The purpose of this review is to describe the most commonly used methods to study Candida biofilms in vitro, to discuss the benefits and limitations of the different methods to induce biofilm formation, and to analyse the architecture, viability and growth kinetics of Candida biofilms. “
“Tinea capitis is endemic among schoolchildren in tropical Africa. The objective was to determine the prevalence of symptomatic tinea capitis in schoolchildren in Gabon. A cross-sectional study was conducted with 454 children aged 4–17 years, attending

a rural school and an urban school. The diagnosis of tinea capitis was based on clinically manifest infection, direct microscopic examination using 20% potassium hydroxide (KOH) selleck solution and fungal culture. Based on clinical examination, 105 (23.1%) of 454 children had tinea capitis. Seventy-four (16.3%) children were positive by direct examination (KOH) and/or fungal culture. The prevalence of tinea capitis depended on the school studied and ranged from 20.4% in the

urban school with a higher socioeconomic status to 26.3% in the rural school with a lower socioeconomic status. Similarly, the spectrum of causative species varied between the different schools. Taken the schools together, Trichophyton soudanense (29.4%) was the most prominent species, followed by Trichophyton tonsurans (27.9%) and Microsporum audouinii (25.0%). Clinically manifest tinea capitis is endemic among schoolchildren in the Lambaréné region in Gabon. buy Palbociclib The prevalence of tinea capitis and the causative PAK5 species depended on the type of school that was investigated. “
“The goal of this study was to determine the prevalence of Malassezia species in pityriasis versicolor lesions and to examine if the range of species varies with patients characteristics such as: age, sex and

family history and also clinical findings such as site and number of the lesions. In a prospective study from July 2006 to July 2007, the patients with a clinical diagnosis of pityriasis versicolor (n = 166) were asked to participate in the study. A total of 116 patients had positive culture for Malassezia species: M. globosa was found in 52 (31.3%) cases, M. furfur in 34 (20.5%) cases, M. pachydermatis in 12 (7.2%) cases, M. restricta in 12 (7.2%) cases, M. slooffiae in 6 (3.6%) cases. According to our data, M. globosa is the main species causing pityriasis versicolor, M. furfur was found to be the second-most frequent species. M. sympodialis and M. obtusa were not found in any case, and in 30.2% of patient’s Malassezia culture was negative. “
“Invasive aspergillosis is an important cause of morbidity and mortality in haematological patients. Current guidelines recommend voriconazole as first-line therapy. A change in class of antifungal agent is generally recommended for salvage therapy.

These studies were supported by a Program Grant (S. R. H. & A. R. K. 334067) and a Postgraduate Research Scholarship (S. A. S. 519426 and R. K. S. P. 284499) from the National Health and Medical Research Council of Australia. None. “
“Leukocyte

movement from the blood to the tissues is a fundamental process in acute and chronic inflammatory diseases. While the role of endothelial cells (EC) to recruit leukocytes to sites of inflammation is well known, the mechanisms that control remodeling of EC shape and adhesive contacts during leukocyte transendothelial migration (TEM) are not completely understood. We studied the role of IQGAP1, an adaptor protein that binds to filamentous-actin and microtubules (MT) at interendothelial junctions, during lymphocyte SAR245409 cell line TEM. EC IQGAP1 knockdown decreases MT AZD1152-HQPA price tethered to the adherens junction, and decreases lymphocyte TEM to ∼70% (p<0.05) versus control. Similarly, loss of adherens junction-associated MT induced by brief nocodazole (ND) treatment decreases

lymphocyte TEM to ∼65% of control (p<0.01). Confocal microscopy imaging indicates that EC IQGAP1 knockdown and MT depolymerization both result in lymphocyte accumulation above the vascular endothelial cadherin (VE-cadherin) junctions and reduces the fraction of adherent lymphocytes that complete diapedesis across interendothelial cell junctions. However, we observe no change in VE-cadherin gap formation underlying adherent lymphocytes among control, IQGAP1 knockdown, or MT depolymerised EC monolayers. These data Oxalosuccinic acid indicate that IQGAP1 contributes to MT stability at endothelial junctions. Further, IQGAP1 is involved in junction remodeling required for efficient lymphocyte diapedesis, independent of VE-cadherin gap formation. Leukocyte extravasation is fundamental to the development of many immune responses including solid-organ allograft rejection. In this process, leukocytes leave the bloodstream and migrate into tissues through the endothelial

cells (EC) that line the walls of vessels, i.e. leukocytes undergo transendothelial migration (TEM). Whereas the specific adhesion molecules, chemoattractants, and possibly signaling pathways involved in TEM are unique among different subgroups of leukocytes and vascular beds, the interaction between leukocytes and EC during TEM can be generalized into a multicascade event, described in recent reviews 1–3. EC and leukocyte adhesion molecules mediate tethering and rolling of leukocytes on EC followed by chemokine-mediated leukocyte activation, then firm adhesion to the EC. Finally, adherent leukocytes crawl on the surface of endothelium, undergo diapedesis, and enter tissues by mechanisms that are not fully understood. Leukocyte transmigration may occur by either a transcellular, through EC, or paracellular route, between adjacent EC 4–6.

The mean fraction of lymphocytes migrating on the EC surface or undergoing TEM among the treatment versus control groups among several experiments was calculated and tested for statistical significance (p<0.05) by paired Student's t-test (SPSS, Chicago, IL, USA). All the data are shown as mean±SEM. To evaluate the position of lymphocytes at the interendothelial junctions, data from four

independent experiments NVP-BKM120 were pooled and tested for significance using Chi square analysis (SPSS). This work was supported by operating grants from the Heart & Stroke Foundation of Canada and the CIHR to A.G.M. M.N. is the recipient of a University of Alberta 75th anniversary studentship award and Queen Elizabeth II Graduate

Scholarship. Conflict of interest: The authors declare no financial or commercial conflict on interest. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-reviewed, but not copy-edited or typeset. They are made available as submitted by the authors. “
“Citation Aldo PB, Mulla MJ, Romero R, Mor G, Abrahams VM. Viral ssRNA induces first-trimester trophoblast apoptosis through an inflammatory mechanism. Am J Reprod Immunol 2010; 64: 27–37 Problem  Infection during pregnancy represents a significant cause of mobility and Sotrastaurin in vitro mortality. While viruses pose a major threat, little is

known about their effect on early pregnancy, or the mechanisms involved. The objective of this study was to characterize the trophoblast response following exposure to viral ssRNA. Method of study  First trimester trophoblast cells were treated with or without viral ssRNA. Cytokine production was measured using multiplex analysis and ELISA. Apoptosis was determined using Hoechst staining, cell viability, and caspase activity assays. Results  Treatment of trophoblasts not with viral ssRNA increased their secretion of IL-8, IL-6, and IFNβ. However, the ssRNA also induced trophoblast apoptosis. To test whether the viral ssRNA-induced inflammatory response was responsible for this induction of apoptosis, conditioned media (CM) from trophoblasts were added to a fresh culture of cells. The CM from viral ssRNA-treated induced higher levels of trophoblast apoptosis than the control CM. Moreover, recombinant IFNβ induced trophoblast apoptosis. Conclusion  We demonstrate that viral ssRNA induces a pro-inflammatory and type I interferon response in the trophoblast and this inflammatory process may indirectly induce trophoblast apoptosis. These results provide a novel mechanism by which certain viral infections might compromise placental integrity and function, and therefore, pregnancy outcome.

Amplification and detection of specific products was achieved with the

ABI Prism 7000 SDS (Applied Biosystems) with the following cycle profile: 1 cycle at 48°C for 30 min, 1 cycle at 95°C for 10 min, and 40 cycles each consisting of 95°C for 15 s followed by 60°C for 1 min. Ct was defined as the cycle at which fluorescence becomes detectable above the background and is inversely proportional to the logarithm of the initial number of template molecules. A standard curve was plotted for each primer-probe set, with Ct values obtained through amplification of known quantities of the PCR products originating from genomic DNA isolated from SF370. Standard BKM120 cell line curves were used to transform Ct values according to the relative number of DNA molecules.

The quantity of cDNA for each experimental gene was normalized to the quantity of proS cDNA in each sample. Data were expressed as means ± standard deviations. Experiments were repeated three times with three samples from each group. For statistical analyses of the data, the differences between groups of M protein-high and -low producers or groups of SF370 ΔcsrS and WT were compared using Student’s t-test. Differences were considered statistically significant if the P value was <0.05. The fragment of M protein recognized by the antibody was identical among the emm1, 3, 6, and 12 strains, but the M proteins present in the emm4 and 28 strains had either more or less than 50% homology with the consensus sequences. To test the affinity of the polyclonal antibody for genotypes other than those selleck compound of emm1, 3, 6, and 12, we constructed a recombinant M4 protein including the portion related to the region common to the four emm genotypes (Fig. 1). The antibody showed a pattern of reactivity comparable to those of the recombinant M and M4 proteins (data not shown). This result indicates that several epitopes

exist in the corresponding region, which could be enough to measure accurately even with a homology of more or less than 50% in the region. The antibody reacted with the SF370 wild type strain but not with SF370 Δemm1 (data not shown). The sensitivity was estimated at 15 ng/mL according to the dot blot method using two-fold serial dilutions of the recombinant M protein. aminophylline In addition, two- or four-fold dilution samples of some strains reacted only with the pre-immune rabbit polyclonal antibody. The results of our dot blot analysis of the cell membrane-associated proteins (Fig. 2) revealed that three genotypes of emm1, 3, and 6 types, produced significantly larger amounts of M protein (one-way ANOVA; P < 0.05). Their mean values were 7.5, 7.8, and 8.6, respectively, while the largest individually measured amount was over 9.7 (M protein-high producer, circled in Fig. 2). Strains with emm12 and 4 genotypes produced less M protein: their mean values were 6.4 and 5.5, respectively.

However, upon incubation of viable immature DC with apoptotic DC followed by LPS treatment, only

20–25% of viable immature DC become CD86+, which is in fact similar to the levels seen in viable immature DC without any LPS treatment (Fig. 4B and C). Furthermore, incubation of viable immature DC with apoptotic splenocytes also resulted in the suppression of LPS-induced subsequent DC maturation. However, the extent of immunosuppression buy Gefitinib induced by apoptotic splenocytes was not as potent as apoptotic DC (Fig. 4B and C). These results indicate that uptake of apoptotic DC by viable immature DC prevents subsequent upregulation of CD86 in response to LPS. In the absence of inflammatory stimuli, viable immature DC do not produce any IL-12. However, in response to LPS, approximately 22% of cells become IL-12+ (Fig. 4D and E). Similarly, viable immature DC incubated with necrotic DC followed by treatment with LPS show similar proportion of IL-12+ DC. In contrast, viable DC incubated with apoptotic splenocytes followed by LPS treatment showed a slight reduction in IL-12 production, as only 8–11% of the cells became IL-12+. However, viable immature DC incubated with apoptotic DC followed by treatment with LPS failed to induce IL-12, as only 1–2% of DC become IL-12+ (Fig. 4D and E). The uptake of apoptotic

DC by viable immature DC is critically important for the suppression of CD86 upregulation, and IL-12 LY2157299 clinical trial induction in response to LPS for no suppression is observed in response to LPS if apoptotic DC and viable DC are separated in culture via transwell (data not shown). In addition to IL-12, DC maturation is also characterized by the upregulation of cAMP other inflammatory cytokines. In order to assess the effects of apoptotic or necrotic DC uptake by viable immature DC on induction of inflammatory cytokines in response to LPS, we looked at the mRNA expression levels of inflammatory cytokines, including IL-1β (Fig. 5A), IL-6 (Fig. 5B), TNF-α (Fig. 5C), IL-12p35 (Fig. 5D) and IL-12p40 (Fig. 5E). These inflammatory cytokines are expressed at very low levels in viable immature

DC at basal levels. However, in response to LPS, there is massive and rapid induction of these cytokines at mRNA levels (Fig. 5A–E). However, incubation of viable immature DC with apoptotic DC but not necrotic DC suppressed induction of the aforementioned inflammatory cytokines in response to LPS. These findings collectively indicate that the specific uptake of apoptotic DC converts viable immature DC into tolerogenic DC. Next, we looked at the ability of viable DC to prime OVA-specific T-cell proliferation upon apoptotic DC uptake (Fig. 5F). Viable immature DC were incubated with apoptotic or necrotic DC and then pulsed with OVA in the presence of LPS. Then, these were cultured with naïve T cells to assess their ability to induce OVA-specific T-cell proliferation.

The development and quality of the humoral immune response is to a large extent influenced by the immunological environment of the responding B cell. An expanding body of literature Selleck LDE225 indicates that IFN-α contributes to shaping the adaptive immune responses47,48 and that direct type I IFN-mediated B-cell activation significantly

affects the quality and magnitude of the antiviral humoral responses.6–9 We and others previously reported that human pDCs, via their secretion of IFN-α, enhance B-cell responses induced by TLR ligation and/or T helper cell stimulation in vitro.1–4 Compared with mDCs, pDCs have shown less efficiency in presenting antigens to naive T cells and induce cellular immune responses.25,34 However, an increased understanding of the contribution of pDCs in shaping B cell responses is needed, especially with regard to vaccine-induced responses as antibodies are known to provide the protective effect

of most successful vaccines. To this end, central questions concern whether pDCs should be specifically targeted and activated by vaccine components. In the last decade, the clinical utility of TLR ligands as vaccine adjuvants and immune stimulatory therapies has evolved as an intensive area of investigation.10,12 Selected TLR ligands are under evaluation for their adjuvant effect both in non-human primate studies18–20 and Barasertib in vitro in human trials21–23 with promising results. As rhesus macaques to a large extent express similar repertoires of TLRs on immune cells

as humans do,26 they represent an indispensible in vivo model for testing of TLR ligands. In this study, we found that proliferation of human and rhesus B cells was induced by ligands targeting TLR7/8 and 9 but not TLR3. The different CpG classes, all binding TLR9, are well characterized on human cells in vitro2,32 and to some extent in vitro and in vivo in rhesus macaques.11,40,43,49 We found that CpG B Rolziracetam was superior to CpG C at inducing proliferation in human B cells and this effect was inverted for rhesus B cells, which is consistent with previous reports.2,43 CpG B was originally identified to be a particularly potent stimulus of human B cells.50,51 There may be differences in CpG recognition mechanisms among primates making CpG C more efficient in the rhesus system. CpG A, in contrast, induces high amounts of type I IFN from pDCs2,32,40 because of its palindromic CpG phosphodiester sequences with phosphorothioate G-rich ends. The phosphorothioate CpG C with a stimulatory CpG and a palindromic sequence at the 5′ or 3′ end combines the effects of CpG A and CpG B32,52 and may exhibit fewer species-specific features. Regardless of stimuli, a higher level of proliferation was observed for human B cells compared with rhesus B cells by TLR ligand stimulation.

In order to control for the effect of infection on the T cell subpopulations, disease controls were recruited from the immunodeficiency clinic. These were immune-competent patients who had an increased infection burden, in whom no clinical or laboratory evidence for immunodeficiency was found. Results from this group were included only once a period of 1 year had elapsed since discharge from the clinic, to rule out an evolving immunodeficiency.

The immune tests undertaken were guided by clinical and family histories. The typical panel of tests performed included: IgG, IgA and IgM, and serum and urine electrophoresis with immunofixation if indicated. Specific antibody responses to the vaccines tetanus, pneumococcal and Haemophilius influenza B were performed, and if absent/low responses were noted the patient Ivacaftor was vaccinated and these retested after 1 month. Lymphocyte subsets, both percentage and absolute count, Tipifarnib were also performed, including measurement of B cells, CD4 and CD8 T cells and natural killer (NK) cells [3,27]. At the time of analysis, all XLA and 55 of 58 CVID patients were on immunoglobulin

replacement, but not on immunosuppressive therapy. Those with autoimmune cytopenia or lymphoid interstitial pneumonia had not received corticosteroid therapy within 6 months, and only at prior doses <25 mg/kg. No patient had an affected parent, sibling or child. CVID patients

were categorized into the following clinical phenotypes, as described in Chapel et al. [2,3]: infection only (IO), enteropathy, lymphoid malignancy, polyclonal lymphoproliferation (PL), organ-specific autoimmune disease (OSAI) or autoimmune cytopenias (AC) which included immune thrombocytopenia (ITP). ITP is defined as platelets <100 × 109/l, persistent Parvulin (>6 months), one episode treated with steroids [3]. The autoimmune diseases in patients in the OSAI group included: autoimmune thyroid disease (n = 5), psoriasis (n = 6), uveitis (n = 2), vitiligo (n = 2), pernicious anaemia (n = 3), ulcerative colitis (n = 4) and type 1 diabetes (n = 2). Only one patient had a subsequent lymphoid malignancy and only three had an enteropathy, so these categories were not utilized in the analysis; these patients were included in the CVID total group. Figure 1 demonstrates the distribution of clinical phenotypes of the CVID patient group. The number of patients stated in each group in Table 1 is the maximum number of patients analysed for a T cell subpopulation. However, for some of the T cell subpopulations smaller numbers were analysed due to either technical difficulties with a particular tube or limited sample availability. All flow cytometric analysis was performed on ethylenediamine tetraacetic acid (EDTA) blood samples within 48 h of venepuncture.

The association of integrin cytoplasmic domains with the cytoskeleton via adaptor proteins (such as focal adhesion kinase) additionally means fibronectin has a central role in migration, Talazoparib morphogenesis and proliferation [17]. In the systemic ECM, the most abundant matrix components are members of the collagen family, providing parenchymal structural integrity and contributing to stability and biomechanical properties of most tissues and organs. There are multiple types of collagen, approximately 90% of which are fibril-forming following association of multiple triple helixes, contributing to the tensile strength of common

systemic connective tissues and cartilage [18]. In contrast, the major collagen in the CNS ECM is Selleck LDK378 the basal laminae component collagen IV. It forms a more flexible triple helix which self-polymerizes into a network and acts as a scaffold to integrate laminin and fibronectins into sheet-like basement membrane; a matrix meshwork additionally interconnected via other glycoproteins and sulphated proteoglycans [19]. In the injured brain and spinal cord, alongside types I and III [20,21] collagen IV is the predominant fibrous element of scar tissue [22], where cells local to the lesion release protocollagen chains that self-assemble into a dense network [23]. HA (an anionic, nonsulphated glycosaminoglycan)

is one of the main components of the ECM and is widely distributed in both diffuse matrix and in PNNs. HA is a long linear polysaccharide composed

of repeating nonsulphated N-acetyl-glucosamine and glucuronic acid disaccharide units joined by β1–4 and β1–3 linkages. High and low-molecular-weight forms of HA confer different charge and hydration properties, which in turn influences biophysical properties such as viscosity and interactions (reviewed in [24]). HA provides matrix architecture, into 4-Aminobutyrate aminotransferase which proteoglycans and glycoproteins are noncovalently recruited. It is known to bind to extracellular receptors CD44 and CD168 [25,26]; however, results from in vitro modelling suggest that, within PNNs, HA is anchored to the neuronal cell surface via its synthesizing enzyme hyaluronic acid synthase (HAS) [27,28]. There are three mammalian HAS enzymes (HAS1,2,3) comprising multipass transmembrane proteins which produce HA on the inner surface of the plasma membrane and extrude nascent HA out of the cell. HA plays an important role in cell proliferation and morphogenesis [29], due to its biophysical properties and contribution to ECM structural integrity, along with cell-surface HA receptor interactions. Cell receptor activation has wide-ranging downstream consequences, including proliferation [30], cytoskeletal reorganization [31] and regulating inflammation (reviewed in [32]) and its organization of other matrix components enables a complex network of protein–protein interactions [33].

6D and E). This finding shows that MPECs formed in the absence of type-I IFN signaling differentiated into functional memory CD8+ T cells. Thus, type-I IFN signaling influences the overall frequency but not the functionality of memory CD8+ T cells. In this study, we have elucidated the role of type-I IFN signaling on CD8+ T cells and its ability to act as a fate-determining differentiation factor in vivo. We found that CD8+ T cells lacking the ability to sense type-I IFN failed to form terminally differentiated SLECs following

an acute viral infection associated with abundant type-I IFN. IFNAR−/− P14 cells, despite demonstrating a reduced expansion potential, could form qualitatively equivalent memory cells compared with WT P14 cells, albeit at a much lower frequency

than their WT counterparts. Moreover, we showed in vivo and confirmed in vitro that type-I IFN signaling on CD8+ T cells leads to upregulation of T-bet which can drive the differentiation AT9283 in vitro of SLECs (Fig. 7). In summary, this study identifies type-I IFN as an important factor instructing the lineage choice toward the differentiation of SLECs in the context of an infection inducing a type-I IFN-dominated inflammatory cytokine milieu. The data presented here expand and complement our current knowledge about the factors involved in the differentiation of CD8+ T cells 25, 26, including both cell intrinsic factors 27, 28 such as T-bet 4, 24, 28–31 and eomesodermin 24, 31–33 as well as cell extrinsic differentiation factors, such as IL-2 15, 34, 35 and IL-12 4, 5, 28, 30. Much like check details IL-12, type-I IFN acts as a signal 3 cytokine promoting expansion, effector cell differentiation and survival of activated CD8+ T cells 36. As both of these cytokines can serve as differentiation factors for CD8+ T cells, the nature of the invading pathogen with respect to predominantly inducing one of those at the expense of the other 37, 38 determines which of these two cytokines will play a more important role in vivo. Of note, less redundancy between IL-12 and type-I IFN

has been found in humans and IL-12 seems to be the main signal driving CD8+ T-cell Org 27569 effector differentiation, whereas type-I IFN enhances the development of memory CD8+ T cells 39. There is ample evidence in the literature that direct IL-12 signaling on activated CD8+ T cells enhances expansion and promotes transition toward an SLEC phenotype 3, 4, 13, 40, 41. An elegant study by Kaech and colleagues 4 further clarified these findings, identifying IL-12 as an important factor regulating memory CD8+ T-cell formation by establishing a gradient of T-bet expression. In particular, this report clearly showed that T-bet is necessary and sufficient to drive the formation of SLECs, with high T-bet expression leading to the differentiation into SLECs, and lower amounts of T-bet facilitating the formation of MPECs 4. This finding supports our in vivo results showing that following an acute LCMV8.

These data strongly indicate that the eight peptides induce HLA-DR restricted responses. It should be noticed that the presence of IVA12 does not affect HLA class I restricted responses and the presence of anti-DR antibody does not affect HLA-DP restricted responses.28 A recently Selleckchem Galunisertib developed assay for peptide binding to recombinant HLA-DR molecules was employed.32 Fourteen recombinant HLA-DR subtypes, representing

33% of all HLA-DR subtypes expressed by the PPD+ donors (Table 2), were assayed for binding of the eight antigenic peptides. However, only three of the eight M. tuberculosis peptides showed binding to HLA-DR subtypes (DRB1*0806, 1*1201, 1*1202), but none of these HLA-DR molecules was expressed by the two donors (no. 19 and 32) who showed reactivity for the three peptides (data not included). To obtain direct evidence of the phenotype of M. tuberculosis-peptide-reactive

cells, anti-M. tuberculosis reactivity was tested in PBMC depleted of CD4+ T cells before peptide exposure in expansion cultures. As shown in Fig. 2, CD4+ T-cell depletion resulted in a total loss of peptide reactivity in all but one (anti-TB https://www.selleckchem.com/products/Lapatinib-Ditosylate.html 60 peptide reactivity) of the CD4+ T-cell-depleted PBMC fractions. To further validate that the ELISPOT responses were in fact a CD4+ T-cell response and not a mixture of CD4+ and CD8+ T-cell responses, we used a flow cytometry-based intracellular cytokine secretion assay. Two donors were analysed in this

assay, Donor 32 stimulated with TB2, TB88 and TB92, and donor 28 stimulated with TB60. After 10 days in vitro restimulation the cells were analysed by intracellular cytokine secretion. For all combinations a low but clear CD4+ T-cell response could be measured, with peptide TB2 and TB92 peptide recognized by donor 32 showing the highest frequency of CD4+-specific T cells (> 1%) (Fig. 3). In all cases no measurable peptide-specific CD8+ T-cell responses could be detected. For the peptide responses in donor 32 this correlates with the finding that the specific ELISPOT response was absent after CD4+ depletion (Fig. 2). The peptide T60 response in donor 28 could only be partially removed by CD4+ depletion (about 30% resides) but only a peptide-specific HSP90 CD4+ T-cell response and no CD8+ T-cell response could be detected by intracellular cytokine secretion. The aim of the present study was to identify CD8+ T-cell epitopes derived from M. tuberculosis using immuno-bioinformatics. We have previously used such an approach to successfully identify T-cell epitopes derived from smallpox virus and influenza A virus.26,27 However, in our previous study 39 and a more recent observation,28 it was shown that HLA-I binding 9mer peptides were able to induce CD4+ T-cell-dependent responses that apparently are restricted by the HLA-II molecules.