8% to 29.6%, the prevalence of PCV2 viremia ranging from 71.4% to 78.6% between 7 and 21 dpc. In addition, except for the PO-PCV2-I group, the mean group PCV2 antigen amount in tissues was reduced by PCV2 vaccination. The differences in vaccine efficacy between the two different administration this website routes may be attributable to the interval between vaccination and challenge (4 weeks). The PO vaccination route appeared to induce a delayed antibody response suggesting that a longer interval is needed between vaccination and challenge. Alternatively, a higher dose may be required for induction of greater protective immunity with this route. In

conclusion, under the conditions of this study, an experimental live-attenuated PCV2 vaccine was safe and efficacious when used IM in a PCV2b-PRRSV dual-challenge model. Administration of the same product

PO resulted in a lower level and delayed onset of protective immunity compared to IM administration. More RG7204 mw studies are needed to improve the immunogenicity of the oral vaccine. We thank the National Pork Board Pork Checkoff Dollars for funding of this study. We also thank Shayleen Schalk and Matthew Umphress for assistance with the animal work. None of the authors of this paper have any financial or personal relationship with other people or organizations that could inappropriately influence or bias the content of the paper. “
“It has not been considered so far that antigen-presenting cells (APC) may phagocytose immunogenic material from autologous cancer cells. Assuming the presence of cancer-immunogenic material buy Forskolin in APC, we developed a novel autologous priming method that does not require tumour cells or identified peptides. Cancer-immunogenic information came from CD14+ monocytes. When stimulated with CD3-activated T cells, monocytes primed CD3+CD4+ and CD3+CD8+ resting/naïve

T cells to become powerful effector cells within 24 h. During priming, depletion of CD14+ monocytes but not CD1a+ CD83+ dendritic cells prevented T cell priming. During cancer cell destruction, dendritic cells, but not monocytes, enhanced cancer cell lysis. The cascade-primed (CAPRI) immune cell quartet comprising monocytes, dendritic cells, CD4+ T and CD8+ T cells induced a significant decrease in the number of suppressive CD25highFoxP3+CD4+ T cells. CAPRI cells induced a marked upregulation of MHC class I and class II expression in cancer cells, which is crucial for autoimmune-like lysis. We show in vivo evidence of the CAPRI cell concept in nude mice. In humans, we present circumstantial clinical evidence showing the efficacy of CAPRI cells in an adjuvant treatment attempt for breast cancer patients with metastasis (N = 42). Compared to patients at the Munich Tumor Center (no CAPRI treatment N = 428), almost double the expected number of patients survived 5 years (P = 1.36 × 10−14). The CAPRI method is a safe procedure without negative side effects.

For this reason, most pathogens possess iron acquisition systems and are able to scavenge iron from the host. Genes for bacterial iron acquisition system are negatively

regulated by a ferric uptake regulator, Fur, and are derepressed under iron-depleted conditions (18,19). Thus, iron starvation is an important environmental signal leading to expression of iron acquisition systems and other virulence factors. Recently, a comprehensive transcriptional analysis revealed that iron starvation induces T3SS expression in B. bronchiseptica (25). We adopted a different approach, namely distinction of environmental signals in the culture medium rather than find protocol the transcriptional profiling used in the former study (25). Our findings clearly support the conclusion that Bordetella learn more T3SS is up-regulated under iron-starved conditions. Genome-wide microarray study of B. bronchiseptica has shown that expression of T3SS genes is up-regulated by growth phase progression, whereas expression of fhaB and cyaA genes is repressed in the stationary phase (26). During bacterial growth, the various environmental signals in bacterial

cultures change markedly in response to bacterial cell density, quorum sensing, and nutrient starvation. In Pseudomonas aeruginosa, T3SS and T6SS are inversely regulated by the RetS-mediated GacS/GacA two-component regulatory system (27). However, the precise mechanisms of the inverse regulation remain unknown. We found that the genes for type III secreted proteins and FhaB are inversely regulated in response to iron starvation, even though both genes are regulated by the BvgAS system (Fig. 2). It is tempting to speculate that the unknown repressor is expressed under iron starvation to shut down expression of certain virulence factors, including

FhaB. Further studies are necessary to elucidate the molecular mechanisms Unoprostone of BvgAS in response to the host environmental signal of iron starvation. This work was supported in part by the Ministry of Education, Culture, Sports, Science, and Technology of Japan through Grants-in-Aid for Scientific Research (B, 21390133; C, 23790484), for Scientific Research on Priority Areas (21022045) and for Japan Society for the Promotion of Science (JSPS) Fellows (23–7356). JK is a Research Fellow of the JSPS. The authors who have taken part in this study declare that they do not have anything to disclose regarding funding or conflict of interest with respect to the findings reported in this manuscript. “
“Plasmacytoid DC (pDC) secrete type I IFN in response to viruses and RNA/DNA/immunocomplexes. Type I IFN confer resistance to viral infections and promote innate and adaptive immune responses. pDC also produce cytokines and chemokines that influence recruitment and function of T cells and differentiation of B cells. Thus, pDC have been implicated both in protective immune responses and in induction of tolerance.

The immune response is often controlled by cytokines,

chemokines, adhesion molecules and oxidant-generating proteins and antioxidant proteins, such as peroxiredoxins (Prdxs) (12). Several specific liver-derived proteins have been examined as potential biomarkers of O. viverrini infection-associated diseases and CCA, including serum glutamyl transferase and other enzymes related to liver function (13), liver procollagen prolyl hydroxylase (14), nitric oxide synthase associated with nitrosamine and nitrate biosynthesis (8) and cytochrome P450, involved in biotransformation of various carcinogenic Depsipeptide price chemicals (15). To obtain a comprehensive understanding of the pathogenesis of O. viverrini-induced disease, we employed a proteomic approach to investigate the alterations in expression levels of hepatic proteins in hamsters infected with O. viverrini. In this study, Prdx6 was detected as a potentially important protein involved in host defence. Histopathological changes also were examined by Haematoxylin and Eosin staining. Opisthorchis viverrini

metacercariae were isolated from naturally infected fish obtained from Khon Kaen Province, Thailand by 0·25% pepsin www.selleckchem.com/products/lee011.html digestion as described previously (11). O. viverrini metacercariae were collected under a dissecting microscope and viable cysts were used to infect hamsters. Four- to six-week-old male golden hamsters (Mesocricetus auratus) were fed a stock diet and provided water ad libitum. Hamsters

(five animals) were infected with 50 O. viverrini metacercariae by oral inoculation (infected group) and five animals were maintained as control. After 30 days, hamsters were anaesthetized with ether and livers were collected. Liver sections (0·5 cm in diameter; approximately 150 mg) were taken from the hilar region and adjacent areas including second-order bile duct, where worms are usually found. check details For total RNA isolation, liver slices were immediately treated with TRIZOL™ (Invitrogen, Carlsbad, CA, USA) reagent and then stored at −80°C until use. For proteomic analysis and Western blotting, liver tissues were immediately snap-frozen in liquid nitrogen and then stored at −80°C until use. For histopathological and immunohistochemical studies, liver slices were fixed in 10% buffered formalin. The procedures were approved by Animal Ethics Committee of Khon Kaen University, Thailand (AEKKU 17/2552). Two independent experiments were performed for each animal, and each experiment was conducted in duplicate.

43 Whether this effect is directly mediated by CG is not clear, as reports show both an activation25 and inhibition26 of NF-κB in monocytes and endometrial stromal cells, respectively. Human CG also exhibits immunomodulatory functions by inducing suppressor T cells27 and has long been known to modulate both B- and T-cell response to mitogen stimulation.28–30 In addition, LH/CG receptors are present on maternal T lymphocytes23

providing for a direct mechanism whereby hCG could alter function of circulating immune cells. During normal pregnancy, there is an elevation of CD25+ CD4+ regulatory T cells (T-reg31), and hCG appears to recruit these cells to the fetal–maternal interface.16,32 Furthermore, CG induced bone marrow–derived, in vitro matured, dendritic cells toward a tolerogenic phenotype characterized by increased IL-10 and indolamine 2,3 dioxygenase production.33 The evidence that P4 shifts the cytokine profile toward Th2 is more compelling.15,34 This learn more action is mediated, in part, through P4-induced production of immunosuppressive molecules including progesterone-induced blocking factor (PIBF115) and glycodelin A,35 among others. Progesterone-induced blocking factor stimulates Th2 cytokine production and can suppress NK cell activity in the uterus and systemically.36

As reviewed by Apoptosis Compound Library chemical structure Lea and Sandra,36 P4 induces a number of cytokines in peripheral T cells, including leukemia inhibitory factor, colony stimulating factor-1, IL-4 and IL-5. Together the uterine and systemic effects of P4 paint a fairly consistent picture of a Th2 bias and indirect suppression of uNK cells that promote immunologic recognition of pregnancy and tolerance. It is increasingly clear, however, that immunomodulation during pregnancy may be more complicated than the Th1–Th2 shift proposed by Wegmann,20,37–39 as evidence by marked activation (as opposed to suppression) of some components of the maternal immune system.40,41 For example, www.selleck.co.jp/products/obeticholic-acid.html hCG treatment

of the baboon uterus upregulates superoxide dismutase 2 and complement component 3, to respond to oxidative stress and enhance phagocytosis, respectively.3,42 In addition, hCG binds to monocytes and increases their trafficking to the endometrium during early pregnancy and increases production of IL-8 via activation of NF-κB.43 From the standpoint of evolution, it would make sense to counter balance the immunosuppressive effects of pregnancy so as not to put the dam at greater risk of infection.44 Clearly, there is evidence that conceptus signals like hCG alter immune cell function in the uterus and peripherally.16,42 Although much work has focused on immunomodulatory mechanisms mediating fetal tolerance and maternal protection, circulating immune cells may play an active role in establishing and maintaining pregnancy.45 Using a luteal cell culture system, Hashii et al.46 showed that peripheral blood mononuclear cells (PBMC) from pregnant women increased P4, IL-4, and IL-10 production.

However, in patients co-infected with HIV, lower production of IL-10 was found. This is in agreement with the previous finding [53, 54] and may be the result of IL-10 in HIV-infected patients primarily being produced in monocytes as opposed to healthy individuals Selleckchem CH5424802 where IL-10 mainly is produced in lymphocytes, although both cell populations contribute to the production of IL-10 in both healthy and HIV-infected individuals. However, the golden

standard for evaluating functional characteristics in Tregs is suppression assays. Future studies using these methods are needed to completely understand the functional characteristics of CD4+ Tregs in patients with chronic HCV infection and HIV/HCV co-infection. In liver tissue, a positive correlation between intrahepatic Tregs and intrahepatic inflammation

was found, suggesting that Tregs are related to ongoing inflammation, and may be a response of the immune system to limit destructive inflammatory activity in the liver parenchyma. Interestingly, Tregs were not associated with fibrosis or cirrhosis, where the degree of active inflammation may have settled down. Likewise, previous studies have demonstrated increased intrahepatic CD4+ Tregs in HCV-infected patients, and no association between CD4+ Tregs and liver fibrosis [15, 55]. However, one study [12] found a significant inverse correlation between the level of intrahepatic CD4+ Tregs and METAVIR fibrosis score. The role selleck products of CD8+ Tregs in HCV-infected patients is yet unclear. Interestingly, HCV-specific CD8+ T cells with suppressive capacity via IL-10 have been isolated from the liver [56, 57]. Furthermore, in one study, HCV-specific intrahepatic CD8+ IL-10-producing cells located to areas with limited fibrosis have been demonstrated [58]. A positive correlation

between intrahepatic Tregs and CD8+ Tregs in peripheral blood was found. As only 12 patients with liver biopsies contributed to this analysis, interpretation is rather speculative, but the positive correlation may suggest that the level of CD8+ Tregs in peripheral blood reflects the level in liver tissue. Alternatively, intrahepatic Tregs are CD4+ Tregs homing to inflamed liver tissue, and consequently Tregs in peripheral blood do not reflect the much level of Tregs in liver tissue. Thus, whether findings in peripheral blood reflect the amount of intrahepatic lymphocytes is still uncertain as other studies also present with contradictory results [12, 15, 55]. Further studies combining the expression of Foxp3 with the expression of CD4 and CD8 are warranted to investigate the role and phenotype of Tregs in liver tissue in HCV pathogenesis. No difference in the frequency of Th17 cells or levels of IL-17 between our study groups was found. Thus, it seems unlikely that the frequency of Th17 cells in peripheral blood is associated with progression of liver fibrosis in patients with chronic HCV infection.

However, this prediction has not yet been demonstrated. As mentioned, although human CCL4L1 and CCL4L2 share 100% sequence identity in the coding regions, a fixed

mutation at the intron–exon AZD2014 purchase boundary of CCL4L2 results in the production of aberrantly spliced transcripts. Specifically, CCL4L2 show one base substitution (rs4796195 in dbSNP) at the acceptor splice site of intron 2 [48]. According to the canonical splicing pattern [86], the donor splice site of the second intron in CCL4L1 has GT immediately after exon 2, and the acceptor site has AG just before the point where intron 2 sequence is cleaved. In CCL4L2, the canonical sequence of the acceptor splice site (AG) has changed to GG and the spliceosome is unable to recognize the mutated acceptor site (GG). Instead, alternative acceptor sites around the original one are selected, and a minimum of eight different mRNAs are generated (Fig. 1c) [48]. The most abundant of these mRNAs derived from CCL4L2 corresponds to the CCL4L2 variant, which accounts for 80% of total mRNA expression [48]). CCL4L2 is generated by the use of an acceptor splice site located 15 nucleotides downstream of the original site. The predicted CCL4L2 mature protein has 64 amino acids and lacks the initial five amino acids encoded by the third exon (Phe42, Gln43, Selleck HSP inhibitor Thr44, Lys45 and Arg46), but the rest of the sequence remains

unchanged (Fig. 2). The functional consequences of deleting these five amino acids in CCL4L2 are unknown and, to date, there are no published functional studies involving CCL4L2. However, some computational data suggest the importance of these five amino acids: (i) critical analysis of the conserved amino acids in CC Beta adrenergic receptor kinase chemokines show that Phe42, Thr44 and to a lesser degree Lys45, are highly conserved residues in this subfamily. (ii) CCL4 (as well as CCL3

and CCL5) tends to self-associate and form homodimers, tetramers or high molecular mass aggregates in vitro, and possibly in vivo under certain conditions, in a process that involves residues Lys45 and Arg46[87]. Furthermore, naturally occurring CCL4/CCL3 heterodimers are present at physiological concentrations [88]. Therefore, the deletion of these five amino acids could have a negative effect on the ability of CCL4L2 to form self-aggregates or heterodimers with CCL3 or CCL3L1. (iii) Additionally, due to the fact that Lys45 and Arg46 are also critical residues in the CCL4 binding to GAGs [80], it is expected that the GAG binding of CCL4L2 will be seriously reduced, if not abrogated. The remaining CCL4L2 mRNA variants occur at very low abundance, and the folding prediction and the functional features of their putative proteins are difficult to establish. The biological relevance of these proteins (if effectively produced) is unknown and may be influenced by their low expression level.

S2a and purity of the sorted cells shown in Supplementary Fig. S2b,c). Unlike the CD11c–CD19+CD24+CD27+CD38+ cells, the CD11c–CD19+CD24+CD27–CD38– cells were unable to suppress T cell proliferation in allogeneic MLC (Fig. 1b,c). Unexpectedly, FACS-sorted CD11c–CD19+CD24+ cells exhibited statistically similar

suppressive ability as the CD19+CD24+CD27+CD38+ B cells (Fig. 1b,c). In all instances, the lower T cell frequency (Fig. 1c) in the MLC was due to decreased proliferation and absolute numbers of buy AZD2014 live CD3+ T cells (Fig. 1c,d) and not to an increase in the numbers of dead cells (including T cells) or changes in B cell frequency (Supplementary Figs S3 and S4). We hypothesized that iDC could directly affect the frequency of the suppressive CD19+CD24+CD27+CD38+ B cells and that a potentially significant increase in their number could account for the increased frequency of B220+CD11c– cells in the PBMC of iDC recipients [31]. To test this, freshly collected PBMC from healthy adults were enriched into CD19+ cells. Of these cells, 2 × 106 were then

cultured in the presence of an equal number of autologous cDC, iDC (generated from the same PBMC) or PBS vehicle for 3 days. The frequency of CD19+CD24+CD38+ cells in those co-cultures was then measured by flow cytometry. Figure  2a shows that, in the presence of iDC, the frequency of CD19+CD24+CD38+ B cells was increased significantly. Furthermore, the frequency of CD27+ cells inside the CD19+CD24+CD38+ population was increased substantially. this website This increase in frequency was due specifically to an increase in the proliferation of CD19+CD24+CD38+ cells, especially the CD27+ subpopulation (measured as the frequency and absolute number of BrdU+ cells; Fig. 2a,b). Interestingly, exposure of the CD19+ B cells to the iDC increased significantly the numbers of viable cells in general (Fig. 2a, P2 peak in the LIVE/DEAD histogram very at the top). When comparing the segregation of the individual cell surface markers used to identify

the B cells, the only discernible difference is in the generation of two peaks representing the CD19+ population in the presence of cDC or iDC (Fig. 2c). There are no other significant differences in the segregation of the other markers used (CD24, CD27, CD38; Fig. 2c). Specificity of the antibodies and non-specific antibody binding was controlled by the appropriate isotypes (Supplementary Fig. S5). Gene chip-based expression analysis of the autologous DC used in the Phase I trial [31] revealed that the rate-limiting enzyme for RA biosynthesis, ALDH1A2, was expressed in cDC and iDC generated from PBMC of normal adults (data not shown). To confirm the gene chip data and to demonstrate that cDC and iDC produce RA, we employed a reagent (Aldefluor) that reacts with RA-producing cells to identify and measure the frequency of RA-producing cells by flow cytometry. In Fig.

The plates were incubated for 1 hr at 37°C under 5% CO2. Cell Titer 96 Aqueous One Solution Reagent (Promega, Madison, WI, USA) was added and incubated for a further 1 hr at 37°C under 5% CO2. Absorbance of each well was measured at 490 nm. The data are presented as percent viability to determine the concentration of toxin causing 50% cell death (EC50) as described previously [23]. Vero cells (3 × 107/mL) were treated with PI-PLC (0.5 U/mL; EMD Biosciences, Darmstadt, Germany) for 2 hr at 37°C in PBS and centrifuged

as described previously [24]. Aliquots of cells and supernatants were used for SDS–PAGE and toxin overlay assay. Vero cells were scraped from 25 cm2 flasks Epigenetics inhibitor with a rubber policeman and harvested by centrifugation at 1000 g for 5 min. After washing, cells were suspended in 1 mL of cold lysis buffer consisting of 10 mM Tris–HCl buffer (pH 7.0) containing 150 mM NaCl, 1% Triton X-114 (Pierce) and 0.1% protease inhibitor cocktail. After allowing them to stand for 1 hr on ice, the detergent-insoluble fractions were separated from the supernatants (the detergent-soluble fractions) by centrifugation at 15,000 g for 15 min, and finally resuspended in 1 mL of PBS. SDS–PAGE was carried

out in 5–20% gradient gels (ATTO, Tokyo, Japan). After electrophoresis, detergent-soluble and -insoluble fractions from Vero cells were blotted onto PVDF membranes. After blotting, the membranes were blocked with Baricitinib 5% skim milk in PBS for 1 hr at room temperature. After washing three times with PBS-0.01% Tween 20, the membranes were incubated for 1 hr at room temperature in the presence of 10 µg/mL wild-type or mutant alpha-toxin KU-57788 manufacturer in 0.5% skim milk. This was followed by washing and incubation for a further 1 hr at room temperature with 5 µg/mL affinity-purified rabbit anti-alpha-toxin

IgG [25] in 0.5% skim milk. The membranes were treated for 30 min at room temperature with goat anti-rabbit IgG (H + L) conjugated with peroxidase (1:3000 dilution; Cappel, West Chester, PA, USA) in 0.5% skim milk. After washing, the membranes were developed in 20 mL of PBS containing 0.05% 3′3-diaminobenzidine (Dojin Laboratories, Kumamoto, Japan) and 0.02% H2O2. Protein concentrations were determined by the method of Bradford [26] with bovine gamma globulin as a standard. To evaluate the roles of the tryptophan-rich region in the C-terminal domain in the cytotoxic effect of alpha-toxin, we constructed several mutant toxins by individually replacing tryptophan and some residues surrounding tryptophan with other amino acids (Table 1). We individually replaced tryptophan (W307, W309, and W311) with phenylalanine (W307F, W309F, and W311F), which is hydrophobic and also has an aromatic side chain. These tryptophans were also replaced with alanine to create loss of an aromatic side chain and substitution by its minimal side chain (W307A, W309A, and W311A).

aureus (Fig. 5B) and influenza virus (Fig. 5D), that is the only two microbes that promoted IL-2 and IFN-γ responses. In this study, we show that cord pDC promote a Th2 phenotype. However, the Th2-skewing effect of cord pDC could be omitted by enveloped viruses. This implies that virus can divert Th2-biased responses in human cord T

cells. Furthermore, we show that microbes capable of inducing IFN-α promote Th1 responses, whereas a microbe’s ability to induce IL-12 does not correlate to its ability to induce IL-2 or IFN-γ responses in vitro. The numbers of human studies of adaptive T cell responses in newborns compared with adults are limited and conflicting [37]. Yet, it is generally thought that the immune system of newborns is immature and differs from that in adults. The T cell polarization in newborns is correlated with impaired Th1 responses [38, 39]. drug discovery However, individual Th1/Th2 balance in newborns varies depending on parental and environmental

factors [40]. In this paper, we show that the baseline production of the Th2 cytokines IL-5 and IL-13 were elevated in cord CD4+ T cells compared with adult T cells. The Th2 cytokine induction observed in cord cells was not an intrinsic function of the neonatal T cells, but rather a Th2-inducing effect of cord pDC. This is in line with previous click here findings where pDC was shown to promote Th2 responses in healthy and allergic subjects [15, 19]. This is, to our knowledge, the first study to show that the levels of Th2 cytokines obtained in vitro activated T cells differs between newborns and adults. We could not detect any significant differences in Th1 cytokine synthesis (IFN-γ and IL-2) between T cells from adults and newborns, even though others have shown that cord blood DC is impaired in their capacity to induce both IFN-γ and IL-2 in responding T cells

[39]. Instead, our data imply that cord pDC were superior to both cord mDC and adult DC in promoting Th2 responses. The Th2-skewing effect of cord pDC can be blocked by viral stimuli. We found that enveloped viruses (i.e. HSV-1, coronavirus, CMV, morbillivirus 4��8C and influenza virus) blocked IL-13 secretion, while bacteria and non-enveloped viruses did not. This confirms previous findings from us and others, showing that the Th2 skewing effect of pDC in newborns and adults can be omitted by microbial stimuli [3, 19]. However, the diminished IL-13 production that was seen in virus stimulated cultures could not be correlated with Th1 polarization, that is IFN-α, IFN-γ, IL-2 or IL-12 secretion. None of the viruses tested could induce IL-12 secretion, and influenza was the only inactivated virus to evoke IFN-α, IFN-γ and IL-2 production. Still, these findings emphasize the importance of early life microbial stimuli of the innate immune system for an accurate maturation of the immune system, that is to avoid unwanted Th2 responses.

Both adaptive and innate immune effector mechanisms are believed to contribute to tissue disease aetiology. HLA-E is a non-classical MHC class Ib molecule that acts as the ligand for the NKG2A inhibitory receptor present on natural killer (NK) and CD8+ cells. Peptide binding and stabilization of HLA-E is often considered to signal infection or cell stress. Here we examine the up-regulation of HLA-E in MS brain tissue. Expression is significantly increased in white matter lesions in the brain of MS patients compared with PS-341 ic50 white matter of neurologically healthy controls.

Furthermore, using quantitative immunohistochemistry and confocal microscopy, we show increased HLA-E protein expression in endothelial cells of active MS lesions. Non-inflammatory chronic lesions express significantly less HLA-E protein, comparable to levels found in white matter from controls. Increased HLA-E protein levels were associated with higher scores of inflammation. These learn more results suggest the potential for an effect in central nervous system pathogenesis from HLA-E modulation in stressed tissue. Co-localization with infiltrating CD8+ cells implicates a possible role for HLA-E-restricted regulatory CD8+ cells, as has been proposed in other autoimmune diseases. “
“Perforin (P) is a prototypical cytotoxic molecule involved in cell-mediated immunity against various pathogens, alloantigens and particularly different tumours. The purpose

of this study was to determine P expression in different lymphocyte subpopulations isolated from

peripheral blood and prostate tissue of patients with benign prostatic hyperplasia (BPH) and prostate cancer (PCa) and compare it with the P expression found in the control group. Twenty subjects were recruited in each of the groups. Prostate mononuclear cells of the BPH and PCa tissues were isolated Carnitine palmitoyltransferase II by enzymatic digestion and gradient density centrifugation, whereas peripheral blood mononuclear cells were isolated by gradient density centrifugation alone. Cells and tissue samples were labelled using monoclonal antibodies against P and different surface antigens (CD3, CD4, CD8 and CD56) and analysed by immunofluorescence and flow cytometry. Total P expression in peripheral blood lymphocytes did not differ significantly between BPH/PCa patients and control group, although the BPH and PCa tissue showed lower P expression level. A negative correlation between prostate-specific antigen levels and the overall percentage of P+, CD3+CD56−P+, and CD3−CD56+P+ cells in the prostate tissue was observed only in patients with PCa. Our findings indicate that the low frequency of P+ lymphocytes, including T, NKT and NK cells, in the prostate tissue of patients with BPH and, particularly, PCa could be the consequence of local tissue microenvironment and one of the mechanisms involved in the pathogenesis of prostate hyperplasia following malignant alteration.