used but due to lack of T-cell help, these gave very weak responses (results not shown). To give a more reasonable comparison, the CTL epitopes were linked to a well known helper epitope which still gave poor responses. This was perhaps not surprising as even linked helper-CTL peptides have a very short half life and are poor immunogens in vivo29.