Macrophages are key regulators of the innate immune system, where

Macrophages are key regulators of the innate immune system, where they can detect, phagocytose and destroy foreign

antigens.91 Apart from tissue destruction, it is now known that macrophages also play an important role in tissue homeostasis, cellular replacement and repair through the clearance of apoptotic cells and cellular debris. They also produce mediators that downregulate inflammation Trichostatin A order and promote remodelling and regeneration. The immunomodulatory effects of MSC on T lymphocytes, B lymphocytes, natural killer cells and dendritic cells have been extensively investigated (for review34,92). However, less is known about their ability to modulate macrophage phenotype and function. The activation state that governs macrophage function is dependent see more on the inflammatory stimuli received from the tissue microenvironment. As the process of repair shifts from the initial inflammatory phase to that of remodelling, macrophages subsequently exhibit varying polarization states and exert a diverse range of functional activities.93 Although a variety of classification methods have been proposed, macrophages are typically

believed to exist in one of two opposing polarization states, that is, the M1 ‘classically activated’ subset or M2 ‘alternatively activated’ subset.94 M1 polarization is achieved through a combination of events. The first ‘priming’ step involves exposure of the

macrophage to IFN-γ.91 The second signal requires the exposure to either a microbial product, such as lipopolysaccharide (LPS), or proinflammatory cytokines, such as TNF, to the macrophage, resulting in M1 activation.91 M1 macrophages are characterized by their enhanced ability to phagocytose and present antigen through the upregulation of MHC class II and the co-stimulatory molecules CD80 and CD86.95 They secrete numerous pro-inflammatory cytokines, particularly IL-12 and IL-23, which induce the downstream production of the toxic intermediates nitric oxide Selleckchem Sorafenib and reactive oxygen species (ROS) as well as promoting the killing and degradation of intracellular microorganisms.91,96 It was previously believed that Th2 derived cytokines had a deactivating effect on macrophages.97 However, in 1992, Stein et al.98 demonstrated that macrophages exposed to IL-4 took on an ‘alternative’ phenotype, characterized by reduced secretion of proinflammatory cytokines. It has since been reported that exposure to IL-13, IL-10, TGF-β, glucocorticoids and immune complexes in combination with IL-1β or LPS can also induce an M2 alternative polarization state.94 In contrast to their classically activated counterpart, M2 macrophages are involved in dampening the inflammatory response, while exhibiting enhanced scavenging abilities that promote tissue remodelling and repair.

After initial T-cell–DC contacts, T cells migrate again and sampl

After initial T-cell–DC contacts, T cells migrate again and sample several other DCs. However, T-cell migration is diminished appreciably in the presence of an antigen with high affinity for a given TCR that elicits a relatively strong Ca2+ signal in T cells. The continued use of intracellular dyes that change their fluorescence properties upon binding to Ca2+ will advance our investigation of this crucial role of Ca2+ signalling in T-cell migration and antigen recognition. Hence, 2P microscopy coupled with the quantification of intracellular Ca2+ signalling by T cells activated by different antigens in vivo can be informative buy MG-132 about the relative strength of T-cell–DC interactions

and the immune responses that follow under conditions of health and disease. The relative strength of TCR signalling in vivo can also be measured

by following the shedding of CD62L from the surface of T cells.[93] A few minutes after TCR activation in a T cell, the CD62L extracellular domain is cleaved by the protease ADAM17 (a disintegrin and metalloproteinase domain-containing protein 17). The extent of CD62L shedding reflects TCR signal strength, i.e. a strong TCR signal elicits increased shedding of CD62L. Hence, T-cell dynamics in vivo may be tracked together with TCR signals by measuring the disappearance of CD62L after in vivo staining with fluorescent anti-CD62 antibody Fab fragments. The functional role of NKT cells has been analysed in mice selleck products using CD1d−/− (lack both type I and type II NKT cells) and Jα18−/− (lack only type I NKT cells) mice as well as using blocking or depleting antibodies reactive to CD1d and the semi-invariant TCR. The combined use of both of these mouse strains and antibodies has allowed us to ascribe the outcome of specific immune responses to the effect of either type I NKT cells or type Fenbendazole II NKT cells. However, various compensating

mechanisms, such as an altered conventional TCR repertoire, may control NKT cell function in such knockout mouse environments. Our understanding of the roles of NKT cells in the induction and/or protection from autoimmune disease has taken advantage of analyses of NKT cells in such diseases that either arise spontaneously or are antigen-induced (Table 4). It is important to note while αGalCer has been informative about type I NKT cell activation and function, it has not revealed a comprehensive understanding of the physiological role of type I NKT cells. A role for type I NKT cells in the regulation of autoimmune disease was provided by observations that fewer type I NKT cells are found in both spontaneous autoimmune disease models, type 1 diabetes in NOD mice and systemic lupus erythematosus in MRL/lpr mice.[94, 95] However, CD1d deficiency did not result in potentiation of disease, as expected in all models.

6B) The epithelial shedding appeared to be highest in 6-week-old

6B). The epithelial shedding appeared to be highest in 6-week-old animals, which differed significantly from 1-week-old animals (Fig. 6C). In the BALF, IL-5, IL-10, IL-17, RANTES and MIP-1α were undetectable or measured at very low levels (data not shown). MCP-1 was detected at higher levels, but was unaffected by the sex and age of the mice (data not shown). The explanation for the low cytokine levels in BALF is most likely because GSK3 inhibitor the BAL supernatant was collected 3 days after the last intranasal challenge. Compared to 1 day after challenge, cytokine levels have decreased significantly at this time point [20]. A pulmonary

tissue inflammation was observed in the mice i.n. sensitized with OVA + Al(OH)3 (Fig. 6G), but not in mice given OVA alone (Fig. 6H). Scoring Ixazomib concentration of the inflammation showed that the perivascular

and -bronchial inflammation were significantly higher in female compared with male mice (Fig. 6D, E). Further, the inflammation tended to increased with age, but this was only significant for the perivascular inflammation. Curiously, this pattern was opposite of what was found for lymphocytes and eosinophils in the BALF, which decreased with age (Fig. 6A, B). PAS staining of goblet cells was only observed in the OVA + Al(OH)3-sensitized mice and not in mice sensitized with OVA alone (Fig. 6I, J). In the former groups, the percentage of PAS stained cells was affected by age comparably to epithelial cells in BALF. A significantly higher score was observed in 6-week-old mice compared Etofibrate with both 1- and 20-week-old mice (Fig. 6F). Compared to the OVA + Al(OH)3 immunized mice, the OVA-specific IgE, IgG1 and airway inflammation in OVA-only immunized mice were diminutive and statistically significantly lower. However, it appeared that in 1-week-old OVA-only immunized mice, some eosinophils and in particular neutrophils were observed in the BALF. This led us to reanalyse the serum for OVA-specific IgG1 in a lower dilution. Comparing the OVA-only groups, a significant effect

of age was found and it appeared that 1- and 6-week-old mice had produced higher levels of IgG1 compared with the oldest mice (Fig. 7A). The same pattern was seen for neutrophils (Fig. 7B) as well as a non-significant tendency to age differences for eosinophils (Fig. 7C). Females also had significantly more neutrophils than males (Fig. 7B). OVA-specific IgE, airway histopathology and cytokine levels were not affected in the OVA-only exposed mice (data not shown). Using two different mouse models of allergic sensitization, we have demonstrated that allergic antibodies and allergic airway inflammation are influenced by sex and age. Further, we demonstrated that the response to immunization dose was influenced by both age and sex of the mice.

The samples were then incubated with 50 µl/well of OVA-biotin (1 

The samples were then incubated with 50 µl/well of OVA-biotin (1 mg/ml; Sigma, St Louis, MO, USA) at room temperature for 1 h. Plate-bound antibody was detected by treatment

with 50 µl/well of streptavidin–horseradish peroxidase (1 : 10 000; Southern Biotechnology) for 1 h at room temperature. The colour reaction was developed by adding 100 µl/well of 200 pmol of OPD (Sigma) in pH 5·0 citrate phosphate buffer plus 0·04% H2O2 for 10 min and stopped with 50 µl of 5% sulphuric acid per well. The plates were read at 492 nm in an ELISA reader (Bio-Rad, Hercules, CA, USA). The lungs of five mice per group were removed and treated with 100 U/ml of collagenase from Clostridium histolyticum (Sigma) for 30 min at 37°C. Subsequently, the digested lung tissue was filtered through a 70 micrometre cell strainer and the red blood cells were lysed with ACK buffer (0.15 M NH4Cl, 10 mM KHCO3, 0.1 mM Na2EDTA, pH 7.2; Invitrogen, CA,

USA). The cell selleckchem suspension was washed twice in RPMI-1640 and adjusted to 1 × 106 cells per well for surface staining and to 2·5 × 106 cells for the intracellular cytokine experiment. For CD4 and forkhead box P3 (FoxP3) staining, the cells were generally blocked with anti-mouse CD16/CD32 monoclonal antibodies (mAbs) (Fc-block) and stained for surface marker using fluorescein isothiocyanate (FITC)-labelled anti-mouse CD4 (BD Bioscience) mAb or isotype control, which were incubated for 20 min at 4°C with antibody dilution Y 27632 solution (PBS 0·15 M, 0·5% BSA, 2 mM NaN3). The cells were then washed with 0·15 M PBS and incubated with strepatavidin–phycoerythrin–cyanine 5 (PE-Cy5) (1 : 200) Aspartate for an additional 20 min at 4°C. Surface-stained cells were washed twice with 0·15 M PBS and incubated with fixation/permeabilization buffer (eBioscience) for 30 min at

4°C. Anti-FoxP3-PE-labelled antibodies in permeabilization buffer (eBioscience) were added to cells and then incubated for 30 min at 4°C. Cells were washed twice with 150 µl of permeabilization buffer (eBioscience) and fixed with 2% paraformaldehyde. For IL-10 and FoxP3 intracellular staining, cells were cultured for 14 h in medium or OVA (25 µg/ml). After this stimulation period, 1 mg/ml of brefeldin A was added to the cell culture, which was incubated for an additional 4 h in a CO2 incubator at 37°C. Before CD4 staining, the cells were treated with anti-CD16/CD32 (Fc-block). Cell surface and intracellular staining were performed as described above for surface experiments; however, the cells were stained for CD4, IL-10 and FoxP3 using anti-CD4 FITC-labelled, anti-IL-10 PE-labelled, and anti-FoxP3 biotin-labelled plus streptavidin–PE-Cy5 antibodies. Data acquisition was performed using fluorescence activated cell sorter (FACScan) (Becton Dickinson, San Jose, CA, USA). Data analysis was performed using a FlowJO interface (Becton Dickinson). Statistical analysis was performed using the software GraphPad Prism (GraphPad Software, San Diego, CA, USA). The mean ± standard deviation (s.d.

Systemic lupus erythematosus (SLE) is an autoimmune disease chara

Systemic lupus erythematosus (SLE) is an autoimmune disease characterised by production of autoantibodies against nuclear autoantigens. Almost all the organs can be affected in patients with SLE. A wide range of molecules are involved

in SLE; therefore, the pathogenesis of the disease is complex and still unclear. The receptor for advanced glycation end products (RAGE) is a multi-ligand member belonging to the immunoglobulin superfamily. RAGE is expressed by many types of immune cells, including macrophages, neutrophils and T cells and interacts with a diverse class of ligands [1, 2]. Up to now Selleckchem MG132 identified RAGE ligands include high mobility group box-1 (HMGB1) protein, advanced glycation end products (AGEs), members of the S100/calgranulin family. AGEs is a class of compounds resulting from glycation of proteins, lipids or nucleic acids under conditions of oxidative stress and hyperglycaemia [3]. The

stimulation of RAGE through AZD1208 datasheet AGEs may contribute to certain disease state such as diabetes and Alzheimer’s disease, in which the accumulation of AGE has been demonstrated [4, 5]. In addition, as a family of over 20 related calcium-binding proteins that exclusively expressed in vertebrates, S100s modulate an array of intracellular functions [6, 7]. S100s released from different cell types during inflammation serve as useful markers of disease activity [8, 9]. It has been demonstrated that increased serum levels of S100A8/A9 correlated to disease activity index in SLE, indicating S100A8/A9 as a more relevant marker of infection in patients with SLE [10]. Besides that, HMGB1 is a ubiquitously expressed

evolutionary conserved chromosomal protein. Intracellular HMGB1 participates in transcriptional regulation [11]. Extracellular HMGB1 binds to cell surface receptors including RAGE, toll-like receptor 2 (TLR2) and toll-like receptor 4 (TLR4). Studies indicate that interaction between HMGB1 and RAGE results in the production of type I interferon, which plays key role in the pathogenesis of SLE [12–14]. In addition, TNF-α and IL-6, which are implicated in association Chlormezanone with disease activity or involvement of some organs in SLE [15, 16], can be induced by extracellular HMGB1 [17]. It has been documented that RAGE seemed to involve in all responses that depend on HMGB1 [18]. Notably, previous studies showed that increased serum level of HMGB1 was associated with lupus disease activity [19, 20]. All these results imply that HMGB1-RAGE pathway may participate in the pathogenesis of SLE. The RAGE protein consists of an N-terminal signal peptide, a V-type immunoglobulin-like domain, two tandem C-type immunoglobulin-like domains, a single transmembrane domain and a short C-terminal intracellular cytoplasmic tail [21].

The small leucine-rich proteoglycans (SLRPs) are a group belongin

The small leucine-rich proteoglycans (SLRPs) are a group belonging to the leucine-rich repeat (LRR) superfamily of proteins.

This includes decorin and biglycan (Figure 1C), which have a central region of 10 leucine residues flanked by cysteine residues [73]. Decorin is the best characterized SLRP member and is traditionally associated with ‘decorating’ collagen fibrils. The core protein is 40 kDa and has a single GAG chain attached to a serine residue near the N-terminus. Biglycan is structurally similar, DAPT concentration with a core protein of 45 kDa and two GAG chains. SLRPs evoke a number of signalling pathways and are implicated in multiple interactions including modulation of collagen I and II fibrillogenesis [74]. Decorin expression may have positive effects on repair. It is known to inhibit activity of TGFβ [75] and EGFR [76,77], which have check details regulatory effects on synthesis of inhibitory CSPGs [78,79]. Biglycan also binds TGFβ, and soluble glycosylated biglycan acts as an endogenous ligand of the innate immunity

receptors TLR4 and TLR2 in macrophages (reviewed in [80]). Thus, the CSPGs comprise a complex family of molecules that are key components of the ECM. The multiple interactions of CSPGs with other ECM molecules as well as their binding affinity for a diverse array of growth factors, cytokines and receptors all suggest that they are crucial players in the CNS response to injury and that ECM modification will be an important therapeutic target. In addition to specific targeting of individual CSPGs (such as the function blocking NG2 antibody), global targeting of CSPGs has been a widely used strategy in experimental studies, for example by enzymatic digestion of CS-GAG chains to reduce the growth inhibitory properties of CSPGs. These approaches will be discussed

in detail later in this review. Many of the above ECM molecules have been targeted in repair strategies, often in an attempt to recapitulate developmental processes, where they play an important role in cell proliferation, migration, axon guidance and plasticity. Below we will discuss some of these PD184352 (CI-1040) processes. Correct wiring of the nervous system requires the precise distribution and connectivity of millions of cells during development. The ECM plays a key role, conferring many of the properties required to form intricate networks with specificity and reliability. During embryogenesis, neural induction and neural tube formation are followed by rapid cell proliferation, migration and differentiation of cells to neurones and glia to form the CNS. Subsequent to regionalization of neurones, connections form between them. Connections form when a differentiated neurone sends out an axon, tipped by a growth cone which responds to multiple sources of extracellular cues to reach its target.

In TLE patients, SV2A and SV2B expression was decreased in areas

In TLE patients, SV2A and SV2B expression was decreased in areas of synaptic loss. SV2C, which is weakly expressed or absent in the hippocampus of controls, was overexpressed in 10/11 cases with classical MTS1A and mossy fibre sprouting but not in cases with other types of MTS. SV2C staining was located in the inner molecular

layer of the dentate this website gyrus and colocalized with dynorphin, ZnT3 and VGLUT1, suggesting selective expression in presynaptic glutamatergic Zn2+-rich terminals of abnormal sprouting fibres. SV2 expression patterns correlated with histological subtypes of MTS, but not with clinical features or therapeutic regimens in this patient cohort. In classical MTS1A, the expression of SV2 isoforms is altered with a marked decrease of SV2A and SV2B paralleling

synaptic loss and a selective increase of SV2C in sprouting mossy fibres. These findings suggest a different physiology of sprouting synapses and the possibility to target them with SV2C-specific strategies. Synaptic vesicle proteins 2 (SV2) are a small family of integral transmembrane glycoproteins that are localized to synaptic vesicles and appear to function as modulators of Ca2+-dependent exocytosis [1]. Lapatinib research buy Of the three known isoforms, SV2A is ubiquitously expressed in the rat brain [2, 3] while SV2B, although widely expressed, is undetectable in several groups of neurones in the hippocampus, central grey nuclei and cerebellum [3, 4]. SV2C has a much more restricted distribution being found mostly in the basal ganglia, midbrain and brainstem [5, 6]. Although SV2 isoforms are not neurotransmitter specific, their distribution has been reported to differ between glutamatergic and GABAergic synaptic vesicles [7]. SV2s also act as receptors for botulinum neurotoxins [8]. Both clinical and experimental data suggest that SV2 Docetaxel mw proteins, and particularly SV2A, are involved in epilepsy [9, 10]. The anticonvulsant

activity of levetiracetam (LEV), a powerful antiepileptic drug (AED), has been linked to its ability to bind SV2A [9, 11]. More recently developed LEV analogues, such as brivaracetam and seletracetam, also bind to SV2A [12]. Moreover, SV2A−/− knockout mice have been shown to die early after birth due to severe spontaneous seizures [2, 13]. SV2A+/− animals display lower seizure thresholds in a number of models, reduced anticonvulsant efficacy of LEV as well as accelerated epileptogenesis [13, 14]. Furthermore, reduced SV2A expression has been reported in rodent models of temporal lobe epilepsy (TLE) [10, 15-18]. In the human, SV2A expression is reduced in the hippocampus of patients with TLE and hippocampal sclerosis (HS) [19].

MCs incubated with WT, but not OX40-deficient, Tregs mediated num

MCs incubated with WT, but not OX40-deficient, Tregs mediated numerous and long-lasting interactions and displayed different morphological features lacking the classical signs of exocytosis.

MC degranulation and Ca2+ mobilization upon activation were inhibited by Tregs on a single-cell Paclitaxel cell line basis, without affecting overall cytokine secretion. Transmission electron microscopy showed ultrastructural evidence of vesicle-mediated secretion reconcilable with the morphological pattern of piecemeal degranulation. Our results suggest that MC morphological and functional changes following MC–Treg interactions can be ascribed to cell–cell contact and represent a transversal, non-species-specific mechanism of immune response regulation. Further research, looking at the molecular composition of this interaction will broaden our understanding of its contribution to immunity. In past decades, it has become widely accepted that the contribution of mast cells (MCs) to immunity goes far beyond their well-known role in allergy. Several lines of evidence highlight an emerging MAPK inhibitor role

for MCs in numerous stages of both the innate and adaptive immune responses by direct communication with other immune cells 1. Functional interplay between MCs and B cells 2, MCs and both effector T cells 3 and Tregs 4, 5 or MCs and eosinophils 6, 7 have been suggested by studies documenting Idoxuridine their co-localization not only in peripheral tissue, but also in lymphatic organs during acquired immune responses, including those involved in host defense, autoimmunity and allergic disorders 2, 5. These cell–cell interactions have been shown to be bi-directional, fulfilling mutually regulatory and/or modulatory roles, including influences on cellular processes such as growth, proliferation, activation, migration and Ag presentation 2–5. Beyond the paracrine communication exerted by cytokines, MCs express a wide array of surface molecules that can potentially mediate this cross-talk directly. Recent findings provide mechanistic insight

in support of such observations. It has been reported that MHC class II expression by MCs is strongly induced by Notch signaling and supports effector and regulatory T cell activation 8. MC-mediated Ag presentation also regulates CD8+ T cell proliferation and cell activation 9. Moreover, several classes of co-stimulatory pathways have been identified and characterized for MCs, each able to operate in a specific physiological condition or disease ensuring a highly regulated response 10, 11. It has been shown that direct contact between MCs and effector T cells causes an increase in MC degranulation following high-affinity receptor for IgE (FcεRI) triggering, and a boost of T cell proliferation 12, 13.


A subtype H5N1 virus has become endemic in poul


A subtype H5N1 virus has become endemic in poultry in Vietnam; therefore, its temporal see more absence implied that the virus was maintained and transmitted in reservoir(s) which were asymptomatic or developed milder symptoms upon infection. Previous reports described a strong association between duck-raising activities and HPAI outbreaks in China (4) and Thailand (5, 6). In the present study, we thus screened ducks to determine the prevalence of influenza A subtype H5N1 virus at a time when H5N1 outbreaks had vanished temporarily. A total of 1106 ducks were randomly chosen from among approximately 20 000 ducks reared on 55 farms distributed in Hanoi, and the Nam Dinh and Vinh Phuc provinces (Table 1) in the period between October and November 2006 when obvious mTOR inhibitor H5N1 outbreaks were absent (3). Nineteen to 31 ducks were collected from each farm in proportion to the number of ducks raised (varying from 31 to 800 ducks). Four hundred and forty-seven (447), 360, and 299 ducks were collected from 22,

18, and 15 farms distributed in Hanoi, Nam Dinh province, and Vinh Phuc province, respectively. Throat and cloacal secretion specimens were taken by swab from each of the 1106 ducks and suspended in 2 ml PBS supplemented with 0.5% bovine serum albumin, 10 000 units/ml penicillin, 10 mg/ml streptomycin sulfate, and 0.3 mg/ml gentamicin sulfate. Sodium hydro-oxide (10 M) was used to adjust pH to 7.4. Blood was also taken from each duck and used for serological analyses after separating serum by centrifugation at 2500 ×g for 20 min. All the specimens were kept at 4°C during transportation to the laboratory for 4 to 6 hr. Sera and secretion specimens were kept at −20°C and −80°C, respectively, until used. 3-mercaptopyruvate sulfurtransferase A 100 μl portion of each secretion specimen was inoculated into the allantoic cavity of two 10-day-old

fertile hen’s eggs. The eggs were incubated at 35°C for 72 hr unless death of the embryo was detected. At the end of the incubation period or upon the embryo’s death, the allantoic fluids were tested for hemagglutinating activity. All allantoic fluids carrying hemagglutinating agents were tested further to determine the specificity HA and NA borne agents by HI tests (7) and NI (8) tests using specific antisera to the following influenza A virus strains: A/PR/8/34 (H1N1), A/swine/Iowa/15/30 (H1N1), A/Singapore/1/57 (H2N2), A/duck/Ukraine/1/63 (H3N8), A/duck/Czech/56 (H4N6), A/whistling swan/Shimane/499/83 (H5N3), A/turkey/Massachusetts/65 (H6N2), A/seal/Massachusetts/1/80 (H7N7), A/turkey/Ontario/6118/68 (H8N4), A/turkey/Wisconsin/66 (H9N2), A/chicken/Germany/“N”/49 (H10N7), A/duck/England/56 (H11N6), A/duck/Alberta/60/76 (H12N5), A/gull/Maryland/704/77 (H13N6), A/duck/Memphis/564/74 (H11N9), and an NDV strain, Miyadera.

0008 [ 0011], z = − 71, p =  4761) Turning to interdyadic

0008 [.0011], z = −.71, p = .4761). Turning to interdyadic

differences (random effects, Table 2), affect and language patterns showed significant values. With respect to affect, the covariance between intercept and linear effect of age was significant (χ2[1] = 4.51, p < .05), with the variability decreasing nonlinearly toward the end of the second year of life. As regards language, significant differences between dyads were found for the intercept (σ2u0), the slopes (σ2u1), and the covariance between intercept and slopes (σ2u01) for the linear trend (respectively, χ2[1] = 4.27, p < .05; χ2[1] = 4.13, p < .05; χ2[1] = 4.21, p < .05). As shown in Figure 6, three of 10 dyads (dyads 8–10) started to increase the proportional duration of language patterns from about 14 months (65 weeks), whereas the others remained quite low until 18 months (80 weeks). Napabucasin Only at that age did these latter dyads begin to accelerate,

although at a slower rate than the former. Finally, the covariance effect signals that differences among dyads in the use of language become more AZD4547 chemical structure and more evident over time. Finally, intradyadic variance for the affect and language patterns showed a systematic time-dependent pattern. As to affect, the covariance between the intercept and the linear effect of age was significant (σ2e01 =.00004, χ2[1] = 3.73, p < .05), meaning that variability among sessions increased at the end of the observational period. As to language, the difference in proportional duration of these frames

among sessions was time dependent (σ2e1 = .00001, χ2[1] = 22. 56, p < .00), meaning that PAK6 this difference increased rapidly and in a nonlinear way with advancing infant age. As the covariance between the intercept and the linear component (σ2e01 =.00027, χ2[1] = 79.77, p < .00) was also significant, the sessions differed more at the end of the second year than at the beginning. Therefore, as for symmetrical patterns, language patterns also increased with a certain degree of fluctuation. This study aimed to examine mother–infant social play in the second year of life. With reference to Fogel’s (1993) model of interaction as a continuous adjustment between partners instead of a sequence of discrete acts, we focused on mother–infant interpersonal functioning during play rather than on individual behaviors. Communicative patterns were identified (Fogel, 1993) to distinguish different forms of coregulation, an intensive longitudinal design was adopted to match the developmental process as closely as possible, a multiple case study was used to make claims about the group as well as the individuals and, finally, a hierarchical linear analysis was performed to model the trajectories of different coregulation forms. We expected to find developmental transitions and individual differences.